On Tue, Dec 20, 2005 at 08:09:04AM -0500, Chuck Swiger wrote: > 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 ;))
Cool. You're definitely winning in the "look what I did with GNU Radio!" category! Looking forward to the next thing ;) Eric _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
