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RE: AO-40 status report by DJ4ZC



> Van: Joel B. Black [mailto:jbblack@mindspring.com]
> 
> Tony,
> 
> Symek, www.symek.com, has the TNC31S and TNC3S.  I am 
> currently using the
> 31S.  It only has one modem and I'm using it to decode UO-36 
> data (or was up
> until a couple of months ago when I started back to school).  
> After reading
> your post, I dug out the manual.  Apparently, the TNC31S 
> supports up to
> 76800baud.  There are some minor modifications that are 
> required.  I *think*
> the manual is available at the above site.
> 
> You should see 38k4 from UO-36.  If you think 9600 is fast 
> (and it is with
> ASCII), you should see 38k4.  It's faster than my ISP 
> connection at 24k.
> 
I have seen 76k8 experiments using a digital repeater (bit regeneration) to
avoid the hidden node effect, it was enough for streaming video of good
qualety over IP, I can't even get that over my isdn link unless I stack.

It was done without tnc's, just the modem and a normal 10 mhz scc card.
using a otowa pi2b dma scc card the speed could go even higher.

curent plans are for using a normal 10Mb ethernet card to drive a trx (talk
about a sheap modem)
 
73 de Andre PE1RDW
aprsdigi co-ordinator Netherlands
member aprs workgroup Netherlands
mailto:pe1rdw@aprsnl.org

> GL,
> Joel, K2SAT
> 
> ----- Original Message -----
> From: Tony Langdon <tlangdon@atctraining.com.au>
> To: 'Phil Karn' <karn@qualcomm.com>; <na9d@mindspring.com>
> Cc: <amsat-bb@AMSAT.Org>
> Sent: Tuesday, November 21, 2000 11:27 PM
> Subject: RE: [amsat-bb] AO-40 status report by DJ4ZC
> 
> 
> > > If you look real hard, you'll find my link budget showing how with
> > > error control coding enabled, the RUDAK 70cm downlink can 
> support a
> > > reliable 67 kb/s from apogee to a simple patch antenna 
> lying flat on
> > > the ground.  That's a pretty major advance over anything 
> that's been
> > > ever possible with amateur satellites and simple unsteered ground
> > > antennas. It should entice many more hams into satellites, which I
> > > assume is our shared goal.
> >
> > Just one question, is anyone close to having working 
> hardware for such a
> > link?  And if so, what applications are being supported?  
> Data only, or
> are
> > their hooks for digitised voice/video/etc?
> >
> > Not picking, just would love to be a part of this sort of 
> thing. :)  A
> 70cm
> > patch on the roof would be invisible, I can see benefit in that too.
> > Though, if the downlink is on the wrong frequency, 70 would 
> be a mess for
> > me, due to cable QRM...
> >
> > > You'll also see that my analysis showed that if you're 
> constrained to
> > > unsteered ground antennas, no other band works as well as 
> 70cm.  As an
> > > interesting aside, the US military has for some time 
> relied heavily on
> > > UHF for mobile satellite communications.
> >
> > I recall seeing something from you on this.  Do you have 
> your analysis
> > online, would like to have a look.

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