[Boatanchors] how to read microvolts

[Al Klase]

Hi Dick,

Not a dumb question.  You need a better signal generator, something like
an HP-606 or military URM-25.  These "standard" signal generators have a
variable output monitored by a high-level RF voltmeter.  The output is
adjusted to 0dbm, about 0.22V in 50 ohms.  The output is then applied to
a built-in calibrated stepped attenuator, say 10dB per step down to
-120dB.  (-110dBm is about 3/4 microvolt in 50 ohms)  Meter scale reads
volts and dBm so you can adjust to a precise value.

There's no prayer of doing this with a cheap generator due to signal
leakage around the attenuator.

Regards,
Al

Dick KF4NS wrote:
> This may be a dumb question but I really cannot find a way to read 
> microvolts of RF.  My old Heath RF sig gen has bad resistors in the 
> attenuator but I only know that by reading the values of the 
> resistors.  What can I use to read the output of the sig gen in very 
> small values of microvolts?
>
> My scope will not read that low and my VTVM with RF probe will not 
> read it either. I can read millivolts on various pieces of my test 
> equipment but the only thing I can think of is to boost the signal 
> with an amp and then allow for the difference as long as I can be sure 
> of the total gain of the amp.
>
> Please enlighten me.
> Thanks and 73, Dick KF4NS
> St Petersburg, FL 33714 USA
> Keep The Glow!
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-- 
Al Klase - N3FRQ
Flemington, NJ
http://www.skywaves.ar88.net/