Chirp-Hell on longwave

On 14th November 2012 I reported success with the tests on the work-bench of the improved ssb phasing exciter for my 2190m longwave transmitter. Soon after that I installed it inside the transmitter enclosure. Since then I had been waiting for an opportunity to test it using full transmitter power into my antenna in a real 'on-air' situation, with a more distant receiver. 

So early this morning at about 1.00am I carried out transmission tests with Jacek, SQ5BPF, in Warsaw. My signal was quite readable on his grabber; screen captures above. The noisy band conditions at his location are also very evident.

I was transmitting on 136.9KHz upper sideband, modulating with 800-810Hz chirp-hellschreiber audio tones. Transmission speed was either 5 or 10 secs/character; the vertical markers are 1min apart. We then completed a chirp-hell to qrss1 cross-mode contact; quite obscure, so it's probably the first time ever it has been done !

Single side band generator for the longwave transmitter

Uses the phasing method for ssb generation. CMOS logic integrated circuits ( D type and J-K type flip-flops ) produce the rf phase shift; a passive R-C phase shift network takes care of the audio phase shift. Plessey SL640 mixers are used. The prototype is shown undergoing tests. It is now fitted inside the transmitter case at the rear left. When it's connected to the PC soundcard, data, encoded as audio tones, can be transmitted.