All, How I isolated radiated RFI is with my portable digital short wave receiver. It is a sensitive receiver with a long portable antenna. It has helped me determine RFI noise sources and their intensity.
I personally chose to change out my lab grade switching power supply. I chose to change it out, not for any RF hash, but because of the high RPM cooling fan noise. The linear supply is almost perfectly quiet. RF ingress issues have been my nightmare, not radiated or conductive RFI issues. I am fortunate that I live on a rural piece of land and no common issues that hams have to deal with having close proximity neighbours. Good luck in finding your RFI source. 73, Robert KB6QXM "Ham Radio Open Conversation" Yahoo group owner/moderator ----- Reply message ----- From: "John Sweeney" <n...@comcast.net> To: Cc: "flexradio@flex-radio.biz" <flexradio@flex-radio.biz> Subject: [Flexradio] PSDR generated broad noise on 21.076 Date: Fri, Nov 30, 2012 7:02 am This could be from a noisy switching power supply. I had the kind of noise as described and changing power supplies cleared it up. A good linear type power supply may help. No such noise as described now, so not characteristic of a Flex Radio. Could even be noise from a close by wall wort supply, even picked up with the dummy load. A mismatched antenna will not cause noise on receive. By using a closer matched antenna you are increasing the atmospheric noise and general signals to cover up the possible power supply hash noise. 73. John. N3WT. On Nov 30, 2012, at 8:46 AM, Drax Felton <draxfel...@gmail.com> wrote: > I see this all the time too. Especially pronounced on 6 meters where I can > chase these but not tune them in as they move. > > I assumed that all radios have glitches the Flex just lets you see them at > -130db > > > Sent from my iPhone > > On Nov 29, 2012, at 5:23 PM, Steve Sterling <f...@sgsterling.com> wrote: > >> My Flex 5000 receivers do not like off-normal (50 ohm) antenna loads. Unplug >> the antenna, or put an unmatched antenna on them and they create all kinds >> of weird oscillations, big wide humps across the spectrum. >> >> Examples: >> >> * short the receiver inputs, all OK, baseline down there below >> -135dbm, all bands >> * put the inputs on 50 ohm dummy load, all OK, all bands >> * open the antenna input (pull the line) and it goes nuts, >> * hook my SteppIR up, but tuned to a different band, many times (not >> all) the receivers go nuts; same with mistuned G5RV >> * tune any of the antennas anywhere close to 50 ohms-- receivers >> behave well, best I can tell (noise may be covering up any >> oscillations that are well below my local noise floor). >> >> I just figured this is the way these receivers worked, and they don't effect >> my operations. Is the antenna you are using a good match? >> >> Steve WA7DUH >> >> On 11/29/2012 1:22 PM, py...@terra.com.br wrote: >>> Been playing with JT65HF which on 15m is confined to the 2KHz in USB >>> on 21.076. I-ve noticed a broad noise covering just about all of that >>> segment and imagined it to be one more of the many noises generated by >>> a big city, but the other day I left the antenna disconnected and the >>> noise is still there! Wonder if anyone else has noticed this and if >>> there is a way to make it go away or move frequency! I´m using PSDR >>> 2.3.5 / Windows 7 on a Flex3000 and have tried other buffer and >>> scanning rate settings, but nothing seemed to make a difference. It is >>> -126dB without an antenna and has a cyclic sound to it.73 Rolf, PY1RO >>> _______________________________________________ >>> FlexRadio Systems Mailing List >>> FlexRadio@flex-radio.biz >>> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >>> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >>> Knowledge Base: http://kc.flexradio.com/ Homepage: >>> http://www.flexradio.com/ >> >> _______________________________________________ >> FlexRadio Systems Mailing List >> FlexRadio@flex-radio.biz >> http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz >> Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ >> Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/ > > _______________________________________________ > FlexRadio Systems Mailing List > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/ _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/ _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
