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Undecodable mode alert
September 7th, 2010 | 
Author: If you’re operating the PSK digimode on the weekend of 18th-19th September and suddenly find your screen full of PSK63 signals that you can’t decode, don’t be worried that there is something wrong with your radio or your computer. You are hearing the 7th CIS DX QPSK63 Contest 2010. Yes, it’s QPSK63, that mode you’ve seen on your menu and never been able to get a reply to when you tried it. If you were ever frustrated by this, now’s your chance to get satisfaction!
Starting at 1200UTC on the Saturday and continuing until 1200UTC the following day, the object is to make as many contacts as possible using QPSK63 (and only QPSK63) between stations in the Commonwealth of Independent States (known to many of us as the Former Soviet Union) and stations who are somewhere else. For more information see the contest website.
If you prefer SSB to digimodes, look for the upcoming 1st DX Esperanto Contest. It’s a contest for phone operators, where all the contacts must be made using Esperanto.
Amateur Radio Communications For Events
This year the club solicited volunteers for the event as usual, despite no need for amateur radio communications. A bit of a brewhaha erupted when it was asked just what would volunteers be doing. No one wanted to flip burgers or park cars, and rightfully so as radio amateurs want to communicate and are not called amateur car parkers or amateur burger flippers. One would think if the event organizers needed such people, they would naturally solicit volunteers from those who are interested in the athletic event itself, not radio amateurs.
Despite not being requested for communications, the morning of the event a few hams were stationed at the usual route checkpoints as in years past giving updates to each other. Three repeaters on two bands covering four counties were linked together resulting in a sequence of varying courtesy beeps sounding like a battle out of one of the Star Wars movies from the 70s. An amateur stationed on the route received a question from an event participant and asked net control for information. Net control couldn't answer the question as they had no one officially stationed at the event central command. Later in the event a ham reported to net control that there was an injured participant and an ambulance was needed. He was advised by net control to call 911 on his cell phone. After phoning 911 he reported back to net control that an ambulance was in route and gave information on the injured participant. He was then advised by net control to call the event organizer on their cell phone to relay the information.
I'm not an expert at providing communications at events, but having organized communications for several events for our club years ago, I learned a few things.
1. Insure event organizers are aware of just what your club wants to provide. You're an amateur radio club; your specialty is communications.
2. Clearly communicate to your club members exactly what their mission is for an event. Members don't want to just show up for an event and not know what they'll be doing for the next six hours in the hot sun.
3. Make sure your club members who are covering an event are taken care of. This means having their lunch provided, reasonable shifts, and event swag such as tee shirts or hats if other event participants are receiving them. Also, make sure they are called back in when the event is over and aren't left at their stations.
4. Provide value for the event participants and leadership. If what you're doing isn't providing value to others and is just entertainment for your radio amateur volunteers (i.e. "playing radio"), you shouldn't be there.There are some danger signs that should make you rethink your support of an event:
- Event organizers are calling you a week before the event rather than several weeks or months ahead
- Your group spends more time keeping the event running or doing things event management should have done (i.e. putting up missing signs for a race route, hauling trash, etc.)
- You have been asked to park cars or do other non-communications functions and event leadership doesn't understand the value of communications
- The event lacks a central control point or the event organizers aren't interested in the information you're relaying during the event
- Another group has been asked to support the event simultaneously and they have their own radios and frequencies (I had this happen at an event with a group of guys with FRS radios. An event participant was injured and 911 was called by two parties, and two different ambulances were dispatched.)
- The event lacks leadership or you have difficulty communicating with the event leader in the weeks leading up to the event
- You have increasing difficulty getting club members to commit to covering an event
Amateur Radio Communications For Events
Making my position clear
Observant readers may have noticed a change in the “strapline” in the header logo of my blog. It now reads “My position on amateur radio.”
The new strapline reflects more accurately what the blog is currently about. If you haven’t already realized, it is also a play on words. “My position” alludes to my present interest in APRS which is the subject of many of my postings. But it also makes it clear that this is an opinion blog; that I use this blog to express my thoughts on various ham radio related matters, to give my point of view without any obligation on my part for that view to be fair, balanced or uncontroversial.
So don’t expect any changes to the content, other than a gradual evolution as my interests move from one thing to another. I expect that I will still occasionally write on topics related to stealth ham radio operation, but I feel I have probably pushed things about as far as they can go in my present situation. Now it’s just a matter of waiting and hoping that I don’t experience the Final QRN that puts paid to my radio activities for good.
The best cheap sound card for digimodes
The popularity of web videos and podcasts means that most ham radio enthusiasts who want to use sound card digital modes no longer want to dedicate their computer’s built-in sound card for that purpose. The usual solution is to buy a purpose made interface such as a RigExpert or SignaLink (expensive but highly recommended by all who own one) or an external USB sound card. However a great many people claim that the cheapest USB sound card “dongle” costing just 99p on eBay is good enough. Take it from me, it isn’t.
I have had several online discussions bordering on arguments with self proclaimed experts who claim that the sound chip in these cheapo “dongles” is exactly the same as the one in a £100 SignaLink USB interface so the £1 dongle must be just as good. I have no idea if they are right about the chip. What I do know is that when I played back a recording of very weak CW using one of these devices all I could hear was noise. And when I tried to use one of these devices to decode a fast digital mode such as packet, I decoded nothing at all, not a single packet, even though I could see the signal loud and clear on the waterfall.
I have tried a number of these cheap devices. I bought two of the cheap thumb sized “dongles”. One I threw away after seeing the noise it introduced on the waterfall. The second I bought thinking it would be good enough for computer audio, which it was, but had to throw it away when it failed after a week. I also spent a bit more on a slightly fancier sound card “dongle” which I currently use for computer audio, but which still displayed the inadequacies on weak signals and fast data modes that I have mentioned.
Finally I tried the device pictured above. It doesn’t have a brand name but can be readily identified from the picture and is advertised on eBay as something like “USB 6 Channel 5.1 External Sound Audio Card For Laptop”. It costs around £8.50 including postage from China. It comes in a small extruded aluminium case, has connections for SP/DIF input and supports sample rates of up to 48kHz so it would probably be suitable for basic SDR use. It has decoded every digital mode I have so far tried it with. And it’s small enough to build into your own box to make a DIY SignaLink.
It comes with a mini-CD containing a Windows driver. This installs a small mixer/control panel application that loads in the task bar and provides the usual control over the various sound effects. I used one of the start-up program managers (Autoruns) to remove it and find that it works perfectly well for my purposes without it, just using the standard Windows mixer settings. This is certainly preferable to the Creative SoundBlaster USB device that some people recommend which allegedly installs 200MB of junk on your hard drive.
I think this is probably the cheapest external sound device that is worth using for sound card digital modes. I’d be interested to know of alternatives, but please don’t recommend something unless you have actually done A/B comparisons with a known good sound card using weak signals, fast modes and different software packages. I hate to think of the frustration some people must have experienced following the advice of the self proclaimed experts, buying one of the £1 “dongles” and wondering why they can see a trace on the waterfall and can’t decode it.
WOTA success
I think it’s fair to say the Wainwrights On The Air (WOTA) scheme has become a big success. At the start it was probably true that the main participants were existing Summits On The Air (SOTA) enthusiasts who appreciated the opportunity to make more of their Lake District excursions by activating the hills they would otherwise have walked past on their way to a SOTA summit. But recently several local amateurs have got started specifically in WOTA chasing and activating. There has even been a request for a list of the easiest Wainwrights to climb! There isn’t an award for that, but it does suggest that WOTA is encouraging people to get out on the hills who were not previously enthusiastic fellwalkers and I think that is one of the best possible outcomes for the scheme.
It’s a pity, though, that no-one offered to design a nice award certificate for the scheme, which the Workington Radio Club was then going to get professionally printed. The ones I made using a free online certificate maker and print on our cheapo HP multifunction printer (with expensivo ink cartridges) look a poor reward for all the time and sweat that has been expended earning them. I always have a fight getting them to print correctly anyway, so having some professionally printed certificates would have saved me a lot of hassle.
The mystery of the failing filters
A couple of months ago I acquired a Kenwood TM-D710 dual band FM transceiver with APRS as it was the best solution to the problem of how to operate an APRS gateway without losing the ability to monitor for voice contacts on 2m when you do not have the space for two widely separated antennas. I have been quite pleased with the radio but rather alarmed at the number of reports of loss of sensitivity due to the failure of one or more of the IF filters. I asked on the Kenwood Yahoo group whether this was just a faulty batch of filters affecting radios of a certain age or a generic problem that was likely to affect any TM-D710 eventually and was directed to this explanation in the blog of Tasos, SV8YM.
It has been a long time since I read such a well written explanation of a technical phenomenon and I’m sure you’ll find it interesting, especially if you own a VHF radio with 455kHz IF filters. In fact I’m sure many of you will find other articles of interest in this blog. I’ve added it to my regular reading list.
