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

David Wise David_Wise at Phoenix.com
Fri May 8 20:06:07 EDT 2009


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.


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