RF Circuits

With snow on the picnic tables here in Minnesota my operating has moved from K1/QRP to the boat anchors in the basement. The AWA 1929 CW Party occurred the first two weekends of December. This contest requires that the transmitters reflect 1929 or older technology and tubes. Participation is in the 50 - 100 station range so it is a fairly low key "contest". Even the required log information forces operators to slow down as name, QTH, signal report and transmitter descriptions are exchanged. Power is limited to 10 watts input (except for late east-west QSOs) on 80 and 40 meters. Many of the transmitters are self excited Hartley, TNT or TPTG oscillators link coupled to the antenna. Some are MOPA (master oscillator-power amplifier) two stage transmitters. I put my TNT transmitter on the air with my National NC-81X receiver. Running about 2 watts out on 3560 KHz I had seven enjoyable QSOs. Longest "DX" was N4GJV in Cleveland, NC. All of the others were in MN and WI. The contest was not without some last minute challenges, but not with the 1929 gear. As I got started I realized that I had no way to zero beat my signal. The '81X muting function has no mute bypass switch. With it wired into my T-R relay to mute on transmit I had no way to tune my receiver to listen for my own frequency. Fortunately the '81X is ham band only with relatively good calibration so I wasn't to far off ... but then the NC-81X receiver dial string broke. My receiver could be tuned just fine but I had no direct frequency readout. I made it through the contest by listening for a signal of known frequency and then not straying far from that. It was a fun evening.