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RE: AO-51 Mode J Desense Solution



See below.

> -----Original Message-----
> From: owner-AMSAT-BB@AMSAT.Org 
> [mailto:owner-AMSAT-BB@AMSAT.Org] On Behalf Of John W Lee
> Sent: Wednesday, 25 August 2004 3:11 a.m.
> To: schiers@netins.net
> Cc: zs1zl@qsl.net; amsat-bb@AMSAT.Org
> Subject: Re: [amsat-bb] AO-51 Mode J Desense Solution
> 
> 
> Regarding where to put the duplexer to reduce the 
> desense on mode J,  I tried it in the receive side and 
> it really didn't help too much, but when I put it in 
> the transmit side, it helped a bit more.
> 
> This is with an FT-847. 
> 
> 73, 
> John K6YK
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of 
> the author.
> Not an AMSAT member? Join now to support the amateur 
> satellite program!
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> 

John,

The idea is to shunt-out as much of the 2m signal before the front-end of
your 70cm receive.

I'm now assuming you added a 70cm shunt on your 2m uplink?

Please provide a few more details of the testing you did, and the final
configuration that is now working for you.

I see two options:
A) What you now have is not the best possible, and someone may be able to
provide you some additional ideas, or
B) You've confirmed another solution that may be of value to others.

Of course, another options is I've fully missed the point, and someone will
put me right.

I assume you have reviewed the notes on the AMSAT-NA web site at
http://www.amsat.org/amsat-new/echo/ModeJ.php

The above article does discuss the option of the filter on the 2m uplink,
but presents the alternative of the filter on the 70cm side.

Regards,
Jim, ZL1TYF.
----
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