[amsat-bb] Re: AO-51 mode L/S

OZ1MY oz1my at privat.dk
Mon Sep 18 11:23:34 PDT 2006

Hi Michael and amsat-bb
There is an explanation to everything. I have used the AO-40 set-up
with 40 W on 1268 MHz to 2 19 turn helix antennas, when it was
That accounts to something like an EIRP of 1 kW taking cable
loss into account.

Again it confirms Mike, N1JEZ's observations for the L band uplink.
For an occasional contact, 150 watts EIRP.
For medium level performance, 500 watts EIRP.
For superior performance, 1 kW EIRP or higher.

As Mike also points out, doppler tracking must be correct, PC time
must be correct, antenna pointing must be correct and so on.

I use SatPC32 to control the IC-910, which I leave on all the
time to avoid temperature drift during warm up periods.

When we get AO-51 in mode-L/U it is time to get the frequency
tracking right for the 1268 MHz uplink.
The 70 cm downlink is much easier to hear than the 2.4 GHz downlink.
That makes it easier to get the frequency right on the L band

October 2 to October 9
FM Repeater, V/U
Uplink: 145.920 MHz FM, 67 hz PL Tone
Downlink: 435.300 MHz FM
FM Repeater, L/U
Uplink: 1268.700 MHz, No PL Tone
Downlink: 435.150 MHz FM

NOTE: The 435.150 MHz downlink is left hand circular.

Have fun.

73 OZ1MY
----- Original Message ----- 
From: "Michael Fletcher" <oh2aue at sral.fi>
To: <amsat-bb at amsat.org>
Sent: Monday, September 18, 2006 7:33 AM
Subject: [amsat-bb] AO-51 mode L/S

> Hi all,
> been copying AO-51 on L/S mode very nicely over the past
> few days. My setup is a hand-held linearly polarized
> (yes, you need rotate it to follow the S/C spin) W-LAN
> patch antenna with a California Microwave downconverter
> feeding an FRG-9600 modified to feed DC to the D/C.
> Excellent signals, absolutely no interference, always
> enjoying the spectacular L band uplinks for various
> European stations, especially OZ1MY, whom has an
> exceptionally solid uplink :-)
> Mostly been listening to eastern and overhead passes,
> simply because I can sit on my veranda steps, sip coffee
> and twiddle the knobs & antenna ;-)
> Really cannot wait for the next L/S session; this mode
> is a very impressive demo mode for experienced hams that
> have no idea what satellites can do for you, not to speak
> of our future generation of hams...
> 73's Michael, OH2AUE
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