[amsat-bb] Re: RH and LH CP simutaniously

Sat Jan 3 20:38:40 PST 2009

The entire RF spectrum is being modulated, so if there is another signal 
30-40 kHz away from the desired signal, it will be modulated and one of the 
sidebands will be on the same frequency as the desired signal.

73,

John
KD6OZH

----- Original Message ----- 
From: "R. Chastain" <suenrod at yahoo.com>
To: "Amsat-BB" <amsat-bb at amsat.org>
Sent: Sunday, January 04, 2009 03:32 UTC
Subject: [amsat-bb] Re: RH and LH CP simutaniously

But if the switching frequency was say.... 30-40khz, wouldn't the sidebands 
be so far out of range so as not to cause interferance.

RoD
KD0XX

--- On Fri, 1/2/09, John B. Stephensen <kd6ozh at comcast.net> wrote:

From: John B. Stephensen <kd6ozh at comcast.net>
Subject: Re: [amsat-bb] RH and LH CP simutaniously
To: "R. Chastain" <suenrod at yahoo.com>, "Amsat-BB" <amsat-bb at amsat.org>
Date: Friday, January 2, 2009, 6:30 PM

You can use a 90-degree hybrid splitter/combiner to produce LHCP and RHCP 
for
two receivers. Switching will produce sidebands at the switching frequency 
and
alias undesired signals into the receiver passband.

73,

John
KD6OZH

----- Original Message ----- From: "R. Chastain"
<suenrod at yahoo.com>
To: "Amsat-BB" <amsat-bb at amsat.org>
Sent: Friday, January 02, 2009 23:15 UTC
Subject: [amsat-bb] RH and LH CP simutaniously

Hi all,
Has anyone ever considered the possibilty of using PIN diodes and a free
running square wave oscillator to electronically switch between RHCP and 
LHCP?
The switching frequency would have to be high enough so as to not introduce
a tone to the signal.

Just a thought I have had for awhile.

RoD
KD0XX

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