[R-390] Signal Generator Impedence Questions

[Flowertime01 at wmconnect.com]

Barry,

I have not used a GR1001A .
Consider stepping the output up to the next output range 
and setting the adjustable attenuation control back under
100% to what would be 150uV. Just because the dial goes
up to 150% the generator may not be able to put that out.
Not that the generator will not do it, but the attenuation network
and maybe current / voltage limiting of an output stage hits
a ceiling before you 150% of output at the low ranges.

 Kludgy, !! Is there some other way?
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I was disappointed that with 150uV(?) at the input, I was not able to
get -7V on the diode load.

Something is wrong, either low output or IF deck needs some work.
The gain adjust should let you get about -15 volts with the pot cranked
over full gain and 150 uV in. 

You are just not going to look at 150uv on a scope or measure it with a
meter. How does the signal gen perform at 1 - 10 uv on another receiver?

As the other mail pointed out, due to lack of shielding you cannot really 
run the 150uv output through an attenuator and see how it performs as a 1- 10 
uV
drive for a receiver.

You will know when you have it right, the R390 will definitely not be deaf.
-----------------------------

I was thinking that the 10-ohm impedance mismatch might be
affecting my ability to set the gain by the manual properly.

Not likely. Either the generator output is low, or you do have
IF, Audio deck problems. Pop the VFO on and you should get 
about -30 volts on the diode load.

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I was just trying to get something close to the procedure that's in the 
manual.

Understandable Barry, when every thing is not going well, 
Try reading the manual. 

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One thing I did notice that was rather humorous.  In the section for
aligning Z503, the manual states that if Z503 is defective, replace it.  I'm
not sure why they felt the need to include that blurb.  Kind of obvious,
isn't it?

Lots of little bits of humor in those TM's dry reading but some error 
included.
____________________________________

Roger KC6TRU