Author Archives: Si Smith

FISTS Straight Key 8

See here for the current FISTS club activity that is promoting the use of character by a mechanical only keying activity week. Not even Bugs are allowed!

I dug out the old Kent brass pounder I passed the CW test on almost 40 years ago and have been participating this week much to the bemusement of my victims QSO partners.

Character signal from the Low Lands

I had the great pleasure of working Hans, PA2MT last night, on 80M, who was in a caravan in the Low Lands ( de Lage Landen ).   He was using a PRC320 Clansman and there was some noticeable chirp but you know how we love a little chirp on this site as it adds true “character” to the signal.

Hans also reports that he was using a leg-mounted key 🙂   Way to go, Hans, however, this makes it impossible to TOF ( try other foot ) as QLF members oft tell each other to do! 🙂

I had worked Hans before; previously he was operating a SEG-15D transceiver, these originated in Eastern Germany where they were manufactured for the Marine/Military markets.

Clansman PRC320

Clansman PRC320

Reverse engineering character into modern transceivers

Leaving aside the subject of drift in free-running VFOs (pre PLL  & TCOs ) one regular feature of old CW transmitters, particularly where they were simply high-power oscillators, was the chirp you got as the frequency dipped on key-down whilst the HT re-stabilized.

In an effort to simulate this an audio keyer is being prototyped to bring back those old days.   The video shows the first hack ( 20 minutes today ) .  The sound is terrible as I have not added low pass filtering to the square wave output and it is playing on a piezo sounder.   It is also dual-tone (selectable by design).

The next step is to change the chirp algorithm to natural log as this better mimics the capacitive recovery effect on old HT keyed circuits.

73  G0FOZ

Update – some drift on this one, a different chirp and amplifier stage was added (3rd-order RC LPF too ).