Re: [amsat-bb] Beacon frequency og AO-40

["Jens H. Jensen" <topcat@xxxxxxxxxxxxxxxxx>]

At 20:46 04-05-2001, you wrote:
>Hello,
>can anybody tell me the exact frequency of AO-40's S-beacon?
>Thanks in advance!

I have been wondering about that one too, Albrecht.

I have ONCE heard the bird with a 5-turn helix tagged onto a 1mtr dish 
which is pointed at 13 deg East (HB). No preamp, just 2 mtr of 75 ohm 
foam-insulated coax meant for DTH. I then waited until AO-40 was supposed 
to come into view at this position, to avoid moving the dish, standing 
rather unsequred in the corner of my apartment, looking out the window....

I DID hear AO-40 at this occasion, rather weakly, but 7 to 8 kilohertz 
HIGHER than expected after dopplercorrection, assuming an initial frq of 
2401.323 Mhz.
So, this either means that the doppler-calculation was way off, or that the 
receiver was.... :-|

Can we please have someone (from the commandteam, maybe, if they have the 
time?) comment as to the exact frq without doppler?

Is this frq, whatever it is, stable, or does the termal changes onboard 
change anything?

If not, can we please, if possible, have an educated guess as to the change 
to be expected?

/speculator on/

Here on earth at room-temperature it is hard enough to get such frequencies 
stable with respect to narrowband, so i suppose in a SC being deepfrozen at 
eclipse and toasted at the sun-side when not in eclipse it must be much harder?

Does gold-foil only get you so far?
Does AO-40 have any?

/speculator off/

Disclaimer:
Please don't consider this as whining, I am just trying to make sense of 
some (maybe flawed) observations. At S-band I can't find any reference 
signals for comparison yet. The only exeption is the LO of my other 
receiver, a COM205 (Pro-2006) which i wouldn't trust as a reference :-)

73 de OZ1LRG, Jens

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