[amsat-bb] Re: S-band on Eagle

kc6uqh kc6uqh at cox.net
Sat Sep 9 11:53:38 PDT 2006

Digital CC Rider transponder requires more bandwidth that a linear 
transponder passing a single SSB or CW signal.
Measurments made using SSB receivers, and recolections of AO-40 reception on 
S Band are NOT valid comparisons.

The 902 MHz to 928 MHz Band in Escondido, Ca. has a solid noise floor of -70 
dBm accross the Band, several years after 900 cordless phones were offered 
for sale. Put that fact in the S Band predictions 5 years from now.

Amateurs should not run away from ISM/License Free intrusion into our bands, 
WE JUST NEED TO MAKE THEM OUTPUTS, and receive on other bands!

----- Original Message ----- 
From: <yokshs at sbcglobal.net>
To: "amsat-bb" <amsat-bb at amsat.org>
Sent: Saturday, September 09, 2006 12:00 AM
Subject: [amsat-bb] S-band on Eagle


I've been following the thread about Eagle, and like many others I am sad to
hear that S-band will not fly. I do
look forward to working S-band on P3E, and hope the Eagle team will
reconsider, and fly an S transmitter, even
if it is considered a backup or emergency transmitter.

I understand why the team wants to drop it, but I have a feeling that if we
DON'T fly it, we'll wish that we had. Sort of
putting all the eggs in one basket to depend on U/v to work for the life of
the bird, isn't it? Remember AO-40 - I never
heard the S1 TX, but aren't we all glad there were two S transmitters

I DO look forward to working U/v on Eagle, but I doubt that my budget will
allow experimenting with new
modes such as C-band anytime soon. With this in mind, as far as I'm
concerned, Eagle will be a U/v bird only.

While I won't argue that the 2.4 GHz spectrum is a 'sewer' in some areas,
I've only had serious QRM on one occasion. The
radar pulses or spread spectrum noise was cured by my radio's Noise Blanker.

One evening while copying AO-40, the bird's signal dropped completely off
the S-meter. It was like my dish had fallen off the
roof or something! Seems a neighbor down the street got a new 2.4 GHz analog
cordless telephone, and (you guessed it)
she was the dreaded full duty-cycle type - a high-school age girl!

Her phone must have broken or was returned to the store soon after (WHEW!)
I never got a chance to DF it, as I only heard it the one time, but was in
horror at the possibility of losing my S-band RX. For those of you that
doubt a non-licensed device can swamp your new downconverter, believe me,
my AIDC 3731 could hear nothing else.

On a related subject, seems like I read somewhere that some C-band
experimenters were considering using
s-band units for the final conversion from 5 GHz? In other words, the C-band
converter would only need to
convert from 5 GHz to 2 GHz, and let the surplus s-band units do the rest?
Anyone know any more about this

Another use for S-band converters might be for RF linking purposes? A small
transmitter and helix or dish at each end should work well
for control links or linking repeater sites maybe?


Kyle Yoksh
Olathe, Kansas
Amsat # 35249
VUCC Satellite # 150

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