[amsat-bb] Geostationary & HEO Satellites

Fri Feb 8 23:17:27 UTC 2019

Yes!  That delay is a problem for Internet (TCP/IP) connections.  Special
proxies are used to increase throughput.

The geosat is not even launched and the ham radio community is exchanging
technics to overcome technical challenges.

I was thinking of other geosat uses.  A beacon in the sky for taking
antenna patterns.  A frequency reference for calibration.  Verifying
antenna G/T.  Calibrating antenna AZ/EL pointing.  Endless uses.

On Fri, Feb 8, 2019, 17:52 Jim Sanford <wb4gcs at wb4gcs.org> wrote:

> Very much what  I see with my satellite internet -- if I ping something,
> I see delay between 600 - 800 msec.
>
> Jim
>
> wb4gcs at amsat.org
>
>
> On 2/8/2019 4:20 PM, Paul Andrews wrote:
> > 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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