There are probably better phase shifters available. I just happened to see these while looking at an MA/COM catalog. LNA MMICs have a gain variation of about 3 dB and at least 1 dB of the variation is probably temperature related, so the phase shifter loss doesn't need to be controlled too precisely.
73,
John KD6OZH
----- Original Message ----- From: "Franklin Antonio" antonio@qualcomm.com To: "John B. Stephensen" kd6ozh@comcast.net Cc: n1al@cds1.net; K3IO@verizon.net; "AMSAT Eagle" Eagle@amsat.org Sent: Friday, March 23, 2007 21:37 UTC Subject: Re: [eagle] Re: Eagle Microwave Antenna Arrays -- mechanical concepts
At 02:05 PM 3/23/2007, John B. Stephensen wrote:
It might even be possible to sum the RF directly and use only an LNA, phase shifter and variable attenuator for each antenna element. The attenuators would compensate for phase shifter gain variation.
I note that the spec for gain variation vs angle choice is 3 dB on these things! Yipes. Are there better ones available that don't have this flaw? We could certainly calibrate it out as you suggest, but maybe we could buy more expensive shifters that have it already calibrated out?