On 12/04/17 17:00, jimlux wrote: > Subject: Re: [time-nuts] Re. DIY atomic "resonator" > Message-ID: <b3926cda-b4ff-2508-1be6-57c2fecf0...@earthlink.net> > Content-Type: text/plain; charset=utf-8; format=flowed > > On 4/11/17 11:09 AM, Mark Sims wrote: >> Apparently fluorescent tubes continuously emit a lot of other microwave >> signals. I once built a homodyne doppler "speed" radar kit (used a coffee >> can for the antenna). The way you calibrated it was to point it at a >> florescent tube and and adjust the reading to a specific value. >> >> -- > That's not because the tube is emitting.. It's a target reflector > turning on and off at twice line frequency. > In most homodyne radars, you filter out the DC (the reflections from > stuff that's not moving), so anything that pulses on and off creates > nice output.
This patent would seem to confirm that discharge tubes do generate microwave noise, and with a DC powered tube too. (Would different gasses produce different microwave spectra?) http://www.google.co.uk/patents/US2942204 I recall seeing such things sold surplus back in the early 70's, pity I didn't know what they were back then. There is also mention of huge mismatches in the guide when the tube was not powered, that would support the homodyne speed calibration comment by pointing it at a working (AC powered) florescent tube. As Jim said, a 100 (or 120) Hz "modulated reflector." Regards to All. Dave G0WBX (or G8KBV both still valid.) ~~~ _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
