On the “Queens Birthday Weekend” each year (It was the 9/10/11th this year) the South Eastern Radio Group (SERG) hold their annual convention. This year was the 48th convention, and the 50th year anniversary for the club. In conjunction with (infact as part of) this event they also hold the Australian Foxhunting Championships. For those who don’t know – no we’re not chasing furry little creatures with guns, we’re actually tracking down hidden radio transmitters through the bush. It’s a nerd thing, if you don’t get it, you’re probably not a nerd
To provide a little bit of backstory, I’ve been foxhunting with a group of Friends (Gary – VK3TXO, Pierre and Hamish) at the regular “Friday night” (Third friday of each month) foxhunts on 2m and 70cm for quite a while now, and we had been intending to get some equipment together to use over at the convention for a while. Friday night foxhunts usually contain hunts on the VHF & UHF bands of 2m and 70cm, but the AFHC has hunts on 23cm, 2m, 70cm, 6m, 10m and 80m, so some work was required to get the gear “Mount Gambier” ready and last year, we got all the equipment together and participated in the championships.
This year, Gary decided to buy a new radio, as the radio that we were using for our IF receiver, an FT-897 is a big, bulky, chunky radio that sat mounted on the equipment between my legs. Quite uncomfortable if I had to move, and made it difficult to get in and out of the car so a new radio was bought, an FT-857D.
This radio was bought second hand “For the right price” however that means it came with some gotchyas – namely, a few lines of the on-screen display were faulty. I used the front panel off my FT-857 at the Vic Champs (a warmup event held each year about a month before the AFHC) but as that radio was for sale I didn’t want to make this a permanent solution and I didn’t like the idea of spending a whole weekend foxhunting with this crappy frequency readout that sometimes decided to work and sometimes didn’t.
Time went by and we were contemplating solutions – including buying a new front panel (quite an expensive exercise) and the solution came to me at work, on the Friday that we were meant to leave for the championships, I was on the phone to Gary talking about what time he would pick me up from work, and it came to me …. Enter, the “Last minute solutions to impending problems to be faced at Mount Gambier, and we joined the code the solution and re-write the software in the back of the car club”
“Hey, I’ve got an Arduino, it’s at Gary’s place, it’s got TTL Serial ports, it can drive an LCD, heck, I can even program the hunts into an array and have it load those hunts”
So I rang Gary, got him to throw in my Arduino Duemilanove (AtMega328 processor) and I headed over to Jaycar to get some parts. Namely:
When I got in the car I opened the macbook, and began programming, plugged it all together started programming and we were somewhere around Hamilton when I finally figured out the oddities of the FT-857 and the BCD conversion of the frequency data coming from the serial port. I had a working frequency display, at this stage I didn’t care about sending commands to the radio to set the frequency (Now that I have a good display I can use the front panel controls to do that. Absolutely awesome – oh, wait, crap, the laptop crashed, what was that, you can’t pull the code back out of the Arduino – shit, I forgot to save. 4 hours of work, lost.
At this point in time I packed the laptop up as it was almost flat, we were about 45 minutes from Mount Gambier, and as I had everything fresh in my mind I closed up the laptop and said I’ll wait until we get there before re-writing the code. I had figured out the strangeness, so when we got to Mount Gambier I put together everything that had previously taken me 5 hours to get working in 45 minutes, and went to bed. At this point in time it was 2am, I was dead tired, but in true mount gambier tradition, I had snatched victory from the jaws of defeat and completed my first “re-write/code the software in the back of the car”.
Over the course of the weekend I gradually improved the interface, including setting up some arrays to store the hunt/frequency information and to allow automatic toggling between hunts so that when you get to the next hunt all you need to do is push a button. I finally got all that working for the second last hunt on the Sunday, but I’m hoping to have a custom built board, with better shielding (There were a few birdies coming from the Arduino that I think were due to a lack of shielding close to, but not quite on the fox frequencies) and a better layout.
Things yet to implement are:
Transverter offsets on the display (When we list on 2m and 70cm, we actually use an IF to listen on, we don’t listen direct on the fox frequency but rather use a downconverter)
Remembering the last frequency/hunt we were on (So that when the power toggles it doesn’t take you back to the beginning)
Mount Gambier/Friday Night mode selection (So that I can use common frequencies used on Friday night foxhunts)
As project development continues I’ll update with more information.