Re: [Elecraft] Intermod or mixing?
On Sun, 13 Jun 2010 11:21:49 -0400, Joe Subich, W4TV wrote: The info below is only partially correct. WBBM-TV has a CP (construction permit) to move to Channel 12. WKYC-TV has a CP to move to Channel 17. Both chose to move to avoid impulse noise that is present on the low-band VHF channels, and causes break-up of the digital signal. Another factor in WBBM-TV's move was problems with close-in high rise buildings. WTVF has a CP for channel 50. WEDY is the only one of those cited who appears to be happy with their low- band VHF assignment. Tom is right -- low band VHF is now used by only a handful of broadcasters in the US. For REAL FCC data, see http://www.fcc.gov/fcc-bin/audio/tvq.html and http://www.fcc.gov/dtv/markets/ 73, Jim K9YC The low-band TV signals are all QRT now, There are more than four dozen full power DTV licenses (including WMAZ-DT on channel 4 in your back yard) and quite a few low power DTV stations. The biggest cities with licensed full power low VHF DTV are Cleveland OH (WKYC, channel 2), Chicago IL (WBBM, channel 3), Nashville TN (WTVF, channel 5), and New Haven CT (WEDY, channel 6). There are construction permits or special temporary authorizations for a couple other large/middle market stations as well. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Larry, Is there a Channel 2 TV station in your vicinity? 73, Geoff GM4ESD Larry Godek wrote on Saturday, June 12, 2010 at 10:34 PM: I've got some local noise around here that sounds like a water heater or sorts or something along that line. Anyway it's really giving me fits on 6 meters. I ahve to run the NB almost all the time and that distorts the signals and sometimes it doesn't even clean up the noise. snip __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
I was using another brand transverter which suffered big time from channel 2 tv signal, I live about 25 miles from the transmitter. The transverter needed a notch filter installed in it to take out the tv signal. Regards Art ka9zap On 6/13/2010 7:42 AM, Geoffrey Mackenzie-Kennedy wrote: Larry, Is there a Channel 2 TV station in your vicinity? 73, Geoff GM4ESD Larry Godek wrote on Saturday, June 12, 2010 at 10:34 PM: I've got some local noise around here that sounds like a water heater or sorts or something along that line. Anyway it's really giving me fits on 6 meters. I ahve to run the NB almost all the time and that distorts the signals and sometimes it doesn't even clean up the noise. snip __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
The low-band TV signals are all QRT now, so that shouldn't be an issue anymore. There is only one VHF high station in range for me. I think it is up around 200 MHz. - Original Message - From: ka9zap ka9...@wowway.com To: K3 list Elecraft@mailman.qth.net Sent: Sunday, June 13, 2010 9:51 AM Subject: Re: [Elecraft] Intermod or mixing? I was using another brand transverter which suffered big time from channel 2 tv signal, I live about 25 miles from the transmitter. The transverter needed a notch filter installed in it to take out the tv signal. Regards Art ka9zap On 6/13/2010 7:42 AM, Geoffrey Mackenzie-Kennedy wrote: Larry, Is there a Channel 2 TV station in your vicinity? 73, Geoff GM4ESD Larry Godek wrote on Saturday, June 12, 2010 at 10:34 PM: I've got some local noise around here that sounds like a water heater or sorts or something along that line. Anyway it's really giving me fits on 6 meters. I ahve to run the NB almost all the time and that distorts the signals and sometimes it doesn't even clean up the noise. snip __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
On 6/13/2010 6:51 AM, ka9zap wrote: I was using another brand transverter which suffered big time from channel 2 tv signal, I live about 25 miles from the transmitter. The transverter needed a notch filter installed in it to take out the tv signal. Is the Channel 2 TV station still on the air after the transition to digital TV a year ago? In this area, 6 meters has been rarely used because of proximity until the Channel 2 station left the air after the transition. Last year we used the by-then unused Channel 2 six bay antenna for the VHF phone contest. We were running a 500 W amplifier only because we couldn't get the promised 1500 W amplifier in time. There was more loss in the 35 feet of RG-8 coax between the amplifier and the antenna patch bay than there was in the almost 1000 feet of 8-inch coax to the antenna. We (inadvertently) overloaded six meter receivers for about 20 miles around. Needless to say, we scored Number One. We can't do it again this year because the antenna has been disconnected and it and the feed line capped off. -- 73 de K2ASP - Phil Kane Skyline Tower Amateur Radio Club Portland, OR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
The low-band TV signals are all QRT now, There are more than four dozen full power DTV licenses (including WMAZ-DT on channel 4 in your back yard) and quite a few low power DTV stations. The biggest cities with licensed full power low VHF DTV are Cleveland OH (WKYC, channel 2), Chicago IL (WBBM, channel 3), Nashville TN (WTVF, channel 5), and New Haven CT (WEDY, channel 6). There are construction permits or special temporary authorizations for a couple other large/middle market stations as well. A good reference to US, Canadian and Mexican allocations is Doug Smith's web site: www.w9wi.com. 73, ... Joe, W4TV On 6/13/2010 10:06 AM, Tom W8JI wrote: The low-band TV signals are all QRT now, so that shouldn't be an issue anymore. There is only one VHF high station in range for me. I think it is up around 200 MHz. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Some careful reading W9WI data may be in order. For example, from the WKYC (analog channel 3) web site: July 12, 2009: Channel 3 moves to all digital broadcasting on digital channel 17 at 10 a.m. (Previously, the station was broadcasting on digital channel 2.) The station would continue its analog broadcast as the nightlight station in Cleveland, broadcasting only transition information through July 26th when the analog transmitter was permenantly shut off. I would suggest going to the individual web sites for stations that are shown as being on channel 2 to see where they really are now. 73 - Mike WA8BXN __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
I would suggest going to the individual web sites for stations that are shown as being on channel 2 to see where they really are now. Some stations may have moved away from low VHF licenses but there are as many who have active applications and/or construction permits to move back to low VHF. The issue is lack of coverage due to bad model data that resulted in excessively low equivalent coverage ERP. 73, ... Joe, W4TV On 6/13/2010 12:43 PM, Mike WA8BXN wrote: Some careful reading W9WI data may be in order. For example, from the WKYC (analog channel 3) web site: July 12, 2009: Channel 3 moves to all digital broadcasting on digital channel 17 at 10 a.m. (Previously, the station was broadcasting on digital channel 2.) The station would continue its analog broadcast as the nightlight station in Cleveland, broadcasting only transition information through July 26th when the analog transmitter was permenantly shut off. I would suggest going to the individual web sites for stations that are shown as being on channel 2 to see where they really are now. 73 - Mike WA8BXN __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Hi, Yet another good reason for a K3 bifurcation of the list. Regards, Mike VP8NO - Original Message - From: Joe Subich, W4TV li...@subich.com To: Mike WA8BXN hubb...@hotmail.com Cc: elecraft@mailman.qth.net Sent: Sunday, June 13, 2010 1:24 PM Subject: Re: [Elecraft] Intermod or mixing? I would suggest going to the individual web sites for stations that are shown as being on channel 2 to see where they really are now. Some stations may have moved away from low VHF licenses but there are as many who have active applications and/or construction permits to move back to low VHF. The issue is lack of coverage due to bad model data that resulted in excessively low equivalent coverage ERP. 73, ... Joe, W4TV On 6/13/2010 12:43 PM, Mike WA8BXN wrote: Some careful reading W9WI data may be in order. For example, from the WKYC (analog channel 3) web site: July 12, 2009: Channel 3 moves to all digital broadcasting on digital channel 17 at 10 a.m. (Previously, the station was broadcasting on digital channel 2.) The station would continue its analog broadcast as the nightlight station in Cleveland, broadcasting only transition information through July 26th when the analog transmitter was permenantly shut off. I would suggest going to the individual web sites for stations that are shown as being on channel 2 to see where they really are now. 73 - Mike WA8BXN __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.829 / Virus Database: 271.1.1/2934 - Release Date: 06/13/10 02:35:00 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
DFing the problem is probably your best bet. I had to do that with a S9+30 noise source on freqs lower than 10 MHz. It was an unused irrigation transformer with open leads (arcing). It was almost 1/2-mile from the shack. Crud like this carries a long distance. Your local electrical utility should be able to help with this, since almost all of them have electrical supply quality departments. In most US states, the utility can also force a customer to fix the problem if it's not utility-owned equipment. The field personnel that do this professionally are very capable, and yes - many of them really can find a needle in a haystack. 73 and Good Luck! matt zilmer, W6NIA On Sat, 12 Jun 2010 14:34:06 -0700 (PDT), you wrote: I've got some local noise around here that sounds like a water heater or sorts or something along that line. Anyway it's really giving me fits on 6 meters. I ahve to run the NB almost all the time and that distorts the signals and sometimes it doesn't even clean up the noise. Doesn't matter if i use the preamp, attenuator, Noise reduction or what. Plus when i turn the NB on i get all sorts of crap from SSb signals 40 plus kc up in the band. If i turn the NB off the SSb crud is gone. I operate mostly in the CW portion of the band. When the NB is off i don't ahve this problem. Other than finding the noise out there in the 0-90 degree quadrant anyone have any idea as to whats going on? I'm really getting sick of the SSb crud showing up when the NB is on down in the CW portion of the band. I only have one antenna hooked to the radio. What else can i tell you? Larry W0OGH __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Hi Larry, I assume you've tried playing with different settings of both the IF and DSP noise blankers. If not, by all means try it and use the least aggressive settings that make the situation tolerable. I'm not sure how the DSP NB works, but the IF NB works by essentially shutting off the signal path in the IF stage for the duration of the noise pulse. For relatively infrequent pulses, these brief blank spots in the received signal aren't very noticeable to our ears. However, if the blanking action is frequent (either because of the nature of the noise or because the threshold is set too low), the blanker effectively becomes a mixer combining the desired signal at the IF frequency with the frequency of the noise pulses (and harmonics thereof, etc.) When this happens, you'll hear distortion and intermod just as you've described. I'm afraid it's the nature of the beast. Your best bet in the long run is to find and fix the source of the noise. A distant second best is backing off the NB settings to find a compromise between the noise and the intermod that's at least tolerable. 73 -- Joe KB8AP On Jun 12, 2010, at 2:34 PM, Larry Godek wrote: I've got some local noise around here that sounds like a water heater or sorts or something along that line. Anyway it's really giving me fits on 6 meters. I ahve to run the NB almost all the time and that distorts the signals and sometimes it doesn't even clean up the noise. Doesn't matter if i use the preamp, attenuator, Noise reduction or what. Plus when i turn the NB on i get all sorts of crap from SSb signals 40 plus kc up in the band. If i turn the NB off the SSb crud is gone. I operate mostly in the CW portion of the band. When the NB is off i don't ahve this problem. Other than finding the noise out there in the 0-90 degree quadrant anyone have any idea as to whats going on? I'm really getting sick of the SSb crud showing up when the NB is on down in the CW portion of the band. I only have one antenna hooked to the radio. What else can i tell you? Larry W0OGH __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Would someone please furnish definitions of these two terms, and explain the difference between them--if there really is a difference. Sent from my iPhone __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?
Mixing is a general term for combining any two or more signals through the process of heterodyning. Intermod is a specific form of mixing which combines harmonic products of two RF signals: the desired receive signal and an undesired, accidental signal, yielding a series of harmonically related RF byproducts that can impair the receive pass band. I hope I stated this correctly and that it helps to differentiate the two terms adequately. Richard wrote: Would someone please furnish definitions of these two terms, and explain the difference between them--if there really is a difference. Sent from my iPhone [snip] -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?CORRECTION!
Regarding Intermod, I misspoke when stating that there was a harmonic relationship. I meant to say a relationship between the sum and difference frequencies that yield products up and down the band spaced these difference frequencies. Sorry, Dick Mixing is a general term for combining any two or more signals through the process of heterodyning. Intermod is a specific form of mixing which combines harmonic products of two RF signals: the desired receive signal and an undesired, accidental signal, yielding a series of harmonically related RF byproducts that can impair the receive pass band. I hope I stated this correctly and that it helps to differentiate the two terms adequately. Richard wrote: Would someone please furnish definitions of these two terms, and explain the difference between them--if there really is a difference. Sent from my iPhone [snip] -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] Intermod or mixing?CORRECTION!
Thank you Dick. Nicely done. Sent from my iPhone On Jun 12, 2010, at 21:30, Dick Roth, KA1OZ raro...@comcast.net wrote: Regarding Intermod, I misspoke when stating that there was a harmonic relationship. I meant to say a relationship between the sum and difference frequencies that yield products up and down the band spaced these difference frequencies. Sorry, Dick Mixing is a general term for combining any two or more signals through the process of heterodyning. Intermod is a specific form of mixing which combines harmonic products of two RF signals: the desired receive signal and an undesired, accidental signal, yielding a series of harmonically related RF byproducts that can impair the receive pass band. I hope I stated this correctly and that it helps to differentiate the two terms adequately. Richard wrote: Would someone please furnish definitions of these two terms, and explain the difference between them--if there really is a difference. Sent from my iPhone [snip] -- 73, Dick ka1oz Middleborough, MA Radio: Elecraft K3/100(Kit) SN 859 Antenna: Titan-DX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
