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Re: Satellite Inquiry



Hi all,
Just would like to point out that a 5KHz deviation signal has an emission
designator of 16FK3. This means that your signal is 16 KHz wide. I found
here with a marginal signal into the satellite that 1 KHz increments and a
reduction of mike gain allow me to get through on my 5/8 wave vertical.
I guess my original question of how accurately you can correct for Doppler
in terms of % corrected, is still not answered.
Art KC6UQH

----- Original Message -----
From: "Emily Clarke" <w0eec@amsat.org>
To: "Andrew Glasbrenner" <glasbrenner@mindspring.com>; "KC6UQH"
<kc6uqh@cox.net>
Cc: "AMSAT BBS" <amsat-bb@amsat.org>
Sent: Wednesday, February 23, 2005 3:43 PM
Subject: Re: [amsat-bb] Satellite Inquiry


> At 11:08 PM 2/22/2005 -0500, Andrew Glasbrenner wrote:
> >By Full Doppler Tuning I'm assuming you mean full computer control of
both
> >uplink and downlink doppler tuning...
>
> Not necessarily - manual FDT is possible, at least on the 910H.  I think
> the 847 and TS-2000 have similar schemes but I don't know for certain.
>
> >Manually tuning in 5 khz steps works fine for UHF FM uplinks. With the
> >exception of the ISS, most FM satellites have a very wide front end
> >designed usually for 9k6 or higher reception. More like 15 khz wide than
> >the 6 khz you assumed in your calculation. (quick reference, AO-51's 4
VHF
> >receivers have 15 or 30 khz wide IFs, page 33 Echo book, first edition)
> >The ISS is different in the fact that it is a terrestrial radio, and
> >therefore is much more picky about being on frequency. For this exact
same
> >reason, narrow FM works MUCH better on the ISS repeater (instead of
making
> >the IF wider, you make the signal narrower). Still, 5 khz tuning is
> >perfectly doable on ISS U/V repeat. In fact, I made several contacts on
it
> >while mobile, tuning in 5 khz steps.
>
> I totally agree that tuning in 5KHz steps is fine.  My observation has
been
> only that it should be done.
>
> While I used an FM repeater as an example my comments were really intended
> to indicate that would be the best situation and that FDT would certainly
> be required for SSB/CW operation.
>
> It's interesting that you mention that AO-51's VHF receivers are 15K+
wide.
> While I know that the IF is that wide, I don't know if that correlates to
> the entire range of FM capture.  Perhaps someone can comment on that.
>
> >I'm sure the AFC feature in the Kenwood up there helps with this too. I
> >also made dozens of contacts on SO-35 U/V FM (R.I.P.) with nothing more
> >than an Alinco DR-605T and a dual band mag mount, again tuning the uplink
> >in 5 khz steps. I don't mean to have a been there and done that attitude,
> >but i _know_ it works because I have done it.
>
> I haven't used it for some time, but I believe AFC on the 910H will track
> the receive frequency but doesn't compensate the transmit frequency in the
> same way that manual FDT (using the tuning knob) does.  I'll try it
tonight
> on 27 to refresh my memory.
>
> 73,
>
> Emily
>
>
> ---------------------------------
> W0EEC - CM87tm
> AMSAT Area Coordinator - San Francisco Bay Area
> http://www.projectoscar.net    http://www.PlanetEmily.com
>
> Join AMSAT!  http://www.amsat.org
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