[amsat-bb] HEO

[Burns Fisher]

As the volunteer who wrote the code that does it, I can tell you with
certainty that when AO-92 is switched to L-band it turns off in 24 hours
automatically (or sooner if the satellite goes into safe mode, resets, or
is commanded to UHF).  The time was chosen just because of the
uncertainties.  Would L-band work?  Would anyone use it? Will the power use
be prohibitive (analysis said it was ok, but...)  The time is hard-coded
in. It would have been nice to be able to change it by command, but the
entire design of the original Foxes were based on a lot of uncertainty.
There was not much time to change after some certainty was gained after the
first launch or 2, so that capability is not available.  Fox-1e is an
improvement over the previous Foxes.  HuskySat was an improvement over
that.  (Despite the opposite launch order).  And Golf will be a big
improvement over both, in all cases because of what we learned from the
earlier satellites and the extra time available.

As to the day that it is switched, that's outside of my pay grade :-)

73,

Burns WB1FJ

On Wed, Jul 22, 2020 at 4:56 PM David Worboys via AMSAT-BB <
amsat-bb at amsat.org> wrote:

> Following on from Patrick’s post (below), I just got home and checked to
> find that the first AO-92 pass for me is at 23:13 edt tonight which, as I
> have to get up at 3.15am for work, is a definite no-no!
>
> What is the reason for L/U to be only switched on for just a 24 hour
> period and during the work week?  Is it automatically switched back or does
> the command station do it? If that latter, can it be left on for say, 48
> hours to give operators a better chance of working L band or moved to a
> weekend slot? What with the non activity last week I think its been about
> three weeks since the last time I could use Mode L and whilst I appreciate
> that there are a lot of people who want to use that mode, opening up the
> ability would give a greater number of operators the opportunity.
>
> If the 24 hour period is the maximum available to preserve the health of
> the satellite then I understand but I would be interested in knowing the
> rationale!
>
> Many thanks
>
> 73
>
> David
> KG4ZLB
>
>
>
>
>
>
> On Jul 22, 2020, at 1:30 PM, Patrick STODDARD (WD9EWK/VA7EWK) via AMSAT-BB
> <amsat-bb at amsat.org> wrote:
>
> Hi Andrew!
>
> I am all for a variety of satellites. When we had AO-51 in the 2000s, I
> found the pieces to work its V/S FM repeater as I started working
> satellites. Doppler at 2.4 GHz made tuning those downlinks an almost
> constant thing on those passes, but it was fun. We have the sort of
> transponder you mentioned in your post with AO-92's L/V FM repeater
> right now. We are only permitted to use the 1.2 GHz band for satellite
> uplinks, not downlinks.
>
> Many satellite operators now have the 1.2 GHz uplink capability with
> the IC-9700, but the only time AO-92 L/V is available appears to be
> inconvenient for many who might want to try it right now (Tuesday
> evenings and Wednesday mornings in North America). We were told that
> the switch from a Sunday UTC activation (Saturday nights and Sunday
> mornings in North America) last year was not going to be a permanent
> change. I think there would be more new call signs heard on AO-92 L/V
> with those IC-9700s and other radios, if that mode was available at a
> more convenient time for those who have work or school commitments
> during the week. It isn't like we lack V/U or U/V FM satellites right
> now.
>
> 73!
>
>
>
>
>
> Patrick WD9EWK/VA7EWK
> http://www.wd9ewk.net/
> Twitter: @WD9EWK or http://twitter.com/WD9EWK
>
>
>
>
>
>
>
>
>
> On Wed, Jul 22, 2020 at 4:46 PM Andrew Lazenby via AMSAT-BB <
> amsat-bb at amsat.org> wrote:
>
> > Hello EveryoneI recently joined Amsat because I felt like a bit of a
> > hypocrite for complaining about things, and not doing my part to change
> > them. One thing that does bug me is the HEO satellites having microwave
> > uplinks and downlinks. I think that will greatly limit the clientele that
> > will be able to use these.
> > I have head many older hams gripe about LEO satellites and reflect back
> > on how back in the day there would be passes up for hours! Many of them
> > where using drifty transverters with terrible noise figures, turning
> > antennas with tv rotators and no preamp! The argument that I have heard
> to
> > move to mircowave uplinks and downlinks is lower noise, but if it worked
> > with them back then, then what's changed?
> > Something else to consider is that the microwave spectrum is under fire
> > from commercial interest more and more. Why not consider like a U/L or
> L/U
> > transponder? That would bring the envelope a little closer to where the
> > average ham could operate with out investing in some serious equipment,
> > while keeping the dream of HEO alive for the large percentage of
> satellite
> > operators, and not just a handful?
> > Forgive me if Im wrong, but I just wanted to put my 2 cents in the pot.
> If
> > we all would learn to work together as much as we fuss we would be making
> > some tracks. Thanks everyone, Andrew N4LAZ
> >
> >
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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
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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>