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Re: [VHFcontesting] DEM 432-38 Receive Problems

To: Jimk8mr@aol.com
Subject: Re: [VHFcontesting] DEM 432-38 Receive Problems
From: George Fremin III <geoiii@kkn.net>
Date: Sun, 8 Jan 2006 10:28:29 -0800
List-post: <mailto:vhfcontesting@contesting.com>
On Sun, Jan 08, 2006 at 01:24:14PM -0500, Jimk8mr@aol.com wrote:
> 
> For most, if not all, of the many years I've had my DEM 432-28 transverter  
> I've been bothered by a swath of crud covering much of the useful 432  band.  
> Being about 2 miles from a tower loaded with pagers, two FM  broadcast 
> stations, and who knows what else, I kind of figured I just had to  live with 
> it.
>  
> Recently, however, I've taken another look and determined that the  offending 
> stuff was the mixing product of a TV channel 23 visual carrier  (525.26MHz) 
> and an FM station at 93.1 MHz creating the FM signal at  432.160.  The 
> amazing 
> thing was that the TV station is 30 miles away  and the FM station 10 miles 
> away.
>  
> Yesterday I was able to check things with a FT-847, which was clean, and  
> also to add a DCI 435-10 bandpass filter in front of the DEM transverter, 
> which  
> also cleaned up things.
>  
> This seems like very poor front end performance in the DEM  transverter.  
> Have other people experienced this problem?  Any  suggestion as to what might 
> be 
> going wrong with mine if this is not a normal  condition? The transverter 
> otherwise seems to be working... the several birdies  I could hear on both 
> rigs 
> seemed even stronger on the DEM than on the FT-847  (and went away on both 
> with 
> the antenna disconnected).
>  

I have this same problem with my DEM transverter - I have not tried a
bandpass filter yet but I have thought of doing something like that
over the past year.




-- 
George Fremin III - K5TR
geoiii@kkn.net
http://www.kkn.net/~k5tr


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