[TowerTalk] Bandpass Filters

[Dave Hachadorian]

----- Original Message ----- 
From: "Al Williams" <alwilliams at olywa.net>
To: <towertalk at contesting.com>
Sent: Thursday, January 10, 2008 2:02 AM
Subject: Re: [TowerTalk] Bandpass Filters


If one has a bandpass filter such as Dunestar or ICE and 
switch it in for rx
and out for tx, is that good enough or is there really a 
filtering advantage
of transmitting through the filter when nearby ax's have 
their filter in
place?

k7puc
---------------------------

You need a bpf on the transmitter also. Synthesized 
transmitters generate broadband cw (continuous, while in 
transmit mode) hiss that spans several bands, so the hiss 
would be heard even with a filter on the rx. For example, a 
tx on 20m will generate hiss on 15m, which will be heard, 
even with a 15m bpf on the rx, because the 15m hiss is 
in-band.

Dave Hachadorian, K6LL
Yuma, AZ
























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