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Author Topic: digital 4 square  (Read 1302 times)
KX0O
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Posts: 49




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« on: September 22, 2009, 02:31:36 PM »

I am looking to see if anyone has pondered using 4 receivers to create a multiband 4 square array achieving phasing with the digital signals and phasing transmit as well for directionality.  This seems technologically feasible and would allow multiband phased operation in both transmit and receive... the software would be a bit more complicated and the horsepower required in the computer side would be high.  I can envision 2 flex 5000's with fuel transmit and receive used in this fashion...any idea if this has been done.  A non-exhaustive search hasnt revealed anything.

doc
KX0O
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W6RMK
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Posts: 650




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« Reply #1 on: September 28, 2009, 08:29:06 PM »

Actually, the computational horsepower required isn't huge. All you're doing is multiplying each input by a complex number and then summing them (or on Tx, taking the samples and multiplying by a constant).  The processing required for filtering and demodulation is much more, but that's after the phasing.

Another, not too complex aspect, is that you'll need to calibrate the array (determine what the "zero phase" offset is for each channel).

Someone has done it with 4 Softrock receivers. I think there was a presentation at Dayton on it.
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KX0O
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Posts: 49




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« Reply #2 on: September 28, 2009, 08:54:05 PM »

i will search around... thanks.... that means the interface/software exists in some form.

doc
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K0OD
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Posts: 2539




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« Reply #3 on: September 29, 2009, 03:54:08 PM »

Looks like K1LT has done it:

http://k1lt.com/
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W9OY
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Posts: 1293


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« Reply #4 on: September 30, 2009, 04:35:53 PM »

If you refer to my blog

http://w9oy-sdr.blogspot.com/

There are several entries that review some alpha software used with the F5K which includes digital variable phase and gain, using 2 antennas and 2 receivers

The articles are labeled "diversity" and are intermixed in the blog over the past few months.  They include so audio examples as well as some shots of PSDR

73  W9OY
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