[VHFcontesting] DEM 432-38 Receive Problems

[George Fremin III]

On Sun, Jan 08, 2006 at 01:24:14PM -0500, Jimk8mr at 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 at kkn.net
http://www.kkn.net/~k5tr