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[Discuss-gnuradio] software controlled antenna
From: |
Chuck Swiger |
Subject: |
[Discuss-gnuradio] software controlled antenna |
Date: |
Tue, 20 Dec 2005 08:09:04 -0500 |
This weekend's project was pretty easy and useful. My indoor antenna is a loop
with pretty sharp Q which requires touching up, manually, even if receiver
frequency
is changed only 50kHz. I have to get up, walk over to the loop and turn a
365pf variable
cap to 'peak' the signal.
I just found out about MVAM109 varactors, which go from about 40 - 400 pf with
0-9vdc bias, so it was fairly easy to use the gnuradio/usrp aux DAC 'D',
the sigma
delta, which is brought out on J17 on the basic RX board, and makes 0-3.3 vdc
with 12-bit precision, a 2N2222 transistor dc amp with a 12v supply to boost it
up to 0-9vdc. Put two MVAM109's back to back on the loop fed thru 100k
resistors
(they're very high Z) and now I can adjust and peak the antenna with a
slider on the gui ;))
--Chuck
http://partsandkits.com/MVAM109.pdf
src.write_aux_dac(0,3,value) 0<value<4095
- [Discuss-gnuradio] software controlled antenna,
Chuck Swiger <=
- Re: [Discuss-gnuradio] software controlled antenna, Robert McGwier, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, Angilberto Muniz Sb, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, Eric Blossom, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, Angilberto Muniz Sb, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, Lamar Owen, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, Lamar Owen, 2005/12/20
- Re: [Discuss-gnuradio] software controlled antenna, cswiger, 2005/12/20