Topband: Re: [CQ-Contest] Re: Topband: TOP BAND RECEIVING ANTENNAS

[Tom Rauch]

> gets well alive when connected to the antenna. Playing with N stacked
> beverages (1 to 2 WL beeing probably best choice) insures a good
> pattern control and offers an output level that surely meets or exceed
> PY5EG system needs. I agree that antenna preamplifiers should be
> avoided when it is possible.
> 
> 73,
> Mauri I4JMY

The old argument or idea you never need an amplifier is just as silly 
as saying you always do need an amplifier.

I would guess the "rule" we never need -140dBm sensitivity is 
based on a suburban location, perhaps with a wide filter, or 
perhaps a very efficient antenna. It is almost certainly NOT based 
on a very directional antennas, in particular inefficient antennas, 
since the more directional the antenna the lower the noise level is.

Suggesting people always do NOT need an amplifier or a very 
sensitive receiver because we read it someplace is like telling them 
they always DO need one. Both are very wrong, because the 
circumstances vary greatly!

There is one rule that always works.

Set your gain with use of preamplifiers or attenuators so you can 
just comfortably hear a noise increase when the antenna is 
connected, and a definite decrease with it removed.  If your receiver 
can not take you comfortably into the noise without overloading on 
the strongest 160 signals, then you need to buy another receiver or 
have your receiver repaired...or give up working some weak signals.

My web page covers this in detail.
73, Tom W8JI
W8JI at contesting.com 


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