(Fwd) Re: [sarex] ISS TEST... who was successful?

["Stan Vandiver" <Stan@xxxxxxxxxxxx>]

Oops, I forgot to include the mailing list!  Sorry!!

------- Forwarded message follows -------
From:           	Stan Vandiver <Stan@Vandiver.com>
To:             	Bob Bruninga <bruninga@usna.edu>
Subject:        	Re: [sarex] ISS TEST... who was successful?
Send reply to:  	Stan@Vandiver.com
Date sent:      	Thu, 24 May 2001 05:17:13 -0000

Hi all,

OK, I'll get in at least another one before I go to bed... which won't be much
longer.

On 23 May 2001, at 23:04, Bob Bruninga wrote:

> In retrospect, we should not have been posting the ISS positions, since
> this was an unattended test, and so there was noone there to see them.
> Good point for lessons learned...

I am happy to offer my critiques, and I am trying not to be unduly harsh 
toward the APRS systems, or you Bob.  APRS is "your baby"... and I 
undoubtedly understand that you are proud of it and do all that you can do to
promote its interest.  And I think its doing very well too... you should be
proud of it!  I just also don't want a nagging feeling of, "Do as I say, not as
I do." coming from big guys like yourself.

You didn't comment (yet that I've seen) on the W3ADO ERP level and 
antenna system.  I am interested to know that, if you would be so kind?  
What raw power level was used for the test, and did you use a satellite 
tracking antenna array?  What kind of antennas, etc?

> > ... shall we conduct an experiment to LISTEN TO THE UPLINK? 

> Great idea!  I would suggest an UPLINK monitoring test on 21 July when
> scouts all across the country will be climbing mountains with HAM gear to
> participate in the "operation ON TARGET".  Scouts climb high places to send
> flashing mirror comms that day.  From that height, it will be good to listen
> on the ISS Uplink during passes... and see what you hear.

Wow, that is an exceptional idea... if the scouts can put together enough 
receivers on the mountain tops too.  I'm sure they'll be climbing in daylight, 
and that's a Saturday, so there is a potential for a LOT of activity on the ISS 
uplink!  I wonder if they might be able (in some cases, anyway) to take 
beams and scan their horizon to cover both rural and urban areas?  Or 
would the height of their climb be enough of an advantage?  

I have not run a projection for pass times that far in advace... but don't think 
it should be off by too awful much using current keps.  Will check on that 
later unless someone else posts it here.  Might we be so lucky that the ISS 
will be in range during the time frames needed for the scouts?  But perhaps 
the astronauts will be watching for their mirror reflections too?!?!  Or trying 
to talk to some of the scout packs on voice?!?!?  

> Otherwise, it would take about 10,000 or more monitoring stations to hear
> what ISS hears... I'd hate to accumulate that data... But actually, having
> another receiver always monitoring the uplink is a good idea in general.  I
> do, and I always hear a few other stations trying.  

Well, yes... its impossible to truly emulate what the ISS is hearing.  But if
there are a lot of participants from home stations and the scouts, it might
represent a good estimate.  Especially in comparing rural to urban areas.

I am kind of in both... I live in a rural area with clear open skies, but I can 
hear packet stations throughout the Chicago area.  At least when 
circumstance are good.  I don't leave a receiver on all the time, but switch 
so rapidly when I'm checking that I still catch most of the ISS downlinks... 
so I should catch at least some uplinks if they're out there (as I have caught 
a couple of friends nearby).  But a lot of factors could keep me from hearing 
an accurate representation from Chicago too... beams pointed toward ISS 
instead of me, lower power stations, etc.  I can setup another computer, 
TNC, and receiver full time for any tests though.  

Bob, you're out east somewhere, and there are generally more people out 
your way.  Or I assume so, even though I am so close to Chicago.  You say 
you hear "a few stations".  Have you examined those more closely... to see 
how many unique stations are trying (could be both fixed or mobile)?  And 
how successful they have been in digipeating?  Have you identified some of 
these stations as "beacon alligators" already?  I could pretty easily scan 
through all of my packet logs if there were particular callsigns to look for, 
but it is a daunting task to try to make sense of all of that traffic unless 
someone might have a program that would "scan" text files and extract the 
callsigns and time stamps for analysis.  That would be a cool program!  

I have said elsewhere that everyone that I know of has been successful here 
near me.  But I have read the reports from some folks who have been  
diligently trying with no luck at all, one just recently with hefty ERP applied 
too.  One person asked if the ISS antenna might be "shadowed" at some 
times... creating "dead zones".  I wonder if this could be evaluated?  If so, 
the "dead zones" should vary with ISS position.  This might be observable, 
but would take a lot of dedication.  And I'd hate to be the one collecting all 
that data too! Another very likely scenario proposed to me recently was that 
the ISS radio uses a "programmed squelch circuit"... and that value may 
not be very good (either open squelch or "too tight" might both be bad 
conditions).  Well... more to think about.  

A "series" of "spot check" tests might also show a good representation of 
activity levels.  Rather than monitoring a long 8-hr session... maybe pick 
one pass per day, over a week or two week period.  But this seems like it 
might be harder to get a lot of participation... having people remember to 
keep the schedules, etc.  Maybe just a comparison between a weekend 
day and a weekday when many folks are working?  Looking for HIGH and 
LOW numbers, generating some averages, etc.  

Would be interesting also to try to continue monitoring how much power 
and transmit rates people are using... well, those who successfully get 
digipeated anyway.  What can we tell newcomers about what "their odds" 
are of getting in.  

The concept of "listen a lot" but only "talk a little" is definately a good idea 
in all of ham radio, but putting that rigidly into practice in the test this 
morning showed me clearly that I cannot have keyboard QSO's at that 
transmit rate (and with the ground plane antenna instead of my beam)... 
even with 100+ watts.  I don't know where to "draw the lines" for what is 
acceptable or what is not.  Its not my job anyway, nor are people 
necessarily interested in "Stan's Rules" either.  

But I think there is a lot for all of us to learn about operating conditions with 
the ISS.  And as the ARISS equipment moves to a new module and gets 
new equipment and modes... they may all have their own operating "quirks" 
and need to be evaluated.  

Well, no new posts to comment on as I sit here, so I'm going off to bed. 
Again, accept my apologies if I don't make further replies for the next few
days due to my work schedule.  But I will if I can...

73 to all,

Stan/W4SV

------- End of forwarded message -------
----
Via the sarex mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe sarex" to Majordomo@amsat.org