[eagle] Re: Another idea on phased array configuration

Matt Ettus matt at ettus.com
Sat Apr 28 23:57:05 PDT 2007


So what?  We can have, and were planning on having, an 18dB gain array.  
That doesn't mean we need to turn any elements off.

Matt

John B. Stephensen wrote:
> The spreadsheet distributed early last year shows a 9 degree squint 
> angle at the leading and trailing horizons at apogee. An antenna with 
> an 18 degree half-power beamwidth has a gain of 41000/(HPBW^2) = 127 = 
> 21 dBi. It would be best to illuminate the earth with a loss of only 1 
> dB at the edges and the -1 dB beamwidth is going to be 2/3 or less of 
> the -3 dB beamwidth. The gain should then be adjusted by 4/9 or 3.5 dB 
> less. This would be 17.5 dBi.
>
> 73,
>
> John
> KD6OZH
>
> ----- Original Message ----- From: "Matt Ettus" <matt at ettus.com>
> To: "John B. Stephensen" <kd6ozh at comcast.net>
> Cc: "Louis McFadin" <w5did at amsat.org>; "Robert McGwier"
> <rwmcgwier at gmail.com>; "AMSAT Eagle" <Eagle at amsat.org>; 
> <K3IO at verizon.net>
> Sent: Saturday, April 28, 2007 19:57 UTC
> Subject: Re: [eagle] Re: Another idea on phased array configuration
>
>
>>
>> John B. Stephensen wrote:
>>> Since the generated beam needs to cover the entire earth from a 
>>> maxmum of
>>> 35,000 km in alttude, the beam can't be made very narrow. I don't think
>>> that all 36 or 43 elements ever need to be on at one time. Many 
>>> could be
>>> held in reserve.
>>
>>
>> Where do you come up with this?  What sort of analysis?
>>
>> Matt
>>
>>
>



More information about the Eagle mailing list