As i spend more time in the microwave region, frequency stability becomes much more of a problem for me. While out in the field I need to be able to point my dish with roughly 2-4 degrees of horizontal/vertical accuracy, then be on the right frequency to make a QSO with the other station. If any of these variables are off I can potentially miss the contact and lose points. With the use of a computer program I can predict the azimuth of the Sun, point my dish at it, then be able to calculate my heading with use of a centerline. Now I only need to worry about frequency.
Currently my method of determining my frequency is to listen for a radio beacon. Around New England there are two regular beacons on 10GHz that I use; the Mt. Greylock beacon and the WA1VVH beacon. One problem is that the WA1VVH beacon is often down during the contest because Harry (WA1VVH) is home operating on the same antenna. Another issue can arise when you don't have a clear shot to the beacon location. This past contest weekend, on Sunday, I had the pleasure of operating with Mike, N1JEZ, who has a portable GPS stablized 10GHz source with him. It doesn't matter where you are, as long as you can lock to the GPS system you can produce a carrier at exactly 10,368.000MHz. My transverter drifts fairly heavily, upwards of 20-30KHz. Having that source was a lifesaver, I simply tuned around .000, calculated my offset, changed back to the frequency we agreed to meet on, then added back in my offset, voila!
My new problem: I'm not going to be operating with Mike, N1JEZ, next contest weekend.
I've been reading about the new DEMI/N5AC Apollo A32 synthesizer board lately, it is being touted as a replacement for the DEMI Microlo (Which is the source of my drifting problem). The only downside to the A32 is it's less than great phase noise, but is bad enough to really worry about? I took the plunge and ordered one. I'm not planning on installing it right away, I may actually just play around with it for a while and see what other folks find with it in terms of performance degredation. Then I had a great Idea, I could use it along with my 10MHz GPSDO to create a 10GHz portable marker! No more guessing at what my frequency is?
Then I realized that DEMI beat me to it and put together the A32 with a nice enclosure with a knob that has several presets. Check it out here! Again, I took the plunge and ordered one. I can envision using this for a number of projects, including using it to test my S-band down-converters from 2401 to 144MHz. It could really come in handy.
Now, both the A32 and WSSA require 10MHz external reference. I had built a GPS disciplined 10MHz oscilator based on the N1JEZ/W1GHZ/G3RUH board, so that was a good start. I also picked up a Thunderbolt GPSDO from Ebay, but it's been sitting on the shelf unused. Tonight I finally assembled the power cable for the Thunderbolt and managed to get it up and running, here is a pic of the unit and power supply.
With any luck, I should now have mostly solved my frequency accuracy issue, I'll always be able to calculate my offset from the marker. If the results come back positive for the direct Microlo replacement, I'll think about changing it out. The issue with going that route means that i have to have 10MHz with my rig, or run a cable from the Car. That isn't always convenient.....
Now, if DEMI ships my order within the week I'll be ready to go for the second weekend of the contest!
Thursday, August 27, 2009
Saturday, August 22, 2009
The first weekend of the ARRL 10GHz Cumulative Contest was last weekend, the 15th and 16th of August. I had really desired to be a little more organised this year in an effort to increase my score over previous years. I managed (or so I thought) to get all the gremlins out of my equipment, and even had enough spare time beforehand to put together a spreadsheet of all the operators who planned on going out for the first weekend, their locations, and their mobile phone numbers. I was far too organised for this to be a smoothe weekend :)
First stop, I planned on being at Mt. Kearsarge from the time the gate opens (9:30a) to closing (6pm). I hadn't even made it to the gate when I realised that I forgot the antenna mast for the 2m ssb antenna. Hrm...well, there is a hardware store down the street from the mountain, I'm sure I could find something there. I did, a 5' 1.5" wooden dowell would do the trick. Thankfully I had a roll of gaffers tape with me to secure the antenna down. Ok, problem solved, off to the mountain! Next problem, they are painting the yellow lines on the road to Kearsarge. Ok, a few minute delay, not a big deal. Well, I get to the gate and the woman tells me I have yellow road paint all over the drivers side of my car and in the wheel well. GRRRR! I didn't drive over the line, just all the arosal they use to spray the lines collected via the vaccum action of the car. Luckily that will come off, with some elbow grease. I noticed the first 3-4 cars up on the mountain all had the same problem.
On to the mountain! I get set up fairly quickly and start to have a normal day contesting, but it was HOT! I had plenty of water with me, but I was getting baked. I had tried using this bugsparay/sunscreen that was on sale at CVS, but It clearly didn't work for either purpose. I got eaten alive and burned to a crisp. I'm not really complaining about that, it happens every year, I've learned to just deal with it. About noon time I start having a re-occuring issue with my rig, the main T/R relay isnt' switching when I'm transmitting. That means I'm putting 8 watts into a relay that isn't terminated! I figured out that it was my sequencer board, one of the relay contacts was intermittent due to a bad solder joint. I found that if I put pressure on the relay it would switch. I could continue the rest of the day like that and fix it at the hotel.....had I not broken a wire of the sequencer board while troubleshooting. D'OH!!! Well, off to Radio Shack I go. There has to be a Radio Shack here in town, right? WRONG! The closest I could find was 40 minutes away. Off I go.....
(Note to self: When packing the night before a contest rover trip, if you have the soldering iron in your hand and say to yourself "Nah, I won't need this"....ignore the inner voice, take it with you)
I finally get to the destination, only to discover this store is about as small as I've ever seen. I kept thinking "there's NO way they sell soldeing irons, I'm screwed". But, I asked the woman behind the counter and was shocked to find that they had no less than 5 types of irons and 8-10 types of solder! I take back all those bad things about Radio Shack over the years, they saved my bacon this day!
Now, here I am in a Rat Shack parking lot, the back of my car open, inverter running, soldering iron getting hot. In about 15 minutes I have the fixes in place and it seems to be working......Ok, back to the mountain.
After some mid-day traffic and a lunch break, I make it back to the mountain around 3pm to find Byron, N1EKV, making some contacts. I pull in next to him and get set back up. The rest of the day was fine, but they relay problem wasn't 100% fixed, there was something still wrong.
I managed to make 22 contacts at Kearsarge, which was the most I've ever made there (17 the previous year). I can only imagine I would have snagged a few more had I not made a 3 hour detour. I was the first person up the mountain, and I was the last one down (As the park ranger sat, staring at her watch). Now, on to my long haul to Gorham, NH at the no-tell Motel.
I had booked this room at an amazingly cheap rate of $50 a night. Afterwards I saw some really horrible reviews online. I expected the worse, but was pleasantly surprised. Everything was clean, no worries. So, I dragged the battery, battery charger and Microwave rig in and got to work. As it turns out, my parking lot soldering session was mis-guided. I completely missed the bad solder joint, but re-flowed a number of working joints :) I re-flowed the bad joint, and I finally fixed the problem. I got a good nights rest and was up at the crack of dawn to be at the gate at the Mt. Washington auto road at 7:30am.
Oh...my....lord....the Mt. Washington Auto Road has got to be about the scariest drive you can make in a car. I've driven to the top of Pike's Peak (14,110ft) a number of times, but that was cake compared to this road. There was one point that I wasn't sure I was going to make it :) My fear of heights was in full swing, my knuckles were as white as ever.....but I made it.
I met N1JEZ, W1AIM and K1LPS at the mountain. We grouped together and had a really great day on Washington. Some of the highlights were working WA2FGK in Fn31bf at over 500 kilometers, VE3FN in both FN14 and FN15, and VE2JWH in nearby FN45 and FN46. All in all, I made 33 contacts in 12 grids. 12 grids in one day!!
It was a long, exhausting ride home, but well worth it. I'm alreadying hatching plans for the second weekend. Look for me on Saturday roving on Cape Cod. I'm likely going to be at 4 locations, including Marconi Station, FN51av. Sunday isn't planned yet, but I may look at doing a CT/RI/MA costal run for three spots. Tune in for more details!
Friday, August 21, 2009
This is one for the archives, for that poor soul who is searching trying to figure out his problem. If you are using The Logitech G15 Gaming keyboard with Ubuntu 9.04 and you are having problems with random changes and flashing AM or PM in the clock module, make sure the keyboard is not plugged into a USB hub. I didn't find this in any of the Ubuntu documentation, but on the G15 Forumns page, which google didn't seem to index.
That is all.
That is all.