source --- amplifier --- relay coil.
When source is present the amplified is detected and drives a relay coil
to keep it energized.
When source fails, relay opens switching to backup source.
When source is again active, relay closes reverting back to primary source.
A 10 MHz xtal or other 10 MHz filter in series with amplifier input will
ensure that amplifier will respond to source going off frequency.
Glenn
On 2/4/2019 9:26 PM, Jeff Blaine wrote:
Wondered if anyone had seen some sort of gadget that would look to see
if there was a 10 Mhz signal and switch a relay (or provide some other
output) in the absence? I would like to cook up some sort of fail
over switch without having to do much actual work. :)
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV [email protected] AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
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