Tuesday, May 24, 2011

Off-air frequency standard

This is an unbuilt kit for an Off-Air Frequency Standard from Spectrum Communications. It is a crystal calibrator phase locked to BBC Radio 4 on 198kHz with an output of 2V peak to peak at 10MHz.

I got this with the intention of using it to frequency lock my Elecraft K3 using the KREF3 module. Regular readers may remember that last year I purchased a surplus Efratom LPRO-101 rubidium frequency standard to calibrate my radios. But a rubidium frequency standard has a finite life which will be used up very quickly if it is turned on all day to use as a real-time frequency reference. My intention is that the off-air frequency standard will run all day and keep my K3 as accurate as I need it to be.

I ordered the full kit from Spectrum. I was disappointed to find that what looked like a die cast box in the picture is actually a plastic box with a grey metallic finish. If I had realized it was not a die cast box I would probably have opted for the cheaper PCB kit and ordered one of the nice extruded aluminium alloy Hammond cases for the project. I hope it will be RF-proof enough to work in my shack environment where up to 100W may be used into indoor antennas.

The other disappointment was the rather home made looking PCB which does not have a silk screened component overlay. There is a printed layout in the instruction sheet but relating the component positions to the holes on the PCB is easier said than done. My initial thought was that I am not going to be able to build this. What I will have to do is draw the component overlay on to the PCB itself prior to construction. But it isn't easy with my diminishing eyesight and need to use different strength lenses which makes switching between things at different distances a real trial. Having a silk screened PCB would just have made things a bit easier. I think my days of kit building are definitely numbered.

Monday, May 23, 2011

Kenwood TM-D710 firmware update

According to Bob Bruninga WB4APR, Kenwood announced an update to the TM-D710 firmware at Dayton. The changes are:

- INTERRUPT ALWAYS: always displays information about every packet received on screen for a few seconds, not just packets from new stations.

- INFINITE: extends the above to retain the information about the last heard packet on screen.

- MY PACKET: now displays the actual digi path used when your own packet is digipeated so you don't just see that it was digipeated you can see which digipeater.

- TOP button: LIST display inserts new entries at the top so no need to scroll down.

- HEADING/UP: you can toggle the compass rose to North-UP or Heading

- PREVIEW of PHRASES: When selecting phrases you can see a preview of
first 9 bytes.

- READ/REPLY keys come up when a message is flashed on the front panel

- OVERLAYS: You can now select overlay characters on any symbol

- TOTAL hops can be set as low as 0 instead of 1.

- Auto-Powerup-Time set (if GPS is connected and is locked)

The update also contains some bug fixes. It does not include support for item-in-message or any other previously unsupported APRS features. :(

At this time the update is not yet available for download from Kenwood's website.

Sunday, May 22, 2011

No charge

The object on the left of the picture is a 9600mAh external back-up battery for MP3 players, mobile phones and other 5V devices. I bought it on eBay (where else?) for $55.99 including shipping with the intention of using it to power my HTC Touch Pro smartphone so that it could run all day using GPS and internet connected apps like the APRS client APRSISCE. Previously I hadn't been able to make much use of such applications when out and about on foot because if I was away from a power supply for more than a couple of hours the end result was a dead battery and a phone that could not be used to make phone calls.

The product arrived after a couple of weeks wait rather poorly packed in a jiffy bag containing the battery back-up unit, a 5V USB charger with the usual two-prong fold-out mains plug, and a USB cable with coiled lead and interchangeable power connectors. There was no box, nor any instructions so I had to figure things out for myself. Clearly the DC IN port was meant for the charger, the USB socket marked DC OUT was the output and the slide switch next to it turned the output on and off. The four LEDs showed the battery state for a few seconds after the POWER button to the left of it was pressed, and the charging state whilst charging.

There was no cable for charging, so I presumed I had to use the USB lead supplied for output and one of the interchangeable connectors. One of them did fit, though not very well, poorly enough in fact that it pulled out of the socket if there was the slightest tension on the coiled cable.

I started charging the power pack. Two lights lit up on the charger and the charge status showed two of the four LEDs lit. Next time I looked at it all the LEDs were off. Surely the batteries could not have charged so quickly? Eventually I measured the output from the charger and found it was about 0.25V. Clearly the charger had failed.

I sent an email to the eBay seller who was anxious enough about the possibility of receiving negative feedback to immediately promise to send a replacement. Meanwhile I found that the charger which came with my HTC phone had a USB output so I charged the battery pack with that. With hindsight that was rather foolhardy and I ought to have attempted to measure the current drawn first, but I got away with it. Though rated at 1.0 Amp output the HTC charger got fairly warm, but eventually the charge level reached full and the charger got cold again so I assume that it finished charging and the pack was fully charged.

The charger that came with the battery pack is labelled as an "MP3 Power Supply" and the output is rated at: DC 200mA +/- 30mA. Even the 1500mAh battery in the little Baofeng radio takes more than 400mA on charge. I managed to find a cable that would enable me to charge the battery pack from my workbench variable metered power supply and even when the battery pack is only half discharged it is drawing a current of almost 800mA. So I think the charger supplied simply blew up! I'm just hoping the eBay seller will provide a more adequate charger as a replacement. Sure, I can use my existing HTC phone charger. It may even be more convenient than having separate chargers for the two devices. But it would be nice to receive what one paid for.

By the way, if you ever wondered what is inside those Chinese wall-wart power supplies, how come they are so light, here are some pictures of the innards of the one that failed.

The answer, it seems, is not much. Call me old fashioned, but I'm just a bit apprehensive about having just a handful of components between my equipment and the 230V mains!

It's a pity that this problem has occurred because I would have liked to have been able to recommend this battery pack to other users of APRSISCE on Windows Mobile. My initial test on the workbench suggest that this battery pack is more than capable of powering the phone with GPS and mobile data connection active during a day's outing. The battery pack itself seems well made and I would guess that it is probably supplied by its Chinese manufacturer in a nice box with instructions and an adequately rated charger. The trouble in this case would seem to be caused by a cheapskate eBay seller.

Saturday, May 21, 2011

6m magic

Today was the first really big Sporadic-E opening of the year. Six metres was wide open across the whole of Europe and Scandinavia. There was even a good 2 metre Sporadic-E opening in central Europe though no propagation appeared to reach the UK.

Yesterday I worked a string of Spanish stations on Six but that opening was not as good as today's. This morning's fun began with a contact with OK2IEN, then it was mostly Germans with a few other countries until round about lunch time.

I prefer the relaxing pace of Search and Pounce but when most of the stations you pounce on either have a pile-up and don't hear you or are S&Ping themselves and move away it's time to call CQ. It's not something I often do and it's almost more than my brain can cope with to talk to people while simultaneously typing into the computer their report, locator and call, but I quickly worked a string of stations and often had two or three at once replying to my CQ calls. This isn't something that happens often when you run a stealth dipole so you have to enjoy it when you can!

In the afternoon, for a break, I tried JT65A. A lot of the interest in monitoring 50.076 seems to have evaporated when conditions were flat but a few stations were on and I made three contacts using the mode, though none were DX I could not have worked on SSB.

Later the propagation seemed to have shifted North to favour Denmark and Sweden and I worked a number of stations from there, many at massive signal strength. In all I made 45 contacts today - probably more than I have ever made during a single day except when playing in a contest.

I love six metres - it really is the magic band!

Elecraft KX3 demo video

A chance to see the new Elecraft KX3 demonstrated by N6KR at the QRP ARCI "Four Days In May" convention in Dayton 2011.

Friday, May 20, 2011

A K3 in your pocket

Elecraft K3 with paddles attached. #hamradio #kx3 on Twitpic

Jeff Davis KE9V was among the first to post pictures from Dayton of Elecraft's latest announcement, a portable all mode HF to 50MHz transceiver - almost literally "a K3 in your pocket."

   Weight: 1.5 lbs
   Size: 1.7x3.5x7.4"
   KX1 form-factor
   internal battery pack & charger
   internal wide-range ATU
   new adjustable, attached keyer paddle

...and a K3-like front panel, including the same LCD.

I want one!

PLT debated in parliament

The issue of interference to short wave from power line networking devices was debated in Parliament yesterday. You can view the televised debate here. It's quite long, but worth watching if you can spare the time.

If you don't, here's a summary: The only complaints are from a few hobby radio amateurs and the number of complaints has been too few to justify banning a technology that brings potential benefits to millions of homes.

Other points: "Hobby radio amateurs are not legally entitled to a completely clean radio spectrum", and "no specific limits on interference levels have been set so that radio users can adapt as the use of PLT technology evolves." It is also projected that the number of installed PLT devices will quadruple by the year 2020. So this spectrum-destroying interference will be coming soon to an antenna near you!

I'm afraid that the writing is on the wall for amateur radio. In today's world, the only things that count are money and big business vested interests. There are too few radio hobbyists to count at the ballot box and they don't contribute anything to the country that can be measured in financial terms. So we are just going to have to "adapt" to increasing interference levels by giving up hope of receiving weak signals, confining our activities to quiet portable locations, or using modes like D-Star which are interference-free once the signal level rises above the noise threshold.

I think we just saw a death sentence passed on our hobby!

Tuesday, May 17, 2011

PLT a threat to British intelligence gathering?

A report produced for the British intelligence gathering organization GCHQ claims that noise from power line networking devices is causing a detectable increase in interference at its monitoring stations and could adversely affect its operations. The report, which can be found on the website Ban PLT, was originally released by GCHQ's Director of Engineering and Technology but has since been disowned by GCHQ which now claims it contained "inaccuracies." The government organization also forced the online tech news journal The Register, which published an article containing details of the report, to remove the author's identity from the article using measures designed, ironically, to suppress information that could be considered a threat to national security. So much for freedom of speech.

Ofcom meanwhile continues to deny that PLT devices cause a problem, stating that there have been "only" 272 complaints of interference (all from radio amateurs) and that of 233 cases referred to BT all but one have been resolved so there is nothing to worry about. Has pressure been brought from on high to force GCHQ to disown the report which is embarrassing to BT which has a couple of million of the Comtrend PLT devices installed nationwide? It is blatantly obvious that Ofcom couldn't give a damn about the possible effects on a few hobbyists who don't even pay a license for the spectrum they use. But a threat to the country's ability to monitor the short waves to gather intelligence about potential security threats is something they would have had to take seriously.

Sunday, May 15, 2011

Inside the UV-3R

Many people have been buying the cheap little dual band Baofeng UV-3R handheld radios from China. Some people have been pulling them apart, such as Fabrice, F4AVI, who has discovered that it is really quite a state of the art radio.

Fabrice found that the VHF/UHF transceiver functionality is provided by an RDA Microelectronics RDA1846 chip. This is a single chip fully DSP based transceiver capable of covering 134-174, 200-250 and 400-500MHz and supports CTCSS, CDCSS and DTMF with an 8dBm on-board PA. The Band 2 broadcast FM receiver uses an RDA5802E chip, also from RDA Microelectronics, which is a single chip broadcast FM stereo tuner. The UV-3R doesn't cover the US 220MHz band, of course, nor is the FM broadcast audio in stereo. But future models might well do.

Some buyers of the Boafeng have experienced minor issues with their radios that suggest the quality control is not all it could be. Still, it is interesting to see innovative designs coming out of China. One can only wonder what next?

A birthday to forget

As you may have noticed, I have been experimenting with making software instruction videos. APRSISCE/32 has been the beneficiary of my attempts, but my real intention has been to make videos that would bring traffic back to the website that for the last few years has provided us with a living. For the core of the videos - and for APRSISCE/32 videos - the screen capture software I have been using (BB Flashback Express) is good enough. But I wanted to make the videos more professional by including shots of me talking to camera - which meant that I needed to buy a camcorder and get to grips with video editing software.

I ordered by post an AgfaPhoto camcorder which captured good quality video, though the sound level was low. I struggled with the supplied Arcsoft Total Media Extreme software. Eventually, and quite by accident, I found that my work laptop which is running 64-bit Windows 7 had on it a program called Windows Live Movie Maker. This is a brilliantly designed piece of software and easy enough even for me to use. Unfortunately I found that the audio level on the video made with the camcorder was much lower than that recorded by the screen capture software. I tried reducing the level in BB Flashback to match that of the clips filmed using the camcorder, but once the video was uploaded to YouTube the audio was much quieter than other videos and even with the PC speakers turned up to the max you could hardly hear it.

Olga made a test clip using the video feature of her digital camera and the audio on that was much louder. So yesterday we decided the camcorder must have a fault and emailed to the supplier saying we wanted to return it. Not wanting to waste time we then went to Argos and bought a different camcorder, this time one from Hitachi, which had received good reviews. You can imagine the sinking feeling when, after waiting for the battery to charge up, we tried it only to find that the recorded audio level was no louder than on the Agfa.

I felt out of my depth, clueless with no idea what to do. Other people managed to upload videos to YouTube with speech you could hear - why was I finding it so difficult? I asked in a couple of familiar ham radio forums if anyone had experience of this and could offer some advice. One person explained how to change the audio level in Windows Live Movie Maker, but as I had already found, the volume slider was at maximum in the video clips and the only direction I could adjust the audio level was down. Few people seemed to have experience of using camcorders, most using smartphones or other pocket devices to make their YouTube submissions, which would not give the HD quality I was hoping for.

Olga, trying to be helpful because I was getting stressed, found what she thought was a Hitachi support forum. Twelve Hitachi technicians were online waiting to answer my questions, the site claimed. I wrote my question and immediately received the response that this had been passed to someone who was an expert in this particular field and I should pay £12 for an answer by email or £18 for a consultation by phone. Ready to try anything at this point, I handed over my credit card details, only to find that this was not Hitachi support at all, but some generic advice service claiming to answer all kinds of questions. More than 12 hours later we have not received any answer for our £12.

Eventually I stumbled upon a workaround. The Hitachi camcorder creates AVI files (unlike the Agfa whose video files are MOV.) Google found several answers to how to increase the audio in an AVI file, which suggests this is a common problem. Many of the answers were couched in gobbledygook I didn't understand, using terms like "demux" that mean nothing to me. But eventually I found a "how to" procedure I could follow. It involved using a free utility called VirtualDub to rewrite the AVI file after processing and increasing the level of the audio track by 12dB. Even that didn't work until I had visited a dodgy looking site and downloaded an iffy looking unofficial codec for the H.264 video encoding used by the Hitachi.

So I have a solution to the problem, though it's a bit of a cumbersome one involving processing every video clip before I can start to assemble them in Movie Maker. To arrive at this point I have ended up buying two camcorders the first of which is probably not faulty as we first thought (it being unlikely they both are.) and been suckered into paying £12 to an internet scam site. This is not to mention the hours spent in front of the computer feeling frustrated and helpless on what was actually my birthday. Certainly not a birthday I particularly want to remember.

I think I'm getting too old for this tech stuff. I wish I could retire somewhere and keep chickens or something that did not require the use of computers at all. You would think that making home videos was something lots of people would want to do. Why is it so difficult?

Wednesday, May 11, 2011

Home-build D-Star radio

Years ago, after I built my Elecraft K2 I had the idea that I would only use home-built radio equipment. However I found that it was no longer possible to buy a kit to build a 2m FM radio. This afternoon I visited a site mentioned by Tim, G4VXE in his latest blog posting and was intrigued to find that a Dutch group is working on a design for a VHF/UHF transceiver kit. Not only that, it is apparently being developed in consultation with Elecraft and is built into an Elecraft EC-1 (K2) enclosure!

The basic kit will be for an analogue FM transceiver with modules for 2m, 70cm and 23cm (it isn't clear to me whether you must choose one of these bands or whether you can fit all of the modules.) But with the addition of another module it can also become a D-Star transceiver!

Now I have never made any secret of my dislike of D-Star, mainly due to the fact that one manufacturer has a monopoly on the provision of radios. But a home-brew D-Star transceiver that doesn't require you to buy anything from Icom and would sit neatly alongside my K2 in a matching enclosure could just be the thing that makes me swallow my objections. Yes, it will still have an AMBE chip containing the proprietary codec. But most of my radios contain chips with proprietary firmware so I don't think that's a good enough reason for continuing to avoid D-Star.

New video: Interfacing APRSISCE/32 to a radio

I have just uploaded a new video to G4ILO's YouTube channel showing how to set up the APRSISCE/32 software to connect with a GPS and a TNC or radio. In the video I actually set up a connection between the software and a Kenwood TH-D72 and you can see and hear packets being received by the radio.

I also cover how to set up a connection with a GPS and how to use the AGW Packet Engine which allows you to use a soundcard as a packet modem.

Another eBay dud

It's the same on 433MHz as well.
In fact I couldn't find any frequency at which this so-called antenna is resonant!

Tuesday, May 10, 2011

Soaked through on Gowbarrow Fell

I'm finally eligible to claim one of my own WOTA certificates! This morning I made a contact with Phil G4OBK/P on Souther Fell and thereby completed working all of Wainwright's Northern Fells.

Phil had preannounced his intention to visit Souther Fell on the WOTA website, which was the last one I needed. This fell is blocked by higher mountains so I can't work it from home - I would have to get to a good vantage point. I could have driven to a suitable spot, parked and waited for Phil to appear but I decided to make the contact from a summit. The weather forecast was for rain, however, not the kind of conditions I normally choose for an activation. Out of the rucksack came the antenna mount (so I could use the waterproof rucksack cover) and the APRS radios (too expensive to risk getting wet.) The rig for the day was the Motorola GP300 with the base loaded Nagoya half wave telescopic.

The weather lived up to the forecast. By the time I reached the summit my boots had taken on water from the numerous puddles and long wet grass I had to traverse to reach it. My Goretex waterproof was letting in the rain, too. Only the inside of my rucksack remained dry. The views from this summit can be spectacular, but today was no day for a camera. So no photos. Instead, I'll link to a page that has some pictures of what I could have seen on a better day.

I had to make several calls before I could raise anyone. Finally Malcolm M0XAT heard me. Next the Penrith duo, G0TDM and G4WHA, and then Colin G4UXH and Sue G1OHH from "down south" who were both at good signal strength. I then had a bit of a wait before Phil arrived on summit and began to call. I passed the time trying to wring the water out of my socks.

Mission accomplished I headed back down to the car, home and a hot bath. The radio and antenna are now in the hot water tank cupboard drying out. My boots will probably take a bit longer.

Friday, May 06, 2011

Installing APRSISCE/32

I have been experimenting with ways to make software tutorial videos for YouTube (for business reasons). For a test, I thought I would make a video showing how to download, install and initially configure Lynn KJ4ERJ's APRS client software APRSISCE/32.

I don't think anyone would give me a job as a TV presenter but I don't think it is too bad for a first attempt, working without a script off the top of my head. If you think it would be useful to encourage people to try APRS or Lynn's program, please feel free to share the video.

I used the free BB Flashback Express software to create the video. I did try the open source CamStudio but it wouldn't recognize my PC's webcam and generally felt a bit amateurish compared to the BB software. I may consider forking out for the full version of BB Flashback so I'd appreciate any comments from folks with experience of making software videos.

Thursday, May 05, 2011

Baofeng in my shirt pocket

Only a few days after I had ordered the little Jin Ma Tong JMT-227 145MHz transceiver from China, news began to appear of a new miniature Chinese transceiver from Vero Telecom called the UV-3R which was a dual band (136-174 and 400-470MHz) transceiver. Eventually these began to appear from eBay sellers under the Chinese brand name Baofeng. The price was an astonishing £25 plus postage from Hong Kong. I ordered one from the seller hk360radio and it arrived in just over a week.

The Baofeng UV-3R comes in a colourfully printed box. Together with the radio the box contains the battery (Li-ion 3.7V 1500mAH), a charger with two-pin socket and adapter for UK mains sockets, two antennas (one for VHF and one for UHF), an earpiece/microphone similar to a mobile phone hands-free kit and a manual written completely in mostly pretty good English. There is also a blue carrying strap carrying the seller's name which is so cheap and nasty it is unlikely anyone would use it.

Not mentioned in the manual's list of included accessories but also supplied was a cradle that can hold the radio while charging the battery externally. Why you should wish to do this when you can charge the battery installed in the radio I have no idea. There are no charging contacts on the radio, you have to charge it by inserting the small barrel connector into the socket in the side or by taking the battery out. There is also a short cable with one of these barrel connectors on each end, the purpose of which no-one figured out yet.

The UV-3R makes the JMT-227 look a quality product. This is the first new electronic product I've had that didn't come with a peel-off protective film over the display. The plastic casing is extremely thin and the plastic belt clip that can optionally be attached looks as if it would easily break. To be fair, the flimsiness of the Baofeng may not be due to cheapness but to save weight. The radio is extremely small and very light, just 125 grams (5 oz) with battery inserted and antenna attached.

The provision of two separate antennas for VHF and UHF may be a cost saving measure or it may be for efficiency reasons (a single band antenna is usually more efficient.) However it is not convenient for a user who wishes to make regular use of both bands. The antenna connector is an SMA female, as used by all the Japanese ham radio manufacturers. Frequent changing of the antenna will result in wear of the connector and ultimately a poor contact as the centre pin of the antenna rotates in the socket. Some eBay sellers are now supplying this radio with a single, dual-band antenna. This is something to look out for when buying.

I had originally intended fitting an SMA to BNC adapter to the Baofeng as I have with all my other handheld radios but the UV-3R is so small and light that it seems inappropriate. I doubt that the radio is ruggedly enough constructed to take the stress of using one of the larger BNC antennas in any case.

Confusingly, the rotary switch on top of the radio must be pulled up before it can be rotated. Once you have realized that, the UV-3R is easy to use and easy to program the simplex channels and local repeaters into the memories by hand. There is free programming software available on the web. Programming cables are becoming available to buy on eBay but it isn't necessary to use the software, unlike with early models of the UV-3R which had very limited menus that did not allow the changing of things like step size or power level except through the programming software. (This is something to bear in mind if considering buying a used one.)

But this radio is evolving rapidly. The manual that came with mine describes 12 different menu settings but the radio actually has 18. Every setting you would want to change can now be set through the keypad. The settings are also stored in the memories - even the selected power level, so that I can have the radio use low power whenever I use it to communicate with my Echolink node. Perfect!

The one thing it does not seem to be possible to do without the software is to program cross-band splits, such as listen on UHF and transmit on VHF. This could be useful for working FM satellites. But I am not very bothered about this.

All the usual RX and TX tones are supported for repeater access. A 1750Hz tone burst is generated by pressing PTT + VOL. The radio also receives Band 2 FM. The quality is not very good, but on the plus side FM reception is interrupted if a signal is received on the currently selected amateur frequency.

The performance of the little radio seemed to be well within spec. On a fully charged battery the output power on 2m was 2.6W while on low power it was 320mW. (At 433.50MHz the respective measurements were 2.4W and 1.2W.)

The sensitivity is also excellent. The box and some advertisements claim the UV-3R uses DSP. As no schematic is available I have no idea. All I can say is that the received audio is very clear and pleasant and that the signal to noise ratio receiving a distant repeater on the UV-3R with its short VHF antenna was better than on the Kenwood TH-D72 with its dual band antenna standing in the same place.

Newer versions of the UV-3R including this one now have an S-meter on receive, though it works in coarse steps. I also checked the strong signal handling performance of the receiver the same way I did recently with my other hand-held transceivers. It was on a par with the VX-8GR and the JMT-227, at the poor end of the spectrum.

The transmitted audio is very good, if slightly lower in level than some of the ham rigs. One local said my audio sounded "just like my normal audio." The LED on the front of  the radio is supposed to glow red on transmit and green when a signal is received. Mine does not glow red, although the S-meter goes full scale to indicate power out. This appears to be a fault, but not one worth sending the radio back to Hong Kong to fix. However, this perhaps tells us something about the level of quality control you can expect for this price.

I have recorded an audio sample off-air, together with one of the Kenwood TH-D72 for comparison:
The earpiece/hands-free mic supplied with the radio is not useful. I had some trouble with the audio but the main problem is that after you press PTT the radio locks in transmit. This appears to be due to RF feedback into the earpiece/mic cable as it doesn't happen on the low power setting.

Using the supplied VHF antenna I can access from indoors a repeater 50 miles away. Not bad for such a tiny radio running 2 - 3 watts. Several people who have bought the UV-3R have commented favourably on the performance of the supplied single-band antennas. I tested the VHF antenna and found an extremely sharp response curve with a perfect 1:1 SWR at about 143.5MHz. At 145MHz the SWR was 1.5:1. The antenna has a high Q which no doubt accounts for its surprisingly good performance for its size. It's a pity the resonant point isn't exactly on 145MHz but that would be difficult to achieve with a mass produced antenna.

It isn't perfect, but all in all I am pleased with the tiny little Baofeng UV-3R - for the price. However there are indications that where quality is concerned you are getting what you pay for. If I was a UK dealer thinking of importing a batch to sell I'd think twice. I think fussy British consumers would send quite a few back because of niggling faults like the non-working TX indicator or the problem with the headset/mic. But if you don't mind taking a bit of a gamble on buying a radio from Hong Kong then the UV-3R would be a good bet for £25.

Tuesday, May 03, 2011

Dodd [LDW-174] all to myself

The weather forecast suggests that the fine spell we have enjoyed for the last few days - which has caused the G4ILO shorts to be brought out of the wardrobe unusually early - is going to end soon. So I thought I would try an activation this morning of the small summit of Dodd, LDW-174 for Wainwrights On The Air. Being a tightwad, I didn't want to pay the Forestry Commission's exorbitant charges to park at the visitor centre so I parked off the road at a spot about a mile north of the official car park. I'll happily walk an extra two miles to save £6.50!

I was afraid this well-known parking spot would be full but in fact there were only two other cars there, a silver Nissan and an old BMW that was very dusty and looked suspiciously as if it might have been there a while. I set off along the path and had hardly walked a few paces when I saw some car keys in the undergrowth beside the path. "I bet they are BMW keys" I thought to myself as I picked them up and sure enough they were.

Now I had a dilemma. Perhaps someone had dropped their keys and would be coming back to look for them, so I should leave them where they were. It was just a gut instinct that made me suspect the BMW had been stolen and some thief had left it in this quiet spot and thrown away the keys before switching to another car. If it wasn't a stolen car, surely it soon would be if I left the keys so close to the vehicle itself. So I decided to walk to the visitor centre and hand the keys in, explain what had happened and suggest they called the police to investigate.

This I did, before beginning the ascent of Dodd up the forestry road. It is a rather dull plod until you reach the col between Dodd and the Ullock Pike ridge and the path curves round Dodd's conical summit until this view over Derwentwater opens up. Then it is another short upward plod until you reach the summit (top picture.)

As I reached the higher altitudes it was clear that the stiff cold wind that has been a feature of the entire weekend and made conditions a lot less pleasant than the photos suggest was still with us. The WOTA Pole was still broken (and probably won't be repaired) so in its place I was using my new rucksack mounted telescopic 5/8 vertical. This is the old telescopic 5/8 BNC antenna with a new more robust whip fitted to the spring/loading coil. Because the weight of the whip makes the spring bend over it is encased in a piece of plastic electrical conduit which is Araldited to the base of the telescopic whip. This fits into the base section of conduit using one of the famous fragile jointing pieces. A female BNC plugs into the BNC base of the antenna, with the coax and a 19in pigtail counterpoise. This gave a perfect 1:1 SWR at 145MHz when tested at home using my antenna analyzer. It fits nicely in the rucksack with the telescopic whip sticking up above my head, the ultimate fashion accessory for the keen WOTAphile.

The radio was the Kenwood TH-D72 stuck on my belt. The headset I first tried on Carrock Fell proved itself once again, both in helping me to hear the other stations in the howling gale and in keeping the wind noise out of my audio. Regular readers can probably detect a trend here. I think the Kenwood is finally coming into its own as my APRS radio of choice.

I called CQ WOTA a couple of times, with no replies! Was this going to be a failed activation? Eventually to my great relief Mark MM1MPB came back. He gave me only a 5 by 5, which I improved to a 5 by 9 by walking a short way to the other side of the summit. I was concerned that perhaps something was wrong with the antenna so I swapped to the Nagoya NA-701 short dual band flexy-whip and Mark gave me only 5 by 3 so the 5/8 seemed to be doing its stuff. Dodd is quite a hemmed-in summit and although I could see across the Solway to Scotland it's possible that the path to Annan was blocked by the Ullock Pike ridge and the northern flanks of Skiddaw.

A few more calls and I was pleased to be answered by Colin G4UXH in Milnthorpe who had noticed the website spot placed by Mark, and then Steve M0IGG from Walney Island. Both stations were beyond the southern boundary of the Lake District and so at a fair distance. Clearly I was getting out, just not many people were listening. I also worked M6BDV/P on Little Mell Fell for a summit to summit contact, who confused me at first by using the call MW6... his home area being Wales. But that was it. None of the Workington mob or the Penrith crew. I guess everyone was WOTAed out after all the activations over the weekend.

I didn't even see another person on the summit, which is quite unusual. Not that I minded that at all, in fact I always prefer to have a summit to myself than have hordes of people wondering what I am doing.

The views as always from Dodd on a clear day were stunning. But it was damn cold no thanks to that icy wind, so I was pleased to pack up and head back down to the car again. The BMW had gone by the time I returned. How it came to be there with its keys tossed in the undergrowth will probably forever remain a mystery.

Sunday, May 01, 2011

Life on 6m

The 6 metre band is showing signs of life, as this map of WSPR activity from this afternoon shows.

However, some of the traces on the WSPR application screen look a bit odd.

I don't claim to be an expert but I think what I am seeing is the result of doppler shift on the signals being reflected by fast-moving Sporadic-E clouds. In several cases what seems to be a trace has not been decoded.

I've said this before, but I wonder if WSPR mode with its 110 second transmit periods and tiny frequency shift encoding is really suitable for detecting Sporadic-E propagation. But no-one has ever commented on this, leaving me to wonder whether they think I'm an idiot who doesn't know what he is talking about or whether nobody knows.

The digital mode most people seem to use on 6m is JT6M, however this entails using the WSJT program which I find rather confusing. I'm interested in trying JT65A but I'm not sure if it is any more suitable than WSPR for this type of work.

In the absence of any expert advice I'm going to try JT65A using a dial frequency of 50.276MHz. With the JT-Alert accessory to tell me when anyone replies I can leave the rig calling CQ whilst I am otherwise occupied. It will be interesting to see what we can work on 6m with the JT65A mode.