There is a procedure for Transmit Image Rejection management on the bottom of page 90 of the manual. It worked for me but I'm using a Delta 44. The section was rewritten by Eric but not published yet. Just use another trusted receiver, tune it to the same frequency but the apposite side band and adjust the SDR slider controls to surpress it.
K6JEK <[EMAIL PROTECTED]> wrote: Here is an update on the poor sideband suppression from my SDR-1000. It is putting significant energy out on the wrong sideband, visible in the panadapter of a nearby fellow Flexer and audible by not so nearby hams listening on the opposite sideband. Yesterday I took the radio over to Jeff, K6JCA's, impressive lab. Together we used as many pieces of test equipment as we could think of -- HP spectrum analyzers, lab grade audio spectrum analyzers, signal generators, and most effectively of all Jeff's SDR 1000 to see what was happening with mine. We haven't completely solved the problem. But here are the weekend's revelations: 1) It not the opposite sideband. Listening on the opposite sideband sounds like SSB through an AM detector 2) Wide band noise was coming out of the Firebox. The little filter on the line-out line knocked it way back. 3) Audio coming out of the Firebox looked really good on the lab grade audio spectrum analyzer -- brick wall, no funny business -120 dBV noise floor (with the filter) 4) Careful adjustment of the TX Image dropped the opposite sideband signal by quite a bit, 10 - 20 dB 5) Jeff's radio has some of the funny opposite side signal too 6) Jeff has too much stuff 7) Two hams can spend an afternoon pushing RF between radios and not blow anything up Jon Begin forwarded message: > From: K6JEK > Date: September 23, 2006 9:54:21 PM PDT > To: flexradio@flex-radio.biz > Subject: Poor sideband suppression > > I'm getting poor opposite sideband suppression. Another Flex owner, > Jeff, K6JCA, took a snapshot of my spectrum off the air and there is > a significant hump on the opposite sideband. Other listeners have > heard the opposite sideband. It's not DSB. It's maybe 30 dB down. > The TX image alignment had very little effect. I performed the > alignment with a receiver, not a spectrum analyzer. > > Where do I start? > > Here's the set-up: Used SDR 1000, age TBD but was on the air before > I acquired it last week. Has the PA. > New PreSonus Firebox, just got it from Flex > 48K sampling. Have not installed the beta firmware > Cables from Flex, the HOSA cables > Firewire to Compaq laptop, 1.3 GHz > External (wall wart) power to Firebox > Parallel cable, computer to radio > 35A linear power supply to SDR1K > 1.6.2 software > > One more thing. The output from the Firebox measures about 1.98V > during the audio TEST, nothing like the 6.93 hardwired into the set-up > form. > > Jon, K6JEK > -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: text/enriched Size: 2734 bytes Desc: not available Url : /pipermail/flexradio_flex-radio.biz/attachments/20060925/301b0e1e/attachment.bin _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/flexradio_flex-radio.biz/attachments/20060925/836e4049/attachment.html _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
