Re: [amsat-bb] AO-51 or ECHO downlink power

["Patrick Green" <pagreen@xxxxxxxxx>]

One of the problems I noticed when AO-51 1st started operations in standard
repeater operations was people kerchunking it to keep it active.  The
repeater comes up and 5 seconds later, it would drop and couldn't track it
anymore.  I'm sure this would be a source of a lot of QRM at the beginning
of passes over populated areas.

Perhaps the control ops can make AO-51 operate like a repeater when it's not
over a populated area and always on when it is.  Doing this should improve
the power budget significantly but will the software remember a schedule or
change modes without control operator intervention?

73 de Pat --- KA9SCF.

On 7/20/06, Bill Ress <bill@hsmicrowave.com> wrote:
>
> Hi Bob, et al!
>
> I have always wondered about the apparent 100% ON time philosophy used on
> AO-51. Perhaps after a few years of operating, AO-51 ops might clear up
> this
> questions.
>
> Also, I never did understand why the 7 watt capability was touted but
> never
> used (to the best of my knowledge). The high power was indicated as
> offering
> simple receiving requirements to a wider community not having more
> sophisticated setups.
>
> Then too, unlike SO-50 which must be PL'ed on and then timed off, the PL
> on
> AO-51 must serve another purpose (ala squelch) since from what I gather
> the
> transmitters (those selected) on ON all the time and the PL just keys the
> modulation.
>
> Just curious...Bill - N6GHz
>
> -----Original Message-----
> From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org]On
> Behalf Of Robert Bruninga
> Sent: Thursday, July 20, 2006 11:38 AM
> To: amsat-bb@amsat.org; tmcgrane@suffolk.lib.ny.us
> Subject: Re: [amsat-bb] AO-51 or ECHO downlink power
>
>
> >>> McGrane <tmcgrane@suffolk.lib.ny.us> 07/20/06 12:24 PM >>>
> >I have a few points regarding the low power downlink of ECHO.......
> >A year and a half ago, I proposed...changeing the satellite
> >control to allow excess solar power, beyong battery charging,
> >to be directed to the transmitters for higher power daylight operation.
>
> I wonder also if the transmitters are on all the time including the 90% of
> the time they are not over the 10% of the earth with Ham radio
> operators?  I don't know, because when I listen (in the usa) of course
> they are always on.  I dont know what they do the other 95% of the
> time.  Since there is PL on the uplink, it would seem possible to
> have that start a 1 minute time out timer that would key up the TX
> while in view of users, and then time out 1 minute after last user?
>
> This would allow a 10dB increase in TX power with no impact on
> average power budget.
>
> >I believe one of the intents of echo was to introduce new users to
> >satellites and amsat.
>
> Being 10 dB stronger when in view, and Off when no one is in the
> footprint  would make it a lot more visible to modest users.
> Again, I could be fully wrong and maybe it does only come up on
> PL 67.  But I could not find any mode-descriptions on the web
> page that gave this kind of detail.  So forgive me for guessing...
> or for not finding the right info...
>
> Bob
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