[R-390] 60 Hz Hum Output from R-390A IF Module

[rbethman]

AN/URM-25s are NOT fixed ouput levels.  They can be dialed down to WELL 
under 1 uVolt.

These are what the R-39X series were worked over with.

I still use one today.  I've gotten my R-2000 to tweak in at the ZERO 
reading.

Bob

David Wise wrote:
> What percentage modulation?
>
> (Pardon me if the URM-25 is fixed-level, I'm not
> familiar with it.)
>
> Dave 
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Flowertime01 at wmconnect.com
> Sent: Friday, May 08, 2009 4:30 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] 60 Hz Hum Output from R-390A IF Module
>
> With modulation on you should get 1/2 watt out on the local audio pins of 
> the rear terminal board. And 100 Mili watts on the line audio as read with 
> the line level meter.
>
>
> Turn the modulation off and you should get a 30 dB drop in the output on 
> the local audio pins. Use an AC volt meter with a dB scale and a 600 ohm load 
> resistor to measure the half watt of power and 30 dB down from that point 
> with the modulation off.
>   

-- 
Bob - NØDGN