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Re: A051



this method of correcting for doppler is an incorrect practice. It might be fine if you and your buddy are the only two on the satellite.  also, notice you say 'you perfer', not the correct method. As doppler affects both frequencies, they should both be corrected using computer control. In the absence of computer control, the higher of the two frequencies is always corrected because doppler affects the higher frequency more. It does not matter if this is your tx or rx, it is always the higher frequency.

73...bruce

-----Original Message-----

From:  "i8cvs" <domenico.i8cvs@tin.it>
Subj:  [amsat-bb] Re: A051
Date:  Thu Aug 23, 2007 3:04 pm
Size:  1K
To:  "Scott Wilson" <s.wilson@yahoo.com>, <k3szh@netzero.net>,        "AMSAT-BB" <amsat-bb@amsat.org>

----- Original Message -----
From: "Scott Wilson" <s.wilson@yahoo.com>
To: <k3szh@netzero.net>; <amsat-bb@amsat.org>
Sent: Thursday, August 23, 2007 5:38 PM
Subject: [amsat-bb] Re: A051

> For those more experienced, I do have a couple of questions:
>
> When operating an inverting linear, do you generally transmit on USB and
> listen LSB or visa versa?

Hi Scott, NW2S

We transmit LSB and we receive USB because doing so many other radio
hams dedicated to tropo traffic in VHF/UHF can hear us from the satellite
by chance in 2 meters and 70 cm where they normally operate in USB for
tropo.

> When operating linear, what's the accepted approach to doppler correction?
> It seems that you would be able to transmit without any correction, but
> that your receive would vary a lot more - or perhaps again, visa versa?

There are various preferences but since OSCAR-6 I prefere to keep constant
the frequency of my return SSB signal while manually correcting the TX
frequency to keep my voice constantly clear while speaking.
If the operator in contact with me do the same then our QSO start and end
on the same frequency during the whole orbit.
I prefere to use separate RX and TX and in my case they are nothing special
very old and mostly homebrewed equipments.


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