[R-390] Yet another question... sigh...

[Barry]

Well, some of my test equipment actually agreed for a change.  42mW measures
5V on my DVM.  Cool.  The audio tests were spot on.  Following the table,
when I inject 0.1V of modulated 455kc on pin 7 of the detector (V506), I
don't get the expected results.  The only difference in my test is my
internal modulated signal is 800cps whereas I think the test states
something like 400cps but I don't think that would really matter.  I suppose
I can hook the audio signal generator to the RF signal generator and use the
external modulator position, but, again, I doubt that would change anything
very much.

According to the table, I have problems in the detector circuit.  I'll start
looking there for problems.

Thanks, guys!

Barry - N4BUQ

----- Original Message -----
From: <ToddRoberts2001 at aol.com>
To: <r-390 at mailman.qth.net>
Sent: Sunday, September 17, 2006 8:09 PM
Subject: Re: [R-390] Yet another question... sigh...


> In a message dated 9/17/2006 6:04:03 PM Eastern Standard Time,
> n4buq at knology.net writes:
> (Trying to answer my own question)
>
> The HP-200CD is supposed to put out 11.5V at full scale when across
> 600-ohms.  11.5V across 600-ohms yields 220mW.  This checks out on my
> TS-585.  Based on that, 5V RMS (which I found out the AN/URM-127's output
is
> measured in) should yield about 42mW.
>
> Should I leave the TS-585 in the circuit such that the 600-ohms load is
> present and set the HP-200CD to get 42mW on the TS-585 to get the 5V
> specified in the test?
>
> Thanks!
>
> Barry - N4BUQ
>
> That sounds correct. It shouldn't hurt anything to monitor the HP-200CD
> output with the TS-185 to be sure you are getting the correct 5V RMS audio
sinewave
> into the test point. It would be nice if you had something like a Boonton
92B
> or similar millivoltmeter to measure the HP-200CD output directly in volts
or
> millivolts but as long as you correctly convert mW at 600 ohms into
voltage
> RMS you should be fine. 73 Todd WD4NGG
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