[amsat-bb] Geostationary & HEO Satellites

[Paul Andrews]

Simon,

I spent 20 years building data circuits using geosynchronous satellites.
During that time, my definition of round trip was
uplink-dowlink-uplink-downlink or 4 x 150ms (plus or minus a small amount
of Doppler).

Yes - you're correct - the loopback delay is 300ms.  But if you communicate
with another person on Earth, the round trip delay is 600ms.

If you tell someone a joke, you won't hear the laugh until after a 600ms
delay.  This is only true for a good joke.  Tell a bad joke and the delay
will be infinite.  :O

73 - Paul - W2HRO




On Fri, Feb 8, 2019, 16:09 Simon Brown <simon at sdr-radio.com> wrote:

> Paul,
>
> Unless there's significant latency inside the satellite, I think you're
> out by a factor of two. Round trip is 2 x 40,000 km (*) = 80,000 km total.
> Speed of light and radio latency says we're looking at closer to 300 ms.
>
> (*) depending on where you are on the mother planet.
>
> Simon Brown, G4ELI
> www.sdr-radio.com
>
>
> -----Original Message-----
> From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Paul Andrews
> Sent: 08 February 2019 19:27
> To: Les Rayburn <les at highnoonfilm.com>
> Cc: AMSAT BB <amsat-bb at amsat.org>
> Subject: Re: [amsat-bb] Geostationary & HEO Satellites
>
> GEOSATs have another interesting characteristic.   600 ms round trip
> delay due to the longer distance.
>
> Does anyone remember when MCI first started providing a discounted long
> distance telephone service?
>
> This will make voice QSOs a little unnatural but certainly not impossible.
>
> 73 - Paul - W2HRO
>
>
>
>
>
> On Fri, Feb 8, 2019 at 12:21 PM Les Rayburn <les at highnoonfilm.com> wrote:
> >
> > I’m also a newcomer to the birds, but very excited about it. Likewise, I
> responded to the survey, but wanted to comment further regarding
> geostationary and HEO satellites.
> >
> > In the camp of “Both, please.” The HEO birds would once again offer the
> possibility of DXCC and make WAS more realistic—it also offers more
> operating challenges.
> >
> > But a geostationary amateur satellite would have many interesting
> benefits:
> >
> > Provide an easier introduction to satellite operation, and attract new
> operators.
> > Excellent tool for emergency communications during a natural disaster.
> > Opportunity to experiment with microwave operations.
> > The ability to enjoy satellite operation any time of the day/night. The
> band is always open.
> >
> > I’m grateful for anyone who incorporates amateur radio into their
> satellites, but feel that birds should include either linear, digital, or
> FM transponders whenever possible. Designers are asking a lot of hams when
> they solicit our monitoring their telemetry signals, and using amateur
> spectrum for their purposes without much tangible benefit to us. My opinion
> only.
> >
> > It’s wonderful that they asked us. Dialogue is the key to most human
> accomplishment.
> >
> >
> > 73,
> >
> > Les Rayburn, N1LF
> > Maylene, AL
> > EM63nf
> > AMSAT #38965, ARRL Life Member, CVHS Life Member, SVHF Member
> >
> >
> >
> >
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
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