Still very busy with work at the moment, but I was trying to get my APRS digi up an running at home again to see if I can fill in some of the holes left by the demise of GB2GP.
The rising cost of electricity means that I don’t want to run a PC all day just to perform the digipeater duties (I calculated the cost as 50p for 24 hours) as there are already three good I-gates in 2E0RNT, M0TEC and MB7UFF already.
I have been looking at using UIDIGI for some time and fortunately I got a prom blown by N1VG at Argent Data systems – the man who makes the open trackers. I finally got around to putting up a low co-linear in the garden last night and inserting a UIDIGI prom into my tiny 2. I had to reconfigure this a few times to get things going, but I think everything is now OK and I am now acting as a fill in digipeater again for North London. The antenna needs to go on the roof, to be really effective, but I have been saying that for months!
I shot off after VHF FD for two weeks on holiday in France. The first week was split between the North (near Calais) and a city break in Toulouse. The second week we had a gite near Pau and a hire car so I threw in my FT-60E, Opentracker+, puck GPS and a ¼ wave mini mag mount to see if things worked out there.
There were several issues learnt: the standard HT battery only lasts about 2 days , but I had two, so I covered most of our trips out and about (I didn’t take a charger to reduce the amount I was carrying). The 1300MAH lithium cells that I used to power the tracker and GPS also had a surprising short life but a recharge half way through covered that off. A final issue was setting up the transceiver/tracker. If I set the squelch to an appropriate level at the gite , out in the sticks, it was useless in town where the noise levels were higher. This meant the tracker thought the channel was busy and didn’t tx for long periods of time. Once I had worked this out and adjusted the squelch in town things were much better. Perhaps I also need to play with the software DCD on the tracker as well to avoid this in the future.
I checked aprs.fi on my mobile a couple of times and was surprised about the level of coverage I received. If you look for M0BPQ-12 on the db0anf site you will see some great tracks.
I see that this is all down to the efforts of the F5ZVO digi at La Pierre St-Martin, which is a ski resort in the mountains. There is no wonder it does such a good job when it is at 1700M ASL.
Looking at the data afterwards, I was also amazed to see that I was logged by EC1H-12 at a remarkable 464Km, also when I was up in the mountains. Not bad for a data mode, 5W and a ¼ wave whip on 2m..... Location, location, location!
Again a big gap between posts.
The radio scouting team dismantled the GB2GP shack last weekend and I have ended up with yet more kit to hide in the loft. Everything went smoothly, but there will be no radio activity from Gilwell until the LID is back running in March 2009.
The group has been offered a time step wx sat receiver and antenna though and we are investigating ways to put this up as a permanent demonstration station, perhaps coupled with a weather station. There are obvious possibilities for publishing data on the web or tying it in with a formal APRS Igate. I find the RSGB packet radio licensing forms baffling, so I may look for some help on how to move that forwards.
It is region1 VHF FD this weekend and the weather forecast is terrible! I am providing the computer network running n1MM and 3G cluster along with the 6/4m and 2m station for the Clifton ARS.
The 6/4m station will be my FT-847 running 100W on 6m and 25W on 4m to a dual band yagi at 10m agl (4 el on 6m – restricted section, 5 el on 4m low power section).
The 2m station will be my IC-756Pro, DEM transverter, linear amp, sequencer, preamp and 9 el DK7ZB at 10m AGL for the restricted section.
I might chuck in the Gilwell TS-200 to run on 70cm if we have enough operators!
That doesn’t look like much gear, but add in tents, poles, ropes, ac distribution, computers, networking, heliax, rotators and all the interconnecting cables it will fill the hire van. Never mind all the effort that goes into making it all fit together in the first place. This will probably be the last time I get so involved as it is becoming expensive and an awful lot of work! Anyone need a seasoned operator for VHF FD next year?
Over a month since my last post – if anyone is reading that is, but lots has happened on the radio front.
I now have a three element yagis for both 4m and 6m on a telescopic pole in the garden. I finished the rotator installation this morning. I only have one feedline at the moment, 35m of LDF4-50, so until I fit a relay I have to dash out, drop the mast and swap over the n-types. Not ideal, but at least I am on the air.
The miniVNA has been amazing to use during this process.
The 6m Moonraker antenna was picked up at a rally for £25. I can tell why – it was rubbish! The miniVNA showed that it was resonant on 48.250MHz. Fine for video, hopeless as TX antenna. A quick nibble of the DE with a plumbers pipe cutter and re-adjustment of the gamma match and it is now on 50.1MHz. I have made a number of QSOs via SpE but I am not confident of the design of this antenna, so I will have to model it to see what it is like. More news later
The 70MHz yagi is a DK7ZB 28opm design that I built two years ago. Martin’s website suggests that you mount an flange co-ax socket on the balun box to attach the feed line. I was rather worried about water ingress with this system so decided to use a flying lead and a cable gland instead. This made grounding the co-ax shield a real pain as the IP66 box I had chosen was a bit too small and made the system rather mechanically weak. Upon reviving the antenna, the balun assembly had shorted and I had to cut it out of the box and build a new one. If I build another DK7ZB design I will follow the instructions more closely or use a bigger box! I see that a couple of people are producing kits of materials for these antennas which makes life much easier as we can only get imperial sized materials in the UK.
Bad news on the radio scouting front as the GB2GP shack is to be demolished this summer. This means the APRS station will be taken out of service in July. I must do something about getting a vertical up at home to provide central London coverage. Perhaps radio will get a new home in the redeveloped Gilwell LID, but I am worried that it is no loner sexy enough. We are currently working out what do with all the equipment as it will need storing. More news as I get it!
Good APRS news is that G5YC is now active during office hours from central London. The RF noise is intense in EC1, but it seems to doing some use gating RF to INET. With a better antenna I am sure I can get better coverage.
I have also built a APRS portable tracker based on an open tracker and an FT-60E. The GPS I bought to go with it doesn’t work so I will have to steal the car based version when I go to Southampton tomorrow to see if it works.
Jobs to do this week are all centred around Region 1HF CW FD which takes place at the weekend. I am providing the full station for G3GHN/p and we will probably do the PW contest at the same time as not all the club can do CW at contest speeds.
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