Monday, August 31, 2009

APRS in the Lake District

I've been playing around with APRS and discovered a Java application called javAPRS - originally written by Steve Dimse, K4HG and now maintained by Pete Loveall AE5PL - which can be used to display live APRS position data on any map of your choosing on a web page. This was too good to resist, so I have added an APRS Spots page covering the English Lake District to the Wainwrights On The Air website. The only problem, and it's a bit of a major one, is that few if any of the people who go up mountains in the Lake District with a ham radio actually use APRS, and very few fixed stations in the area monitor the APRS channel 144.800MHz to receive spots and post them to the Internet.

It seems to me that one of the problems with this hobby is that we are constantly reinventing the wheel, instead of making use of those we already have. So for example we have half a dozen MFSK-type data modes when just one would simplify things for everyone. Similarly we have D-Star now muscling in on territory that was the preserve of EchoLink and APRS. By fragmenting the user base for this type of system into two incompatible camps the net result is to make each of the technologies half as useful as they could be. So why not encourage more use of the things we already have instead of coming out with new ones?

Technologies like APRS need to be widely used and achieve a critical mass in order to reach their full potential. From where I am in the back of beyond it's a bit like being the guy who invented the telephone and then found he had no-one to call because nobody else had one.

Sunday, August 30, 2009

Signals from space

The September issue of the RSGB's excellent RadCom was awaiting me on return from holiday. It contained an article about two new atmospheric research micro-satellites, Castor and Pollux, which transmit telemetry using AX.25 packet in the 2m band. This piqued my interest enough to try to have a go at receiving them.

The tiny satellites consist of two 19in. diameter spheres separated by an insulator, which form the two halves of the 2m antenna. There is a super photograph of the two satellites, taken shortly after they were launched at the end of July from the Space Shuttle Endeavour, which can be found on many of the websites that carry information about the launch.

My first problem was to find some way to decode 2m packet. I used to have a copy of MixW, but I had not used it for a couple of years and when I tried, it crashed immediately after start-up. I deleted it and tried installing a new copy but it came up in German! I also realised that I no longer had the registration code for it. So I decided to look for another solution.

I found it at SV2AGW's website. I installed the AGW Packet Engine (AGWPE) and then AGWMonitor to receive the telemetry. Setting up the Packet Engine to receive packet using the sound card is not very intuitive, and in fact I gave up the first time and spent another couple of hours trying to find a backup copy of my MixW installation, without success. Then I found an excellent step-by-step guide to setting up AGWPE with a sound card by KC2RLM that got me going. AGWMonitor requires AGWPE, and the trick is to put it into the Startup Programs option of AGWPE so that the monitor is launched directly after you start the engine.

I used the N2YO Live Real Time Satellite Tracking website to find out when the satellites are visible from my QTH. This shows that they currently pass over very late at night and during the small hours of the morning, when I am asleep, so I left everything on overnight to see what I could receive. The first time, all I got were a number of packets from the International Space Station, RS0ISS.

This morning, I received one packet from Pollux-1 and one from Castor-1 (which confusingly identifies itself as KD4HBO-1 in the packet header.) Just for fun, I decoded the packets using the telemetry decoders written by Mike Rupprecht, DK3WN - though to be honest, the information didn't mean anything to me. Captured telemetry should be sent to and QSL cards will be sent to anyone who submits data.

I also received many more packets from the ISS, which uses the same frequency of 145.825MHz. The result of this is that I have now become interested in trying to make packet radio contacts through the ISS digipeater!

What a great hobby this is! There seems to be no limit to the different things you can try to do with amateur radio!

Wednesday, August 12, 2009

My first meteor-scatter contact

I have been interested in meteors ever since, as a teenager back in the '60s, I and a couple of friends formed a small school astronomy club, joined the British Astronomy Association Meteor section and submitted meteor observations. So ever since I found out about WSJT, JT6M and its potential to enable even low-powered stations to make meteor-scatter (MS) contacts I had been looking forward to the Perseid shower. Unfortunately other matters took priority and I didn't think I was going to have a chance to try anything at all. But I did manage to leave the system on just receiving for a couple of times, and this morning when I saw CQ 236 PA4VHF being sent on 50.230 I could not resist tuning the K3 up to 50.236 and replying to him.

My PA4VHF G4ILO almost immediately produced a response of G4ILO PA4VHF 27 as you can see from the screenshot. It took a couple of minutes before the response to my PA4VHF G4ILO R27 of RRRR PA4VHF was seen on the screen. I replied with 73 G4ILO and immediately saw 73 TNX RRRR PA4VHF come back. That's the last message in the sequence, but I sent a couple of periods of 73 TNX G4ILO for good measure. Then I switched back to 50.230 and saw PA4VHF calling CQ again. It was all over in about six minutes. Not bad for 50W to a dipole using the (allegedly deaf on 6m) Elecraft K3.

I think that's probably my lot for this shower, but at least I can now say I've worked MS! Our contact is already in PA4VHF's 2009 6m JT6M Challenge list; I was a new grid (IO84) for him. Nice!

Friday, August 07, 2009

Why I hate PayPal

Many radio amateurs have a PayPal account. It's a convenient way to send and receive payments for equipment advertised on the web, and it's often the only way to pay for kits and components from QRP clubs and so on. When it works, it's great. But consider what can happen when something goes wrong.

Supposing that the person to whom you wish to send a payment makes a mistake when typing their email address. Or suppose that you mis-type it into PayPal yourself. You might think that PayPal would reject the transaction, with a message such as "This email address is not registered with us." But no. PayPal sends a message to that address saying "Someone has sent you cash. Please open an account with us to claim it." Meanwhile you and the person you are buying from both sit waiting for something to happen until one of you sends an email to the other to ask why nothing has.

If the address you sent the money to doesn't exist, PayPal doesn't detect this. And it allows 30 or 60 days for the recipient to open an account and claim the money. When you realize the error, you can cancel the transaction. But PayPal only allows you to cancel if the recipient doesn't claim the cash. So it "freezes" your money until the 30 or 60 days are up. That means that you have got to find the money from somewhere else to pay the seller, and then wait until PayPal gives you the original payment back.

If the address you mis-typed happens to be a real email address, then the recipient may think that it's their lucky day. You will then have to fight with them to get your money back. PayPal is an accident waiting to happen.

If you are the "lucky" recipient of mis-sent cash then you can still lose out. Someone once sent me $108 by mistake. It turned out to be someone I had once exchanged emails with, so I guess my address was in their auto-complete list next to the intended recipient and they picked it by mistake. I didn't turn on the computer for a couple of days so I didn't realize this had happened until after the sender panicked. They tried to stop the payment before I had the opportunity to simply refund it and as a result I was charged $15 by PayPal for processing a charge-back. My attempt to dispute this resulted in no more than a series of automated responses. PayPal "support" stinks.

I currently have an amount of money "frozen" in my account because it was sent by mistake to a non-existent address. I hate PayPal.

Monday, August 03, 2009

Busy, busy

I'm going to be taking a bit of a break from radio this month. I'm going to be rather busy between now and the end of August, and if I do find the time for some radio activity I may not have the time or be in the position to blog about it.

However I did manage to find the time to finish the article describing my Wonder Loop. Enjoy!

Saturday, August 01, 2009

SSB a struggle

There is an IARU contest on this weekend and the thought occurred to me that this might be a good opportunity to try to make some SSB contacts with the Wonder Loop and FT-817ND. It started well enough on 20m when S53M came right back to my call and completed the contact without difficulty. A few minutes later DJ1AA was in the log - I had to repeat the exchange a few times and make sure he logged my call as ILO not LLO, but he got it in the end. But after that, nothing. One station copied me as G4LLO and gave up after failing to get the year of my license. Another heard that a G4 was calling, but that was all.

I think conditions must have been extremely poor. I cannot recall a contest where no stations were above S9 on the FT-817 meter.

I then decided to try my K2 to get a bit of extra power - 10W instead of 5W. But it was as if I was not there. I started to wonder if something had gone wrong with the Wonder Loop so I took the feeder from my multi-band dipole and plugged it into the K2's other antenna socket. But there was very little difference in signal strengths between the two.

While tuning around 40m I heard DJ2OD calling CQ on CW, so I plugged my Russian straight key into the K2 and called him on the Wonder Loop using 5 watts. He came straight back to my call, gave me a 579 report and we completed a QSO. No hassle, no frustration!

CW Rules!