[Boatanchors] how to read microvolts

[Glen Zook]

Those generators have been used in the commercial
two-way field for decades as well in many laboratories
during the period up to at least the 1980s.  All of
them are at least double shielded with solid metal
shields around the oscillator and double shielded
coaxial cable to the attenuator.  You can definitely
measure signal levels down to under 1 microvolt with
any intact unit.

Now a 6 dB attenuator definitely needs to be attached
directly to the output connector and these attenuators
were "stock" when the generators were shipped new. 
This is necessary to match the output of the generator
to 50 ohms and to provide additional shielding.

Now if modifications have been made, shields removed,
and so forth, then all bets are off.  But, as
originally designed those signal generators that I
mentioned previously are definitely capable of low
level measurements.

Glen, K9STH


--- Gary Schafer <garyschafer at comcast.net> wrote:

While those generators mentioned are very handy and
can be used for tuning things up and measuring levels
above a few microvolts they are not good for making
accurate low level signal measurements. They all have
too much leakage and trying to measure below 1
microvolt with them is impossible. The attenuator
reading does go below 1 microvolt but the signal level
doesn't follow because of leakage around the
attenuator. Still much better than the heathkit type
generators though. I have a URM-25 that I drag out
once in awhile when I need a low frequency signal
source.









Glen, K9STH

Website:  http://k9sth.com


 
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