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Digital TV Antenna Design
Anybody have a good antenna design for the new UHF digital TV
stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Anybody know the dimensions of such an antenna, probabaly in the frequency range of 400-800 Mhz ? -Bill |
Digital TV Antenna Design
On Sun, 15 Feb 2009 21:59:13 -0800 (PST), Bill Bowden
wrote: Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Rule of thumb: The bigger and uglier the antenna, the better it works. Anybody know the dimensions of such an antenna, Various commercial digital TV antennas: http://www.hdtvprimer.com/ANTENNAS/comparing.html with Eznec NEC2 files at: http://www.hdtvprimer.com/SIMS/ probabaly in the frequency range of 400-800 Mhz ? There are going to be some DTV stations in the VHF range. You might want to check the new channels for your area: http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-07-138A2.xls List of frequencies: http://en.wikipedia.org/wiki/North_American_broadcast_television_frequencies Note that the upper end of the UHF TV band will be channel 51 at 698Mhz. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Digital TV Antenna Design
"Jeff Liebermann" wrote in message ... On Sun, 15 Feb 2009 21:59:13 -0800 (PST), Bill Bowden wrote: Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Rule of thumb: The bigger and uglier the antenna, the better it works. Anybody know the dimensions of such an antenna, Various commercial digital TV antennas: http://www.hdtvprimer.com/ANTENNAS/comparing.html with Eznec NEC2 files at: http://www.hdtvprimer.com/SIMS/ probabaly in the frequency range of 400-800 Mhz ? There are going to be some DTV stations in the VHF range. You might want to check the new channels for your area: http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-07-138A2.xls List of frequencies: http://en.wikipedia.org/wiki/North_A...ion_frequencie s Note that the upper end of the UHF TV band will be channel 51 at 698Mhz. Many good all-channel antennas exist but the absolute best-performing antennas are limited to covering one band, sometimes just a portion of one band. (This idea started a lot of do-it-yourself antenna projects.) If you determine that you have some stations on VHF and some on UHF, consider having more than one antenna. In a home where I lived in the pre-cable days, I had four different antennas. Of note: The bigger the antenna, the more likely it will be highly directional. If you expect to receive weak stations from more than one direction, you'll probably need either a rotator or more than one antenna. It's probably better to connect multiple antennas through an A/B switch, rather than combining them. |
Digital TV Antenna Design
In article ,
Jeff Liebermann wrote: On Sun, 15 Feb 2009 21:59:13 -0800 (PST), Bill Bowden wrote: Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Rule of thumb: The bigger and uglier the antenna, the better it works. Anybody know the dimensions of such an antenna, Various commercial digital TV antennas: http://www.hdtvprimer.com/ANTENNAS/comparing.html with Eznec NEC2 files at: http://www.hdtvprimer.com/SIMS/ probabaly in the frequency range of 400-800 Mhz ? There are going to be some DTV stations in the VHF range. You might want to check the new channels for your area: http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-07-138A2.xls List of frequencies: http://en.wikipedia.org/wiki/North_American_broadcast_television_frequencies Note that the upper end of the UHF TV band will be channel 51 at 698Mhz. EXACTLY, after conversion, some VHF stations will return as Digital, a few low-band and many high-band -- -------------------------------------------------------- Personal e-mail is the n7bsn but at amsat.org This posting address is a spam-trap and seldom read RV and Camping FAQ can be found at http://www.ralphandellen.us/rv |
Digital TV Antenna Design
Bill Bowden wrote:
Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Anybody know the dimensions of such an antenna, probabaly in the frequency range of 400-800 Mhz ? -Bill You could just cut off the long VHF elements and use them, cut to UHF size, to extend and increase the number of director elements. MTV |
Digital TV Antenna Design
On Mon, 16 Feb 2009 00:32:22 -0800, "Sal M. Onella"
wrote: Many good all-channel antennas exist but the absolute best-performing antennas are limited to covering one band, sometimes just a portion of one band. (This idea started a lot of do-it-yourself antenna projects.) Sure. I can always trade bandwidth for gain. If you only watch one DTV station, a single channel antenna is a good idea, especially if it's distant and weak. If you don't like rotators, perhaps a collection of single channel antennas pointed at each station might be useful. I live in the mountains where reflections are a problem for OTA reception. For a time, I was building and selling custom single channel TV antennas, with built in preamps. They worked great, but when Comcast started offering $13/month for local only TV, I gave up. If you determine that you have some stations on VHF and some on UHF, consider having more than one antenna. In a home where I lived in the pre-cable days, I had four different antennas. Same here. Back in the 1970's, I lived in Israel for a while. In the cities, everyone lived in big apartment complexes. Nobody watched the official Israeli stations. The good programming was on the various Arab stations, which were diverse, distant, and politically incorrect. There was no cable TV (because the government didn't want to make it easy to watch the Arab stations) so every apartment had its own collection of antennas. Typical was a 3 meter pole with at least 4 yagis. Multiply that by at least 4 apartments per building and the roof tops looked like an aluminum forest. Somewhat later, I lived in Smog Angeles where everything is on Mt Wilson. Only one antenna needed. Of note: The bigger the antenna, the more likely it will be highly directional. http://groups.google.com/group/rec.radio.amateur.antenna/msg/8535c986a167ac41 "small - efficient - broadband: pick any two." Roy Lewallen, W7EL I've dealt with some rather monstrous log periodic directional antennas. They cover the entire HF spectrum, but only have about 4dBi of gain at any frequency. Directionality is about what you would expect for a 4dBi antenna (about 80 degrees -3dB beamwidth). Just because it's big, doesn't mean it has gain or a narrow beamwidth. The same thing applies to TV antennas. If you compromise on the bandwidth by reducing the number of channels it covers, then you can get some more gain and narrower beamwidth (for a given size). That seems to be what's happening as the highest frequency goes from 900 to 700MHz. However, that's not going to make a huge difference is size of gain. More useful is ignoring the VHF channels and making the antenna UHF only. That really reduces the size of the antenna or increases the gain (for a given size antenna). If you expect to receive weak stations from more than one direction, you'll probably need either a rotator or more than one antenna. True. I once was involved in building direction finders. I got greedy and decided to find a commercial application. What the world needed was a direction finder tied to a rotator and yagi. The yagi would automatically rotate to the direction of the strongest signal. I first tried it with a TV antenna and it worked. Unfortunately, my pre-microprocessor circuitry did not have any way to distinguish between multiple peaks in the signal strength as well as antenna side lobes. It would often pick the wrong lobe. Making a 360 degree scan would solve this problem, but that increased the complexity beyond acceptable limits. So, I decided that perhaps it might be useful for commercial two-way radio. I installed one on a mountain top site on a UHF commercial frequency. Useful range was dramatically increased for the repeater. However, during a typical conversation, the antenna would rotate back and forth between each mobile and base. Commodity antenna rotators are not designed for near 100% duty cycle. It was also a dice toss as to whether a mobile could be heard, depending totally on the current antenna orientation. I could have improved things with a better and faster motor, but didn't. I know a bad idea when I design one. I also built an omnidirectional TV antenna designed to be hung near the top of the local 50 meter redwood and fir trees. There was enough vertically polarized TV signal to make it usable. However, it also picked up reflections from every possible direction, resulting in multiple obnoxious ghosts. Bad idea, but fun to try. It's probably better to connect multiple antennas through an A/B switch, rather than combining them. Yep. If the signals from multiple antenna could just as easily cancel as they could add. However, if you installed a band pass filter between the antenna and the combiner, the signals from one channel will only appear on one port, thus eliminating any chance of cancellation. I would filter and combine. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Digital TV Antenna Design
Jeff Liebermann wrote:
Same here. Back in the 1970's, I lived in Israel for a while. In the cities, everyone lived in big apartment complexes. Nobody watched the official Israeli stations. The good programming was on the various Arab stations, which were diverse, distant, and politically incorrect. There was no cable TV (because the government didn't want to make it easy to watch the Arab stations) so every apartment had its own collection of antennas. Typical was a 3 meter pole with at least 4 yagis. Multiply that by at least 4 apartments per building and the roof tops looked like an aluminum forest. Those days are gone, we have cable TV, DBS TV and streaming video on the Internet. In the cities the antennas remain, no one wants to pay the money to remove them. Eventually it will be necessary to repair the roofs under them and take them down. We are also supposed to have digital terrestrial TV in a few months, but instead of each station having various programs, there will be multiple channels on the same frequency. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
Digital TV Antenna Design
Jeff Liebermann wrote:
If you don't like rotators, perhaps a collection of single channel antennas pointed at each station might be useful. Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. -- 73, Cecil http://www.w5dxp.com |
Digital TV Antenna Design
Cecil Moore wrote:
Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
Digital TV Antenna Design
Cecil Moore wrote:
Jeff Liebermann wrote: If you don't like rotators, perhaps a collection of single channel antennas pointed at each station might be useful. Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. I'm not sure what "GPS coordinates" means, but this site will draw you a map and give you regular coordinates: http://www.fccinfo.com |
Digital TV Antenna Design
Geoffrey S. Mendelson wrote:
Cecil Moore wrote: Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Geoff. It's totally a matter of public record. You'd have to be really paranoid crazy to try to hide something that sends out a Megawatt homing beacon 24/7. |
Digital TV Antenna Design
Geoffrey S. Mendelson wrote:
Cecil Moore wrote: Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Geoff. It's totally a matter of public record. You'd have to be really paranoid crazy to try to hide something that sends out a Megawatt homing beacon 24/7. |
Digital TV Antenna Design
Geoffrey S. Mendelson wrote:
I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Then how can I aim my antenna while on top of a tower with no one to assist me? -- 73, Cecil http://www.w5dxp.com |
Digital TV Antenna Design
dave wrote:
I'm not sure what "GPS coordinates" means, but this site will draw you a map and give you regular coordinates: http://www.fccinfo.com Does one have to download Google Earth? -- 73, Cecil http://www.w5dxp.com |
Digital TV Antenna Design
Cecil Moore wrote:
Geoffrey S. Mendelson wrote: I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Then how can I aim my antenna while on top of a tower with no one to assist me? However a location such as" 5 miles east of town on the Interstate" is good enough to aim the antenna, but may be obscure enough to prevent vandalism, theft, etc. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
Digital TV Antenna Design
In message , Geoffrey S.
Mendelson writes Cecil Moore wrote: Geoffrey S. Mendelson wrote: I'd be surprised if they gave them to you if they had them. Publishing the exact location may be a security risk. Then how can I aim my antenna while on top of a tower with no one to assist me? However a location such as" 5 miles east of town on the Interstate" is good enough to aim the antenna, but may be obscure enough to prevent vandalism, theft, etc. It's pretty hard to keep secret the location of (say) a 1000 foot TV transmitter mast! -- Ian |
Digital TV Antenna Design
Cecil Moore wrote:
dave wrote: I'm not sure what "GPS coordinates" means, but this site will draw you a map and give you regular coordinates: http://www.fccinfo.com Does one have to download Google Earth? Negative. That is one of several options but you don't have to use it if you don't want to. |
Digital TV Antenna Design
On Mon, 16 Feb 2009 12:32:51 -0600, Cecil Moore
wrote: Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. Sure. It's on the FCC page for the station. Start he http://www.fcc.gov/mb/video/tvq.html Inscribe the call sign in the call sign box. For example, this is the results for KNTV: http://www.fcc.gov/fcc-bin/tvq?list=0&facid=35280 Incidentally, I've tried to obtain transmitter locations, power line routes, water line routes, location of telco central offices, and other utility information from the operators at various times. After 2001, the standard answer is that it would compromise their security if such information was disclosed. Sigh. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Digital TV Antenna Design
Jeff Liebermann wrote:
On Mon, 16 Feb 2009 12:32:51 -0600, Cecil Moore wrote: Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. Sure. It's on the FCC page for the station. Start he http://www.fcc.gov/mb/video/tvq.html Inscribe the call sign in the call sign box. For example, this is the results for KNTV: http://www.fcc.gov/fcc-bin/tvq?list=0&facid=35280 The Cavell Mertz web page does a much more elegant job than the FCC's: http://www.fccinfo.com/CMDProEngine....Number=1087036 The info is identical. |
Digital TV Antenna Design
"Cecil Moore" wrote in message
... Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. They used to be able to be found in the FCC database. I recall when a digital station in Kingsport, TN, first went on the air several years ago, I looked up the data on location. The FCC even had the antenna pattern on file. -- 73, Dr. Barry L. Ornitz WA4VZQ [transpose digits to reply] |
Digital TV Antenna Design
Dr. Barry L. Ornitz wrote:
"Cecil Moore" wrote in message ... Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. They used to be able to be found in the FCC database. I recall when a digital station in Kingsport, TN, first went on the air several years ago, I looked up the data on location. The FCC even had the antenna pattern on file. www.fccinfo.com will give you an aerial photo of the transmitter site. |
Digital TV Antenna Design
On Mon, 16 Feb 2009 15:55:39 -0800, dave wrote:
Jeff Liebermann wrote: On Mon, 16 Feb 2009 12:32:51 -0600, Cecil Moore wrote: Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. Sure. It's on the FCC page for the station. Start he http://www.fcc.gov/mb/video/tvq.html Inscribe the call sign in the call sign box. For example, this is the results for KNTV: http://www.fcc.gov/fcc-bin/tvq?list=0&facid=35280 The Cavell Mertz web page does a much more elegant job than the FCC's: http://www.fccinfo.com/CMDProEngine....Number=1087036 The info is identical. Agreed. I just noticed that they have a link to a Google Earth map of various services: http://www.fccinfo.com/fccinfo_google_earth.php Oh swell... Google Earth crashed while trying to view everything at once. Oops. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Digital TV Antenna Design
"Cecil Moore" wrote in message ... snip Are the GPS coordinates for the transmitting antenna available anywhere? I called the local TV station and they don't know the coordinates for their transmitting antenna. -- 73, Cecil http://www.w5dxp.com This thread got a little tangled. If, as I think, you're asking for coordinates for a US station, try, http://www.fcc.gov/mb/video/tvq.html 1. Enter the call letters for a known station. KLTV might be a good one. 2. Press Enter or scroll down and click Submit Data. 3. On the following page, click the station call letters. If a station has more than one listing, click any of them, as they all lead to the same web page. 4. On the next page, scroll down, observing the different documents issued by the FCC for the station. They may have a "TV" license for analog, also have a "DT" license and/or a DT Construction Permit. KLTV has seven irons in the fire, those busy bees. 5 Each one of the entries for a different document provides specifics for the installation (or proposal) document. You will see ERP, transmitter location, antenna height above ground, above average terrain and above sea level. There are links to area maps, including a coverage map. (For an agency that wants its licensees to toe the mark, this FCC database is not free of errors. If the given locations are, in fact, correct, your desired coordinates are provided to the arc-second, about 100 feet.) Here's a quick sample: Licensee: KLTV/KTRE LICENSE SUBSIDIARY, LLC Service Designation: DS Special Temporary Authority (digital) Channel: 10 192 - 198 MHz Application File No.: BSTA-20060217AAS Facility ID number: 68540 CDBS Application ID No.: 1115172 32° 21' 6.50 " N Latitude 95° 15' 59.20" W Longitude (NAD 27) This website accepts data query in a variety of formats. Interesting to enter a LAT/LON and a distance (in km). The website returns all stations within that distance. (Some may be low-power translators aimed away from you, thus useless.) |
Digital TV Antenna Design
"MTV" wrote in message ... Bill Bowden wrote: Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Anybody know the dimensions of such an antenna, probabaly in the frequency range of 400-800 Mhz ? -Bill You could just cut off the long VHF elements and use them, cut to UHF size, to extend and increase the number of director elements. MTV Yes. I have a seven foot TV parabola on my roof, but my next-best antenna is an absolute piece of junk, literally. My neighbor was throwing out an all-channel antenna that was blown down in a storm and badly damaged. I clipped the connections between the UHF & VHF sections and hacksawed off the mostly undamaged UHF section (12 directors, I think). With a section of pipe rudely jammed into the boom as a counterweight, I'm pulling in stations 125 miles away almost as well as with the parabola. Turning other people's discards into functional devices is an art. (I'm the guy who worked Hawaii on 20m with 100 Watts into an extension ladder. ... and no, I wasn't feeding it with ladder line.) "Sal" (KD6VKW) |
Digital TV Antenna Design
"Sal M. Onella" wrote in message ... snip coordinates for a US station, try, http://www.fcc.gov/mb/video/tvq.html For many people, the Cavell Mertz site beats the pants off the FCC site I posted. It must use the FCC raw data, since I see it has a long-standing FCC error, KFMB-DT on Channel 55. They moved to Channel 7 (interim) last summer. "Sal" |
Digital TV Antenna Design
Sal M. Onella wrote:
"Sal M. Onella" wrote in message ... snip coordinates for a US station, try, http://www.fcc.gov/mb/video/tvq.html For many people, the Cavell Mertz site beats the pants off the FCC site I posted. It must use the FCC raw data, since I see it has a long-standing FCC error, KFMB-DT on Channel 55. They moved to Channel 7 (interim) last summer. "Sal" fccinco.com is a third party front-end for the FCC Query database. When you submit a search Cavell Mertz submits a query to fcc.gov. There is a little report at the bottom of the page. |
Digital TV Antenna Design
Ian Jackson wrote:
It's pretty hard to keep secret the location of (say) a 1000 foot TV transmitter mast! Not much of a T-hunting challenge, is it. :-) ac6xg |
Digital TV Antenna Design
On Feb 15, 6:59*pm, Bill Bowden wrote:
Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Anybody know the dimensions of such an antenna, probabaly in the frequency range of 400-800 Mhz ? -Bill All my antennas for DTV and analogue are Quads and Quagi antennas. A two element Quad for channel 2 and 5 VHF(its wideband enough for this), a three element for channel 11 VHF and a 9 element Quargi for channel 63 UHF. Thats all the TV stations we have here on the island. Easy and cheap to make and they perform like hormones IMHO. My non technical wife says they and the array looks like a Christmas tree, therefore not ugly but cute -) Need more info... Tons on the Inet or let me know. Chris |
Digital TV Antenna Design
On Feb 16, 10:35 pm, "Sal M. Onella"
wrote: "MTV" wrote in message ... Bill Bowden wrote: Anybody have a good antenna design for the new UHF digital TV stations? I get reasonable results from my old VHF/UHF antenna (55% signal strength) , but it's big and ugly, and I want to replace it with a smaller, more efficient UHF design (maybe a Yagi) I can construct at home. Anybody know the dimensions of such an antenna, probabaly in the frequency range of 400-800 Mhz ? -Bill You could just cut off the long VHF elements and use them, cut to UHF size, to extend and increase the number of director elements. MTV Yes. I have a seven foot TV parabola on my roof, but my next-best antenna is an absolute piece of junk, literally. My neighbor was throwing out an all-channel antenna that was blown down in a storm and badly damaged. I clipped the connections between the UHF & VHF sections and hacksawed off the mostly undamaged UHF section (12 directors, I think). With a section of pipe rudely jammed into the boom as a counterweight, I'm pulling in stations 125 miles away almost as well as with the parabola. Turning other people's discards into functional devices is an art. (I'm the guy who worked Hawaii on 20m with 100 Watts into an extension ladder. ... and no, I wasn't feeding it with ladder line.) "Sal" (KD6VKW) I found an old 5 element yagi cut for channel 52 which was used years ago for a pay TV station called "ON TV". It has 3 (10.5 inch) directors spaced apart 5 inches, one (12 inch) reflector and the driven element is about 11 inches. The diameter of all elements is a little larger than a coat hanger. Wondering what the bandwidth would be for other UHF stations below and above 52? And is there an easy way to modify it for wider band? I also need to get the high VHF band for channel 7-13, so maybe one more reflector is needed? -Bill |
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