[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Discuss-gnuradio] software controlled antenna
From: |
Lamar Owen |
Subject: |
Re: [Discuss-gnuradio] software controlled antenna |
Date: |
Tue, 20 Dec 2005 22:20:22 -0500 |
User-agent: |
KMail/1.9.1 |
On Tuesday 20 December 2005 16:30, Eric Blossom wrote:
> On Tue, Dec 20, 2005 at 03:30:56PM -0500, Marcus Leech wrote:
> > Paul Shuch was working on a phased-array panel antenna for
> > SETI work. I don't know how many elements, but it was
> > steered using varactors. For some environments, this would
> > be really nice--no need to build mechanicals to swing a dish
> > around.
> For narrow-band arrays (bandwidth < 1% of center freq), we think we
> can steer the array with DSP in the FPGA and/or host. This would
> allow us to build 4 antenna arrays with a single USRP.
Having been chief engineer for a directional AM broadcast station, phased
arrays are right up my alley, even though this particular array was a
transmit array (four inline 1/4-wave towers, spaced 1/4 wave apart, throwing
the equivalent to a 20-element yagi pattern; front to back was 6KW:180mW).
I've done 3D modeling of transmit phased arrays, and tuned them (the classic
'rocking the phasor' routine (yes, the phasing equipment is really called a
phasor).
See http://www.pari.edu/telescopes/RadioTelescopes/ETA and
http://www.ece.vt.edu/swe/eta/ for details on a big phased array project
being built at PARI. The short form: imagine repointing a dish after the
observation has been taken. 12 terabytes per day required storage. Big time
phased array; uses multiple Xilinx XC2VP30 boards (ML310) for the beam
forming calculations.
--
Lamar Owen
Director of Information Technology
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC 28772
(828)862-5554
www.pari.edu
Re: [Discuss-gnuradio] software controlled antenna, Eric Blossom, 2005/12/20