Wednesday, April 28, 2010

GP300 success

Two more items for the Motorola GP300 arrived from Hong Kong today, an 1800mAH NiMH battery pack and a charger. I'm a bit dubious about the charger. I put the battery pack on the radio and started charging it, and when I checked six hours or so later the battery pack and radio were really hot. I would have thought the charger should have shut off by that point. So I'll have to watch the charge times.

I wanted to have another try at programming the radio using a newer version of the software from the hampedia site but when I started up the Toshiba Satellite 1800 and tried to go into the Bios to re-enable the cache (which I disabled yesterday to slow the computer in the hope of overcoming the programming problem) it asked for a password. Somehow when I disabled the cache I must have accidentally enabled a Bios password, but of course as I didn't do it intentionally I have no idea what the password is. I tried to start Windows 98SE but it took 20 minutes to load and was unusable once it eventually did. So that's that.

But in the end another solution was found. I registered with the forum at the curiously named Batwing Laboratories website, which apparently is the fount of all knowledge for all things Motorola, and posted about my problem there. Tom in D.C. (W2NJS) replied that the DOS in Windows 98SE wouldn't do, I must use MS-DOS 6.22.

Now I was programming micros since before IBM invented the PC. I've read Ray Duncan's "Programming MS-DOS" from cover to cover several times so I was pretty much an expert on the subject at one time (though I've forgotten just about all of it now) and I would never have thought that there were any differences between the two versions affecting the use of the serial port. But Tom was firm enough in his advice that I downloaded an MS-DOS 6.22 boot CD image and made myself a boot disk. It wouldn't recognize my Windows 98SE partition so I had to vape that, reformat under MS-DOS 6.22 and set everything up from scratch. Fortunately I still remembered enough about things like config.sys and autoexec.bat to get it to work.

I reinstalled the programming software, connected the interface, and this time I got "Radio Communication OK!" Tom in D.C. probably heard my cheers from there. So I was finally able to program eight 2m frequencies into the radio - five simplex channels plus the three local repeaters - and have just completed two QSOs on the GB3LA repeater from inside the house using a quarter wave telescopic whip, so it works!

The Motorola GP300 seems to work a bit differently to ham radios. For example, there are three power levels but the power level is fixed for each channel, so if I set High power in order to access a repeater from home I can't reduce the power to Low to save batteries when I'm in line of sight of it from a hilltop. And if you want a Scan function you have to dedicate a channel to that.

Possibly there are some tips for setting up these radios for ham band use that I'm not aware of yet. But even if there aren't, it's still a nice radio for £1. Even if by the time you add in the cost of the programming interface, the battery pack, the charger and the adapter that converts the Motorola proprietary antenna socket into a BNC it ended up costing more like £40.

Motorola programming frustration

The renovation of the G4ILO shack is about half completed. The wood for the new shelf module needs another coat of paint, then it can be built and everything put back in again. Unfortunately old age is catching up with me and I am just sooooo tired and have so many aches and pains from all the work so far that progress is (literally) painfully slow. I missed the talk on SOTA at the radio club on Monday evening because I would probably have just fallen asleep!

After the flying hiatus some items I ordered from China and Hong Kong are starting to filter through including the programming interface for the Motorola GP300 radio. It is a Maxton RPC-M300, pictured on the right, and it came with a CD containing the necessary programming software. (The software can also be found on the hampedia website, so please don't ask me for a copy.)

The software runs under real MS-DOS, not a DOS window. My researches had already established that it doesn't run properly on newer, faster computers, so I installed it on the oldest PC I had available, a 2002 vintage Toshiba Satellite 1800, which happens to have both a floppy drive and a serial port. It doesn't have network access, so getting anything on and off it is a bit of a headache, but I still have a copy of a Windows 98SE install CD and the required boot disk, so I was able to use that to provide the MS-DOS access.

No instructions came with the interface. It's obvious that it clips on the back of the radio, and the red and black wires are used to provide power, but there is no indication of what voltage to use. Some DIY interfaces that have been published use a 9V battery so I set the variable power supply to 9V. The other two plugs - one like a telephone plug and the other a 3.5mm stereo jack - are presumably for other radios that the interface can be used with, so I left them dangling free.

I applied power and the red light on the interface came on. I then tested communication between the software and the radio, and the green light flashed for a few seconds, then I got an error #2 "No acknowledgement." I tried again, this time after switching the radio on with the volume control, but then I got an error #7 "Invalid opcode."

I had read that the programming software may not run properly on any Pentium computer at all, due to its use of timing loops. One of the suggestions to slow a faster computer down is to disable the CPU cache, so I went into the Bios and did this. This didn't make any difference to my inability to program the radio, but it did make Windows 98 take 20 minutes to load and be unusable once it has done so. Unfortunately I discovered this morning that I had somehow managed to set a password on the Bios which of course I don't know, so now I can't get back in to the Bios to re-enable the cache. :(

It seems as if I will have to give up on the idea of programming this radio myself. My only hope now is that someone at my radio club is able to help with this. Unless anyone has any other suggestions?

Saturday, April 24, 2010

Temporary QRT

This afternoon I disconnected all the equipment in my shack and removed it. I shall be off the air for a while.

The room I use for my shack is very small and I have run out of space to store all my electronic parts, tools and books. There is no space to permanently set up all my radios, so my K2 and FT-817 rarely get used in the shack although they could be. The only solution is to make some proper built-in cupboards and shelving. Before I do that it makes sense to rip out the worn-out carpet and replace it with something better. So I have to completely dismantle the shack and remove everything.

Hopefully it won't be too many days before I can get the radios and computer back up and running again. No doubt, whilst I am unable to take advantage of them, there will be some major band openings!

Friday, April 23, 2010

Detecting Sporadic-E on 2m

We are entering the Sporadic-E season, the favourite time of the year for those who enjoy operating the VHF bands. As Roger G3XBM suggested today, more stations this year will be using WSPR on the 10m and 6m bands, so many openings may be detected that would otherwise be missed. I am WSPRing on 10m at the moment, and will probably move up to 6m later on once 10m starts opening on a regular basis.

However, my first love will always be 2m. From this QTH surrounded by hills Sporadic-E is the only type of propagation that allows me to work DX on that band. On 2m, Sporadic-E openings are much rarer because much smaller patches of the Sporadic-E clouds are dense enough to reflect signals at this frequency. This makes propagation between two points on 2m much more fleeting. A station can be 59+ one minute and gone the next, which makes it essential to keep QSOs short and sweet: report, locator, and name only if you are sure you have got the time.

Some people are planning to use WSPR on 2m as well, but because of the fleeting nature of propagation I am not convinced that the 2 minute periods of WSPR make it the most appropriate method of detecting propagation on this band. I think it might be more fruitful to monitor 144.8MHz which is the APRS frequency in Europe.

APRS packets take only a second or two to send, so you don't need propagation to be good for two whole minutes to receive one. Packets do need to be received clearly, but the "strong or gone" nature of Sporadic-E on 2m suits that quite well. The main difficulty is knowing the location of the station that sent the packet you heard, since it could well be a digipeater retransmitting a packet sent from somewhere else.

There used to be a website that displayed a propagation map based on APRS packets received. But in the last few days it appears to have gone QRT, which is rather a shame. But if you are in a location that doesn't normally hear much APRS activity, even just hearing a number of signals going "braaap" on 144.8MHz could be the alert you need that some unusual propagation is about.

If anyone has any other ideas on how to improve the detection of Sporadic-E on 2m without sitting in front of the receiver listening to band noise for hours on end I'd be interested to hear them. If you aren't familiar with this mode of propagation and how it works and would like to learn more about it then there is an article about Sporadic-E on my website.

The Amazing KGD

On the WSPRnet website DM1RG posted some results obtained using a 30m dipole 1.3m long, the "Kurz Geratener Dipol". His 5W signal made it all the way from Germany to Australia. He finds the KGD to receive only 3 to 5dB worse than his "big vertical antenna."

I tried translating the article about the KGD using Google but it didn't make enough sense for me to understand how to make one. Perhaps someone will figure it out and publish a better explanation. It looks to me to be an interesting idea for anyone with antenna restrictions or simply wanting a second antenna so they can run WSPR or monitor a band while they operate somewhere else.

Thursday, April 22, 2010

First sporadic-E of 2010

I heard a little bit of sporadic-E propagation on 10m this afternoon. Tuning around the beacon segment I heard the beacon DK0TEN on 28.257.5MHz quite strongly for about a minute before it faded away.

There have even been some contacts made and beacons heard on 6 metres, according to Let's hope for some good openings on VHF this year.

Switcher interference

I was tuning around the top end of 10m yesterday and noticed a lot of strong bubbly warbly noises, the unmistakable sound of switched mode power supply interference. It didn't take long to track this down to the power supply for my QNAP TS-109 Turbo Station.

The TS-109 is a network attached storage device. But it is actually a small computer with a big hard drive, running Linux. I use it mainly as a backup drive for all our PCs, but it also hosts the shared documents folder so that we can easily exchange files from one computer to another. It runs a script that updates DynDNS when our IP address changes, which it does quite often at the moment. I could even run a web server on it if I wanted. So it really needs to run all the time. But the amount of interference it produces isn't acceptable. I tried adding some clamp-on ferrite suppressors but they didn't make much of a difference.

The power supply for this device is a plug mounted switched mode supply rated at 12V 3A. This is probably over-generous as the specification for the TS-109 gives the power consumption as 14.4W in operation. There are plenty of alternative 12V switched mode supplies available but I have no way of telling whether they would be better or worse than the manufacturer-supplied one as regards RF interference.

The only transformer based power supplies capable of supplying this sort of power are CB radio power supplies such as those sold by Maplin which have a 13.8V DC output. QNAP doesn't, unfortunately, specify a voltage range for the Turbo Station so I don't know if this higher voltage would be permissible. It would be very convenient if I could use the power supply I made for my QRP K2, which these days just keeps the K2's battery charged up, but the output from that is 14.2V.

Switched mode power supplies really are the bane of the radio amateur's life. I don't know how to solve this problem at the moment, except to switch off the TS-109, which is inconvenient.

Wednesday, April 21, 2010

Measuring milliwatts

One K3 setup adjustment that I have never done is to check the power level of my K3 transverter output, because I don't have an RF millivoltmeter. I do, however, have an Elecraft DL1 dummy load which has a test point fed by a 1N5711 diode and capacitor. You can take voltage readings there, and then calculate power using the formula:

Power = (( Voltage * 1.414) + 0.15) ^2 / 50

and I normally use this whenever I want an accurate power measurement rather than rely on the readings of analogue meters.

What I don't know is whether this is accurate enough to measure power at levels as low as 1mW. So I asked the question on the Elecraft email reflector, rashly forgetting that the function of of the reflector is for users to flame each other and speculate on or redesign Elecraft products. Don, W3FPR, who was usually good for an answer to a technical question, has left the reflector after he was flamed for some imagined breach of netiquette. Frankly, the reflector is now worthless. I wish Elecraft would create an announcements-only mailing list so that one could stay informed of new developments and firmware updates without having to see all the ego clashes and endless questions about problems with USB serial adapters.

When I measured, using the DL1 and my DVM, the output from the K3 transverter port with the level set to 1mW, I got a reading of 36mV. Plugging that into the formula, I get 0.8mW. But the 0.15 is, I presume, a "fudge factor" to compensate for the voltage drop in the detector diode, which gives me a result of 0.45mW even if zero voltage was detected. So I'm wondering if my 0.8mW is within the limits of error of my measurement method and that I should leave my transverter drive level as it is. I assembled my K3 myself and the transverter board was added later so I don't believe the level has ever been set at the factory.

Tuesday, April 20, 2010

Under the volcano

On a clear day from here you can normally see at any one time two or three vapour trails from transatlantic jets at 35,000 feet on their way to London's airports. For five days there have been none. The weather has been fine and the sky blue, so blue that it's easy to doubt whether the density of dust from the Eyjafjallajokull volcano in Iceland poses any real threat to aviation, or whether it is just bureaucrats being over-cautious.

Whatever the risk, the aviation ban is real and there can be no-one in Britain who has not been affected by it one way or another. The first effect we noticed was when we went to a classical music concert last Friday in Carlisle. The piano soloist was unable to get there so the Mozart piano concerto was played by a stand-in.

I received an email from one Hong Kong eBay seller to tell me that the programming interface for the Motorola radio I bought at Blackpool which I ordered from him would take longer to arrive. I expect other items I have ordered from eBay and elsewhere, including a transmitter module for my dedicated Echolink node radio, will be similarly delayed, as there is no air mail. We take for granted that we can order things from China or the USA and have them in a few days. Not any longer.

Friends of ours who are due to return from Ukraine tomorrow are probably not going to be able to make it unless London Luton airport is miraculously opened. They are due to return to work on Thursday and are very anxious not to provide their employers with an excuse to terminate their contracts.

That's the situation now, but with seismologists saying that the volcano could continue to erupt off and on for the next year or two and even suggesting that another, larger Icelandic volcano is due for an eruption, what is the future for the airline industry? If there's a high probablility of getting stranded abroad like so many people are now, how many are going to decide to change their travel plans and stay close to home for the next few months? I will, for sure.

I dare say canny investors will be selling airline shares and investing in shipping. And I don't suppose it will be long before the first package holiday companies start going bankrupt because of all the refunds and cancellations. Like the banking collapse, I think this is another event that is going to have permanent repercussions.

Trust Nature to cut us down to size. We humans think we are so powerful we can end global warming, yet in a few hours the earth achieved what governments alone could never have managed - a complete grounding of aviation. I suspect that a really big volcanic eruption could have a bigger impact on global climate than any of the measures agreed by the politicians.

Could D-Star destroy ham radio?

In a comment to an old posting about D-Star in G4VXE's blog, Lee N2LEE accuses me of being closed to new ideas. Does it matter that the AMBE codec is patented if it is the best one for the job, he asks? And how can you compare Echolink/IRLP to D-Star when D-Star is an digital end to end system with routing, linking and networking built in to the system so you can just enter someone's callsign and the network will find them automatically?

To me, ham radio is not and never has been about reliable point to point communication. Communication is just the end-product of a process of experimentation and construction, or a pastime (think contests, DXing) where the unreliability and unpredictability of it is what makes it a challenge.

D-Star's use of a proprietary codec closes that aspect of the system to experimentation. It doesn't even permit interested amateurs to look at the code and see how it works. This is contrary to the spirit of amateur radio and the openness that has facilitated most developments to date by letting one idea lead to another. But to be honest I'm not all that bothered about the issue because codec technology, whether proprietary or not, is a closed book to most. I am more concerned about the possibility that digital voice modes might one day make analogue modes obsolete so that building a simple phone transmitter using SSB, FM or AM becomes a pointless activity. Ham radio does not have to slavishly adopt new technology, especially if that technology forces more of us to become appliance operators by making simple rigs that anyone can build obsolete.

As for digital end to end routing, why do we need it? We already have a system that can do that. It is called the mobile phone network. I didn't get into ham radio in order to be able to do something ordinary people can already do. I want to be able to do things that they can't. The unpredictability of propagation and the uncertainty of who you might work on a given band at any time are what makes a ham radio contact more interesting and more of an accomplishment than making a phone call. D-Star may be very clever technology but what it delivers is not what ham radio is about.

If the time ever comes when I think to myself "why am I struggling to make this contact on 20m SSB or whatever when I could simply type the guy's call into my D-Star radio and have a comfortable chat" then that is the day I will give up the hobby for good. And I make no excuses for resisting the adoption of technologies that will bring that day closer.

Sunday, April 18, 2010

Arecibo success

This evening I managed to hear signals bounced off the moon using an FT-817 and an antenna made from a stick and a few bits of wire.

I took the battery out of the clock / weather station to silence its interference and went down to the bottom of the garden with the home made antenna and the FT-817. I couldn't see the moon this evening as it was cloudy - in fact, attempting to drizzle - but I pointed the beam in the same general direction as last time, turned it vertical to minimize the QRN and started tuning around 432.045MHz. After a minute or so I heard some weak CW.

If I had to give a signal report it would have been 319, the signal was about equal to the noise. Sometimes it would pop up a few dB above the noise for a second or two, and I heard the call KP4AO (though not all in one go), reports being sent, R, 73 and BK, but I couldn't make out any other calls.

I had the computer interface plugged in to the FT-817 so I brought down the Samsung NC10 netbook which I have been using for my Echolink node and tried to make recordings of what I heard using Sound Recorder in order to listen to them again and even put some samples here. But for some reason when I played them back on my shack PC all I could hear was noise - the CW had all but disappeared. What a disappointment, to have no record of this rare event.

Then, on a sudden stroke of inspiration, I changed my computer sound card settings so that I was using the Realtek internal sound card - normally used for HF digital modes - to play back the audio in place of the cheap USB "dongle" I normally use for computer sound. What a difference! Instead of just hiss with a barely detectable hint that a CW signal might have been there, I now heard the KP4AO signal via the moon just as I heard it live off-air. I have converted a couple of samples to MP3 format without much loss of fidelity so you can hear for yourself what I heard:
The CW certainly is weak but you can pick out letters now and again. If you manage to pick any calls out of those samples then you have better ears than me (which is certainly possible.)

An interesting evening's experiment. Not just because I heard signals bounced off the moon for the first time ever but also for the unexpected demonstration of how weak signals get lost when you use a cheap sound card. I had been planning on using one of those USB dongles to make my own SignalLink interface. I think it's back to the drawing board on that one.

Noise generator

I heard nothing during my attempt last night to receive signals from KP4AO bounced off the moon. Nothing, that is, except a lot of noise. Sitting at the bottom of the garden with my newly constructed hand-held 6 element 70cm beam, the Moon was above and just to the left of the roof of our house. And the nearer I moved the beam to the house, the greater the noise. This house is truly a disaster area for radio reception!

This afternoon I thought I would try to see where the noise was coming from. With the beam horizontally polarized the noise was a broadband hash, white noise, indistinguishable from band noise except that its level is much greater with the beam pointing towards the house. If I turned the beam vertical then the white noise faded out almost to receiver noise, but another pulsing noise came up. It went kerchunk chunk chunk chunk, kerchunk chunk chunk chunk, ad nauseum. And the level of this noise peaked up with the beam pointing right at the shack window!

I switched everything off in the house and it made no impact on the noise whatever. I decided that it must be something battery powered. There is a radio controlled alarm system in the house that has a built-in backup battery. Nothing I can do about that. However I could not hear any noise increase when I went near it with the TH-F7E and a whip antenna. The noise level goes up and down as you walk about the house, as does the kerchunk chunk chunk noise, as if the noise source is invisible.

Eventually I did locate the source of the kerchunk chunk chunk noise. It was coming from an Ascot radio controlled clock sitting on the shelf in the shack just above my radios. I removed the batteries and after a few seconds the noise stopped. I walked about the house some more and in places I heard it again! This sort of thing can make you start to doubt your sanity.

Eventually I found that exactly the same noise was coming from another clock / weather station in our conservatory. It's a different brand, not radio controlled, and (probably not coincidentally) it receives temperature and humidity readings from the same external sensor. Presumably they have some electronics in common and this is transmitting a signal in the 432MHz band.

But I haven't found the source of the broadband hash, which may or may not be related to the crackly S9 noise that plagues most of the HF bands. I think the noise problems at this QTH are beyond solution. I haven't logged an HF band contact from here since 13th March. It isn't that I can't work anything on HF from here, it's just the demoralizing effect of hearing this dreadful noise as soon as you switch on and knowing that there are interesting signals buried under it that I have no chance of hearing.

Britain cut off, but Dunkirk spirit still alive

Flights in or out of the UK are banned for a fourth day due to the alleged effects of dust from the Icelandic volcano. Flight restrictions have been just been extended until midnight tonight, with suggestions that they could extend for "several more days". Britain is virtually cut off, with the Channel Tunnel and ferries to and from continental Europe fully booked. There is talk of an economic disaster, with some European airlines in serious financial difficulties as a result. Tens of thousands of people are stranded, unable to get home from their Easter holidays and facing financial ruin, loss of pay and even the loss of their job as a result. Travel insurance companies in most cases are refusing to pay out for additional accommodation or the cost of returning by alternative means.

However, the Dunkirk spirit is not dead. Just as in 1940 when Brits with small boats went across the Channel to bring our defeated troops back, TV presenter Dan Snow is today mounting an operation with inflatable craft to bring stranded Britons back from Calais to Dover. You couldn't make it up. (Postscript: The attempt was halted by authorities, presumably for health and safety reasons. Oh well. Nice try.)

It is reported that the Dutch airline KLM has flown a Boeing 737 to 13km over Dutch skies with no adverse effects, whilst Germany's Lufthansa has flown several planes from Frankfurt to Munich without any harm being caused to the windows, fuselage or engines. But Dutch and German airspace are also closed for the time being. However the Ukrainian International airline - which coincidentally Olga used on her recent trip to Ukraine - is to recommence flights at 0900 UTC today as it believes the skies are safe. Hooray for the Ukrainians! At least someone has some sense.

According to some aviation experts, the only time aircraft have suffered from volcanic ash is when they flew right through a plume of it as the volcano was erupting. The ash here is so thin that you can see the moon and stars when the sky is clear. Isn't this just another case of out-of-control safety mania, with bureaucrats being afraid to make any decision that just might lead to them being blamed later on, regardless of the probability of risk? Isn't it time for someone to use some common sense?

Saturday, April 17, 2010

EME with a handheld

This morning I made a 6 element Yagi for 70cm using some 25A copper mains wire with the insulation stripped off and a length of wooden dowel. I copied the design from CT2GQV's blog. The object is to see if I can hear radio signals bounced off the moon.

If you didn't know, a bunch of guys that include Joe Taylor K1JT of WSPR fame have got permission to use the 1000-foot dish of the Arecibo Radio Telescope (shown above) for a couple of hours each day over this weekend to make radio contacts via EME. Using full power their signals should be strong enough to be heard using a hand held yagi and it should be possible to work them using just 100W with the same antenna.

I only have the FT-817 with 5W so it isn't possible to try to work them, but I thought I would try to hear them, which is why I made the antenna. I think you'll agree that their antenna is more impressive than mine! There are, of course, no 70cm signals to test it on, but there are plenty of noises and the yagi seems quite directional. The SWR is about 1.7:1 at 432MHz and falls gently as you go lower in frequency, but I'm not sure how to adjust it so I'll leave it as it is for the moment.

The first session was yesterday. Unfortunately their PA blew up so they were only able to run 25W of power. Some contacts were made, but obviously not with people using low power and hand held antennas. Hopefully they will have got a PA working in time for the remaining two sessions, otherwise I am not going to hear a thing.

This evening they should be on between 1740 and 2020 UTC - that's 1840 to 2120 BST. They will be transmitting on 432.045MHz using SSB or CW. Their call is KP4AO. The moon is only showing quite a thin crescent at the moment so it may not be easy to spot during daylight, even assuming the sky is clear as it is here. If you are in the UK the moon will be at an elevation of about 45 degrees to the south-west at the start of the session, declining to about 25 degrees due west by the end of it. If your QTH is elsewhere you can use this web site to locate it.

Tomorrow's session is scheduled for 1840 to 2125 UTC - 1940 to 2225 BST. The moon will be in the same position relative to the start of the session.

Fingers crossed that they get the PA going so we can have a chance to hear something. If not, the antenna won't be wasted as I've been meaning to have a try at satellite communications.

Thursday, April 15, 2010

Scrubbed out

One of the greatest uses of WSPR is to get accurate, real-world comparative reports on antennas. When comparing antennas in the past I have used two computers and two radios on two different frequencies using the same power and manually set the WSPR programs to both transmit on the next cycle so that they send their beacon signals simultaneously. During the transmission I set both programs back to "no transmit". This way I get directly comparable reports from both antennas at the same time and I don't have to worry about one transmission being received and reported by the other system.

Now, this is no longer possible. The WSPRnet website has implemented a "data scrubber" which will filter out invalid spots including bad calls (bogus decodes), bad timestamps, wrong band reports and duplicate reports. The latter are apparently the most common type of error, accounting for 1.7% of spots. I wasn't aware this was that common, though it can happen due to reciprocal mixing in the receiver or the computer sound card. But one result of this is that you can no longer intentionally transmit two beacons at the same time using the same call, locator and power level, because if you do all but the strongest report will be filtered out.

I think this is an ill thought out move that will result in deleting valid spots just because they can't be distinguished from invalid ones. The WSPR software does report the transmit frequency being used by each instance of the software so it should be possible in some cases to determine whether duplicate spots in the same timeslot are genuine or not. This won't help those using hardware based WSPR transmitters that don't connect to the website though.

Safety mania

Troubled car maker Toyota has suspended sales of its Lexus GX 460 worldwide after the US consumer magazine Consumer Reports claimed that the vehicle could roll over.

"When pushed to its limits on our track's handling course, the rear of the GX we bought slid out until the vehicle was almost sideways before the electronic stability control system was able to regain control," the magazine claims. "We believe that in real-world driving, that situation could lead to a roll-over accident, which could cause serious injury or death."

Let me get this straight. If you drive like an idiot, the vehicle is supposed to prevent you from suffering the consequences of your stupidity?

I think the nanny state safety obsession in the western world has got totally out of hand. I don't know how we put the genie back in the bottle (or even whether the population as a whole feels the same way and would want to) but any political party that would repeal the health and safety legislation, outlaw the compensation culture and put the emphasis back on common sense, personal responsibility and the need to prove criminal negligence in order to win a claim in the event of an accident would get my vote.

Wednesday, April 14, 2010

Shootout on Tallentire Hill

It has been a glorious day today. After lunch I set off for Tallentire Hill armed with the TH-205E and three antennas: a 2m telescopic quarter wave, a 45" 2m 5/8 wave Black Whip telescopic from eBay seller jeepbangkok and the SOTA Beams MFD.

I set up the MFD in the vertical position strapped to a fence post and put out some calls. Despite my high elevation the 2m band was quiet and I only managed to raise "the usual suspects". Richard MM1BHO/M heard me calling through the GB3DG repeater and we had a short QSO. Then Keith G0EMM heard me call on 145.500 MHz and was willing to spend a bit of time doing some antenna tests.

Prior to this I had heard a contact on the GB3CS repeater and had quickly swapped all three antennas to see what the difference was on receive. There was no noticeable difference between the MFD and the Black Whip but both were significantly superior to the 1/4 wave telescopic (which is itself an improvement over the short whips and "duckies" normally used with 2m handhelds.) However the signal was steady on the MFD whereas it varied depending on the position in which I was holding the TH-205E with the BNC mounted antenna. When using the MFD I was sitting on the ground so it was above my head and my body wasn't interfering with reception. When using rig-mounted antennas it is best to stand up as an extra couple of feet above ground make a noticeable improvement. But it is also worth turning around and moving a short distance as the direction you are facing can make a big difference to signal strength.

Keith confirmed that there was no difference in my signal between the MFD and the 5/8 telescopic. I was 59 on both of them, whereas I was only 4 by 3 on the quarter wave. Keith also gave me my second unsolicited complimentary report on the TH-205E audio, saying it was "just like my voice." I was using one of the cheap Kenwood speaker mikes which I bought on eBay originally for the TH-F7E.

We were then joined by Colin 2E0XSD who again said that I was the same strength, 59+ on both the MFD and the 5/8 wave. I was only 4 by 7 on the quarter wave.

After I finished the contact with Keith and Colin I tried some more calls. I was able to access the GB3CS repeater using the MFD and the 5/8 - when in the right position - but not with the quarter wave. Some repeaters I could hear but not access even with 3W, which is what the TH-205E appears to put out on "high power" with the 7.2V battery pack, but perhaps they don't respond to 1750Hz tone-bursts.

When I bought the Black Whip a few weeks ago I put it on the antenna analyzer and got this SWR curve. I seem to remember that I had to collapse the topmost section to get the SWR null spot on 145.000 MHz but I don't suppose it makes any difference in practise.

I think the Black Whip 5/8 telescopic is a superb antenna for 2m FM use and well worth the few pounds it costs, as long as you have a radio that can handle it. The base is sprung to absorb any shocks but even with the HT Saver SMA to BNC adapter I was a little uncomfortable using it on the tiny TH-F7E. The big old TH-205E has no such problems with a large antenna, although its lower power output with the battery pack I have is a slight disadvantage.

Is it worth carrying the MFD instead of the 5/8, which telescopes down to the same length as a quarter wave telescopic antenna? Well, if you are using a modern hand-held radio then the MFD's coaxial connection will avoid putting undue strain on the SMA connector. You can secure the MFD to a fence post or stuff the support mast in your rucksack allowing you to operate sitting down and even let go of the radio when receiving. The MFD is also convertible to a horizontal dipole for SSB use. So it still has several benefits. But I expect I will be taking the Black Whip on most of my hilltop outings.

Tuesday, April 13, 2010

Wainwrights On The Air Blog

Just over a year ago I started Wainwrights On The Air (WOTA) as an adventure radio scheme to encourage people like myself to get out of the shack and up in the hills (or fells as they are known locally) of the English Lake District for a bit of fun with radio. You collect points by making contacts from the tops of the fells (which is called activating.) Armchair fellwalkers can also collect points by working stations on the tops of the fells (which is called chasing.) Certificates are awarded when you have made contacts from (or with) all of the fells in each of Alfred Wainwright's seven Pictorial Guides, and for completing all 214 Wainwright fells.

WOTA has been more successful at getting other people out on the fells than me. To date, Phil G4OBK has been the most active WOTA activator and has already claimed a certificate for activating all of the fells in the Pictorial Guide to the Eastern Fells. He has stated that he intends to do all the Wainwrights within two years. Now he has started a blog to describe his progress towards completing this challenge.

Called "Wainwrights On The Air", Phil's blog has details of the routes taken as well as the people contacted from the fells. It has some great pictures, too, that really capture the flavour of this beautiful part of England.

If you like operating radio from the great outdoors, if you are interested in the English Lake District or if you are thinking about becoming a WOTA activator yourself, I think you'll enjoy Phil's Wainwrights On The Air blog.

Charger for the TH-205E

The TH-205E transceiver was finally restored to full working order yesterday. After some thought I finally decided how to fit the 3A diode that was somewhat larger than the recommended part which was unobtainable. I extended the left-over wires from the old fuse using thin wire taken from the leads of a small capacitor. I then shortened to a few millimetres and tinned the leads of the new diode. I wound the thin wires on to the stub leads of the diode and then soldered them whilst using tweezers as a heat sink on the thin wire to prevent the other end coming unsoldered.

The radio now works off its new battery. It made its first QSO with Derek G1GDB via the GB3LA repeater, and received complimentary reports on the audio. I even took it along to the Workington Radio Club meeting in case there was a "largest 2m hand-held" competition!

I also finished up the drop-in battery charger which I built using this circuit using an LM317T voltage regulator. It is simple to make and has an LED to show that it is charging. The hardest part was cutting the rectangular hole in the plastic project box. It's best not to look too closely or you can see that the edges are not perfectly straight.

This picture shows an internal view of the charger. It doesn't show the contacts for the charging tabs on the battery which were made from a paperclip. The sleeve that holds the radio or battery in position was cut from the cardboard box that my UNI-T Oscilloscope Digital Multimeter came in, and is super-glued to Veropins to hold it in place. Hopefully the heat sink for the LM317T will be adequate - the battery hasn't lost the charge I gave it using the shack power supply so I haven't yet had the chance to test it for a full 15 hours.

Monday, April 12, 2010

Bye bye Beaconworld

The Beaconworld website will be closing down in May. If you've never heard of it before, neither had I until I read about it in M0XPD's blog. But having visited the site, it seems to be an excellent and comprehensive resource for anyone interested in beacon DXing. It's a shame that it will disappear even though it is being closed for reasons that I can understand.

Have a look while it's still here. Perhaps someone will step in and offer to take over the site and carry it on, or at least to preserve the pages as they are.

Motorola Radius GP300

I seem to be collecting VHF handhelds at the moment. This is the Motorola Radius GP300 I bought for £1 at the Blackpool radio exhibition yesterday. The seller had quite a number of shiny new-looking commercial handhelds in a heap on the table, all without batteries, which were being sold for £1 each. He told me they were all UHF. Most were Midland radios, but there was this one Motorola which in the end I decided to get because I thought it might be easier to find information about it. I should have got one of the Midlands as well, after all, it was only a quid!

Today I took a closer look at what I had bought, and tried to find out something about it from the internet. From the model number I was able to find out the capabilities of the radio and I actually have a VHF handheld which can cover 144 - 176MHz in 12.5kHz steps, 8 programmed channels with 5W output. I can't test if it works because I don't have an adapter for the strange type of antenna socket, but Motorola to BNC adapters are available on eBay. However for the radio to be any use I will need to program it with some 2m band frequencies.

There is information on the web showing how to build a programming interface, but you can actually buy one ready made from Hong Kong for little more than the cost of the parts. The difficulty appears to be getting hold of the all-important programming software. Apparently it was very expensive and Motorola doesn't turn a blind eye to free sharing of it among the amateur community so I was unable to find any download link.

None of the sites that give information about programming these radios provide any help about how to get hold of the software and they are obviously fed up with being asked about it. So there probably isn't much that I am going to be able to do with this radio. A pity, as it seems to be well regarded judging by the reviews on eHam, presumably posted by users who got them from dealers pre-programmed with the channels of their choice.

APRS absurdity

Following a posting and subsequent clarification on the APRS UK Yahoo Group I have discovered that in order to legally operate an APRS digipeater or Internet Gateway it is necessary to apply for a Notice of Variation (NoV) to my license that must include the nomination of at least three people who can close down the station within 30 minutes, even if the station will only be operated when I myself am present.

The reason for needing an NoV is because all authorization to transmit third party traffic (i.e. traffic not from you, nor for you) was removed from the new Lifetime License that was introduced in 2004. I don't actually have any problem with needing an NoV, though I'm sure I am not the only person who used packet radio back in the '80s without any special dispensation and didn't realise that this was no longer possible. However, the requirement for the NoV application to nominate three closedown operators even if the gateway or digipeater will only be operated when the licensee is present is simply ludicrous, as well as being a major obstacle for anyone who does not have three people who can meet that requirement. If the rules are silly, I won't play the game.

As I understand it, it is legal to transmit position reports on RF (because they are from you), it is legal to transmit APRS messages (because they are from you) and it is legal to run a receive-only Internet Gateway (because you are not retransmitting what you receive.) But digipeating or transmitting packets received from the Internet for other stations heard by you is carrying third party traffic and therefore illegal without an NoV. I think many people such as myself who are not dedicated APRS operators but see it as just another mode to use from time to time will take the easier option of operating without an NoV even though in the opinion of Rob Compton M0ZPU receive-only gateways "cause problems to the network in terms of it's capability to carry messaging ... by causing "dead-ends" to intelligent routing (where software utilises the reverse route for a message)."

It's hardly surprising that the RF APRS network in the UK is so poor compared to the USA and other parts of the world.

Sunday, April 11, 2010

Blackpool weekend

I hadn't been to a hamfest (or radio rally as such events are known over here) for several years. On Friday I mentioned to Olga that the Northern Amateur Radio Societies Association Amateur Radio, Computer and Electronics Exhibition was being held at Blackpool on Sunday and it was supposed to be quite a good one and she said "why not go?" I then suggested that we book a hotel for the Saturday night so we could travel down the day before and see some of the sights of Blackpool, which neither of us had been to before. So we did.

The sights of Blackpool served only to help me understand why most Brits these days go to Spain for their holidays, but the NARSA Exhibition lived up to its reputation and was well worth the trip. I spent very little but came back with a large bundle of components most of which I will probably never use, plus an apparently unused Motorola Radius GP 300 handheld, sans battery, which I was unable to resist as the price was £1. It was also nice to meet in person several people I had previously only worked on the air, exchanged emails with or who were readers of my blog.

It's impossible to give a full picture of an event this size so I'll just mention a few of the stands that were of particular interest.

Occupying a prime position right by the entrance was the stand of Cross Country Wireless run by Chris G4HYG and his XYL. He was displaying the new end-fed antennas I mentioned a couple of days ago, as well as his well-established APRS products and the new program APRS Messenger. Chris commented that the number of visits to his site increased noticeably after I'd mentioned the antennas in my blog - hopefully he got some sales as well!

Ian G0VGS and Kev G6FKE were manning the Sands Contest Group stand and also giving visitors a chance to look at the K2 and K3 transceivers by Elecraft.

My local club, Workington Radio Club is a NARSA member and had an impressive stand, manned in this picture by Barry G0RZI and Tony G1OAE.

Summits On The Air also had a stand where I was able to chat about WOTA with Tom M1EYP and his son Jimmy M3EYP, and meet Phil G4OBK who is the top activator in the Wainwrights On The Air (WOTA) scheme (and the only one so far to have earned a certificate.) Olga took this picture but unfortunately she caught me just as I blinked!

It was a very enjoyable day, but now you'll have to excuse me, I have a large bag of components to sort out!

Saturday, April 10, 2010


The diode I ordered yesterday to do the mod on the TH-205E came this morning, but it is a bit big.

It looks as if I might have to use a thin wire link after all.

The diodes I ordered have a rating of 3A whereas the one specified by Kenwood - part number ERB83-004 - is rated at 2A. You can see an ERB83-004 which is used as a reverse polarity protection diode mounted vertically just to the left of where I hoped to put this one in. It is much smaller.

There is room for the big diode but it will not be easy to get a soldering iron bit in and trying to solder such heavy leads to the thin leftovers of the old one could result in more problems.

Back to the drawing board.

Friday, April 09, 2010

Blown fuse

My hopes that the TH-205E I bought on eBay would be fully operational after connecting the fully-charged new battery were dashed last night when I attached the battery, switched the radio on and got ... precisely nothing. However I already had a suspicion as to what was wrong. Whilst searching for information about the radio I had found information about a design fault in early models of the TH-205 that was corrected by a modification in later versions.

The original TH-205s had a miniature 4A fuse in line between the battery and the power switch. However if external power was applied using an incorrect type of DC plug, the battery was not disconnected from the supply line. The external power could overheat the battery and blow the 4A fuse. I suspected that the fuse had blown.

In fact, I'm afraid it was probably me that blew the fuse. When I first plugged in external power from my shack GSV3000 power supply I noticed the current meter quickly blip as contact was made before the power jack disconnected the battery from the circuit. I didn't know at that time about the fault, or that the original battery was a dead short. It probably isn't a good idea to plug in DC power leads while the power is on, but I expect I had other radios on at the time and didn't want to turn the power off.

I opened the TH-205E up again. I could see the wires from the battery went to a jack on the RF board which is underneath the IF board, so I had to remove the IF board to get to it. This really is a nicely made radio and it is easy to take apart. The fuse, with a ferrite bead on one of the leads, was in the obvious position next to the red wire from the battery. In the picture you can see its position marked L23 after I had snipped the fuse out (I didn't want to remove the RF board from the chassis to unsolder it completely, so I will solder the replacement to the lead ends that are left.)

I didn't have a miniature 4A fuse to replace it with. The official Kenwood modification is to replace the fuse with a blocking diode to prevent DC power reaching the battery pack. But they use not just any old diode, but a Schottky barrier rectifier diode which has a low voltage drop of about 0.4V. (A regular silicon diode would cause a voltage drop of about 0.9V.) Of course, I didn't have a 2A Schottky barrier rectifier diode in my parts drawer either.

I did consider simply replacing the fuse with a thin strand of wire. Since I only have the low voltage 7.2V battery pack I don't really want any additional voltage drop. I know about the problem so I could simply avoid it by not hot-plugging external power into the power jack. But there is always the risk I might forget and I don't want to do the repair again, so I decided to do the proper modification.

I ordered the diode from eBay supplier PIC-Projects. I have to say that eBay has become my main source of electronic components and is a major salvation when you need an odd part like this. There is no minimum order charge or handling fee that makes it uneconomic to order less than £30 worth of stuff, and the prices of both parts and postage are very reasonable. Sometimes you have to order cheaper parts in quantities of 10 or 50, just like the "professional" suppliers like Farnell, but the prices make it worth while and it helps to build up a stock of parts for future projects. I ordered 5 of these Schottky diodes because they were only 35p each, and I'm sure I'll find a use for the other 4 eventually.

Hopefully the diodes will arrive in tomorrow's post and I'll finally be able to put the TH-205E on the air with its new battery!

New British end-fed antenna

Cross Country Wireless will be announcing a new product at the Blackpool radio rally this Sunday. It's an end-fed antenna consisting of matching unit, wire and an insulator, and comes in three versions for 40m, 30m and 20m.

Many users speak highly of the performance of the Par EndFedZ antennas from the USA. It will be convenient to be able to buy such antennas from Europe without the hassle and expense of import charges, and it's good to see new amateur radio products being made here in the UK.

Thursday, April 08, 2010

A stroke of luck

Sometimes you just get lucky. After I repaired the TH-205E I recently won on eBay, I was looking around for ideas on what to do about the dead battery pack and I found someone selling brand new Kenwood KNB-4 battery packs for £2.40. Well, not brand new, but never used, in the manufacturer's box, though they would have been manufactured some time around 1993. The seller claimed that, although stored for a long time, after three full charge / discharge cycles they should be capable of holding a reasonable charge.

The KNB-4 was not actually made for the TH-205E. However due to Kenwood keeping the same form factor for its hand-held transceivers for several years the newer battery pack is able to be used in the older radio, as I was able to confirm from the W&W Manufacturing website, which claims it is equivalent to the PB-4 accessory battery for the TH-205. This is the large "high capacity" battery, with 1500mAH capacity as compared to the 500mAH of the one that came with the radio. Unfortunately it is only 7.2V which gives a power out of 1.5W according to the manual. It would have been nice to have had the 12V 1200mAH one which gives 5W out but you can't have everything.

This is a big battery pack and it turns the already large TH-205E into a veritable giant, as the picture of it next to the TH-F7E shows. This is more than just a radio! You give your biceps a workout every time you use it. The radio will hold down your log sheets on a windy hilltop where lesser rigs would blow away and it also makes a handy weapon to beat off any assailants who might try to mug you whilst you are on the air.

Unlike the supplied battery, the KNB-4 doesn't have its own charging socket, just contacts for a drop-in charger. So I will need to make a drop-in charger for it. I have already made a start using a piece of Veroboard with contacts made from a paperclip. The battery is charging at 240mA from the shack power supply, so after 10 hours I'll know if it can hold a charge. If it does then I'll make up a proper constant current charging circuit and put it in a nice box. Then I'll have a great little, err, I mean great big 2m radio that will certainly attract a lot of attention wherever it goes!

EchoLink hotspot update

I just had a reply from the RSGB's ETCC regarding my NoV application. In a nutshell, applying for an NoV to use a 2m frequency for a personal short-range node is a non-starter as "it would be entirely inappropriate for RSGB to assign one of the scarce channels available within the 2M band for your personal use." However it is possible to use provisions already in the license for "remote control of your station" to operate on any frequency I choose, without an NoV. So I have asked them to withdraw my application.

As a holder of a full UK amateur radio license, there are apparently no restrictions on frequency or power that I can use for the remote control circuit (other, of course, than those that apply to normal amateur radio operation.) However the link has to be "adequately secure" to prevent unauthorized transmissions. Typically for a legal document, no specific guidance is given as to what "adequately secure" means from a technical point of view. Limiting the power - or, perhaps more importantly, the receiver sensitivity - so that it cannot receive anything other than my own transmissions might be good enough, but I certainly would not consider it adequate security for my WiFi network (though a few years ago, before everyone got WiFi equipment, I certainly used to.)

Using a transceiver that supports DCS like my FT-817 - as I am currently doing - might be considered acceptable, though it wouldn't take too long for someone to run through all the available codes and find out which one I am using. However I don't want to use the FT-817 for this forever, I'd prefer to find something cheap that I can dedicate to it, and most of the cheap ex-commercial radios don't support things like DCS. They also run too much power. So at the moment I'm not sure what the best long-term solution is.

I hate to admit it, but I can see that D-Star has the advantage here. Being digital, it knows who is calling in to the system. I presume that the DVAP Dongle has a facility to limit access to your own specific call, which would solve the security issue once and for all.

Perhaps I'm worrying too much about this. After all, the reason I'm doing this is because there is very little local VHF FM activity receivable from here. Which means the likelihood of anyone accessing my node, even if it was unsecured, is practically zero.

Postscript: I think I may have found the solution.

Wednesday, April 07, 2010

Broken duck

I went for another stroll up Tallentire Hill this afternoon with the TH-F7E. The FT-817 is tied up running my EchoLink hotspot until I can find something cheap I can dedicate to the task - I have my eye on a pair of PMR446 radios that are modifiable to 70cm.

I took along my DIY 2m rubber duck antenna and a "Black Rod" 2m 5/8 telescopic whip that I recently bought on eBay. In case you are wondering, I use an "HT Saver" SMA to BNC adapter to take the strain of the longer whip. But I am seriously considering using the TH-205E for such outings in future, if I can sort out a battery pack for it, because it has a proper BNC antenna socket and is much better suited to use with a large telescopic whip.

The 2m FM channels were not exactly buzzing with activity but I heard the GB3CS repeater 100 miles away and a GW station (Wales) in QSO. I tried swapping the two antennas for a comparison, but could hear nothing on the rubber duck at all. This surprised me, as the last time I did a comparison there was hardly any difference between it and a quarter wave telescopic, and I didn't expect the 5/8 to make such a huge difference.

The TH-F7E is multimode on receive, so I took a listen on 2m SSB as well. I heard the GB3NGI Northern Ireland beacon much stronger than I can receive it from here. But I couldn't hear GB3VHF from South East England at all. I haven't heard it from home at all recently either, although it is supposed to be back on the air after a move to a new location. I guess the new location isn't as favourable as the one it has operated from for longer than I have held a ham radio license. GB3VHF was the first amateur 2m signal I ever heard, after building my first 2m receiver, so hearing its call in Morse always causes some nostalgia.

I put out several CQ calls on 145.500 and was eventually called by Bill G3WJH in Seaton, only a few miles away by line of sight. I swapped the antennas again, and he couldn't hear me at all on the duck. Colin, 2E0XSD then joined us, and then we were called by Richard G0IBE/P on Lord's Seat (a SOTA and WOTA summit) so we all exchanged reports with him for chaser points. Jim G3ZPD from just south of Cockermouth then called in and worked Richard as well. By that time I was getting a bit chilly as it was a lot colder up there than it was at home, so I came back.

On my return I checked the DIY Duck on my antenna analyzer and found an infinite SWR. I pulled off the whip and the copper wire had fractured just about level with the top of the BNC adapter, which is probably the point that experiences the most bending. I guess 22SWG enamelled copper wire isn't flexible enough to use for a helical antenna. Back to the drawing board.

Tuesday, April 06, 2010

G4ILO-L EchoLink hotspot

If you're a regular reader of this blog you'll probably have observed my comments about the lack of activity on VHF hereabouts. Even though I can raise three 2m repeaters there is next to no activity on any of them. And although there are several active amateurs in West Cumbria most are "over the hill" from me so I never hear them.

Some time ago I thought about setting up an EchoLink node to make it possible to have some contacts on VHF. But when I realized how much trouble I would have to go to in order to get permission for this I went off the idea pretty fast.

My interest in this basic idea was rekindled when I read recently about the D-Star Digital Voice Access Point. Personally I'm not going to be interested in D-Star until the prices of compatible radios come down and you can buy them from other manufacturers than Icom. Besides, I like my little TH-F7E with its wideband AM/FM/SSB/CW receiver and don't want to change it for one that doesn't have that facility. But why shouldn't I set up a very low power EchoLink node for my personal use so I could make some contacts using my TH-F7E hand-held from round and about the house?

I put in an online application for a Notice of Variation (NoV) to my license to run an attended simplex node - which so far hasn't made any progress. However, fellow blogger Tim G4VXE writing about his experience with the DVAP mentioned that he made some quick enquiries via the RSGB's ETCC as to the legality of using the DVAP without an NoV and they were not concerned about DVAPs or hotspots as long as there is no third party traffic.

I presume that D-Star, being digital, knows who is calling in to the system so you can set it so only you have access. With EchoLink you can really only have security by obscurity, using low power, a poor antenna and an obscure frequency so that it won't pick up transmissions from anyone else. I'm not sure if this meets the official standards for not allowing third party traffic, but my enquiry to the ETCC has also gone unanswered (so far.) I got fed up with waiting and decided to go ahead.

I first tried EchoLink many years ago when it first was announced. At the time I had no way to access the system except direct from my computer. After making a few contacts that way I found that talking to hams without using any radio wasn't very interesting, so I didn't use it again.

Even though I am only using RF to make the link of a few metres to the radio connected to the computer, because I am using an actual radio it really feels like I am making a radio contact. I have set up the G4ILO-L node so that it doesn't allow connections from computer-connected users. There may be disadvantages to this and perhaps some will consider it a bit unsociable but I still feel that using amateur radio at each end of the link is an important distinction that differentiates EchoLink from internet chat. I can still join EchoLink conferences and conferences may include directly connected users so talking to people who aren't using a radio isn't completely ruled out.

I dare say there are some who will still consider that making contacts in this way isn't amateur radio. But the fact that my RF is not going directly from my radio to his is of no great importance as far as I am concerned. This isn't meant to be a way to explore propagation or work DX. It really isn't much different from using a repeater.

If I find that it is worthwhile keeping my EchoLink node running then it will create a couple of new radio projects to work on. I will need to make a new computer/radio interface and either build or modify a radio that I can dedicate to the link so that the equipment I am currently using for it can be released for other uses.

Because I signed up for EchoLink soon after it was announced I have a coveted low node ID number: 3098. I have swapped this number over to use for the link. The G4ILO-L node is running low power to a leaky dummy load so it can only be used to contact me. If you have access to the EchoLink network by radio, please give me a call. It would be great to talk to you.

Sunday, April 04, 2010

Tallentire Hill

By the time I had finished repairing the TH-205E the sky had cleared and the sun had come out so after tea I thought I should go for a bit of fresh air and exercise. Olga is still suffering from a chesty cough and didn't want to come so I decided to drive over to Tallentire village and walk to the top of Tallentire Hill. A couple of weeks ago I had spent a couple of hours parked near the top making some contacts from my HF mobile station. But it isn't possible to get right to the top by car unless you have a 4 wheel drive vehicle, because the track is rather stony. Even if you had a 4x4, there is nowhere to park off the road right at the top. The actual summit is in a small field and accessible through an unlocked gate from the track, but it is presumably private land so whilst walkers enjoying the view may be welcome, hams setting up a portable station would probably be accused of trespassing.

But on a day like today it is worth going just for the view. The picture above shows the trigonometrical point (a reference point for measuring height used by the Ordnance Survey) looking south east towards the Skiddaw range. On the larger version (click on the small one to see it) you can see snow-covered mountains beyond Keswick in the background.

The next picture shows the view south west and on the large version you can see some of the buildings of Cockermouth nestling in its valley. The big mountain on the left is Grasmoor with its steep drop towards Crummock Water. In the distance you can see the Buttermere fells.

The last picture shows the view north across the Solway to Dumfries and Galloway in Scotland. I don't know the names of the Scottish mountains.

I would love to own the field containing this summit so I could use it as a portable site whenever I wanted, even if it meant buying a 4x4 vehicle! With the take-offs shown in the pictures the site might be quite good for VHF, so I will have to take the MFD and the FT-817 up there one day when there is a 2m contest in progress.

Today I didn't manage to raise anyone with the TH-F7E I took with me. But despite the sun it was pretty cold up there with a stiff breeze so after a few calls on 145.500 I headed back down again.

Kenwood de-gunked

It's probably a character weakness, but I have always had a tendency to push my luck a bit too far and end up regretting it. That thought was in my mind when thinking about what to do with the Trio / Kenwood TH-205E that I got for a song on eBay. The rig worked well enough already to do what I thought I would do with it if it worked. But I was finding it hard to resist the temptation to see if I could restore it to full working order even though there was a risk that I might end up breaking it completely.

In the end, the temptation to try to restore it won. The radio came apart quite easily - it is a big radio, and fairly easy to work on, though surprisingly for 1986 vintage equipment it uses a lot of SMT parts. The back half is a solid cast metal chassis containing the IF and RF boards, and the front half is plastic and contains the front panel with the control logic. The two halves are linked by two ribbon cables and one had been inserted a bit crooked, which led me to hope that repositioning it might solve the problem of the inoperable buttons, but that proved not to be the case, so the front panel board had to come out.

The front panel board is secured to the front panel itself with a large number of small self-tapping screws. Once they were removed and the wires to the speaker and mic unsoldered, the board came out to reveal the sight shown above. The front panel buttons were not sealed units but capacitive switches operated by contact with the rubber buttons, and they were covered by a sticky mess of gunk - presumably the same stuff I had found on the outside of the case which a couple of readers informed me was a cleaning agent used to spruce plastic items up prior to sale. This hadn't just distributed itself over the switch area, it had even penetrated through some of the vias to reach the other side of the board. What a mess!

Olga found me a few small pieces of rag and I went to work with some white spirit from the garage. I eventually managed to clean most of it off. My fears about causing even worse damage were raised when the LCD display fell off. It didn't seem to be attached to the board and had perhaps become stuck to it with some of the gunk. However when I reassembled the radio I just rested it in place while I fixed the PCB in place and it still worked.

There was no way I could test if the switch contacts were clean enough without reassembling so eventually I decided that it looked good enough and back it all went. I applied power with trepidation. The display lit up and I could hear hiss in the speaker. I then pressed the Offset button and was able to select repeater shift! The Scan function set the receiver scrolling slowly through the entire 2m band in 5KHz steps - very useful that! I was also able to program and recall frequencies in the three memories, although the memory buttons still need a bit of persistence to get them to work. It isn't worth taking it all apart again just to try to improve that.

While I had the rig apart I took the opportunity to reset the power levels to give 5W on High power with a 13.8V supply and 0.5W on low power. Some previous owner had probably tweaked the power controls to give 7W out. No point in stressing the probably irreplaceable power transistor for a barely detectable 1dB or so of extra power. Then I put it all back together. Job done, and the TH-205E restored to full working order. I was feeling pretty chuffed.

As usual, there was no-one around on any of the simplex channels to do a test with but I was able to access the GB3DG repeater and even GB3LA on 145.7125 (a 12.5kHz channel) by tuning to 145.715.

I'm starting to feel a bit of affection for this big old radio now that I've made it as good as new. I'm thinking that it would be worth trying to resurrect the NiCad battery pack, which at the moment is showing a dead short. But there I'm really stumped, as I can't see a way in. Clearly the plastic case is made in two halves, but sticking a screwdriver in the crack and twisting is just going to chew up the plastic. Anyone know if it's possible?

Saturday, April 03, 2010

eBay bargain

Whilst buying on eBay can sometimes result in a piece of junk, it can also produce the occasional lucky find. The radio pictured on the right is my latest auction success which arrived this morning. It is a Trio / Kenwood TH-205E of 1986 vintage which was being sold as for spares or repair. It cost me all of ten quid ($15 for my US readers), four of which were for postage.

When it arrived it was a bit oily, for some reason, but a wipe over with some tissues took care of that. From the front it looks almost like new - no scratches or signs of wear on the markings or buttons. The rig has obviously had an active life though as on the back the paint has worn away and the serial number plate and the warning notice on the battery pack have been polished almost clean of lettering.

The seller stated that they could not get the radio to charge up, which is no surprise, as for 24 year old NiCads to still retain a charge would be nothing short of a miracle. I applied 9V of external power, switched on, and was pleased to see "144.000" appear on the display and hear the hiss of an unsquelched receiver from the speaker. My initial delight at having acquired a worker was short-lived, however, as the frequency display failed to respond to the up/down buttons and the squelch did not seem to work either.

After a while spent pressing buttons in the faint hope of getting the frequency to change, it suddenly did increment a few steps and the squelch also operated. Then the radio gradually became more responsive to the buttons and I was eventually able to persuade it up into the 145.500 region. I connected my QRP power meter and was delighted to observe that the TH-205E was putting out a good 5W in the high power position and 1W in low power. I could also receive the signal on the TH-F7E standing nearby, which was somewhat dwarfed by its older sibling. I'd forgotten hand-helds were still this chunky in 1986!

I connected an antenna and found that I could receive all the local repeaters, so sensitivity is acceptable. The TH-205E will only do 5kHz steps so it isn't suitable for 12.5KHz channeling, but the receiver is broad enough to receive the GB3LA repeater on 145.7125 when tuned to 145.710 with perfect audio. There is no CTCSS, though there is a tone-burst switch (which I haven't tested.)

Apart from the up/down frequency selectors the only other front panel button that appears to work is the Lamp button which backlights the LCD display. I can't activate the repeater offset or program or recall any of the three frequency memories. Possibly these buttons will eventually spring to life after repeated pressing. Otherwise it may require a look inside to see if it is possible to clean the switch contacts. But to be honest I'm not all that bothered, as I'm unlikely to be using the TH-205E on any repeaters.

The most I hoped for when bidding for this was a radio that could easily be got working and could then be put to use as a dedicated rig for APRS on 144.800 or something similar. The least I expected was something I could cannibalize for £10 worth of useful parts. So already I have got more than I hoped for!

Friday, April 02, 2010

Chinese crap

Several months ago I had a plan to build a project using Manhattan style construction so I decided to get a tool to make myself some Manhattan pads. Constructors in the US can buy a nice hand punch from Harbor Freight for $25 - that's less than £18. Over here the nearest equivalent cost around £90 from a tool supplier, except on eBay. I bought the eBay one, but even that cost over £30 including postage.

In the end, apart from punching a couple of test pads using the 7mm punch that was already fitted when I opened the box, I didn't use it. Until this afternoon, when I wanted to make some smaller pads. That was when I discovered what a shoddy piece of manufacturing this eBay hole punch is.

The 7mm die was a bit stiff to remove but came out with the aid of a screwdriver in the slots provided. The 4.5mm one I put in would bind at each turn and got more and more stiff. Eventually it wouldn't budge, so I put the screwdriver blade in sideways to get a bit of leverage. There was a crack and a whole piece of the die broke off! I guess it was made by the same firm that makes K3 knobs for Elecraft!

It's far enough in that I can make 4.5mm pads, but not only does it not want to go in any further but it also doesn't want to come out. I might be able to get it out with some Mole grips but this is probably the most useful size and I might never be able to get it back in again next time I need it. Crap!

Thursday, April 01, 2010

A five-star blog

A new posting by Dan KB6NU alerted me to the fact that is now allowing users to rate ham radio blogs. I followed his link, selected the Blogs category and found that of all the blogs currently rated, G4ILO's Blog is (or was, when I went there just now) the only blog that had a rating of five stars! I am amazed, humbled and proud, even if only two people had actually contributed to the rating. :)

If you would like to help keep my blog at the top of the table, please pop over to eHam, click on the stars next to G4ILO's blog and add your rating and comment. Thanks!

VOIP contacts now valid for ham radio awards

With the growing popularity of ham radio simulations like QSONet and HamSphere, I guess it had to happen sooner or later. According to an announcement just out on the IARU website, from today contacts made using these VOIP systems are now officially amateur radio contacts and can count towards amateur radio awards.

The announcement says: "There is an ever increasing use of computer and internet technology to facilitate the making of contacts between amateur radio operators. For many years use of the DX Cluster has been permitted to locate DX contacts to work and many operators now use internet sites to arrange skeds for needed contacts. We also see the development of new digital modes that can make possible contacts between stations that neither side can even hear. Permitting the use of VOIP modes to make contacts is simply an extension of the use of this facilitating technology, by removing the unreliability caused by the behaviour of the ionosphere. This move will also be welcomed by the many radio amateurs living in antenna-restricted locations who are no longer able to be active on what have traditionally been regarded as 'the airwaves'."

Addressing the criticism that no radio is actually used when making contacts via QSONet or HamSphere, the statement says: "Many amateur operators nowadays use laptop computers which are connected to the internet via a wi-fi router. This does, of course, involve the use of radio. Initially, therefore, only contacts made using a laptop with a wireless connection will be allowed to count under this new ruling. The frequency should be logged as 2.4GHz. This restriction will be reviewed at a later date."

More information on this development will apparently be posted on the site at midday today.