>With the narrowest selectivity filters in the receiver if
>you can't hear a clear increase in noise level when you
>connect the antenna and a clear noise decrease when the
>antenna is removed, you need a preamp.
That is also my criteria for switching in my K9AY preamp. On rare occasions,
mostly at my SR/SS, the ambient noise is so low that only the internal RX
noise in my R-4C is heard when the Beverages are connected/unconnected. I
use the preamp until the ambient noise comes up to a level greater than the
internal RX noise. I have found that anytime a pre-amp is used in conditions
other than the above, the signal-to-noise ratio suffers. When the pre-amp is
switched off, I have to increase the AF gain on the RX a bit, but copy is
always better without the pre-amp under normal band conditions. My RG-6 feed
line lengths to my Beverages average around 300 feet.
(((73)))
Phil, K5PC
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|