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Re: Helping Pacific G4FVG/MM on P&O Nedlloyd "Mercator" hear AO51



Hi Amsat folk

Firstly - thanks much those who helped on Great Circle navigation.
I found a site with a JAVA applet calculator, and figured the positions.
This proved to be a lot of work because his QTH is capable of moving
several hundred miles in a day!

Mike has reported failure in hearing Echo, and maybe this is because
we are both a bit klutz, and have never done this before. Hence we have
some questions.

1. Does AO51 recharge/sleep/quit during periods over the oceans when the
footprint is assumed unlikely to have any users?

2. Can he manage to compensate doppler shift with a handheld Rx?

3.There are times when the footprint covers both his ship and the western
regions of Canada & USA. Is it possible he can't hear it because everyone
assumes there is only water and sharks out there?

Mike will definitely be in range of some active ham radio satellite operators
soon, because he approaches Vancouver. Perhaps I should explain that Mike's
ocean emails are seen by everyone on his mail list because Inmarsat email shots
are so expensive that he makes do with only one for all. 

___________________________________________________________

<quote> (Mike G4FVG/MM on P&O Nedlloyd "Mercator")

A mark 1 schedule has been received from the trade department in Singapore 
who think we will be:-

Port       Arrive                  Depart
Vancouver  1600  SUN  03-Oct-2004  0800  WED  06-Oct-2004  at 18.0 kts, for
Seattle    1800  WED  06-Oct-2004  0800  FRI  08-Oct-2004  at 22.0 kts, for
Kaohsiung  2300  TUE  19-Oct-2004  1300  WED  20-Oct-2004

but the first arrival will depend on the weather. Our poor engine is 
guzzling the fuel in the hopes of keeping up sufficient speed but we need
around 24.9 kts to make the eta at the pilot station for 11am in readiness
for the 4-5 hour pilotage up to Vancouver. Time will tell ......

Thanks to GRAHAM for the efforts on the satellite predictions during the 
last week (that has been the only emails received). The layout of the second
message looks the best on the screen and on paper with the tabulated 
columns.
Example:-

SATELLITE----DATE- TIME----    S-AZ    MAX EL-----    DURATION    E-AZ
ISS (ZARYA)  30    07:15:18    290     16 (AZ 226)    00:09:14    161
AO-51        30    07:27:52    099     09 (AZ 052)    00:10:47    007
AO-51        30    09:03:32    153     58 (AZ 063)    00:15:04    351

and I tried all three of the above, unfortunately, with no success.  I said
that the azimuth wouldn't make a difference to my omni-directional handheld
but in fact it does, as it tells me which side of the ship to stand on!! :-)
I'm not sure whether the ISS/AO51 transmit a beacon when there is no voice
activity and, of course, I am having to try and "guestimate" the doppler 
shift for the transmit and receive - so the lack of signals may be attributed
to this.

 Perhaps David/MAL could throw some light onto this satellite reception
as to the required maximum frequency offset and whether, in practice, it 
makes any difference to a wide band receiver with a 25 khz filter??

Failing that, Frank Bell might know a bit more but he is not on Dave's
mailing list (yet!) As you said yourself, the difference in timings between
your very good guestimations of our location every 5 degrees of longitude
isn't very much..

[Predictions for Waypoint W11 <46-19N 160-00W> at 05:23 on Oct 1st will only
be an hour out as we are struggling maintaining 24 kts - in reality only 
doing 22.3 kts; making a realistic eta at Vancouver pilots for 1400 LT; three 
hours later than planned] As I am ready to receive the satellite around 4-5 mins
before and remain listening afterwards for another 2-3 mins, I think your
waypoints could be 15-20 degrees of longitude apart with little noticeable
change (especially if I continue to hear nothing!)

Perhaps there will be  some shore generated activity whilst alongside at
Vancouver, so can try those predictions out.

<end quote> (Mike G4FVG/MM P7O Nedlloyd "Mercator")
_____________________________________________________________________

OK - so I know we need a little handholding. Quite the opposite extreme from
those slick dudes who can hop from sat to sat (see Sat Hoggs WA6FWF 29 Sept) :-)

My regards to all

Graham G4WNT
----
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