Dear Bill, Thanks for the tip. I will give that a try.
--- 73 de Clemens / DL2ZZ / PA7T On 2017-03-03 19:48, Bill Somerville wrote: > On 03/03/2017 18:17, Clemens Heese wrote: >> Somehow I have a similar issue. Using an SDR (RedPitaya) with a >> variable >> gain amplifier as preamp (and a 30 MHz low pass). I am wondering how >> to >> best set the preamp. Currently I have just experimentally set the gain >> to get most decodes in 24h (weighted by my reference station) > > Hi Clemens, > > empirical testing is hard to beat. > > Other than that I can't see any serious problem with the following > approach: > > use a two way aerial coax switch with your aerial and a dummy load. > Adjust the preamp gain to the minimum level where switching to the > dummy > load reduces the background noise. Turn the gain up a notch to allow > for > noise QSB. > > My thinking is that an amplifier is a source of noise which may be > directly related to gain setting so using the minimum level that > doesn't > loose the band noise floor is probably best. > > I'm sure the EME operators will have more scientific methods for > setting > pre-amp gain. No doubt some will ask which end of the feeder the > pre-amp > is located. > > YMMV, 73 > Bill > G4WJS. > > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, SlashDot.org! http://sdm.link/slashdot > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
