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Re: Wish list (was RE: FM on ssb/cw designed hamsats)



----- Original Message -----
From: "Fabio Roccatagliata" <roccaf@gmail.com>
To: "Tony Langdon (ATC)" <tlangdon@atctraining.com.au>
Cc: "AMSAT" <amsat-bb@amsat.org>
Sent: Friday, November 25, 2005 9:07 AM
Subject: Re: Wish list (was RE: [amsat-bb] FM on ssb/cw designed hamsats)


> Sincerely I don't think 70cm and upper bands are the easiest for uplink.
> Common V/U setups are not enough strong for satelites operations
> expecially for those living in not good locations (mountains,
> etc....).

Hi Fabio, F5VKV

For those living in no good locations AO40 demonstrated that using 
70 cm with 100 watt to a 13 dBic yagi or using 23 cm with 20 watt 
to a 20 dBic yagi it was possible to communicate worldwide SSB 
for hours using 13 cm for downlink with only a small dish 60 cm in 
diameter so that many of us where simply using a camera tripod with 
the antennas mounted on it over the balcony or in the garden and aiming 
the antennas time to time by hand with the additional advantage of 
running very short transmission lines.........and all of this advantages 
because they where living in a no good locations.

>
> I would definitely prefer to have perhaps some uplinks on 29Mhz or
> 144Mhz than on 70cm where, expecially with HEOs, the visibility
> home-bird is very important.
>
You cannot easily move in elevation a 29 MHz ground antenna to send
the necessary EIRP to an HEO satellite.
In addition the man made noise level picked up by the satellite receiver
would be very high at 29 MHz and the 29 MHz EIRP would be highly
reflected by the ionospere in periods of good ten meters propagation
and because of this 29 MHz will be used for uplink on P3E only for
RUDAK multimode low-speed mode but not for SSB or CW

AO40 demonstrated that using 2 meters uplink when the matrix was
experimentally switched ON in mode V/S the noise piched up from the
earth was so strong that EME array where necessary to communicate 
having the bird at apogee with good squint angle.

If you like to know what is the best uplink choice for a HEO satellite look
please at the  "P3-E Frequenztabelle " in to the AMSAT-DL site and you
will realized that for the uplink to a HEO satellite 70 cm, 23 cm and 5.7
GHz is the way to go.

> Newbie sat specs: Mode A, K or T ! (Most of us started with RS12/13/15)

This sound good and very interesting for LEO satellites.

> 73
> Fabio
> F5VKV
>
Best 73" de

i8CVS Domenico
----
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