TopBand: Re: Bandpass Filtering
Tue, 23 Feb 1999 09:16:17 -0500
Date sent: Fri, 19 Feb 1999 07:57:09 -0600
Subject: TopBand: Re: Bandpass Filtering
Copies to: email@example.com
> Concerning how to split one antenna to a couple of receivers, the
> easiest way is to use an inductive directional coupler that gives
> two outputs of typically -4db but with some 30-50db isolation
> between ports.
Most books don't warn you of this, but splitters only offer high port
isolation when perfectly terminated. They are nothing but bridge
circuits, and anything that upsets bridge balance (at least one port
is always part of the system that sets bridge balance) upsets
If you want 40 dB of isolation into varying loads or source
impedances, you need to use a lossy pad splitter and an amplifier
system. But in general receivers are not isolation critical, so a
simple cheap magic T splitter works just fine.
> -----Original Message-----
> From: firstname.lastname@example.org
> [mailto:email@example.com]On Behalf Of Peter
> Sent: Thursday, February 18, 1999 8:22 AM
> To: CQ-Contest@contesting.com
> Cc: firstname.lastname@example.org
> Subject: [CQ-Contest] Bandpass filtering
> Has anybody out there some experience with homemade band pass filters
> for the 200 watt level?
> yes I kwon there are dunstarr and ice filters, but howebrew is still my
> favourite way!
> Second are there any drawings for the use of 1 berverage and two rigs
> e.g. 80 and 160?
> How does the group handle this?
> FAQ on WWW: http://www.contesting.com/topband.html
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73, Tom W8JI
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