[amsat-bb] FW: Oh - my - God - (AO-7 uplink power).

john hackett la2qaa at hotmail.com
Fri Feb 1 00:57:57 PST 2008

For those that don't understand power budgets on satellites - especially ailing ones - *PLEASE* make the effort to read up on the subject - so you can honestly say "your" operating *DIDN'T* shorten a particular satellites life ... or ... you were *NOT* being an alligator ... (all mouth and no ears) ... and using more than your fair share of the available power.

Remember ... there are potentially many !! users on AO-7 and the available power is distributed among them ... a LINEAR transponder isd *NOT* like an FM transponder.

There is an excuse for simply "not knowing" - but there is no !! excuse for knowing and ignoring the facts - that's just plain anti-social.

If you're not aware of it, do please !!! take the time to read up on the subject.

73 John   <la2qaa at amsat.org>

From: la2qaa at hotmail.com
To: w7lrd at comcast.net
CC: eu-amsat at yahoogroups.com; allan_gm1sxx at hotmail.com
Subject: Oh - my - God - (AO-7 uplink power).
Date: Fri, 1 Feb 2008 09:41:04 +0100

Oh - my - God!,

>On 70cm I run about 80-100 watts to a 40 el cp 
>yagi.  I can pick up my down link when the sat 
>is about 7 degrees.

73 Bob W7LRD That's not an AO-7 station Bob, it's an EME station. 

Did you not read the recommended operating proceedure for AO-7


5 watts or less to a decent aerial is adequate. Personally, I have *NEVER* used more than 5 watts to a homebrew 6 element yagi but this gave me 3rd place worldwide - (currently 5th) - when I was more active.

I have taken the liberty of CC'ing part of your mail to the EU amsat reflector because like me - they won't believe! the power you're using ... 100 watts to 40 elements is several kilowatts !! EIRP.

I would respectfully suggest you do some research about *WHY* one should maintain a reasonable power budget when operating satellites ... afterwards - (hopefully) - you'll see what I mean.

AO-7 is not in the best of health at at the best of times but hitting it with so much uplink power is most certainly not going to prolong it's life.

It is also thoroughly recommended to use a "receiver" with an aerial attached - though with your uplink power - (if it's true) -
a wet shoelace ought to suffice.


You did say 40 elements ... did you mean 4 ???.

73 John.   <la2qaa at amsat.org>

> From: w7lrd at comcast.net
> To: AMSAT-BB at amsat.org
> Date: Fri, 1 Feb 2008 03:58:29 +0000
> Subject: [amsat-bb]  antenna attenuation
> Hello
> Has anyone encountered this situation-  My satellite antennas are about 15 feet off the ground.  approximatly 18 feet away at that height is the base of a  25 foot tripod that holds my HF quad.  When aiming at a certain direction about 15-20 degrees I can't seem to get through to AO-7.  I am trying to connect with OH8MBN.  Other directions I can usually hear my downlink almost down to the horizon.  On 70cm I run about 80-100 watts to a 40 el cp yagi.  I can pick up my down link when the sat is about 7 degrees.
> 73 Bob W7LRD
> Seattle
> --
> "if this were easy, everyone would be doing it"
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