[R-390] AN/URM-25s

[Joe Foley]

Gee, I have a Faraday cage not 20 miles from me,......... doesn't everyone?

Unfortunately the Seneca Nation wants to use that building to make cigarettes, used to be some radio company out of Ohio.

Joe



--- On Fri, 3/2/12, Roger Ruszkowski <flowertime01 at wmconnect.com> wrote:

From: Roger Ruszkowski <flowertime01 at wmconnect.com>
Subject: Re: [R-390] AN/URM-25s
To: r-390 at mailman.qth.net
Date: Friday, March 2, 2012, 7:16 PM


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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