Sunday, November 22, 2009

SO2R -- The hard way


This past weekend I had the privilege to be a guest operator for the Radio Club of America on their special event station W2RCA, celebrating the 100th anniversary of the RCA. The station was co-located with the anniversary event in Washington DC, and I wasn't able to attend in person, so the operation was handled using remote PC access and VOIP software, similar to the setup which I described back in late 2007.

A problem with remote setups is that they require a fast Internet connection to work well; the primary challenge being the speed (or lack thereof) at which you can switch from receive to transmit and back again. Because the W2RCA special event station was scheduled to happen during the ARRL's November SSB Sweepstakes, it was decided that we would work the contest as W2RCA. Being in a contest situation meant that rapid TX/RX switching would be a must.

As it turned out the network connection between my home and the RCA event location wasn't quite fast enough for the furious pace of the contest. I was having a hard time getting the remote radio keyed quickly enough to bust the pileups. In some cases I would bust the pileup only to have the target station get frustrated because I wasn't coming back to him fast enough. Not good, not good...

Out of curiosity I turned on my home station and tuned to the same frequency as the W2RCA remote. I found that despite being separated by 2,500 miles I could hear the target station well on both radios! Not wanting to give up on the contest for lack of fast TX/RX switching I decided to try an odd twist on SO2R (Single Operator-Two Radios) setup. I activated transmit on the W2RCA remote station, muted my microphone, and plugged my headphones into my home station. Because SSB is carrier-less mode the remote radio would not transmit any power with the microphone muted.

The next time the target station called QRZ I unmuted my microphone and called him, and heard him come back to me on my home station! I was able to work several stations this way, although there were still a few challenges. First was the effort of keeping the frequency of ftwo radios in sync. Second was some of the stations I could hear clearly on my home station were outside the range of the W2RCA remote station. But in general it worked and was an interesting way to get around the slow TX/RX switching issue.

Thursday, September 10, 2009

..-. .. .-. ... - -.-. --- -. - .- -.-. - <= (First Contact)


This week marked a big milestone for me; I successfully completed my first radio contact using CW aka Morse Code. It was a tough contact; conditions were bad but the guy I worked was polite and patient with me so we managed to pull it off.

I had always believed that I simply did not have an "ear" for code; it sounded like noise to me and I was never able to get past a basic understanding of the mechanics. After the amateur radio code requirement was lifted I was thankful and quickly upgraded to the highest level license. Still, in the back of my mind I felt I should make a real effort to learn code; if for no other reason than to overcome a personal limitation. (If you think I have a strong aversion to being told what to do; I have an even stronger aversion to being told what I can't do -- even if I'm the one doing the telling.) So my 2009 resolution was to learn enough code to complete a radio contact. It took me nine months, but I made it. I don't know that I will ever be a "real" CW operator, but right now I'm having fun and feeling good about my accomplishment.

I would like to thank the following people who helped make this happen for me:
  • Gerald Wheeler (W6TJP) - Author of the Code Quick learning method. A great basic foundations course.
  • Fabian Kurz (DJ1YFK) - Developer of the LCWO.net website. An awesome online Koch-method trainer. Did I mention it's free?
  • Leon "Skip" Stem (WB4DAD) - CW operator, FISTS member, and the first entry in my CW contact logbook. Thanks for being patient with me.

Wednesday, August 26, 2009

You, um, expecting trouble? BIG Batteries...


Through a contact at an SF Bay Area web hosting company I recently obtained for free a set of used -- but still very strong -- UPS batteries; the Deka/Unigy 31HR5000. This hosting company offers their customers a 100% uptime guarantee which means that they can't wait for their UPS batteries to fail; they are used for a number of months and then they're replaced. Since the hosting company has to pay someone to come haul them away they're happy to see them repurposed.

These batteries aren't the typical deep-cycle marine variety you see on Field Day. They weigh 95 lbs each. Fresh from the factory they're rated at 135 amp-hours, which is about 1,800 watt-hours. My main HF rig (Kenwood TS-2000) consumes about 200 watts worst-case (when keyed on 2 meter FM, set for 100 watts) which means that using one of the Deka batteries I could leave my rig keyed-down on 146.520 FM @ 100 watts and it would remain on the air for about 9 hours.

I now have 3 of these monsters running in parallel on my home station. That's over a full day of continuous talk time. Left in receive-only mode my station will run off-grid for about 8 days.

Total cost? About $40 for some 4-gauge jumpers and misc hardware.

Bring on the zombie attack. I'm ready.