[digitalradio] Noise Folow up
Original post by Ron W4LDE >>>If this question is inappropriate for the reflector I apologize but as of last Friday 9-5-08 I started to experience significant noise (S-9) on all bands from 160 through 15M with the lower frequencies much stronger. I thought that it was due to power line noise but it appears to be intermittent in that it completely disappeared last Friday evening but once again showed up last Saturday and stayed this way. On the Ft1000mp the noise blankers are completely ineffective. At the same time I started having internet problems and the cable company indicated they should have the speed issue fixed by Tuesday.<<< >>>The cables are run on poles until they enter a subdivision which then run underground. My question is can cable lines be the possible problem to HF frequencies? The power and cable companies have been installing new poles and running new lines in the area which initially led me to believe it was a power issue however, while I was writing this email the noise completely disappeared for a few seconds and then reappeared. As I was looking out my window I noticed a cable company buck truck through the woods towards the main road, I am off now to talk to them and see what I can discover. Any suggestions?<<< --Follow up !!! 9-15-08 -- On 9-8 I contacted the local power company via email regarding the above, unexpectedly I received a call from the Maintenance Manager who stated don't worry we will be out maybe tomorrow and find the cause. They did show up, two buck trucks and full crews plus a 332-335 MHz Yagi and noise receiver. Unfortunately they said that they couldn't find anything and suggested it might be from a neighbors home. They scanned my home but couldn't find a thing. I was one unhappy ham and expressed that they needed to keep looking. I believe I have ruled out a radio problem since the noise was about the same on a FT-1000mp and a FT-847 and neither noise blanker would dent the noise. A MFJ-Noise phasing unit helped some but only improved the noise by about 1-2 S-units. I spent some time connecting and disconnecting home devices plus disconnecting one house breaker at a time. Friday the 12th I decided that maybe I could help find the problem and using a Yaesu VX-5R and rubber ducky at 134MHz and also at 329MHz AM started my search. I found significant noise at three different power poles, all new ones, with two west of my antenna about 1/8 mile and the other to the east at also about 1/8 mile. So I thought I had found the problem and would be reporting this condition today. When I came into the shack this AM to compose the email I happen to turn on the rig and to my amazement the noise was gone. eleven days I had a Ham Radio Black out on the low bands. Was I one happy guy. I thought I better go check out the poles. Off I went and yes the noise was gone at the poles, very quite. Went out later this afternoon and took the VX-5R, things were still quite up and down the main road. After being gone for three hours as I was approaching the sub-division I turned the VX-5R back on and WAM there was the same power poles and noise. My heart sunk, O-Sh_t I shouted and my XYL who understood the situation gave me her famous look and said keep on looking, write the reflector they can help. Well after arriving home and one hour later in the shack I turned on the radio and found NO significant noise. S-0 on 20-meters, S-2-3 on 30 meters and maybe as high as S-4 on 40M, at 4PM thats not bad. I was amazed once again and kinda dumb founded as to were to look next if I have to. Here's some of my thoughts, 1. Today for the first time in the past few weeks we finally had a cool day, high around 80 (occurred around 5PM) and a low tonight of 60 a) Lower temps caused all connections to tighten and when it finally warmed up around 4-5pm it started again at the poles. 2. Since there is still home building going on near us as the crews were leaving the construction site a week ago maybe they left chargers on for there power equipment and after doing there thing finally turned them off this AM and left the site. 3. I did find out that the telephone company was having lots of noise problems from there own installation. Not at my home but close. a) Can't believe thats the fix since the noise stopped early on Monday which didn't give them much time to complete the task, they started last Wednesday. 4. Cool days, less power consumed by the A/C units, less amps, less noise (is it s stretch?) Ok I thought, maybe I should invest in a 144/440 hand held yagi plus the cables and adapters to help in a wider search area but wanted recommendations as to what I should be looking at if the noise returns I would be using the VX-5r on 138 am MHz and 332 am MHz. Any thoughts are appreciated. I believe I have ruled out a radio problem since the noise was
[digitalradio] Noise
If this question is inappropriate for the reflector I apologize but as of last Friday I started to experience significant noise (S-9) on all bands from 160 through 15M with the lower frequencies much stronger. I thought that it was due to power line noise but it appears to be intermittent in that it completely disappeared last Friday evening but once again showed up last Saturday and stayed this way. On the Ft1000mp the noise blankers are completely ineffective. At the same time I started having internet problems and the cable company indicated they should have the speed issue fixed by Tuesday. The cables are run on poles until they enter a subdivision which then run underground. My question is can cable lines be the possible problem to HF frequencies? The power and cable companies have been installing new poles and running new lines in the area which initially led me to believe it was a power issue however, while I was writing this email the noise completely disappeared for a few seconds and then reappeared. As I was looking out my window I noticed a cable company buck truck through the woods towards the main road, I am off now to talk to them and see what I can discover. Any suggestions? Thanks for the bandwidth if this question is inappropriate for this reflector. 73 de Ron W4LDE
Re: [digitalradio] Noise Reduction and the digital modes
Patrick Lindecker wrote: > Hello Robert, > > TKS for the correction. I returned to my books. LMS filters are in > general linear (LMS-FIR), however they can also be in a recursive > structure (LMS-IIR). Patrick, thanks for your reply. An IIR filter (with an FIR component and a feedback component) is still a linear filter. Even if you are adapting it, it is still a linear transfer function for each and every sample. The transfer function is Sum(Outputs * Feeback_coeffients) = Sum(Inputs * FeedForward_ Coefficients is linear on both sides and this is an IIR. The adaptation is funky and may be a nonlinear adaption, but at each sample instant a linear filter is applied to all samples in its delay lines and so no mixing can occur. Now, if you are thinking about decision directed LMS equalizers, where you make a hard decision as the output, that is most decidedly nonlinear. You do not hard limit the output of your NR filter! The typical AGC circuit in a receiver is more nonlinear than any LMS based NR filter, FIR, IIR, etc. could ever be. Bob > > >We agree that they are no good for digital modes. > Yes the a priori is not very favourable. > > 73 > Patrick > 73's Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest." - Piet Hine
Re: [digitalradio] Noise Reduction and the digital modes
Hello Robert, TKS for the correction. I returned to my books. LMS filters are in general linear (LMS-FIR), however they can also be in a recursive structure (LMS-IIR). >We agree that they are no good for digital modes. Yes the a priori is not very favourable. 73 Patrick - Original Message - From: Robert McGwier To: digitalradio@yahoogroups.com Sent: Sunday, March 04, 2007 6:15 PM Subject: Re: [digitalradio] Noise Reduction and the digital modes Patrick Lindecker wrote: > Hello Andy and all, > > I don't think NR must be a so good idea for digimodes. Because, it can > be seen as non-linear filter. I disagree on the transfer function. It is an adaptive linear filter. Since it does not mix two tones in the passband, it can't be nonlinear. However, it does indeed introduce serious phase and amplitude distortion on the signals. This is not the way to better copy. These Widrow type/ LMS adaptive filters, in single sample update, or block adaptive form are intended TO AID THE HUMAN FATIGUE FACTOR in listening to noise or interfering tones. We agree that they are no good for digital modes. > In that type of filter, the next sample is calculated, knowing the > previous symbols and guessing what is the most probable symbol if > nothing change (a sort of "no more set of information" condition)... > > You are surely going to produce interference between symbols: the > decoding will be not so good and the necessary synchronization will be > more difficult because the difference between one symbol and the > following will be reduced (i.e the difference between two successive > symbols will be softened). > > But it would be interesting to experiment on calibrated signals and > different speeds (from the PSKAM10 to ALE or PSK220F). > > 73 > Patrick > > > Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest." - Piet Hine
Re: [digitalradio] Noise Reduction and the digital modes
Patrick Lindecker wrote: > Hello Andy and all, > > I don't think NR must be a so good idea for digimodes. Because, it can > be seen as non-linear filter. I disagree on the transfer function. It is an adaptive linear filter. Since it does not mix two tones in the passband, it can't be nonlinear. However, it does indeed introduce serious phase and amplitude distortion on the signals. This is not the way to better copy. These Widrow type/ LMS adaptive filters, in single sample update, or block adaptive form are intended TO AID THE HUMAN FATIGUE FACTOR in listening to noise or interfering tones. We agree that they are no good for digital modes. > In that type of filter, the next sample is calculated, knowing the > previous symbols and guessing what is the most probable symbol if > nothing change (a sort of "no more set of information" condition)... > > You are surely going to produce interference between symbols: the > decoding will be not so good and the necessary synchronization will be > more difficult because the difference between one symbol and the > following will be reduced (i.e the difference between two successive > symbols will be softened). > > But it would be interesting to experiment on calibrated signals and > different speeds (from the PSKAM10 to ALE or PSK220F). > > 73 > Patrick > > > Bob N4HY -- AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL, TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair "Taking fun as simply fun and earnestness in earnest shows how thoroughly thou none of the two discernest." - Piet Hine
Re: [digitalradio] Noise Reduction and the digital modes
Hello Andy and all, I don't think NR must be a so good idea for digimodes. Because, it can be seen as non-linear filter. In that type of filter, the next sample is calculated, knowing the previous symbols and guessing what is the most probable symbol if nothing change (a sort of "no more set of information" condition)... You are surely going to produce interference between symbols: the decoding will be not so good and the necessary synchronization will be more difficult because the difference between one symbol and the following will be reduced (i.e the difference between two successive symbols will be softened). But it would be interesting to experiment on calibrated signals and different speeds (from the PSKAM10 to ALE or PSK220F). 73 Patrick - Original Message - From: Andrew O'Brien To: digitalradio@yahoogroups.com Sent: Sunday, March 04, 2007 4:01 AM Subject: [digitalradio] Noise Reduction and the digital modes Noise reduction on my old rig never did much. Now I have a new rig the NR buttons actually appear to do some things. What about noise reduction and the digital modes, is it really helpful? I did just notice that with a Hell QSO NR made the print more blurred. For other modes I have not noticed much other than a lot less "speckles" in the waterfall. Maybe a graphically empty waterfall helps when a weak signal comes along but i worry the weak signal may get zapped by the NR. Comments ? -- Andy K3UK Skype Me : callto://andyobrien73 www.obriensweb.com
[digitalradio] Noise Reduction and the digital modes
Noise reduction on my old rig never did much. Now I have a new rig the NR buttons actually appear to do some things. What about noise reduction and the digital modes, is it really helpful? I did just notice that with a Hell QSO NR made the print more blurred. For other modes I have not noticed much other than a lot less "speckles" in the waterfall. Maybe a graphically empty waterfall helps when a weak signal comes along but i worry the weak signal may get zapped by the NR. Comments ? -- Andy K3UK Skype Me : callto://andyobrien73 www.obriensweb.com
Re: [digitalradio] Noise
Mike I've noticed it too so it ain't local. Have no idea what it is. 73 Brad N1NPK [Non-text portions of this message have been removed] Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [digitalradio] Noise
KV9U wrote: > I don't know what it is, but I can hear it here in SW Wisconsin. It is > fairly weak on my ICOM 756 Pro 2 from a ground mounted Butternut > vertical and not moving the S meter. I can hear it here in SE Iowa. It just paused, then the rapidity of the clicks picked up a bit. -- 72/73/oo - Rob, w0jrm - Centerville, IA - http://www.robmatherly.com/w0jrm FP-QRP #-330; FP-Z #4(1); QRPp-I #19; SKCC #29; ARS #1143 Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [digitalradio] Noise
Maybe HELLscriber, does it look like a narrow signal on the waterfall?, cant turn on the rig, still at the office but Hell sounds like CW to some. Ron W4LDE - Original Message - From: mac2251 <[EMAIL PROTECTED]> Date: Thursday, July 27, 2006 3:48 pm Subject: [digitalradio] Noise To: digitalradio@yahoogroups.com > Anyone know what the signal is on 14071.944 ? It runs about S8 > with > some qsb, and sounds like high speed clicking noise. Hope its not > a > local problem. Mike K9HCK > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org > > Other areas of interest: > > The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ > DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy > discussion) > > Yahoo! Groups Links > > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [digitalradio] Noise
I don't know what it is, but I can hear it here in SW Wisconsin. It is fairly weak on my ICOM 756 Pro 2 from a ground mounted Butternut vertical and not moving the S meter. On the waterfall, it looks like a groups of three carriers separated by 25 Hz or so, and several of these groups which make for a wide bandwidth due to weaker groups on either side of the center groups and extending 500 Hz on either side. Maybe my sound card is ghosting? It sometimes seems to be overdriven and the sound gets more rattled sounding like other overdriven digital signals. But it always has a sort of clicking sound as you describe. 73, Rick, KV9U mac2251 wrote: >Anyone know what the signal is on 14071.944 ? It runs about S8 with >some qsb, and sounds like high speed clicking noise. Hope its not a >local problem. Mike K9HCK > > > > > >Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org > >Other areas of interest: > >The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ >DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) > > >Yahoo! Groups Links > > > > > > > > > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
[digitalradio] Noise
Anyone know what the signal is on 14071.944 ? It runs about S8 with some qsb, and sounds like high speed clicking noise. Hope its not a local problem. Mike K9HCK Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
