[time-nuts] Re. DIY atomic "resonator"

Dave B g8kbvdave at googlemail.com
Wed Apr 12 13:28:31 EDT 2017


On 12/04/17 17:00, jimlux wrote:

> Subject: Re: [time-nuts] Re. DIY atomic "resonator"
> Message-ID: <b3926cda-b4ff-2508-1be6-57c2fecf0ad6 at 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.)

~~~



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