Re: [Flexradio] PSDR generated broad noise on 21.076
Perhaps the wiring of the radio picks up extraneous signals which are too weak to retain amplitude when the dummy load is plugged in. The dummy I assume is about 50 ohms. That would load weak sources pretty heavily and drag them down into the noise or lower especially if they were of high impedance origin. 73 Patrick AF5CK -- From: Steve Sterling f...@sgsterling.com Sent: Friday, November 30, 2012 10:44 AM To: flexradio@flex-radio.biz Subject: Re: [Flexradio] PSDR generated broad noise on 21.076 So John-- if a mismatch can't cause the receiver front end to oscillate, why when I completely disconnect antenna leads from the SO-239 connectors in the back of my Flex 5K, totally open connection, I get wild broadband oscillations and spurs across the spectrum on most bands averaging -95dbm, but if I hook up a dummy load, it all goes away instantly, and I get a nice flat baseline at abt -138dbm or so? And why when I plug in a matched antenna, those wild oscillations and spurs go away, and I just have normal band noise and signals? A closer match doesn't increase the oscillations, it makes them go away. It's not power supply noise. On 11/30/2012 7:02 AM, John Sweeney wrote: 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
Re: [Flexradio] PSDR generated broad noise on 21.076
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/
Re: [Flexradio] PSDR generated broad noise on 21.076
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/
Re: [Flexradio] PSDR generated broad noise on 21.076
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:
Re: [Flexradio] PSDR generated broad noise on 21.076
One of my annoying noise sources is the overhead florescent lighting in my shack. I have to turn those lights off when trying to hear a weak signal on certain bands while my antenna is pointed right at my shack. Fortunately, my desk lamp doesn't generate any noise even though it does have a CFL in it. 73, Rich - W3ZJ Robert Costa, KB6QXM wrote: 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 ___ 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/
Re: [Flexradio] PSDR generated broad noise on 21.076
So John-- if a mismatch can't cause the receiver front end to oscillate, why when I completely disconnect antenna leads from the SO-239 connectors in the back of my Flex 5K, totally open connection, I get wild broadband oscillations and spurs across the spectrum on most bands averaging -95dbm, but if I hook up a dummy load, it all goes away instantly, and I get a nice flat baseline at abt -138dbm or so? And why when I plug in a matched antenna, those wild oscillations and spurs go away, and I just have normal band noise and signals? A closer match doesn't increase the oscillations, it makes them go away. It's not power supply noise. On 11/30/2012 7:02 AM, John Sweeney wrote: 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/
Re: [Flexradio] PSDR generated broad noise on 21.076
Gentlemen: This problems or questions, especially related to the 5000A, is one of the most enjoyable threads I've read for some time! I had provided that substantial pre-introduction downpayment when the radio was still pretty much only an idea and so I think I've been able to experience just about everything that has been mentioned this morning! And I can honestly say that purchase of the radio has never been regretted. If you haven't experienced it yet, just wait until you hit commercial power line noise and try to use the panadapter display to illustrate to someone just what's going on! I had a slight advantage in that I had owned a Squires-Sanders nice green CRT panadapter so I wasn't starting from scratch but I do feel that if you are ever tempted to use the Flex display in ordinary conversation with knob and button people don't expect them to understand what you are talking about! You might consider these big drifting noise bumps, when they appear, as an indication that perhaps you need to go out to inspect your antenna and feed system! Best Flexing, Lee K9WRU - Original Message - From: Robert Costa, KB6QXM kb6...@yahoo.com To: John Sweeney n...@comcast.net Cc: flexradio@flex-radio.biz Sent: Friday, November 30, 2012 9:15 AM Subject: Re: [Flexradio] PSDR generated broad noise on 21.076 - 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 ___ 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/
Re: [Flexradio] PSDR generated broad noise on 21.076
Steve, If your spurs and noise not from a power supply noise rf hash , I then do not know the cause. I was just throwing out an idea to check.I can report that these spurs and noise do not appear on the Flex 5K here with any type of antenna connected or no antenna or dummy load. John. N3WT On Nov 30, 2012, at 11:44 AM, Steve Sterling f...@sgsterling.com wrote: So John-- if a mismatch can't cause the receiver front end to oscillate, why when I completely disconnect antenna leads from the SO-239 connectors in the back of my Flex 5K, totally open connection, I get wild broadband oscillations and spurs across the spectrum on most bands averaging -95dbm, but if I hook up a dummy load, it all goes away instantly, and I get a nice flat baseline at abt -138dbm or so? And why when I plug in a matched antenna, those wild oscillations and spurs go away, and I just have normal band noise and signals? A closer match doesn't increase the oscillations, it makes them go away. It's not power supply noise. On 11/30/2012 7:02 AM, John Sweeney wrote: 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 anten ___ 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/
Re: [Flexradio] PSDR generated broad noise on 21.076
This noise could also come from the power supply in your PC or monitor. John. N3WT On Nov 30, 2012, at 11:44 AM, Steve Sterling f...@sgsterling.com wrote: So John-- if a mismatch can't cause the receiver front end to oscillate, why when I completely disconnect antenna leads from the SO-239 connectors in the back of my Flex 5K, totally open connection, I get wild broadband oscillations and spurs across the spectrum on most bands averaging -95dbm, but if I hook up a dummy load, it all goes away instantly, and I get a nice flat baseline at abt -138dbm or so? And why when I plug in a matched antenna, those wild oscillations and spurs go away, and I just have normal band noise and signals? A closer match doesn't increase the oscillations, it makes them go away. It's not power supply noise. On 11/30/2012 7:02 AM, John Sweeney wrote: 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 anten ___ 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/
Re: [Flexradio] PSDR generated broad noise on 21.076
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/
Re: [Flexradio] PSDR generated broad noise on 21.076
I operate 99% of the time on JT65-HF from 160 to 6 meters and I have NOT notice what you are experiencing.Once in a while I have seeing what you described as noise. However, a well known local ham, gave a talk atour radio club in which he described that noise you are seeing as over the horizon radar that covers not just a portion of the band but a huge if not all the HF spectrum.He makes a living monitoring from DC to GHZ etc... I use PDSR 2.4 with F5,3 and 1.5k radios. My noise level is better than -130 dBm on the ridge of our mountain location. The antennas I am using is 18HT Hy-Tower (no radials ,yet) 5 band dipole. However, the big 5 band beamis under construction and waiting to be install on the tower.73, Ernest - W4EG - DM13ji To: flexradio@flex-radio.biz Date: Thu, 29 Nov 2012 21:22:20 + From: py...@terra.com.br Subject: [Flexradio] PSDR generated broad noise on 21.076 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/
