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 power 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 result.
Clare VE3NPC
----- Original Message ----- From: "Phil Karn" [email protected] To: "Mike Schaffer" [email protected] Cc: [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb