[amsat-bb] Re: FO-29 users where are you?
domenico.i8cvs at tin.it
Sat Aug 30 06:34:30 PDT 2008
----- Original Message -----
From: "Sebastian" <w4as at bellsouth.net>
To: "AMSAT BB" <amsat-bb at amsat.org>
Sent: Saturday, August 30, 2008 6:41 AM
Subject: [amsat-bb] FO-29 users where are you?
> It seems that most of the time when there is a pass in my area from
> FO-29, there are no users on the bird. FO-29 is an excellent & loud
> satellite, and it requires very little output power.
> I just spent 10 minutes or so calling cq, and listening up and down
> the passband, and there is no one around. It gets boring listening to
> myself on the downlink! This is generally the case, no matter the
> time of day or night.
> Please, those of you who have the equipment - FO-29 is alive and well,
> let's use it!
> 73 de W4AS
Hi Sebastian, W4AS
Over Europe there are many users of FO-29 but all of them are equipped
with low noise preamplifiers antenna mounted and good antennas.
By the way when FO-29 comes up at AOS it is very common to listen for
many stations trying to get back for their own signals back and fort all
over the pass-band without success because their receiving sensitivity is
Since the FO-29 sensitivity is very high only a very low EIRP is necessary
to be translated with sufficient power for a decent QSO in SSB or CW
provided that the ground station sensitivity is adeguate as well.
Quoting many succesfull ground stations using FO-29 over EU it is possible
to state that for good operation all over the orbit from AOS to LOS a
minimum ratio G/T = - 2 dB is necessary.
As an example:
Antenna gain G = 13 dBi = 20 in power factor
Overall receiving Noise Figure = 0.45 dB equal to T= 31.6 kelvin
G/T = 20 / 31.6 = 0.63 and 10 log 0.63 = -2 dB
In order to get about the same ratio G/T = - 2 dB and following the
above formula we see that it is possible to use an antenna with
G= 16 dBi = 40 in power ratio and a greater receiving system overall
Noise Figure = 0.9 dB corresponding to T = 67 kelvin
And so on..........
Many years ago the recommended ratio G/T for every satellite was supplied
The above G/T = -2 dB for FO-29 has been experimentally derived knowing
the working conditions of many succesful stations in QSO with me over
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