Simple QRP projects, 10m, 6m, WSPR beaconing, LF/MF, sub-9kHz, nanowaves and other random stuff
I wish there was someone near me like Andrew M0BXT to conduct experiments with . What was the R.F output power of Andres Tx?You have to shout to get any depth of modulation.Try a 6v Mains transformer to step up the modulation.73 Tony G4llw
Hi Tony,I am sure we will try things like the mains transformer to improve mod depth. The input on Andrew's TX was about 60mW so the output was most likely 10-20mW? All great fun.73s Roger
Hi RogerI like reading about your experiments with Andrew M0BXit would great if there was someone like minded and local to me.That's a good output for a one transistor transmitter.Please post the circuit on your blog.I have got some 6 metre crystalsmight give that a try.
Further to this I've done some measurements. As noted the DC input was about 60 mW but that includes power dissipated in the carbon granule microphone.The RF output with this setup appears to be about 4 mW (+6dBm) as measured by a spectrum analyser and confirmed on a (200 MHz bandwidth) oscilloscope.For next week perhaps we can try DSB using and SBL-1 mixer, my signal generator and the same carbon granule microphone (probably with a step down transformer).I’ll see if I can hash something together in time!Yes, I guess Roger and I are lucky to both enjoy very simple gear and live locally to each other but the GQRP club (and the corresponding Yahoo group) will be full of like minded individuals – hopefully all over the country.73,… AndrewM0BXT/G6ALB
Yes,definitely game to try DSB next week Andrew.73sRoger
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It was cold and bright here today. The photo was taken by my XYL on our way to Cambridge this afternoon.