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Old January 27th 06, 04:08 AM posted to rec.radio.shortwave
Tom Holden
 
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Default Opinions/experience Radio Shack DX-394?


"HFguy" wrote in message
news:eF6Cf.22997$nQ3.1107@trndny03...
Lisa Simpson wrote:
I got it off ebay;
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=5855157653

I'm surprised the previous owner took the time to install the shielding. I
don't recall that being a recommended mod' for the DX-394. Does it still
have the original label on the rear which gives the model and serial
number? The ferrite rod antenna is mounted on the top circuit board inside
the case. This is for MW (AM) reception. The shielding must have reduced
or even eliminated the effectiveness of this antenna. How is reception on
the AM band (525-1615)?


Shielding is a recommended mod to reduce interference from VDT's and other
nearby equipment. The LW/MW ferrite rod is sensitive mainly to the magnetic
field so shielding that is effective on the electric field and is not
ferro-magnetic has little effect on the LW/MW sensitivity but is effective
at SW. If you want the best results on LW/MW, it is advisable to replace the
ferrite rod antenna with shielded or toroidal transformers, shield the
receiver for both electric and magnetic fields, and use a directional
outdoor antenna with shielded transmission line. Leaving the internal
antenna in place degrades the directivity of the outside antenna and picks
up more local interference. This would be true for any radio with a built-in
antenna, not just the DX-394.

Tom