Packet lives!

I thought packet radio was all but dead. Yesterday I heard Richard MM1BHO mention that there was a packet node in Scotland on 70cm at the same location as the GB3LA repeater which is a monstrous signal here. I asked Richard to tell me the frequency so I could have a listen. I wasn't optimistic about hearing anything as 70cm has always seemed a bit of a dead loss for me. I had to wait a while to hear anything, and when I did, I found the packet signal was 20dB over S9 which is the strongest signal I've ever heard on 70!

I then spent a couple of hours trying to sort out a way of receiving the packet. TrueTTY seemed like a good choice. It decoded the packets and displayed them on its screen. But I couldn't find any software that would work with its virtual TNC.

I also tried AGW Packet Engine in sound card mode. That, too, decoded packets, so I got the AGW Terminal software as well. But I could not transmit. The software keyed the PTT when it was supposed to, but there was no audio modulation.

Finally I bit the bullet, shut down the APRS gateway and put the Kenwood D710 into packet mode. I then set up AGWPE to talk with the Kenwood's TNC. That worked, and I was able to connect to the node whose call is GB7WD. I was wondering what to do next when Clive GM4FZH connected to me and I had my first chat over packet radio since the mid-1980s!

I'm afraid after all that time I have forgotten just about anything I knew about packet radio so I'm still pretty clueless as to what to do. I don't know how to set up a mailbox, or even where to set one up. There seems to be a shortage of material on the interweb aimed at packet newbies (or oldies like me where the onset of Alzheimer's has erased any memory of what we once knew!)

I think packet radio is something I will enjoy playing with again. I went back to AGWPE soundcard mode and found that the reason I was not getting any audio was because although the software says it uses the left channel which online references claim is the tip of the stereo jack, it was actually present on the ring. After resoldering the connector on the audio cable I was able to transmit packets as well as receive them, and G4ILO is now listening on the GB7WD frequency on the A side of my TM-D710 while my 2m APRS gateway is using the B side. There are just so many things to do in this hobby!

Sporadic-E on 6m

The first bit of live data I received from my APRS VHF propagation alert reflector was a warning of a possible Sporadic-E opening on six metres. I was rather surprised that there was Sporadic-E this early in the year, but I went to the DX Sherlock website and sure enough contacts had been reported between a station even further north than here and one in the Czech Republic. I then clicked on the map to see the actual contact details and was surprised to find they were WSPR spots!

I went to the WSPR website and sure enough the same signals were shown. I decided to fire up WSPR on 6m myself but by then the OK station had gone and no new spots appeared from anywhere.

I have been, and still am, somewhat sceptical of the value of WSPR in showing VHF Sporadic-E propagation. One of the characteristics of Sporadic-E, particularly at the start and end of the season or on the higher frequencies like 2m is that it is very fleeting. A signal can be there for one minute, literally, and gone the next. On the other hand, signals can be really strong when reflected by Sporadic-E. WSPR is designed for detecting weak signals under steady propagation conditions and uses a 2 minute transmit cycle during which the data is transmitted very slowly. It seems to me that what you want to detect Sporadic-E is a mode with short transmit cycles where the data is transmitted quickly, perhaps something more akin to the modes used for meteor-scatter. I wonder if K1JT could come up with something?

Nevertheless I am very interested in anything that helps to detect VHF openings that might otherwise go undetected. I plan on WSPRing more on the 6m band, as long as there are others doing likewise so there is a chance of being received!

VHF propagation alerts over APRS

I have just set up an ANSRVR notification group (the APRS equivalent of an email reflector) called CDGVHF. The purpose of the group is to alert interested subscribers in the Cumbria, Dumfries and Galloway area to possible openings on the 6m, 4m, 2m and 70cm bands.

The APRS alerts make use of the email alert service of DX Sherlock which sends alerts of possible band openings customized to the subscriber's location, based on DX Cluster spots and other reverse beacon information. I have set up a subscription to send alerts of possible band openings workable from the IO84 grid locator to a special email address on the G4ILO's Shack web server. Using a feature of the cPanel web hosting, the email is "piped" to a script written by me in the PHP language. This extracts the subject header of the email which contains a succinct description of the alert, shortens it as much as possible and then sends it as a message to the CDGVHF ANSRVR group, which then forwards it to all interested subscribers.

Why is this better than just subscribing directly to receive the alert emails? Because I can now receive the alerts on my APRS-equipped hand-held, which should greatly reduce the chance of missing a good band opening because I wasn't in the shack at the right moment.

60m WSPR using 500mW QRP

I have been beaconing WSPR using 500mW all day today. The KAT3 didn't want to repeat its trick of matching my multi-band dipole so the best SWR I could manage was about 1.8:1. I don't know how much of the 500mW ended up warming up the ATU or the coaxial feeder.

This is a shot of the WSPR propagation map taken just before 1800z today. As you can see, the 500mW is getting out pretty well. I think I have been received by all the G stations that have been monitoring at some time during the day, and a few others. And it was nice to see fellow bloggers Paul PC4T and Bas PE4BAS monitoring even though they can't transmit on 60m, and better still spotting me!

Just after I posted this, my 500mW was also spotted by LA3JJ!

First emissions on 60m

On looking through the mail at lunch time I saw that I had received a letter from Ofcom. My NoV permitting me to operate on the 60m experimental band had arrived!

Until now I hadn't been bothered about operating on 60m because I couldn't see how I could possibly find room for an antenna for that band. However a couple of weeks ago I heard someone activating a SOTA summit in the Lake District on 60m and was frustrated that I could not reply to them. So I decided to put in an application for permission to operate and here I am.

I don't have an antenna that is resonant on 60m so I tried tuning up my multiband dipole using the K3 auto ATU. After a lot of persuasion it managed to find an acceptable match on the higher frequency channels but it gave up on the lower ones. So I should be able to manage some activity on the new band.

Fortunately, the channel allocated for beacon and WSPR use is one of the ones I was able to match. And today just happened to be a 60m WSPR activity day. So I fired up the WSPR software and beaconed on 60m using 2 watts, increasing to 5 watts in the evening when propagation went long and most of the traces faded out. The 5 watts did me no good at at all, but my 2 watt signal was heard by 7 different G stations all around 400km distance from me plus F/G6AIG at 760km. I received 6 different G stations including G4ZFQ at 458km running 20mW, plus OZ1PIF (my best DX at 984km) and LA3JJ.

Tomorrow is QRP day on 60m when everyone is supposed to run 500mW or less. I have not decided yet how little power I will run but I will be WSPRing on 60m all day. Hopefully there will be a few more people who manage to spot me.