14.03 MHz Continuous Tone/Carrier?@#$
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I have been hearing this for many days in row now and doing a Google search on it I found some disturbing info. It seems that this freq. is being used for telephone equipment. Intel among others has applied for patents using this frequency.
Does anyone know what the signal I am hearing on 14.030 MHz actually is? Thanks, Jack, AE6GC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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Hi Jack,
In my shack, the carrier on 14.030 is from my Linksys Wireless router. 73, ed - k9ew _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: 14.03 MHz Continuous Tone/Carrier?@#$
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<> In my shack, the carrier on 14.030 is from my Linksys Wireless router. Same here, but from a NetGear router. Fortunately very weak and hasn't prevented any QSOs yet that I know about. ... Craig AC0DS _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Jack
Do they have the license to emit this frequency, or just use it internally inside some equipment?
-- Alan, wb6zqz -------------- Original message -------------- From: Jack Regan <[hidden email]> > I have been hearing this for many days in row now and doing a Google search on > it I found some disturbing info. It seems that this freq. is being used for > telephone equipment. Intel among others has applied for patents using this > frequency. > > Does anyone know what the signal I am hearing on 14.030 MHz actually is? > > Thanks, > Jack, AE6GC > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Craig Smith
Also 21.060. It is from 100 megabit ethernwt devices. Switch your
shack to 10 megabit ethernet and it will be only your neighbors QRP transmitters with end-fed long wire antennas (CAT5 wiring) that you hear. Leigh/WA5ZNU On Tue, 14 Aug 2007 3:06 pm, Craig D. Smith wrote: > > <> In my shack, the carrier on 14.030 is from my Linksys Wireless > router. > > > Same here, but from a NetGear router. Fortunately very weak and hasn't > prevented any QSOs yet that I know about. > > ... Craig AC0DS _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Alan Biocca
This comes under the category "unintentional radiator" and there are legal
limits that must be met. One problem I can see is that the equipment could be tested and approved without wiring it into a "system" and it might meet the requirements, but when fitted with all the accessories it may not, but these may be deemed to be in your domain not the manufacturer's (I'm guessing and supposing). You need to find whether the interference is coming directly from the box (unlikely in my view) or is radiated from attached wiring, most likely. Snap-on cores on these wires, including the supply wire to the wall wart, should cure the problem. You may need more than one pass through each core; up close to the router. David G3UNA ----- Original Message ----- From: <[hidden email]> To: "Jack Regan" <[hidden email]>; <[hidden email]> Sent: Tuesday, August 14, 2007 11:12 PM Subject: Re: [Elecraft] 14.03 MHz Continuous Tone/Carrier?@#$ > Do they have the license to emit this frequency, or just use it internally > inside some equipment? > > -- Alan, wb6zqz > > -------------- Original message -------------- > From: Jack Regan <[hidden email]> > >> I have been hearing this for many days in row now and doing a Google >> search on >> it I found some disturbing info. It seems that this freq. is being used >> for >> telephone equipment. Intel among others has applied for patents using >> this >> frequency. >> >> Does anyone know what the signal I am hearing on 14.030 MHz actually is? >> >> Thanks, >> Jack, AE6GC >> _______________________________________________ >> Elecraft mailing list >> Post to: [hidden email] >> You must be a subscriber to post to the list. >> Subscriber Info (Addr. Change, sub, unsub etc.): >> http://mailman.qth.net/mailman/listinfo/elecraft >> >> Help: http://mailman.qth.net/subscribers.htm >> Elecraft web page: http://www.elecraft.com > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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On Tue, 14 Aug 2007 23:48:57 +0100, David Cutter wrote:
>This comes under the category "unintentional radiator" and there >are legal limits that must be met. One problem I can see is that >the equipment could be tested and approved without wiring it into >a "system" and it might meet the requirements, but when fitted >with all the accessories it may not, but these may be deemed to >be in your domain not the manufacturer's (I'm guessing and >supposing). It is well known to us who work in this field that the FCC noise limits for computing equipment are so loose that even if the equipment - with or without the wiring - meets the specs, there is still sufficient signal radiated to cause harmful interference. The law does require that the operator of the offending equipment cease operation if harmful interference is being caused, but this is a very delicate situation because in general the operator of the equipment does not have the technical savvy to understand why and how interference is being caused. If not handled correctly, the problem then escalates from a technical problem to a legal confrontation, which is never pleasant. -- 73 de K2ASP - Phil Kane Elecraft K2/100 s/n 5402 ARRL Volunteer Counsel -- Philip M. Kane P.E. / Esq VP - General Counsel & Engineering Manager C.S.I. Telecommunications Consulting Engineers San Francisco, CA - Beaverton, OR _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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In reply to this post by Leigh L. Klotz Jr WA5ZNU
Hi Group,
I have this problem too. I fixed a lot of the initial interference (mostly hash) by going from wired to wireless, but I still have these CW signals on several bands. I can't figure out how to switch my gear to limit it to 10 mB. I'm using a D-Link wireless G airport/access point. Any help? Thanks, Tom, klj3d -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Leigh L Klotz, Jr. Sent: Tuesday, August 14, 2007 6:25 PM To: [hidden email] Subject: Re: [Elecraft] 14.03 MHz Continuous Tone/Carrier?@#$ Also 21.060. It is from 100 megabit ethernwt devices. Switch your shack to 10 megabit ethernet and it will be only your neighbors QRP transmitters with end-fed long wire antennas (CAT5 wiring) that you hear. Leigh/WA5ZNU _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: 14.03 MHz Continuous Tone/Carrier?@#$
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I have two 100 megabit switches within six feet of the radio, and can
barely hear the spur on 14.030, so experience varies. Two spurs at 21.055 are below s0 with preamp #2 on. Wonder where the gigabit spurs are, that may be another solution, though gig switches are 100 compatible as well.. -- Alan, wb6zqz At 04:40 PM 8/14/2007, KJ3D wrote: > Hi Group, > >I have this problem too. I fixed a lot of the initial interference (mostly >hash) by going from wired to wireless, but I still have these CW signals on >several bands. > >I can't figure out how to switch my gear to limit it to 10 mB. I'm using a >D-Link wireless G airport/access point. > >Any help? > >Thanks, > >Tom, klj3d > > > >-----Original Message----- >From: [hidden email] >[mailto:[hidden email]] On Behalf Of Leigh L Klotz, Jr. >Sent: Tuesday, August 14, 2007 6:25 PM >To: [hidden email] >Subject: Re: [Elecraft] 14.03 MHz Continuous Tone/Carrier?@#$ > >Also 21.060. It is from 100 megabit ethernwt devices. Switch your shack to >10 megabit ethernet and it will be only your neighbors QRP transmitters with >end-fed long wire antennas (CAT5 wiring) that you hear. >Leigh/WA5ZNU > >_ _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Leigh L. Klotz Jr WA5ZNU
On Tue, 14 Aug 2007 15:25:06 -0700, Leigh L Klotz, Jr. wrote:
>Also 21.060. It is from 100 megabit ethernwt devices. Switch your >shack to 10 megabit ethernet and it will be only your neighbors QRP >transmitters with end-fed long wire antennas (CAT5 wiring) that you >hear. Not that easy. If your 100MBit system is connected to a 10 MBit device (like most Internet modems), it will carry that traffic as 10 MBit traffic, and you'll hear the birdies. See my RFI tutorial for more details and fixes. http://audiosystemsgroup.com/RFI-Ham.pdf >I have two 100 megabit switches within six feet of the radio, and can >barely hear the spur on 14.030, so experience varies. No, experience doesn't vary, it has NOTHING to do with proximity to your radio. What matters is proxmity to your ANTENNA, the degree to which that RF trash is suppressed by the router, and the ANTENNAS connected to the router (the Ethernet cables and the power cable)! 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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Jim,
I know you and I have a different understanding, that he birdies come from 100Mb (my belief) and that they come from 10Mb (yours), but I would like to straight out a couple of issues, perhaps minor ones. 1. I didn't write the second quoted paragraph below about 6' distance from the radio; someone else did, even though your message has my name above it. You are of course correct on this point, but I didn't make the point. (I suspect your RFI-Ham PDF file does say, though, that if you have not taken care, your rig's coax and other surrounding objects may be part of the antenna and so noise from something in proximity to the rig may be an indicator of other problems.) 2. Regardless of whether the birdies come from 100BaseT or 10BaseT, if you force your equipment all to the same, your switch will be forced to use the same. And better yet, if you use a hub, forcing one jacked piece of equipment to 10MB (or 100MB in your view, doesn't matter for this case) is enough to force all to the same. I've asked a number of ethernet luminaries to explain to me the source of the birdies, and gotten blanks. Leigh/WA5ZNU Jim Brown wrote: > On Tue, 14 Aug 2007 15:25:06 -0700, Leigh L Klotz, Jr. wrote: > > >> Also 21.060. It is from 100 megabit ethernwt devices. Switch your >> shack to 10 megabit ethernet and it will be only your neighbors QRP >> transmitters with end-fed long wire antennas (CAT5 wiring) that you >> hear. >> > > Not that easy. If your 100MBit system is connected to a 10 MBit device > (like most Internet modems), it will carry that traffic as 10 MBit > traffic, and you'll hear the birdies. > > See my RFI tutorial for more details and fixes. > > http://audiosystemsgroup.com/RFI-Ham.pdf > > >> I have two 100 megabit switches within six feet of the radio, and can >> barely hear the spur on 14.030, so experience varies. >> > > No, experience doesn't vary, it has NOTHING to do with proximity to > your radio. What matters is proxmity to your ANTENNA, the degree to > which that RF trash is suppressed by the router, and the ANTENNAS > connected to the router (the Ethernet cables and the power cable)! > > 73, > > Jim Brown K9YC > > > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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My experience with network gear is that different designs use
different frequencies for the oscillators and such, so it is likely that both of you are correct! Newer gear tends to have higher frequencies and lower power in the general trend, so changing or upgrading gear may help the level of interference. Interestingly, lower priced gear generally uses higher levels of in-chip integration and has less effective antenna area. Of course really low cost gear may skip some filtering, so testing is really the only way to tell. Perhaps we should collect info on which switches seem to be better or worse and see if there is a correlation between different people's experience and maybe provide some useful info. If the birdies were net traffic related they would vary over time, and probably would not be referred to as 'birdies' which implies a CW note. The thing we are most likely to hear is the oscillators feeding the chips - elements with higher power and more radiative capability over multiple traces on the pcb, etc. The chips that do the encode/decode generally develop the different frequencies for different network speeds internally, so those signals would be lower power and have negligible antennas and not tend to be radiated. 10 and 100 megabit twisted pair network signals are transformer coupled, and with the FCC certification requirements of this gear those transformers are likely designed to help reduce EMI at HF, I don't know the precise characteristics, but common mode EMI is something they are designing to avoid. I have not looked at the details of Gig hardware interfacing yet, but the requirements of network ground independence generally demand isolated connections, so they are likely transformer coupled as well, and are also designed to reduce EMI to meet specs. None of the noises I hear seem to be net traffic related. Those would tend to be very brief most of the time. The design of these network system components varies with their bitrate, manufacturer, model and age. Higher bitrate capable devices tend to have different basic oscillators. In general the higher speed devices have higher frequency oscillators which are often above HF. Each link has multiple speed capabilities in modern switches, independent of the other links. As Leigh hints, Many stations have inadequately balanced feedlines (whether coax or balanced lines), so noise and carriers in the shack conduct out to the antenna and come back into the receiver rather easily. An effective balun can help here, and ferrites on the lines coming out of the switch. Distance to the antenna and radio all matter to some degree, as both radiated and conducted RFI are attenuated by distance. Distance to the radio should not matter, but many stations use inadequate baluns and so are quite susceptible to common mode noise and EMI at the radio. (Note that no balun at all is also an inadequate balun). Jim's paper, link below, has a lot of good information in it, and agrees that most baluns are inadequate (less than 5,000 ohms choking Z). . In my shack these birdies are all extremely weak and readily covered by minor band noise. Two switches and the cable modem and cable entry and several computers plus the wifi are all within a six foot sphere including my HF station, and the antenna is 30 feet away fed by 6 feet of coax to a substantial balun to 30 feet of balanced line to the lower leg of the inverted L fed against radials. Just a data point, each station will be different. Network gear here is Linksys and Netgear both of 100 megabit fairly recent vintage. Cable modem is probably the only 10 megabit device, though perhaps the networked printer is also 10, also within this six foot sphere. As Leigh mentions, the best way to force things to a certain speed is to use a 10 megabit hub. However this does force to half duplex which is a pretty low level of performance. Adequate for your internet connection but it will take a long time to do your backups or transfer large files over it. Also note that hubs that do 100 megabits often have a funny mode where different ports run at different speeds and the hub speed shifts, so you will have a real mix, and of course switches negotiate each port independently. The net speed is 10 megabits when these hubs have at least one 10 megabit device connected, and the 100 megabit devices are forced to wait 90% of the time so the hub can translate their data to the lower speed. Another technique is to put things on wifi and reduce or eliminate the wired network. 2.4 GHZ doesn't generally bother HF. 73, -- Alan, wb6zqz At 11:52 PM 8/14/2007, Leigh L. Klotz, Jr. wrote: >Jim, >I know you and I have a different understanding, that he birdies >come from 100Mb (my belief) and that they come from 10Mb (yours), >but I would like to straight out a couple of issues, perhaps minor ones. > >1. I didn't write the second quoted paragraph below about 6' >distance from the radio; someone else did, even though your message >has my name above it. You are of course correct on this point, but >I didn't make the point. (I suspect your RFI-Ham PDF file does say, >though, that if you have not taken care, your rig's coax and other >surrounding objects may be part of the antenna and so noise from >something in proximity to the rig may be an indicator of other problems.) > >2. Regardless of whether the birdies come from 100BaseT or 10BaseT, >if you force your equipment all to the same, your switch will be >forced to use the same. And better yet, if you use a hub, forcing >one jacked piece of equipment to 10MB (or 100MB in your view, >doesn't matter for this case) is enough to force all to the same. > >I've asked a number of ethernet luminaries to explain to me the >source of the birdies, and gotten blanks. > >Leigh/WA5ZNU > > >Jim Brown wrote: >>On Tue, 14 Aug 2007 15:25:06 -0700, Leigh L Klotz, Jr. wrote: >> >> >>>Also 21.060. It is from 100 megabit ethernwt devices. Switch >>>your shack to 10 megabit ethernet and it will be only your >>>neighbors QRP transmitters with end-fed long wire antennas (CAT5 >>>wiring) that you hear. >>> >> >>Not that easy. If your 100MBit system is connected to a 10 MBit >>device (like most Internet modems), it will carry that traffic as >>10 MBit traffic, and you'll hear the birdies. >>See my RFI tutorial for more details and fixes. >>http://audiosystemsgroup.com/RFI-Ham.pdf >> >>>I have two 100 megabit switches within six feet of the radio, and can >>>barely hear the spur on 14.030, so experience varies. >> >>No, experience doesn't vary, it has NOTHING to do with proximity to >>your radio. What matters is proxmity to your ANTENNA, the degree to >>which that RF trash is suppressed by the router, and the ANTENNAS >>connected to the router (the Ethernet cables and the power cable)! >> >>73, >> >>Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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Gentlemen,
I have had some success in reducing the level of "unwanted" signals heard in my receiver by isolating my antenna from its feedline using common mode chokes. One method of propagation of the signals is up the feedline from my house wiring to the antenna. You should be able to find an article on the net by W1HIS discussing this in more detail. The article is about Common Mode Chokes. Robie - AJ4F ----- Original Message ----- From: "Alan Biocca" <[hidden email]> To: "Elecraft List" <[hidden email]> Sent: Wednesday, August 15, 2007 9:02 AM Subject: Re: [Elecraft] 14.03 MHz Continuous Tone/Carrier?@#$ > My experience with network gear is that different designs use different > frequencies for the oscillators and such, so it is likely that both of you > are correct! Newer gear tends to have higher frequencies and lower power > in the general trend, so changing or upgrading gear may help the level of > interference. Interestingly, lower priced gear generally uses higher > levels of in-chip integration and has less effective antenna area. Of > course really low cost gear may skip some filtering, so testing is really > the only way to tell. Perhaps we should collect info on which switches > seem to be better or worse and see if there is a correlation between > different people's experience and maybe provide some useful info. > > If the birdies were net traffic related they would vary over time, and > probably would not be referred to as 'birdies' which implies a CW note. > The thing we are most likely to hear is the oscillators feeding the > chips - elements with higher power and more radiative capability over > multiple traces on the pcb, etc. The chips that do the encode/decode > generally develop the different frequencies for different network speeds > internally, so those signals would be lower power and have negligible > antennas and not tend to be radiated. 10 and 100 megabit twisted pair > network signals are transformer coupled, and with the FCC certification > requirements of this gear those transformers are likely designed to help > reduce EMI at HF, I don't know the precise characteristics, but common > mode EMI is something they are designing to avoid. I have not looked at > the details of Gig hardware interfacing yet, but the requirements of > network ground independence generally demand isolated connections, so they > are likely transformer coupled as well, and are also designed to reduce > EMI to meet specs. > > None of the noises I hear seem to be net traffic related. Those would tend > to be very brief most of the time. > > The design of these network system components varies with their bitrate, > manufacturer, model and age. Higher bitrate capable devices tend to have > different basic oscillators. In general the higher speed devices have > higher frequency oscillators which are often above HF. > > Each link has multiple speed capabilities in modern switches, independent > of the other links. > > As Leigh hints, Many stations have inadequately balanced feedlines > (whether coax or balanced lines), so noise and carriers in the shack > conduct out to the antenna and come back into the receiver rather easily. > An effective balun can help here, and ferrites on the lines coming out of > the switch. > > Distance to the antenna and radio all matter to some degree, as both > radiated and conducted RFI are attenuated by distance. Distance to the > radio should not matter, but many stations use inadequate baluns and so > are quite susceptible to common mode noise and EMI at the radio. (Note > that no balun at all is also an inadequate balun). Jim's paper, link > below, has a lot of good information in it, and agrees that most baluns > are inadequate (less than 5,000 ohms choking Z). > . > In my shack these birdies are all extremely weak and readily covered by > minor band noise. Two switches and the cable modem and cable entry and > several computers plus the wifi are all within a six foot sphere including > my HF station, and the antenna is 30 feet away fed by 6 feet of coax to a > substantial balun to 30 feet of balanced line to the lower leg of the > inverted L fed against radials. Just a data point, each station will be > different. Network gear here is Linksys and Netgear both of 100 megabit > fairly recent vintage. Cable modem is probably the only 10 megabit device, > though perhaps the networked printer is also 10, also within this six foot > sphere. > > As Leigh mentions, the best way to force things to a certain speed is to > use a 10 megabit hub. However this does force to half duplex which is a > pretty low level of performance. Adequate for your internet connection but > it will take a long time to do your backups or transfer large files over > it. Also note that hubs that do 100 megabits often have a funny mode where > different ports run at different speeds and the hub speed shifts, so you > will have a real mix, and of course switches negotiate each port > independently. The net speed is 10 megabits when these hubs have at least > one 10 megabit device connected, and the 100 megabit devices are forced to > wait 90% of the time so the hub can translate their data to the lower > speed. > > Another technique is to put things on wifi and reduce or eliminate the > wired network. 2.4 GHZ doesn't generally bother HF. > > 73, > > -- Alan, wb6zqz > > > At 11:52 PM 8/14/2007, Leigh L. Klotz, Jr. wrote: >>Jim, >>I know you and I have a different understanding, that he birdies come from >>100Mb (my belief) and that they come from 10Mb (yours), but I would like >>to straight out a couple of issues, perhaps minor ones. >> >>1. I didn't write the second quoted paragraph below about 6' distance from >>the radio; someone else did, even though your message has my name above >>it. You are of course correct on this point, but I didn't make the point. >>(I suspect your RFI-Ham PDF file does say, though, that if you have not >>taken care, your rig's coax and other surrounding objects may be part of >>the antenna and so noise from something in proximity to the rig may be an >>indicator of other problems.) >> >>2. Regardless of whether the birdies come from 100BaseT or 10BaseT, if you >>force your equipment all to the same, your switch will be forced to use >>the same. And better yet, if you use a hub, forcing one jacked piece of >>equipment to 10MB (or 100MB in your view, doesn't matter for this case) is >>enough to force all to the same. >> >>I've asked a number of ethernet luminaries to explain to me the source of >>the birdies, and gotten blanks. >> >>Leigh/WA5ZNU >> >> >>Jim Brown wrote: >>>On Tue, 14 Aug 2007 15:25:06 -0700, Leigh L Klotz, Jr. wrote: >>> >>> >>>>Also 21.060. It is from 100 megabit ethernwt devices. Switch your >>>>shack to 10 megabit ethernet and it will be only your neighbors QRP >>>>transmitters with end-fed long wire antennas (CAT5 wiring) that you >>>>hear. >>>> >>> >>>Not that easy. If your 100MBit system is connected to a 10 MBit device >>>(like most Internet modems), it will carry that traffic as 10 MBit >>>traffic, and you'll hear the birdies. >>>See my RFI tutorial for more details and fixes. >>>http://audiosystemsgroup.com/RFI-Ham.pdf >>> >>>>I have two 100 megabit switches within six feet of the radio, and can >>>>barely hear the spur on 14.030, so experience varies. >>> >>>No, experience doesn't vary, it has NOTHING to do with proximity to your >>>radio. What matters is proxmity to your ANTENNA, the degree to which that >>>RF trash is suppressed by the router, and the ANTENNAS connected to the >>>router (the Ethernet cables and the power cable)! >>> >>>73, >>> >>>Jim Brown K9YC > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Leigh L. Klotz Jr WA5ZNU
On Tue, 14 Aug 2007 23:52:04 -0700, Leigh L. Klotz, Jr. wrote:
>I've asked a number of ethernet luminaries to explain to me the source >of the birdies, and gotten blanks. That's probably because they're digital guys, not RF guys. :) They should attend one of Henry Ott's excellent classes on EMC. There is either a clock or a component of the Ethernet signal that is coupled as a common mode current to the Ethernet cable. That cable acts as an antenna, and radiates it, and we pick it up on our receiving antennas. The Ethernet transmitter and receiver SHOULD be perfectly balanced with respect to impedance, but it is not. It is that imbalance that causes the radiation. I've never found an Ethernet device that doesn't have this problem. From a practical point of view, the most effective fixes are to either turn them off or stick ferrite chokes on the wires to prevent common mode current. Even when you've done that effectively, you may still hear radiation from the internal wiring of Ethernet devices that are badly shielded and have large internal ground loops. 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Robie Elms
On Wed, 15 Aug 2007 10:12:41 -0500, Robie Elms wrote:
>You should be able to find an article on the net by W1HIS discussing this in >more detail. The article is about Common Mode Chokes. Those things we call a "current balun" are common mode chokes. W1HIS's paper is good, but my piece has MUCH better measured data on these chokes and how to wind them. There are some SERIOUS measurement errors that are the basis of W1HIS's work, and they cause his recommendations for how to wind chokes to be wrong. Otherwise it's a very good piece. BTW -- I recently got email from W2DU, who had just read my tutorial and liked it a lot. If you haven't been there, his website is well worth the visit. It includes several chapters from his book "Reflections." They are excellent. 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: 14.03 MHz Continuous Tone/Carrier?@#$
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In reply to this post by Jack
In my house, I installed optical fiber when the walls were open for a
remodel. I chose unpopular and cheap ST connector style and used multimode fiber, which is good only for "short" runs (i.e. not for metropolitan wiring. As a result, I was able to get 10mb and 100mb to fiber converters for $30 and cable for free or cheap. In my shack Linux box, I used a fiber PCI for I paid $10 on eBay. So, there are no long runs of Cat5 anywhere in my house, only short runs from DSL modem to the fiber converter and the 802.11 device. As a result of doing this and switching to 10mb for the places where that was fast enough, I have eliminated the birdies I generate. Now I have a directional antenna on 20m and can rotate it to find the null. Someday I may go door-to-door and offer "help" but I may wait until 802.11n comes out and see if I can find a good device, and then recommend it as an upgrade. 73, Leigh/WA5ZNU On Wed, 15 Aug 2007 7:01 am, Alan Biocca wrote: > Another technique is to put things on wifi and reduce or eliminate the > wired network. 2.4 GHZ doesn't generally bother HF. > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: 14.03 MHz Continuous Tone/Carrier?@#$
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> Does anyone know what the signal I am hearing on 14.030 MHz actually is? 100Bt ethernet hardware puts out birdies around this frequency (I have several such birdies in the house, from 14.028 up to 14.031). It carries quite far; when we last had the entire house's power off (at the meter), I still heard them - presumably from one or more of my neighbors. 73 de chris K6DBG _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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