Re: [amsat-bb] Interference on AO-51

[k0vty@xxxxxxxx]

Hi All

Ah yes, thanks Dom for the memories
Memories of my first Qso through a satellite, OSCAR III
All that home brewing for two years in preperation for that bird.
That CW contact with a straight key might as well been done with a loose
toggle switch.
Never will forget the promises and the absolute joy of the start of my
satellite hobby.

Thanks again Dom

Joe  K0VTY
=======================
On Fri, 5 May 2006 21:21:28 +0200 "i8cvs" <domenico.i8cvs@tin.it> writes:
> ----- Original Message -----
> From: "Tim Tuck" <tim.tuck@penrith.net>
> To: <amsat-bb@amsat.org>
> Sent: Friday, May 05, 2006 1:41 AM
> Subject: Re: [amsat-bb] Interference on AO-51
> 
> 
> > Robert Bruninga wrote:
> > >>>> "Phil Paulhus" <ppaulhus@verizon.net> 05/04/06 10:47 AM >>>
> > >> I thing Bob's ideas are right on target.  Using 2 meters
> > >> for both the up and down links would open the door ...
> > >
> > > Ah, but that is the problem.  We cannot have the uplinks
> > > and downlinks in the same band.  That is the current
> > > problem on ISS.  Because they use 2m for both up and
> > > downlinks for school contacts, no other system can
> > > use 2m at the same time becuase it will either be
> > > jammed when the ARISS system transmits, or it will
> > > jam ARISS when it transmits.
> >
> > Umm... I may be missing something here but cant we use some nice 
> cavities
> > or helical filters  just like we do in normal repeaters to reduce 
> or
> > eliminate this  problem ?
> >
> > regards
> >
> > Tim
> 
> Hi Tim VK2XTT
> 
> OSCAR III the first radio amateur active real-time communication 
> satellite
> lanched 9 march 1965 in a LEO orbit 565/585 miles carried a 50 KHz 
> wide
> 1 watt transponder that received radio signals near 146 MHz and
> retransmitted them,greately amplified, back to earth near 144 MHz 
> thereby
> demonstrating that big cavity filters where not needed on board of 
> it and
> infact you can see the small size of this satellite reading the book 
> " The
> Satellite Experimenter's Handbook " written by Martin Davidoff  
> K2UBC
> Chapter: The Early Days, page 2-11
> 
> Probably well designed helical filters were used as you suggested to
> sufficiently isolate the upconverter and downconverter only about 2 
> MHz
> apart on this 2 meter in-band transponder in a epoch time 1965 in 
> wich high
> dynamic range mixer and transistors were not yet invented and 
> available
> and so............imagine the difference in now'adays technology !
> 
> Quoting K2UBC,  "OSCAR III operated only 18 days during wich time 
> about
> 1000 amateurs in 22 countries were heard trough it .A numbar of long
> distance communications were reported, including Massachusetts to 
> Germany,
> New Jersey to Spain, and New York to Alaska "
> 
> Best 73" de
> 
> i8CVS Domenico
> ----
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----
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