One of my new year’s resolutions for 2021 was to make some contacts via the QO-100 satellite.
This would normally require equipment like an ADALM-PLUTO or other transmit-capable SDR, transverter, power amplifiers etc. This is necssesary for SSB and other modes, but for CW it should be much easier and cheaper.
I’ve added two etherify articles to the Soft TEMPEST series, one showing an exceptionally strong signal radiated from a raspberry pi 4b, and another showing that regular ethernet hardware can also be used.
I’ve always wanted to make a Moxon antenna, but didn’t have an excuse to do so. Recently i needed a very lightweight directional antenna for Etherify with not so much gain, but considerable F/B, so i finally had the excuse i needed.
To transmit CW on the Kenwood TR-9000, TR-9130, TR-9300, TR-9500 (and maybe other) transceivers one has to hold the PTT on the microphone (or on the optional BO-9 base) and only then transmit using the KEY. For some reason the Kenwood thought this would be an excellent idea.
This is a simple external semi-BK circuit implementation, so that you can just press the key to transmit. No modifications inside the radio are necessary.
The circuit is connected to the STBY (2.5mm jack) and KEY (3.5mm jack). Connect the key to the CW KEY terminals. To increase the time make the capacitor bigger, currently it is 3000uF (3x 1000uF in parallel). The diodes are any silicon diode like 1N4148, 1N914, 1N4001 etc.
Keep in mind that the capacitor is charged to 8V, so that the key has temporarlily 360mA flowing thorugh it. No problem for a straight key, but it might be an issue with some electronic keyers.