[amsat-bb] Re: FW: ARLB013 ARRL aiding effort to mitigate repeaterinterference to military radars

Edward Cole kl7uw at acsalaska.net
Tue Apr 24 19:12:02 PDT 2007

Yeah, I thought about that.  If your antenna has 20-dB gain, like my 
eme array has, it has a 3-dB beamwidth of 20-deg.  So at elev. 20 I 
could transmit 10w and only have 5w on the horizon.  Restricting my 
satellite operation above 20-deg. would be needed.  If you ran 25w, 
you would be restricted to above 40-deg.  But didn't someone say that 
most satellite passes are below 40-degrees?  How many folks use eme 
arrays for satellites?

Now if you uplink on 5.7 GHz with a 3-foot dish then beamwidth is 
4-deg. with 33-dB gain.  Your EIRP is 5w x 2000 = 10 kw  ...kind of 
shows the advantages of mw for space comm.

I know I have definitely gone off topic...but it gives one something 
to think about.

73 Ed

At 07:36 AM 4/24/2007, Margaret Leber wrote:
>On 4/24/07, Edward Cole <kl7uw at acsalaska.net> wrote:
>>Build satellites that require no more than 5w EIRP from the ground
>>station may be the only answer.
>Or transmit with a more directional antenna aimed skyward...which is
>not a practical solution for terrestrial repeaters.
>73 de Maggie K3XS
>Editor, Phil-Mont Mobile Radio Club Blurb - http://www.phil-mont.org
>Elecraft K2 #1641 -- AOPA 925383 -- ARRL 39280

Ed - KL7UW
  BP40IQ   50-MHz - 10-GHz   www.kl7uw.com
144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w
DUBUS Magazine USA Rep dubususa at hotmail.com

More information about the AMSAT-BB mailing list