[amsat-bb] Re: Official Word for the 70cm Antenna?

Clare Fowler clarefowler at rogers.com
Fri Aug 19 19:02:18 PDT 2011

As ARISSat1 now is opertional in high power at a decent hour in the evening
here I have been making a few attempts at SSB transponder operation.

I have 2x10 turn helix atennas and a 100 watt brick amplifier which
would give me an ERP in the order of 4KW on the 70 cm uplink.

The Aug 19 23:55 UTC pass had a max el of 78 degrees. For some
reason the satellite turned off and on or switched between high and low 
several times during the pass.  The transponder downlink background noise
as it went to high power was clearly noticeable and the S meter went up
from S1 to S2.  The 145.950 FM voice was 10 over S9.

With 100 watts SSB out my 2 m downlink sig at peak went up to S4
and was Q5 but still with some noise.  Reducing the uplink to 50 watts
produced a noticeable reduction of the downlink into the noise.

On two previous passes I was able to detect that another operator
had gotten my call OK but I was unable to get theirs as their signal
was well into the noise.

I have not attempted CW which of course will give a much better


----- Original Message ----- 
From: "Phil Karn" <karn at philkarn.net>
To: "Mike Schaffer" <daetsort at yahoo.com>
Cc: <amsat-bb at amsat.org>
Sent: Thursday, August 18, 2011 11:16 PM
Subject: [amsat-bb] Re: Official Word for the 70cm Antenna?

> On 8/17/11 5:29 PM, Mike Schaffer wrote:
>> What is the official AMSAT/ARISSat1 team finding on the ARISSat-1 70cm 
>> quarter-wave
>> receive antenna on the bottom of the satellite? I have not heard updated 
>> news about that
>> since the jettison occurred.
> As far as I know, and this is *NOT* the official word, the correct
> antenna was installed but the external section of the element was broken
> off. There's about 1.5" of antenna blade embedded in the epoxy, which 
> isSSB
> why the antenna still hears pretty well. Reports of users getting into
> the transponder with as little as 1W prove it can't be the dummy load.
> -Phil
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