AmateurRadio.com

My gardener XYL Olga has been waiting for rain as eagerly as I have been hoping for a Sporadic-E opening on 2m and today she got what she hoped for. As I was shack-bound I decided to hook the IC-910H up to the computer.

A few days ago I noticed to my amazement that the accessory connector on the IC-910H is exactly the same as the one on the FT-817. I could have simply used the interface I used with the ‘817, except that I had shortened the serial cable to make it the same length as the audio cables when used with a USB to serial adapter. My new PC has two real serial ports one of which was earmarked for exactly this purpose so I had to make up a new, longer cable before I could get started.

On the audio side I needed to use a USB audio “dongle” as the on-board sound card is used by the K3. I already use a Daffodil USB sound adapter for the computer audio. The dongle I used for the IC-910H is an even cheaper, more basic one than the Daffodil and I had purchased it to make an interface for my Echolink node. It appears to be satisfactory for that. Hopefully it will also be good enough for 1200baud APRS packet using the AGWPE sound card software as well. I doubt that it would be good enough for any kind of weak signal work like WSPR, as I observed a few weeks ago that the Daffodil adapter could not reproduce my recordings of weak CW bounced off the Moon from Arecibo. But I don’t plan on doing EME or even WSPR or PSK31 on VHF anyway.

I set up APRSIS32 with the AGWPE software so I will be able to run an APRS gateway again when not needing the VHF radio for any other purpose. This may be useful as there seems to be an increase in APRS activity in the area. As well as Colin 2E0XSD getting set up on RF I have tracked G1TGY driving around the area. I’m not sure if I have the audio levels correct as I haven’t heard any APRS to see if I can decode it and APRSIS32 doesn’t support transmit through AGWPE yet.

I also installed the Echolink software on the shack computer and set up my Echolink node / hotspot. This is a personal node operated under the remote control provisions of my license so it is a bit wasteful that I have to generate 5W or RF – the minimum the IC-910H will go down to – and then dissipate it all in a dummy load to stop it being heard outside my property boundary. However it is nice to have the node available again as my back is playing up a bit today and it enables me to do some ham radio from a reclining chair downstairs or even lying on the bed if I need to.

Whilst setting up Echolink I noticed a conference called *QRP* which I hadn’t seen before. I see that several QRP bloggers have been trying Echolink recently so perhaps we could use this conference for an occasional get-together? I’ll connect to *QRP* more often over the next few days to see what if anything goes on there.

Colin, 2E0XSD, raised an interesting question this afternoon in the Wainwrights On The Air forum when he asked what the rules were regarding making contacts using APRS. I confess that I hadn’t thought about it and haven’t come to a conclusion at the moment.

For those who think that APRS is merely a way of using ham radio to transmit position reports that can be received and tracked I should explain that it is a lot more than that. One of its best features, if one that is not all that widely used, is the ability to send text messages to other APRS users. For example, if you see someone’s position on the map and would like to contact them on the radio you could send them a message to ask whether they are on the air and what frequency and mode they are using.

You could use APRS text messages to exchange exactly the same kind of information with another station that you might exchange in a normal digimode contact – signal report, name, QTH, locator and so on. This could arguably constitute a valid contact. But most of the time APRS users are not in direct radio contact with one another so the messages may be passed with the aid of digipeaters: stations that receive an APRS packet and rebroadcast it. Even more common these days is the use of internet gateways (IGates) that route messages between APRS stations via the internet. There are also an increasing number of APRS users who use mobile devices and the cellular network to send and receive APRS. So I have come to regard APRS as a kind of hybrid system that is not purely amateur radio and I do not regard conversations held using APRS messaging as radio contacts in the sense that I would log them, QSL them or use them to qualify for an operating award.

But that’s just me. If two people exchange APRS messages over RF with no digipeaters or IGates involved, is there any reason that this should not count as a contact?

I must confess to having mixed feelings about APRS. When I first found out about it I thought it was an extremely useful system and I still do. My wife Olga worries when I go walking in the hills on my own and likes being able to see where I am at any moment on a map on her computer. If I don’t return she will know my last position and could send someone to look for me. And it is a useful way to alert WOTA summit chasers to the fact that you are approaching a summit that you are going to activate. But I quickly became disappointed when I discovered that this functionality could not be achieved if you relied solely on amateur bands RF.

Then I discovered Lynn KJ4ERJ’s program APRSISCE which can run on a data enabled mobile phone and connect to the internet-based APRS infrastructure and I was able to get the kind of usage I envisaged from it. (In this part of the world even the cellular data coverage isn’t 100% but it is still a big improvement.) But although I now use the mobile client whenever I am on some radio related outdoor activity, I found that using an internet connected client destroyed the radio interest because I could now communicate using APRS with anyone, anywhere with the same kind of reliability as sending an SMS or an email.

APRS is too useful to hobble it by insisting on using only amateur bands RF as the transmission medium. Because of that I don’t feel it can be used to make contacts or QSOs in the sense that is generally accepted within the hobby and I’m not convinced that it would be right to make an exception for message exchanges that are “direct.” But I’d be interested in other people’s opinions on the matter.

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.

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!

I got fed up rather quickly with the new digital mode ROS. On 20m it is a zoo, with everyone calling on top of everyone else and very little being worked. I tried it on the advertised frequency on 10m and got nothing, despite the fact that DX is being heard via WSPR on that band.

What this proves, I think, is that it isn’t enough to be clever enough to come up with a new super duper digital mode. That might be fine if you keep it between you and your fellow experimenters. But if you release it to the masses you need to have a plan for how it will be used given the expected number of users and how you will educate people on how to use it.

If you develop a weak signal mode you have to take account of the fact that a lot of people don’t have a QRP mentality. They can’t see the point in trying to make a contact with low power when they can simply crank the power up. And if they do that, they miss the whole point of the mode and ruin it for everyone else. If a mode cannot be used on a particular band for its intended purpose because of overcrowding or interference perhaps it would be best if it was not used at all.

Instead I decided to use my FT-817 lash-up to try the APRS Messenger APRS-over-PSK63 software instead. Whilst doing that I noticed on the waterfall a strange signal almost spot on the 10.149.70 frequency used for APRS over PSK63. It looks like an upside down three pronged fork but comes in two sizes, one wide and one narrow. It starts sounding like a single tone, and then widens to a chord of three distinct tones. But what is it, why is it on that frequency, and are my PSK63 beacons interfering with it?

Chris, G4HYG, has just released a new Windows program called APRS Messenger which supports APRS messaging using the PSK63 mode. Various experiments made in the past suggest that this could give better reliability at low power levels than 300 baud packet which is normally used on HF. APRS Messenger also functions as an Internet gateway so any error-free packets received over HF are sent to the APRS-IS network.

An unfortunate limitation of the program at the moment is that it will only talk to the “default sound card” which on most Windows computers is the one used to play system noises, listen to Internet audio and video and so on. So I am unable to use it with my K3 at the moment. For test purposes I have connected my HB-1A QRP transceiver to my 30m antenna and fed the headphone output into the mic socket on the front of my PC.

I have decoded a few packets already, though many seem to contain some corruption. I am wondering why the little-used QPSK63 mode was not used for this application? As I understand it (and I could be wrong) QPSK63 takes up the same amount of bandwidth but incorporates some forward error correction that improves the likelihood of good copy compared with plain PSK63.

Chris has apparently agreed to talk with Lynn, KD4ERJ, about the possibility of making APRS Messenger work with APRSIS32. The possibility of using Lynn’s full-featured APRS client to send and receive APRS over HF using PSK is quite exciting.

By the way, if you are wondering why the screenshot shows a Mac program the reason is that I’m using an OS X theme under Windows XP!

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In this episode, we address listener feedback and comments, and then in a burst of inspiration invite listeners from the chat room to come onto the program for a lively and very fun roundtable discussion. Topics were varied, from portable antenna design, to life without Red Bull; from the HAARP VLF array in Alaska to D-STAR, PACTOR and other digital ham radio communication modes. And since I was on meds and Richard was off his, things got a little crazy towards the end.

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