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RE: [aprssig] Re: RE: AO16/LO19 Uplink w ANY PC!



Yes, if it were not for the extra noise you would be opening the receiver 
to.  It is really best to match the receiver bandwidth to the transmitter 
signal.


John W. Wilson, KN4HX
z004391b@bcfreenet.seflin.lib.fl.us


On Sun, 19 Sep 1999 schoon@amgt.com wrote:

 > So, would it be safe to say that by replacing some filters with 20 khz
 > bandwidth and a decent preamp, one could forget about doppler??
 > 
 > .mark
 > 
 > 
 > =================================================
 >  Mark Schoonover KA6WKE	           IS Manager
 >  Trail Runner,HAM	             schoon@amgt.com
 >           ka6wke@wb6dgr.#sca.ca.usa.noam  	   
 >  http://www.qsl.net/ka6wke       ka6wke-1 145.05
 >                Mobile: 146.52 & 28.470
 >    Lat: 32.85380 Long: -117.00980 Grid: DM12LU
 > =================================================
 > 
 > 
 > >----------
 > >From: 	John W  Wilson[SMTP:z004391b@bc.seflin.org]
 > >Sent: 	Sunday, September 19, 1999 1:06 PM
 > >To: 	Bob Bruninga
 > >Cc: 	Mark Schoonover; TAPR APRS Special Interest Group;
 > >aprssig@lists.tapr.org; aprssig@tapr.org; amsat-bb@amsat.org
 > >Subject: 	Re: [aprssig] Re: [amsat-bb] RE: AO16/LO19 Uplink w ANY PC!
 > >
 > >You actually only need down tuning.  As the bird comes over the horizon 
 > >toward you the doppler shift is greatest and only reduces to zero 
 > >overhead and goes negative as it sails off to the other horizon.  I have 
 > >found that max doppler shift has been less than 10 khz plus as it is 
 > >first seen, and 10 khz minus as the satellite disappears.  The shift is 
 > >much less than 10 khz if the satellite does not pass overhead.
 > >
 > >
 > >John W. Wilson, KN4HX
 > >z004391b@bcfreenet.seflin.lib.fl.us
 > >
 > >
 > >On Sun, 19 Sep 1999, Bob Bruninga wrote:
 > >
 > >> > > But of course, a $89 UHF downconverter and an old 10m SSB rig would
 > >>make a
 > >> > > great portable AO16/LO19 downlink..
 > >> > 
 > >> > Remember, most of the software that is out there on the market that does
 > >> > rig tuning thinks it's going to see something nice and shiny-new, with
 > >> > a computer post of some sort to talk to, so either you manual tune,
 > >> > or get really familiar with C or whatever language your tracker/tuner
 > >> > was written up in......
 > >> 
 > >> I think most PSK modems generate up/dn key clicks.  My PSK1 only requires
 > >> tuning initially at AOS, and from then on throuhgout the pass its hands
 > >> off.  Since I was talking about portable operation, the assumption is that
 > >> you manually tune out the doppler at the start of the pass until you get
 > >> lock.  Most 10m SSB rigs (CB market) have microphone up/dn buttons..?  Im
 > >> going to be using the RCI-2650 10m rig... (though not hooked up yet)...
 > >> 
 > >> bob
 > >> 
 > >> 
 > >> 
 > >> ---
 > >> You are currently subscribed to aprssig as: kn4hx@amsat.org
 > >> To unsubscribe send a blank email to leave-aprssig-9933D@lists.tapr.org
 > >> 
 > >
 > 

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