[amsat-bb] Re: S band downlink on P3E

Bill Ress bill at hsmicrowave.com
Thu Sep 7 12:48:10 PDT 2006


Congratulations for speaking your mind on this touchy subject and that can't
be easy being involved within the AMSAT circles as you are.

I'll be watching Eaglepedia for the evidence from the Eagle design team that
convinces me (and many of us) that 2.4 GHz has to go.

I have more interference problems on 70 CM with 433.9 stuff not to mention I
look down on the back side of a PAVE PAWS radar (I'm in the Sierra foothills
looking down into the Sacramento Valley). While I receive random, periodic
clicks and clacks, it hasn't prevented me from working AO-51 most of the
time using just a ground plane on 70 CM. (I hate to track and really don't
need to!!). Compared to 70CM, the 2.401 GHz region here is "down right
quiet" when using a decent direction antenna.

If it's OK for P3E it should be on Eagle. Convince me that Eagle science is
better and wiser than P3E science.

Thanks for speaking up Drew....73s...Bill - N6GHz

-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org]On
Behalf Of Andrew Glasbrenner
Sent: Thursday, September 07, 2006 11:39 AM
To: Rick Fletcher; 'AMSAT'
Subject: [amsat-bb] Re: S band downlink on P3E


I am in _TOTAL_ agreement. I live in the suburbs of Tampa/St. Pete and never
had an interference problem on my 3 foot dish. I have used the same dish to
log well over a dozen WiFi access points in that immediate neighborhood.
With properly designed equipment, all that trash on 2.4 ghz goes away with
some elevation. What won't work is helixes with multiple sidelobes, and
surplus dishes that let one whole polarity of noise right thru the back.

Everyone knows I'm a big supporter of AMSAT, but I gotta call it as I see
it. It makes me think of "bait and switch" to collect money for a project
featuring such a popular mode and then drop it.

The loss of Mode B on AO-40 caused a lot of the hardcore AO-10/AO-13 types
to walk away, and that was tough to overcome. Now that we have, and we have
people wanting S band, we leave them behind too. Even if it's a sound
engineering decision (and that hasn't been proven to me) it's a horrid
marketing decision. Bad mojo for a organization that lives on the donations
of it's members.

Sorry if this causes any pain to those involved with Eagle, but I needed to
get it off my chest.

73, Drew KO4MA

>While AO-40 was still alive and I was working it from deep within "Silicon
>Valley", an area blanketed by WiFi, 2.4GHz cordless phones, etc., I
>discovered that a parabolic dish with a properly positioned and designed
>patch feed (slightly under-illuminating the dish and having no significant
>side-lobes) would bring in AO-40's S-band downlink very nicely and cleanly.

>Of course, other feed or antenna types such as helical antennas/feeds were
>useless in that environment.

>I have to admit that I don't buy the "too noisy" argument.



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