The problem is that in most cases the sensor is connected to something that is
likely to be sensitive to
RF unless you use an analog meter with a thermocouple.'
You could use an aftermarket engine head temperature gauge available at most
auto parts stores.
Many are just a thermocouple and analog meter, but very poor resolution and
accuracy. Usually go up to
250 Degrees F.
All sorts of digital meters and thermocouple to go with them are available
on ebay but they are just as likely
to be affected by RF. I got one digital one with 4 selectable inputs from China
for around $20 or so. Just add
a type K thermocouple and you are ready to go....maybe after adding lots of
bypass capacitors.
A DC source, thermistor and analog meter would work. May need to play with
balanced bridge arrangement and
then calibration using a water bath and accurate thermometer.
Good luck.
Don't forget the cheap infrared Harbor Freight hand held. But it has
problems. Need a good flat black surface
and have to have it aimed right at the device, it does not measure a small area
either... may still be affected by
RF.
73
Bill wa4lav
________________________________________
From: Amps [amps-bounces@contesting.com] on behalf of Bill Turner
[dezrat1242@yahoo.com]
Sent: Sunday, June 09, 2013 3:04 PM
To: Amps
Subject: [Amps] Monitoring temperature
I would appreciate any suggestions for monitoring temperature on a solid
state power amp. I have used the LM34 with success in the past, but not in
the presence of strong RF fields. After all, it is a diode, sort of. :-)
The thing I like about it is it reads out directly in mV per degree, so no
calibration is necessary. Just connect a meter of the appropriate scale and
off you go.
It would work fine while not transmitting of course, so one option is to
apply power only during receive but I'd prefer to have it on all the time.
Are there any thermistors or related products which are not sensitive to RF?
Something which can be fastened to the heatsink and read remotely? Any
drawbacks to them?
All ideas appreciated.
73, Bill W6WRT
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