144 MHz Telegraphy Marconi Memorial Contest 2020
Participated in the 144 MHz Telegraphy Marconi Memorial Contest in the weekend of 7 and 8 November 2020. It was special for me because I am not a telegraph operator. But the will to make qsos is greater than the limitation of not having the skill to do Morse Telegraphy. I have limited to search and pounce and if the course of the qso does not deviate too much from the normal then I will succeed.
In addition, I had previously decided to use my old 36-year-old homemade tranceiver and amplifier for this contest. Nice for the nostalic feeling.
I had to make a modification in the transceiver, readjust the MF crystals and get the output stage working again. Cables also had to be made to connect the keyer. In the end all worked out and I had a reasonably working system.
We are very spoiled with our modern tranceivers. It was fun playing with the old tranceiver, but I wouldn't want to go back to this situation......
9 element DK7ZB yagi at 6m AGL
In the output stage a BLY88 and BLY90 transistor. The BLY90 gives a maximum of 50 watts output and has a gain of 5 to 6 db at 12v. Incredibly bad if you compare that with today's modern MOSFET 1kw amplifiers.
Amplifier with BLY88 + BLY90 transistors
The last stage in the transceiver was originally a BLY87 transistor amplifier with a BGY module in front. I removed it and replaced it with a RA08H131 .. amplifier module. Much less hardware and a much nicer signal.
Also a separate PCB with an inhibit function built in. This allows the sequencer to hold the transmitter until the coax relays and preamp are switched.
The new RA08H131.. module and inhibit circuit.
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