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Re: Re: RE: Geo Opportunity



Im not sure how to interpret this nugget of info.  Doesnt the sky noise
you reffer to only appear if you point directly at the galactic center?
It does not appear anywhere else to that degree, so this seems like a red
herring.?

 On Thu, 31 Jul 2003, John Stephensen wrote:

> There is background noise at GEO generated by the black hole(s) at the
> center of our galaxy. At 28 MHz it is about 17 dB above thermal noise at 290
> K. It increases by 6 dB/octave at lower frequencies and decreases by 6
> dB/octave at higher frequencies, intercepting the 3 K thermal background
> noise of the Big Bang at about 2000 MHz.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message -----
> From: "Bob Bruninga" <bruninga@usna.edu>
> To: "Keith N6ORS" <k2@pe.net>
> Cc: "amsat" <amsat-bb@AMSAT.Org>
> Sent: Wednesday, July 30, 2003 22:19
> Subject: Re: [amsat-bb] Re: RE: Geo Opportunity
>
>
> > On Wed, 30 Jul 2003, Keith N6ORS wrote:
> >
> > > ok, this is for a Mode K transponder.  21.4 mhz uplink /29.4 mhz dnlink.
> > > Using 5w on the uplink (portable qrp type nuts) , and 10w (single
> > > signal) on the downlink.
> >
> > Yes, but if you use HF for the downlink, you have to throw in 18 dB of
> > atmospheric noise to the link equation which washes out all advnatages of
> > the better link budget.  That is why we only planned to use 10m for uplink
> > (where it has hardly any noise out at GEO)...
> >
> > I think...
> >
> > Bob
> >
> > > This would work nicely with a diplexer and a single tape whip with a 3/8
> > > wave on 10m (1/4 on 15m).
> > >
> > > Keith (N6ORS)
> > >
> > >
> > >
> > > Uplink 15m
> > > TX power          5W    37 dBm
> > > TX Antenna Gain          3 dBi
> > > Polarization loss       -3 dB
> > > Resulting EIRP          37 dBm
> > > Path Loss at 10m      -150 dBm
> > > Receiver Antenna Gain    0 dBi
> > > Received signal       -113 dBm
> > > Required for 10dB SNR
> > >   in 3 KHz bandwidth  -119 dBm
> > > ------------------------------
> > > Margin                 +6 dB
> > >
> > > downlink 10m
> > > TX power         10W    40 dBm
> > > TX Antenna Gain          3 dBi
> > > Polarization loss       -3 dB
> > > Resulting EIRP          40 dBm
> > > Path Loss at 10m      -153 dBm
> > > Receiver Antenna Gain    0 dBi
> > > Received signal       -113 dBm
> > > Required for 10dB SNR
> > >   in 3 KHz bandwidth  -119 dBm
> > > ------------------------------
> > > Margin                  +6 dB
> > > ----
> > > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > > Not an AMSAT member? Join now to support the amateur satellite program!
> > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> > >
> >
> > de WB4APR@amsat.org, Bob
> >
> > PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
> > ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
> > CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
> > APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
> > APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
> > MIM/Mic-E/Mic-Lite  http://ssdl.stanford.edu/mims/
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
>
>

de WB4APR@amsat.org, Bob

PCsat WEB  page     http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ:       http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs     http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages     http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES     http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite  http://ssdl.stanford.edu/mims/

----
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