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OTA TV reception problems
I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on.
I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny |
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OTA TV reception problems
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OTA TV reception problems
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#5
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OTA TV reception problems
On Sunday, November 6, 2016 at 7:40:38 PM UTC-5, wrote:
I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny |
#6
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OTA TV reception problems
I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here.
Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny That sounds as if you may have a multipath situation. The signal from the transmitters is reaching your receive antenna via two different paths - e.g. once directly, and once after reflection off of a building or mountain or ???. If the two different paths deliver signals that happen to be of nearly equal strength, and nearly 180 degrees out of phase with one another, they will largely cancel out when they are combined by your antenna, and the signal strength will take a huge dive. Because the effective length of the signal paths (measured in wavelengths) is a function of the frequency, it's entirely possible for two different channels transmitted from the same tower to behave very differently. Even a small frequency difference can shift the difference-in-path-length by 180 degrees. 60 MHz difference is far more than enough for this effect to show up. Other possibilities: - Somebody may have put up some sort of structure which happens to resonate at the UHF Channel 30 frequency, thus creating a frequency-selective reflector. - It's possible that another station is now operating on Channel 30, somewhere within antenna range of you, and its signal is now interfering with WBZ. This might indicate that a new station has gone on-line (or an existing one has changed frequencies) or might indicate that there's some tropospheric ducting or other form of "skip" bringing an out-of-area station's signal to you. - There might be some form of local interference - a spurious transmission on or near the Channel 30 frequency. https://www.fcc.gov/media/television/tv-query can be used to find stations on specific frequencies. You could plug in your location and get a list of all stations (or those on channel 30) within a specific radius of your location. |
#7
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OTA TV reception problems
On Mon, 07 Nov 2016 09:09:26 -0800, Jeff Liebermann
wrote: https://transition.fcc.gov/fcc-bin/tvq?call=WBZ https://transition.fcc.gov/fcc-bin/tvq?call=WCVB Coverage maps of WBZ and WCVB. Please note that WBZ has or had a transmit power upgrade application pending with the FCC to increase their output to 941kW. I'm not sure if the coverage map is for 825kW or 941kW. http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-coverage.jpg http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WCVB-coverage.jpg Both coverage maps look fairly close. However, at 60 miles you're well outside the "normal" coverage area. I'm wondering why WCVB works at 60 miles. What do you have for an antenna and amp at your end? I'm otto time for this today. More tomorrow. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#8
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OTA TV reception problems
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#9
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OTA TV reception problems
On Sunday, November 6, 2016 at 4:40:38 PM UTC-8, wrote:
... for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. If there's a nearby signal to "channel 30", it could be saturating your input amplifier. It's counterintuitive, but try a passive attenuator and see if it improves your reception. The attenuator has to be between the antenna and the FIRST amplifier for the RF signal, so if you have a mast-mounted preamp, that's a problem. Saturation can happen in an RF input amplifier, reducing the signal gain, due to an off-frequency signal that is completely filtered out in later stages. I'm not sure if your signal indication would read the spurious signal or not. If this is a longterm problem, the best solution is an RF trap tuned for the too-strong signal. That won't hurt your signal strength for the other channel, like an attenuator does. http://www.mcmelectronics.com/browse/Attenuators/0000000801 |
#10
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OTA TV reception problems
On Sunday, November 6, 2016 at 7:40:38 PM UTC-5, wrote:
I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny Here is some background information from my previous posting: (I was thinking "drive" miles when I said that we were 60 miles from Boston). As the crow flies we are about 45. Sorry for that bit of misinformation. The following previous post was when the problem first surfaced. Sep 21 For the past ten days or so we have been having problems with TV channel 4. This station broadcasts on UHF from Boston Mass. and we are about 45 miles (as the crow flies) from the transmitter. The antenna is an old, but in good condition, very high gain Channel Master 5 foot parabolic which is mounted on a tripod about 6 feet off the roof. There is a mast mounted Winegard GA 8780 preamplifier with a 28 DB UHF section along with a very low noise figure mounted about 2 feet from the antenna. The cable is RG6 Quad which goes into a two way splitter. We have several different receivers, Converter boxes) but the one I use for assessment because it shows signal quality as well as signal strength is a Channel Master 7001. Our elevation is 410 feet and we are surrounded by trees, some deciduous and some pine. Most of the time, in spite of this not so ideal situation, (location) I can receive the three networks and a few independents. The signal display on the converter shows, as two horizontal bars, "signal quality" and "signal level". On most channels most of the time signal quality is pegged at 100 percent and signal level runs between 45 and 55 percent. Within this window I usually have no problems with reception. As long as signal quality doesn't fold back I usually will get no drop outs. If it should falter excessively though both picture and sound will break up and intermittently freeze. So I'm pretty familiar with what conditions will produce a good signal. Lately Channel 4 although displaying 54 percent signal level and 100 percent signal quality has had very slight "tearing streaks" going through the picture. If these aberrations only affected the picture we would be able to watch the program. However this problem seems to chop up the sound as well. This makes it impossible to watch a program. The weather of late has been hot and humid, which is atypical for New England this time of year. I've noticed in the past that during this type of weather we do sometimes lose reception on several channels for a day or two but never this long. I'm just wondering if anyone might have a theory as to what could be happening here. This only seems to affect channel 4, (where all our shows happen to be). Thanks, Lenny I also corresponded with the chief engineer at WBZ and got this back. Lenny, My apologies for the delay in replying. I dont have a good answer for why your reception has degraded recently. We have not been having any trouble with our transmission systems. Your installation sounds like a good one, though I think it may be a bit overdone, as a high-gain antenna in combination with 28 dB of amplification is probably more than you need, even at that distance. For comparison, I live 43.1 air miles from the transmit antenna, and I use a Channel Master 4228 8-bay bowtie antenna on the roof of my one-story house, with no amplification. I get full-bore signal into the TV on almost all channels. We have had incidences with viewers who had too much amplification in which they lost WBZ and WFXT, which had the most powerful signals in the Boston market (at the time). They were overdriving their TVs and as a result suffering the loss of the two stations they should have received with the least effort. Wish I had a more definitive answer€¦ Robert Yankowitz, CPBE WBZ-TV WSBK BOSTON 1170 Soldiers Field Road, Boston, MA 02134 Chief Engineer file:///M:/pmasucc/Work/General%20Info/email-combo%20logos.jpg o 617 562-5044 c 617 828-1041 f 617 787-7106 www.cbsboston.com Then I replied back: Lenny I wish I had answer for why your reception has degraded recently. We have not been having any trouble with our transmission systems. Your installation sounds like a good one, though I think it may be a bit overdone, as a high-gain antenna in combination with 28 dB of amplification is probably more than you need, even at that distance. For comparison, I live 43.1 air miles from the transmit antenna, and I use a Channel Master 4228 8-bay bowtie antenna on the roof of my one-story house, with no amplification. I get full-bore signal into the TV on almost all channels. We have had incidences with viewers who had too much amplification in which they lost WBZ and WFXT, which had the most powerful signals in the Boston market (at the time). They were overdriving their TVs and as a result suffering the loss of the two stations they should have received with the least effort. Wish I had a more definitive answer€¦ Robert Yankowitz, CPBE WBZ-TV WSBK BOSTON 1170 Soldiers Field Road, Boston, MA 02134 Chief Engineer file:///M:/pmasucc/Work/General%20Info/email-combo%20logos.jpg o 617 562-5044 c 617 828-1041 f 617 787-7106 www.cbsboston.com -------- Original message -------- From: Wufoo Date: 9/21/16 11:00 PM (GMT-05:00) To: CBS Local Site Contact Us , "Eich, Julie O" Subject: General Information - Boston - [#95913] Name * Leonard Stein Email * Phone Number * (603) 887-4253 Direct Your Message To CBS Local Staff In... * Boston Link (if appropriate) Please forwaed this to engineering dept. Comment For the past ten days or so we have been having problems with TV channel 4. We are located in Chester N.H. about 45 miles (as the crow flies) from the transmitter. The antenna is an old, but in good condition, very high gain Channel Master 5 foot parabolic which is mounted on a tripod about 6 feet off the roof. There is a mast mounted Winegard GA 8780 preamplifier with a 28 DB UHF section along with a very low noise figure mounted about 2 feet from the antenna. The cable is RG6 Quad which goes into a two way splitter. The receiver, (converter box) is a Channel Master 7001. Our elevation is 410 feet and we are surrounded by trees, some deciduous and some pine. Most of the time, in spite of this not so ideal situation, (location) I can receive the three networks and a few independents. The signal display on the converter shows, as two horizontal bars, "signal quality" and "signal level". On most channels most of the time signal quality is pegged at 100 percent and signal level runs between 45 and 55 percent. Within this window I usually have no problems with reception. As long as signal quality doesn't fold back I usually will get no drop outs. If it should falter excessively though both picture and sound will break up and intermittently freeze. So I'm pretty familiar with what conditions will produce a good signal. Lately Channel 4 although displaying 54 percent signal level and 100 percent signal quality has had very slight "tearing streaks" going through the picture. If these aberrations only affected the picture we would be able to watch the program. However this problem seems to chop up the sound as well. This makes it impossible to watch a program. I am a TV repair technician and I have never seen this type of choppy sound on either OTA or cable before.. The weather of late has been hot and humid, which is atypical for New England this time of year. I've noticed in the past that during this type of weather we do sometimes lose reception on several channels for a day or two but never this long. I'm just wondering if anyone there might have a theory as to what could be happening here. This only seems to affect channel 4, (where all our shows happen to be). Thanks, Lenny Reply | Reply to all | Forward | Print | Delete | Show original Add star Klem Sun, Oct 2, 2016 at 3:55 PM To: "Yankowitz, Robert B" Reply | Reply to all | Forward | Print | Delete | Show original Hi Robert Thank you for getting back to me. One thing that I failed to mention is that this is not a new installation. We put this antenna up about three years ago and it has always seemed to perform well. I hear what you are saying about overload, and in theory Chester NH is not such a haul from Boston. TV Fool never mentions the use of an amplifier for my location relating to Boston, and I have used that resource a lot to determine whether an antenna job at a certain location would be feasible or not. The preamp though has always seemed to make a substantial difference here as well as throughout town. I had a customer years ago who lived out of town near the top of the mountain that is partially blocking our South West view. He was watching everything from Boston including 10 and 12 from Providence, with rabbit ears. So I've always figured that it must be the foliage and the terrain that's attenuating my signal. Before digital, for my own house I used separate VHF and UHF antennas. We never needed any help with VHF, but UHF was always a challenge for us. The UHF antenna at the time was an 8 bay. During this period Winegard had just come out with a commercial preamp that had slightly lower gain but boasted an unheard of 1DB noise figure. I had to try this so I ordered one and installed it after the 8 bay. I pointed it towards Boston but channel 50's transmitter in Hudson NH splattered across the entire band. Although having a very hot front end the commercial preamp was not nearly as forgiving of overloads as the 8780. I eventually put a 20 DB trap set for channel 50 in line and that solved the overload problem. However in spite of all this, UHF reception with the 8 bay from Boston was never really very good at our house. Since as we all know it's not possible to watch a polar bear in a snow storm with digital three years ago I realized that I had to do something. This parabolic which I'm presently using is a 300 ohm antenna which I had liberated from a job about 20 some odd years ago. I had always planned to use it "some day" and it had been sitting in the woods behind my house since. It had a few broken reflectors which I repaired.I looked up the specs recently on this antenna and it seems to beat everything out there. Gain is between 13 to 16 DB, but it's narrow beam width is really where it excels. Early on I had considered that my problem could possibly be multipath, however just turning this antenna a few degrees and signal starts to drop like a rock. We didn't have cable TV here in Chester until the early 1990's, and back then I used to install quite a few antennas and retrofit existing ones with preamps. I had a nice Sadelco signal meter that tuned up to channel 83. I no longer do antenna work so I don't presently have equipment to measure OTA signals. So now admittedly a lot of this is an educated guess. Back then most consumer equipment particularly antennas were 300 ohms, and since the GA8780's input impedance also was 300 ohms I kind of standardized on this amp for my retrofits as well as new installations. The noise figure was about 3 DB which was the best of the time, beating Channel Master's figure of 5. However the real attraction of this amp was the very forgiving limiter circuit. I never had one overload on me, including those used in installations much higher than mine. So as you might imagine I've been very frustrated with this problem. However as of five days ago the problem has disappeared. Signal levels and quality as measured on my converter boxes show no difference, and if this was weather related we have had varying degrees of weather through this period as well. We do sometimes experience days at a time where reception is poor for whatever reason but it's always reflected on the signal strength and quality indication on the converter box meter. This was definitely not the case this time though. To the best of my recollection in this past three years this particular type of problem has never happened before. I do have a theory though that I wanted to suggest. The orientation of my antenna when it is optimized for Boston puts it a few degrees South East of New York City. Do you think that skip conditions were such through this period of time that this could possibly have been CO channel interference from WNBC in New York? As I had previously mentioned no other channels were affected nor have I noticed anything unusual on any of the Amateur frequencies or my low band two way business radio system. We do occasionally see what I believe must be tropospheric inversion, and we do seem to experience them at different times of the year. During these periods, which typically last up to five days, Boston UHF TV stations that I never can pull in such as 56 and 68 come bombing in, and many times with 90 percent signal strength. Then as mysteriously as they appeared, after a period of time they're gone. This episode however didn't seem to be an inversion, as there were no newcomers in my channel line up through this time. In 1975 I decided that I wanted to work in broadcasting. I got my First and I was hired as a studio technician for a UHF TV station in Central New York. Much of that work involved translator maintenance. I still recall (although not fondly) those awful cold trips up the mountains when the snowmobile wasn't running to service those miserable things. After that stint I switched careers to military, and then industrial electronics. I took a hard look at my life after that and since I had been repairing TV's from the time I was a teenager I decided to go in for myself. So since 1983 I've operated my own consumer electronics service business. Now I'm semi retired, (whatever that means) and I haven't seen the inside of a TV studio no less a network studio in 45 years. I'm sure much has changed. I'm sure that you are more than familiar with it than I but I found a rather interesting article on tropospheric propagation on Wikipedia, and there was also if you are interested some propaganda on my antenna. Thank you very much for trying to help me evaluate this problem. I appreciate the time and trouble you've taken. Very truly yours, Lenny Stein, KC1CPX https://en.wikipedia.org/wiki/Tropospheric_propagation http://www.rocketroberts.com/cm4251/cm4251.htm I wanted to include all the background information before this thread began.. Lenny BTW, here are my coordinates: and although the topo maps said different according to Google my altitude is 115 meters 465 Derry Rd, Chester, NH 03036, USA Latitude: 42.930838 | Longitude: -71.281921 |
#11
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OTA TV reception problems
On Sunday, November 6, 2016 at 7:40:38 PM UTC-5, wrote:
I tried posting something about this in the past but got no response. More than likely because you're posting from google groups. * Killfiling google & XXXXbanter.com: jonz.net/ng.htm |
#12
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OTA TV reception problems
Jon Elson wrote:
wrote: I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny Anybody hit or knock down a pole in the area? I assume your neighborhood is wired for cable. Damage to poles can knock connectors partially loose, allowing a LOT of signal to flow onto the outer sheath. Could be a signal right on the same frequency as Chan 4. Digital CATV uses QAM modulation, not ATSC. -- Never **** off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-) |
#13
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OTA TV reception problems
On Wed, 9 Nov 2016 15:25:58 -0500, "Michael A. Terrell"
wrote: Jon Elson wrote: wrote: I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny Anybody hit or knock down a pole in the area? I assume your neighborhood is wired for cable. Damage to poles can knock connectors partially loose, allowing a LOT of signal to flow onto the outer sheath. Could be a signal right on the same frequency as Chan 4. Digital CATV uses QAM modulation, not ATSC. What is your point? His point was that a leaky cable system with signals on channel 4 could interfere with the OP's over the air channel 4 signal. That is certainly possible even if different modulation schemes are used. (And by channel 4, we mean virtual 4 - RF 30). |
#14
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OTA TV reception problems
On Thu, 10 Nov 2016 08:08:50 -0500, Pat wrote:
On Wed, 9 Nov 2016 15:25:58 -0500, "Michael A. Terrell" wrote: Jon Elson wrote: wrote: I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny Anybody hit or knock down a pole in the area? I assume your neighborhood is wired for cable. Damage to poles can knock connectors partially loose, allowing a LOT of signal to flow onto the outer sheath. Could be a signal right on the same frequency as Chan 4. Digital CATV uses QAM modulation, not ATSC. What is your point? His point was that a leaky cable system with signals on channel 4 could interfere with the OP's over the air channel 4 signal. That is certainly possible even if different modulation schemes are used. (And by channel 4, we mean virtual 4 - RF 30). Besides using different modulation schemes, cable channels are also interleaved with OTA channels to prevent mutual interference (via leakage and ingress). For example, broadcast channel 30 goes from 566-572MHz OTA. The closest CATV channel is channel 81, which goes from 564-570MHz. Most of the leakage I've seen from CATV systems comes from poor Type-F coax connector installations by home owners and unterminated coax cables. It takes quite a bit of cable leakage to produce interference with an OTA signal, but it might be possible in weak areas and if the OTA TV system uses a pre-amplifier. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#15
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OTA TV reception problems
On Tue, 8 Nov 2016 13:56:36 -0800 (PST),
wrote: On Sunday, November 6, 2016 at 7:40:38 PM UTC-5, wrote: I tried posting something about this in the past but got no response. (...) I wanted to include all the background information before this thread began. Lenny I can see why you received no response. 357 lines of disorganized ranting is difficult to parse. Please get organized and save readers the effort of wading through your mess. Same as always: 1. What problem are you trying to solve? Keep it very simple. 2. What equipment do are you using? Numbers and details are good. 3. What have you done so far and what happened? I'm busy for a few days and will hopefully do a path profile this weekend. I don't know if I can squeeze much out of the path analysis except that you might have some obstructions or Fresnel zone diffraction problems. From the plots I previously posted, the coverage of both stations look identical. Did you do any of the substitution tests that I recommended? The best test would be just the TV, a length of RG-6/u, and a simple 1/2 wave (at 500MHz) dipole hund outside the window. No amps or splitters. Did you run your address through TVfool.com to see what signal levels they predict? BTW, here are my coordinates: and although the topo maps said different according to Google my altitude is 115 meters Slight misunderstanding. I need the type of antenna you are using at your house, and its elevation above ground level. You can save me some trouble excavating the information from your archive by listing everything (inclusive) between the antenna and the TV receiver. 465 Derry Rd, Chester, NH 03036, USA Latitude: 42.930838 | Longitude: -71.281921 Thanks for using a decent (decimal degrees) format. I hate DMS. From the FCC data, WBZ is at 42° 18' 37.00" N, 71° 14' 14.00" W but in NAD27. Converting the FCC DMS to decimal and datum into WGS84: (42.310278 N, -71.237222W) NAD27 - (42.31025 N, 71.23669 W) WGS84. Antenna height above ground 387 meters (1270 ft). Nice little monster tower: http://www.necrat.us/bztower.html Well, I have a few minutes I'll throw together a Google Earth path profile. It won't be very accurate and won't show Freznel zones, but will show any obstructions. Looks like drawing a 1270ft tower is gonna be difficult, so I guessed: http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-Lenny.jpg If you have Google Earth, here's the PRELIMINARY KMZ file: http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ%20path.kmz Looks like you have a rather large hill directly in the path and very close to you. A 150ft or so tower at your end would be needed to clear the hill. Incidentally, I vaguely recall a similar OTA problem where one channel was uncharacteristically low in receive signal. It turned out to be an unterminated length of coax on a coaxial splitter. Even though the splitter was suppose to have perhaps 20dB(?) of isolation between ports, the device was so badly built that I'm sure it was much less. http://802.11junk.com/jeffl/crud/CATV-splitters.jpg The unterminated length acted as a notch filter which just happened to land on the TV channel frequency. Replacing the spllitter and removing the coax or terminating it with 75 ohms solved the problem. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#16
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OTA TV reception problems
Jeff Liebermann wrote:
Most of the leakage I've seen from CATV systems comes from poor Type-F coax connector installations by home owners and unterminated coax cables. It takes quite a bit of cable leakage to produce interference with an OTA signal, but it might be possible in weak areas and if the OTA TV system uses a pre-amplifier. The OP is definitly in a weak area (45 miles from stations) and IS using an aplifier just under the antenna. Anybody within a fe miles in the general direction of the broadcast antenna could be trashing his signal. Without the proper equipment (portable spectrum analyzer), it could be quite hard to find the problem. Jon |
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OTA TV reception problems
On Thu, 10 Nov 2016 14:40:12 -0600, Jon Elson
wrote: The OP is definitly in a weak area (45 miles from stations) and IS using an aplifier just under the antenna. Yep, and there's another problem: http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-Lenny.jpg That a really rough and crude guestimate of the path, which shows a 150ft pile of dirt blocking the signal. It could be knife edge diffraction, but I don't think so. My guess(tm) is some part of his system (antenna, amp, coax, splitter, power injector, TV) is broken. Anybody within a few miles in the general direction of the broadcast antenna could be trashing his signal. Yep. I didn't check for other UHF TV stations in his area. Overload (blocking) is possible, but usually affects ALL the channels. Since I determined that the theoretical signal strength from both WBZ and KVCB are almost identical, I don't see a nearby signal trashing one signal, but not the other. The lack of complaints about other channels also points to a specific problem on UHF channel 30. Without the proper equipment (portable spectrum analyzer), it could be quite hard to find the problem. Test equipment is always nice to have. However, I think this one can be nailed by simply substituting parts of the puzzle and comparing the effects on both WBZ and KBCZ. When something is replaced that makes the signals equal, then the problem has been found. However, if you really want to use a portable spectrum analyzer, any of the RTL2832U SDR receiver dongles make a nifty spectrum analyzer. http://www.rtl-sdr.com/?s=spectrum+analyzer I run several RTL-SDR programs on my Google Nexus 7 tablet that acts something like a spectrum analyzer. https://play.google.com/store/apps/details?id=marto.androsdr2 The basic sensitivity of the typical USB SDR dongle sucks without an RF preamp, but should be good enough to see what's arriving from the antenna mounted amplifier. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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OTA TV reception problems
Pat wrote:
On Wed, 9 Nov 2016 15:25:58 -0500, "Michael A. Terrell" wrote: Jon Elson wrote: wrote: I tried posting something about this in the past but got no response. I'm holing that this time someone might read it who may have a theory as to what could be going on. I live in southern New Hampshire and watch OTA TV out of Boston, which is about 60 miles from here. Lately I as well as several other people I know have been experiencing intermittent problems with channel four. While most other channels are presently operating fine, for the past 10 days or so channel 4's signal has been in the toilet. This station, WBZ TV operates on UHF channel 30, runs 825KW, and has an antenna height of 390 meters. By contrast Channel 5, WCVB, operates on UHF channel 20, runs 625 KW, and shares the same tower and has it's antenna at the same height as channel 4's, and we never have any problems with that channel. Could propagation be that much different 60 MHZ apart? What is really weird is that the signal just drops to almost nothing. I discussed this with the chief engineer at Channel four and he had no explanation for this. Does anyone have any theories about this? Thanks, Lenny Anybody hit or knock down a pole in the area? I assume your neighborhood is wired for cable. Damage to poles can knock connectors partially loose, allowing a LOT of signal to flow onto the outer sheath. Could be a signal right on the same frequency as Chan 4. The connectors on the trunklines and feeders are 5/8-27 thread, and are quite strong. The housings have a pressed in stainless steel insert so the threads don't strip out easily. Also, the 60VAC @30A, modified square wave that powers the trunk and bridging amplifiers is carried on the rigid coax. If it is loose enough t radiate, it will have a high enough resistance to prevent the amplifier from working. The RayChem heatshrink ceramic connectors we used in the mid '80s were so strong that the outer aluminum tubing would break, instead of the connector to shield connection. Digital CATV uses QAM modulation, not ATSC. What is your point? His point was that a leaky cable system with signals on channel 4 could interfere with the OP's over the air channel 4 signal. That is certainly possible even if different modulation schemes are used. (And by channel 4, we mean virtual 4 - RF 30). Different modulation systems would not mesh, and cause a weak signal from phase reversal. Download the Blonder Tongue Design Guide, and read it. CATV systems rarely carried A TV station on the same channel that it was transmitted on. For instance, United Video in Cincinnati, had custom labels for their converters. Instead of Ch 2 to 37, they were labeled 1 to 36. So, Channel 12 was actually on Ch 13 to prevent problems with direct pickup. The actual Ch. 12 carried one of our in house generated channels. http://www.blondertongue.com/UserFiles/file/documents/2012%20BRG%20FINAL_lo-res.pdf -- Never **** off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-) |
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OTA TV reception problems
On Sat, 12 Nov 2016 06:32:48 -0500, "Michael A. Terrell"
wrote: http://www.blondertongue.com/UserFiles/file/documents/2012%20BRG%20FINAL_lo-res.pdf Thanks, but the 2014 version is more current: http://www.blondertongue.com/UserFiles/file/Marketing%20Literature/2014_BRG_lo-res.pdf Other documents and catalogs might be of interest: http://www.blondertongue.com/about/request_a_catalog.aspx -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#20
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OTA TV reception problems
Jeff Liebermann wrote:
On Sat, 12 Nov 2016 06:32:48 -0500, "Michael A. Terrell" wrote: http://www.blondertongue.com/UserFiles/file/documents/2012%20BRG%20FINAL_lo-res.pdf I have several other dates archived, as well. Sometimes you need the older information for existing systems. Thanks, but the 2014 version is more current: http://www.blondertongue.com/UserFiles/file/Marketing%20Literature/2014_BRG_lo-res.pdf Other documents and catalogs might be of interest: http://www.blondertongue.com/about/request_a_catalog.aspx Several other companies had useful publications, but the slow conversion to Fiber Aided CATV killed them off. -- Never **** off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-) |
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OTA TV reception problems
On Sat, 12 Nov 2016 23:25:15 -0500, "Michael A. Terrell"
wrote: Jeff Liebermann wrote: On Sat, 12 Nov 2016 06:32:48 -0500, "Michael A. Terrell" wrote: http://www.blondertongue.com/UserFiles/file/documents/2012%20BRG%20FINAL_lo-res.pdf I have several other dates archived, as well. Sometimes you need the older information for existing systems. Good point (after I erased the 2012 version from my machine). I did some Googling and found the 2008 version of the Blonder Tongue guide at: https://www.sateng.com/downloads/btbroadbandrefguide.pdf After a quick glance, it seems to have quite a bit on antenna systems, which are not used very much these days thanks to fiber and satellite backhauls. Also, the 2009 version at: http://www.blondertongue.com/UserFiles/file/documents/2009%20BBand%20Ref%20Guide.pdf Thanks, but the 2014 version is more current: http://www.blondertongue.com/UserFiles/file/Marketing%20Literature/2014_BRG_lo-res.pdf Other documents and catalogs might be of interest: http://www.blondertongue.com/about/request_a_catalog.aspx Several other companies had useful publications, but the slow conversion to Fiber Aided CATV killed them off. The Motorola (now Arris) 2014 guide is what I like to use: https://www.arris.com/globalassets/resources/other/cable_technology_pocket_guide.pdf (6MB) 302 pages. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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OTA TV reception problems
Jeff Liebermann wrote:
On Sat, 12 Nov 2016 23:25:15 -0500, "Michael A. Terrell" wrote: Jeff Liebermann wrote: On Sat, 12 Nov 2016 06:32:48 -0500, "Michael A. Terrell" wrote: http://www.blondertongue.com/UserFiles/file/documents/2012%20BRG%20FINAL_lo-res.pdf I have several other dates archived, as well. Sometimes you need the older information for existing systems. Good point (after I erased the 2012 version from my machine). I did some Googling and found the 2008 version of the Blonder Tongue guide at: https://www.sateng.com/downloads/btbroadbandrefguide.pdf After a quick glance, it seems to have quite a bit on antenna systems, which are not used very much these days thanks to fiber and satellite backhauls. Also, the 2009 version at: http://www.blondertongue.com/UserFiles/file/documents/2009%20BBand%20Ref%20Guide.pdf Thanks, but the 2014 version is more current: http://www.blondertongue.com/UserFiles/file/Marketing%20Literature/2014_BRG_lo-res.pdf Other documents and catalogs might be of interest: http://www.blondertongue.com/about/request_a_catalog.aspx Several other companies had useful publications, but the slow conversion to Fiber Aided CATV killed them off. The Motorola (now Arris) 2014 guide is what I like to use: https://www.arris.com/globalassets/resources/other/cable_technology_pocket_guide.pdf (6MB) 302 pages. Just like early electrical engineering books that explained the things that are just glossed over in current books. P Millet's website is a wealth of early electronics books. -- Never **** off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-) |
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OTA TV reception problems
On Sun, 13 Nov 2016 15:53:54 -0500, "Michael A. Terrell"
wrote: Just like early electrical engineering books that explained the things that are just glossed over in current books. P Millet's website is a wealth of early electronics books. Yep. http://www.tubebooks.org/technical_books_online.htm I downloaded a mess of those (mostly radio books) a few years ago and amd sloooowly going through them. What's interesting to me is that the origins or reasons behind various modern technical decisions and standards can be found in the old books. However, I doubt any of this will help deal with the current OTA TV reception problem. I'm not getting any response from CaptainVideo so I guess I'll drop the project for now. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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OTA TV reception problems
captainvideo:
Your problem is two-fold: distance, and the all-digital broadcast requirement. 8 years ago, on NTSC(analog), distance would not have been been such an issue. You probably would have had snow on a lot of channels, but you still had picture and sound. Now, on ATSC(digital), you don't get certain stations at all, and frequent dropouts on others. This is why I maintain that ATSC is 'less Green' than NTSC was: While with digital stations can piggy-back channels (4.2, 4.3, 4.4, etc.) they must BOOST THEIR SIGNAL for people with same OTA setup to receive them in the first place. And increasing signal strength meansUSING MORE ENERGY - something the folks over at Alt.Video.Digital.Tv fail to grasp. You said you are using a 'parabolic' antenna currently - I'm assuming that is dish-shaped. Have you looked into a variation on this form factor yet? It's all I'll ever use, even just 35 miles away from my market: https://m.lowes.com/pd/Channel-Maste...0-f2260ea5c961 |
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OTA TV reception problems
Pat wrote: "You may fail to grasp it, too. When you hear about TV stations
(especially UHF stations) using millions of watts of power, they are referring to ERP - Effective Radiated Power. That means the actual power going into the antenna is much lower but the antenna has very high gain. Rarely do stations use more than a few thousand watts of actual power. The transmitter's actual power usage is a drop in the bucket compared to all the other energy a TV station uses for lights, cameras, HVAC, etc. " ________ Alright, say a typical medium market station has historically transmitted 2,000W as a NTSC. 2009 they go fully ATSC, still at 2,000W. Hundreds of letters from viewers flood their mailbox, and thousands of callers jam their phone boards about not being able to pick them up over the air with their new TVs. Most are from viewers in the outer one-third of the station's transmission radius. Station board deliberates, and after a couple months decides to increase transmitter wattage to 2,500W. Viewer complaints plummet, while greenhouse gas emmissions steadily rise to generate additional electricity as this scenario is mulitiplied across dozens of medium markets and many major markets. Grasp that! Yeah, I get that actual wattage is but a fraction of ERP, but it still adds up as many TV stations must increase their signal strength to cover the same audience area in digital as they did via analog. |
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OTA TV reception problems
On Sun, 6 Nov 2016 16:40:35 -0800 (PST),
wrote: (...) This is too easy. WBZ has been running on reduced power for most of the last few weeks thanks to an antenna problem: http://boston.cbslocal.com/2016/11/07/wbz-tv-wsbk-tv-operating-at-reduced-power/ http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/ No clue if it has been fixed, but judging by the lack of updates, probably not. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#29
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OTA TV reception problems
Pat wrote:
On Tue, 15 Nov 2016 04:10:07 -0800 (PST), wrote: And increasing signal strength meansUSING MORE ENERGY - something the folks over at Alt.Video.Digital.Tv fail to grasp. You may fail to grasp it, too. When you hear about TV stations (especially UHF stations) using millions of watts of power, they are referring to ERP - Effective Radiated Power. That means the actual power going into the antenna is much lower but the antenna has very high gain. Rarely do stations use more than a few thousand watts of actual power. The transmitter's actual power usage is a drop in the bucket compared to all the other energy a TV station uses for lights, cameras, HVAC, etc. I was an engineer at an analog UHF station with a 5 MW EIRP, on a 1700' tower. The Comark transmitter used a pair of 65 KW EEV Klystons, for 130 KW of RF into the diplexer. A third 65 KW Klystron was used for the aural signal. That was in the late '80s, and our electric bill for the transmitter site was $45,00 a month. Solid state transmitters are modular, with around 1KW output, per tray. Look at the Harris Broadcast website for some actual data. -- Never **** off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-) |
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OTA TV reception problems
On 18/11/16 13:44, Michael A. Terrell wrote:
Pat wrote: Solid state transmitters are modular, with around 1KW output, per tray. Look at the Harris Broadcast website for some actual data. I have a half-dozen such modules here, unfortunately with the water-cooled heatsink removed, if you want photos or to ask any questions. The modules are single or dual, using a BLF278 dual FET each. A 30W input is split into six to drive three duals, which are then combined to produce about 1KW from about 6KW input at 50V. The power supply rectifies three-phase 415V mains and chopped it to produce 50V at 60A, scary. A local ATV transmitter was using more than 50 of these to put 50KW up the spout. Pretty old-tech now though, the new lateral MOSFETs from NXP produce 1500W from a single device (two FETs), as Michael T has pointed out recently. The really interesting bit to me is how simple the baluns are - just a couple of 8cm lengths of special hardline to match from about 12 ohms up to 50, at 225MHz. Transmission line transformers FTW! There's quite a few reference designs for this class of transmitter at http://nxp.com Clifford Heath. |
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OTA TV reception problems
Clifford, Michael:
So you're saying modern ATSC transmitters actually use less power then the old NTs? |
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OTA TV reception problems
On 11/10/2016 11:28 AM, Jeff Liebermann wrote:
On Tue, 8 Nov 2016 13:56:36 -0800 (PST), wrote: I would try what the station engineer pointed out. You have a high gain antenna and a 28db amplifier, try it without the amp. I'm 51.9 miles* from a digital channel 36, I cut a folded dipole using 300 ohm twin lead, as I recall about 9.5" long. No Amp. It is no more than 10ft off the ground. I have zero dropouts and no audio problems. WTVY http://www.tvfool.com/?option=com_wr...af29715115a b Opps, just saw a glitch go by in the video. Mikek *According to TVfool. |
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OTA TV reception problems
On 11/15/2016 11:09 AM, Jeff Liebermann wrote:
On Sun, 6 Nov 2016 16:40:35 -0800 (PST), wrote: (...) This is too easy. WBZ has been running on reduced power for most of the last few weeks thanks to an antenna problem: http://boston.cbslocal.com/2016/11/07/wbz-tv-wsbk-tv-operating-at-reduced-power/ http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/ No clue if it has been fixed, but judging by the lack of updates, probably not. Well that takes all the fun out of it! But do note my post of good reception at 51.9m miles with cut to length folded dipole, 10 ft off the ground. Channel 36, about 9.5" long. Mikek |
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OTA TV reception problems
On Fri, 18 Nov 2016 15:06:37 -0600, amdx wrote:
On 11/15/2016 11:09 AM, Jeff Liebermann wrote: On Sun, 6 Nov 2016 16:40:35 -0800 (PST), wrote: (...) This is too easy. WBZ has been running on reduced power for most of the last few weeks thanks to an antenna problem: http://boston.cbslocal.com/2016/11/07/wbz-tv-wsbk-tv-operating-at-reduced-power/ http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/ No clue if it has been fixed, but judging by the lack of updates, probably not. Well that takes all the fun out of it! Occam's Razor. But do note my post of good reception at 51.9m miles with cut to length folded dipole, 10 ft off the ground. Channel 36, about 9.5" long. Mikek Sure, it can be done at 45 miles depending on tx power and frequency. However, Captain Video has an additional problem in the form of a mound of dirt in between his antenna and the station transmitter. http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-Lenny.jpg or if you have Google Earth handy: http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ%20path.kmz The above path profile is NOT very accurate. I stopped working on the problem after Captain Video disappeared from the thread. Incidentally, I sometimes can watch KMPH TV from Fresno, CA which is about 200 miles away from Ben Lomond. I live on the side of a hill which helps. The real culprit is atmosheric ducting and edge diffraction from two mountain ranges in between. It only happens a few days per year, usually in the summer, but the picture is 100% perfect. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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OTA TV reception problems
On 11/18/2016 5:02 PM, Jeff Liebermann wrote:
On Fri, 18 Nov 2016 15:06:37 -0600, amdx wrote: On 11/15/2016 11:09 AM, Jeff Liebermann wrote: On Sun, 6 Nov 2016 16:40:35 -0800 (PST), wrote: (...) This is too easy. WBZ has been running on reduced power for most of the last few weeks thanks to an antenna problem: http://boston.cbslocal.com/2016/11/07/wbz-tv-wsbk-tv-operating-at-reduced-power/ http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/ No clue if it has been fixed, but judging by the lack of updates, probably not. Well that takes all the fun out of it! Occam's Razor. But do note my post of good reception at 51.9m miles with cut to length folded dipole, 10 ft off the ground. Channel 36, about 9.5" long. Mikek Sure, it can be done at 45 miles depending on tx power and frequency. However, Captain Video has an additional problem in the form of a mound of dirt in between his antenna and the station transmitter. http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ-Lenny.jpg or if you have Google Earth handy: http://802.11junk.com/jeffl/coverage/KBCZ-WBZ/WBZ%20path.kmz The above path profile is NOT very accurate. I stopped working on the problem after Captain Video disappeared from the thread. Incidentally, I sometimes can watch KMPH TV from Fresno, CA which is about 200 miles away from Ben Lomond. I live on the side of a hill which helps. The real culprit is atmosheric ducting and edge diffraction from two mountain ranges in between. It only happens a few days per year, usually in the summer, but the picture is 100% perfect. When I was a lot younger living in Kalamazoo Michigan, late one night I received a Wisconsin TV station across lake Michigan. Mikek |
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OTA TV reception problems
Michael Terrell wrote: - hide quoted text -
wrote: Clifford, Michael: So you're saying modern ATSC transmitters actually use less power then the old NTs? "The heaters in Klystons used a lot of power, that had to be removed as heat, in a water chiller. One 25 KW UHF transmitter that I rebuilt used a pair of 1.5V, 1000A heaters per tube. That was 3 KW, then the fan on the water chiller was a 480V, three phase, 5 hp motor. The circulating pump was anther two HP. None of this ended up at the output port. " - show quoted text - That doesn't answer my question of whether or not AT transmitters use less power than NT. Just a simple Yes or No would suffice. |
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OTA TV reception problems
On 11/15/2016 12:09 PM, Jeff Liebermann wrote:
On Sun, 6 Nov 2016 16:40:35 -0800 (PST), wrote: (...) This is too easy. WBZ has been running on reduced power for most of the last few weeks thanks to an antenna problem: http://boston.cbslocal.com/2016/11/07/wbz-tv-wsbk-tv-operating-at-reduced-power/ http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/ No clue if it has been fixed, but judging by the lack of updates, probably not. The problem (defective transmission line to the upper master antenna on the CBS tower in Needham) was finally fully resolved this morning at 4:55AM. Lots more details at http://www.wgbh.org/about/Tower_and_...nal_Issues.cfm (The CBS tower carries virtual channels 2, 4, 5, 8, 38, 44, and 48.) Tony Matt |
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OTA TV reception problems
On Saturday, November 19, 2016 at 2:52:21 AM UTC-5, wrote:
Michael Terrell wrote: - hide quoted text - wrote: Clifford, Michael: So you're saying modern ATSC transmitters actually use less power then the old NTs? "The heaters in Klystons used a lot of power, that had to be removed as heat, in a water chiller. One 25 KW UHF transmitter that I rebuilt used a pair of 1.5V, 1000A heaters per tube. That was 3 KW, then the fan on the water chiller was a 480V, three phase, 5 hp motor. The circulating pump was anther two HP. None of this ended up at the output port. " - show quoted text - That doesn't answer my question of whether or not AT transmitters use less power than NT. Just a simple Yes or No would suffice. there is not a simple answer.. if the station stayed on the same frequency, then it can use lower power digital compared to analog. Digital fundamentally requires less power to close the link. HOWEVER. many stations also switched from a VHF frequency to a UHF frequency. The FCC allows more power to be used on UHF. So in each case the answer is ...it depends. I think it would be a gross exaggeration to say that digital TV is environmentally more friendly compared to analog because of power consumption. m |
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