[R-390] AN/URM-25s

[wb5uom at hughes.net]

All of you have some interesting stories (and many more probably) [ I am 
very interested in those from SE asia]
but I dont think a modern top of the line signal generator has the issue 
being referenced.

At least  I have not seen it in my limited playing with HF here at home with 
my commercial playtoy service monitors.

I do know if I leave the sig generator with a 3 foot jumper unterminated on 
the output with a couple of microvolts of rf
being generated it is heard in several receivers nearby, but when below 
.35Uv or so,  it does not happen. At least  I have not seen it.

I thought a faraday cage was where capacitors were kept.

David / WB5UOM



----- Original Message ----- 
From: "Roger Ruszkowski" <flowertime01 at wmconnect.com>
To: <r-390 at mailman.qth.net>
Sent: Friday, March 02, 2012 6:16 PM
Subject: Re: [R-390] AN/URM-25s


>
> Barry,
>
> Its not so much that we worry about leaking on the bench.
> It's when you go back to trying to receive with that radio.
>
>
> At Ft Devens Mass about 50 miles from WBZ Boston, WBZ was every where on 
> the dial. To get WBZ every where it had to mix with some thing else in 
> some kind of mixer. We found all kinds of things that would mix two RF 
> signals OK WBZ and some other signal. I pick on WBZ but almost every other 
> AM station had a signal at more than on spot on the R390/A's with just a 3 
> foot test lead for an antenna in the class room. Radios all over that base 
> were radiating non stop as were generators and transmitters.
>
> I wish I had a radio room screened as well as the rooms I use to get to 
> work in. The stuff that invaded my receivers in San Diego and LA for years 
> made reception almost not worth turning the radio on. My site here in 
> Westminster South Carolina is a lot better but not like a good screened 
> room. Just adding a top and bottom cover does not fix most of the 
> problems. Also just parking the receiver in a metal cabinet does not do 
> much better. Maybe if I had the rack setting in several inches of water 
> (That expirment was conducted at  least once at Phu Bia during a typhon.) 
> I could get a good ground and better shield the receiver.
>
> Not that the screened rooms were all that great. We would have operators 
> come into the shop and ask us to to get our --- ---- off that frequency as 
> soon as we could because it was parked on some thing that was beating with 
> some thing else on the antenna and killing the dit of real interest. The 
> real problem was we did have signal generators in the box that leaked and 
> you could tune then to frequencies that would cause receiver interference.
>
> Roger AI4NI
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