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R: 1269 power???



Hi Perry, WB8OTH

Probably you was not in the right frequency for the uplink because of
doppler shift during the orbit.

To excite my 23 cm transverter I use a FT290R for 2 meters wich has
10 memories.

I use the 2 meters memories to get output in 23 cm in 5 KHz steps in the
following frequencies.

1268.675 MHz  at AOS or acquisition of satellite
1268.680 MHz
1268.685 MHz
1268.690 MHz
1268.700 MHz  at TCA or time of closest approach (nominal frequency)
1268.705 MHz
1268.710 MHz
1268.715 MHz
1268.720 MHz  at LOS or lost of satellite

This metod obviously is tedious but is works and with less than 5 watt at an
array of 4 x 23 elements yagi horizontally polarized currently used for
AO40 I got a full quite downlink to day particularly during the ascending
orbits when I was able to use and test the L/S mode for three or more
minutes only for myself because at the moment there are not users in range
south of my QTH

Even if my array is linearly polarized and the AO51 antenna for 23 cm is
also linearly polarized the QSB on my downlink was not deep at all.

Switching the memories while manually traching AO51 just for testing
and curiosity to day was satisfactory and my calculated EIRP was about
650 to 1000 watt

Increasing the power from 5 to 10 watt or more and more power do not
produces a significant change in readability.

My receiving system is the same currently used for AO40 e.g. 1.2 meter
dish with helix feed preamplifier and downconverter.

The only advantage to use more than 650 watt EIRP was a signal readable
even if  I was not in the exact uplink frequency but just in the dead zone
between two 5 KHz steps.

I hope this helps for your evaluations.

Best 73" de

i8CVS Domenico

----- Original Message -----
From: Perry Yantis <pyantis@earthlink.net>
To: Amsat BB <amsat-bb@amsat.org>
Sent: Wednesday, March 30, 2005 6:07 PM
Subject: [amsat-bb] 1269 power???


> How much power are you using to access AO51 when using 1269 uplink???
>
> I have only 10 watts and thought that would at least get me into the bird
> but it doesn't.
>
> I did hear myself on AO40 in the past but it was weak.
>
> I figured that with AO51 being in a lower orbit that 10 watts would work
OK.
>
> I guess I will have to look around for a 1269 amp??
>
>
> Perry Yantis WB8OTH
> pyantis@earthlink.net
> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
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----
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