Sanyo TV FAQ - PDF download.
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( 2.9 / 220 )From CGC Communicator ...
In the event of a major disaster, most portable battery operated TVs will become useless as of February 2009; people might actually have to listen to radio, imagine that.
LINK TO STORY
Fred replies ...
I've seen some new digital televisions that use a 12-volt wall wart to power them. With the correct connector, a television could run for several days off a battery.
However, at my house, I have a Sharp digital TV plugged into an old computer backup. When we lost power back on June 9th, it lasted for about 12 hours.
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( 3 / 224 )A viewer sent me this Article on TV Antennas, and said it provided a lot of good information. I have to agree.
Although this is old information, (from the 50s?), it is well worth reading. Ignore the highly technical stuff if you are not into radio and television, or engineering. But the overall scope of the article in the aiming, positioning, and cabling of antennas is very good.
Fred
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( 3 / 299 )It's funny how the more we advance, the more things stay the same. Take for example a viewer trying to get distant stations. Such was the case with one of our viewers in Putnam County who not only wanted to see WLIO's signal, but also the Toledo stations and Fort Wayne.
I had suggested that he look at one single antenna, on a small tower on his farm. However, he did some research and found an article about stacking two or more antennas together for added gain. The result? Read below....
Dear Fred,
I took your suggestion for the antenna on a 30 foot tower. It worked well, and I could get your station, as well as all the other stations in Lima. I also received Bowling Green and some of the Fort Wayne stations in both regular and digital.
Since we had a little down time on the farm, I did some fishing on the Internet and found an article about stacking antennas. I got curious if it would help and I purchased another antenna. After installing it, all I can say is WOW! I could get all the Lima stations, Fort Wayne, and Toledo. I even had channel 9 from Canada on with some snow, but that is 100 miles away.
I'm sending you the article. Thanks again for your help! This antenna works great.
Ted
Here is the article that Ted sent to me. The amazing thing? Look at the date of the article. Some things don't change, do they?
From The June 1975 Issue Of ELECTRONIC TECHNICIAN/DEALER
Stacking TV Antennas
By James E. Kluge
The author is a technical editor in the Engineering & Research Division of the Winegard Company.
The improved directivity achieved by stacking antennas can significantly reduce or eliminate many types of television interference.
Multiple TV-antenna arrays, reminiscent of the ‘50s, are making a reappearance around the country. Today, however, the principal reason for stacking antennas is not only to achieve increased gain out in the fringe areas, but also to solve interference problems through the use of highly directional antenna arrays.
Many urban areas today are plagued with multiple high-rise buildings and heavy users of electrical power, both of which cause television interference (TVI) problems. Typical TVI problems include ghosts, electrical noise and interfering radio signals which usually arrive from a direction slightly off axis from that in which the antenna is pointed. Ground reflections, ignition noise and reflections off moving ground or airborne reflectors, such as trucks and large aircraft, arrive from above or below and cause picture breakup.
Proper stacking of today’s highly sophisticated TV antennas can significantly improve directivity and selectivity, as well as gain.
OPERATION OF A SINGLE YAGI
The Yagi antenna, the most commonly used type for TV, "sees" electromagnetic radio waves in a manner similar to the way we see. Our eyes see in the general direction in which our head is pointed. Similarly, the Yagi antenna "sees" in the general direction in which its boom is pointed. When viewed from above (Fig. 1), the Yagi antenna’s outline more or less resembles an arrowhead because it tapers out from front to rear. The taper is more pronounced in broad-band antennas than in single-channel antennas. The arrowhead formed by the antenna should, generally speaking, point in the direction from which the desired signal is arriving; i.e., toward the TV transmitter.
Ideally, a TV receiving antenna should "look" in a straight-line path toward the transmitting antenna and "see" nothing above, below or to either side. Not being ideal, of course, even the best TV antennas "see" a considerable amount of undesirable signals arriving from an angle off the axis of the antenna, just as our eyes have some side vision. These signals can cause ghosts and other interference patterns on the TV screen.
A Yagi antenna is made up of many parallel elements arranged along a common axis in a horizontal plane and all oriented toward the signal source. The length, spacing and phasing of each element relative to that of the others determines how the.voltages induced in individual elements reinforce (add) at the antenna terminals. The elements are arranged and spaced so that the signal wavefront arrives at each element sequentially and so that the voltage induced in each antenna element combines at the antenna terminals with voltages from the other elements, to yield an optimized voltage which produces maximum gain over the desired bandwidth.
If the signal arrives from a source above or below the horizontal plane of the antenna, it will arrive at all of the Yagi elements simultaneously instead of sequentially. Under these conditions, the combined voltage at the antenna terminals will be something less than the optimum for which the antenna was designed.
VERTICAL STACKING
Stacking two identical antennas on a common vertical mast significantly narrows the vertical beam-width angle. That is, vertically stacked antennas more effectively reject those interfering signals arriving from above or below their horizontal plane than does a single antenna. It’s as though they were looking through a horizontal venetian blind. Because there’s nothing mounted to the side of either antenna, their side-to-side vision is virtually uneffected. In the process, gain increases about 2.5 dB over that of a single antenna.
Vertical stacking improves both gain and vertical directivity. This helps reduce airplane flutter and attendant picture roll, and certain types of ground noise and ground reflections.
The basic principle of stacked antennas involves the difference in the time of arrival, and therefore the phase, of signals intercepted by the antenna combination. If a pair of identical Yagi antennas are mounted one above the other, a wavelength apart, on a common vertical mast and are oriented identically (pointed) toward the signal source, any TV signals traveling horizontally and arriving from any direction will be intercepted simultaneously by both antennas.
Those signals arriving on axis from the direction in which the antenna is pointed will be strongest.
Because the antennas are identical, the generated signal voltages arriving at the output terminals shared by the antennas will be in phase, causing them to add directly. Theoretically, there should be a 3 dB increase (double) in signal power over that of a single antenna, but, because of losses in the coupler and cable, the actual gain increase will be somewhat less than 3 dB.
An important point to remember is that, regardless of the azimuth angle between the antenna orientation and the signal source, the arriving signal will strike any given identical points on the two antennas simultaneously. However, if the signal is arriving from a source above or below the horizontal plane of the antenna, the previous statement is no longer true. For example, if the wavefront is from a source below the plane of the antenna, the signal will arrive first at the lower antenna and the signal voltage from the top antenna will lag the signal from the lower antenna. The signal voltages at the antenna output terminals will no longer be in phase, and partial cancellation will take place. The opposite is true if the signal arrives from above (Fig.2C).
The angle of arrival and the resultant difference in arrival time causes a phase difference which reduces the magnitude of the combined voltages. You should begin to see now why two vertically stacked, identical antennas have a more restricted "vision" to signals arriving from a point above or below the horizontal plane than does a single antenna.
HORIZONTAL STACKING
Stacking two identical antennas side by side in a horizontal plane significantly narrows the horizontal beam-width angle, as shown in Fig. 4. That is, the antenna combination, like a horse wearing blinders, "sees" fewer interfering signals arriving from the sides while its vision up and down (in a vertical plane) is virtually unaffected. In the process, gain increases approximately 1.2 dB over that of a single antenna.
If two identical antennas are arranged side by side in a horizontal / plane and the signal wavefront arrives directly from the front, each antenna "sees" the same wave or field at the same time. If the wavefront arrives from a source above or below, the same is still true, except that the individual antennas are not operating as efficiently. However, if the wavefront arrives from one side or the other , the antenna on the side from which the signal is arriving will "feel" the signal first, causing the voltages induced in each antenna to be out of phase. This, in turn, causes partial cancellation of the antenna voltages when they are combined.
The up and down (vertical) "vision" of a horizontal stack is comparable to that of a single antenna, but its side-to-side "vision" is more restricted.
QUAD_STACKS
Stacking four identical antennas, two vertically and two horizontally in a rectangular or diamond pattern, restricts the vision of this combination in all directions off the axis. Called a quad stack, it "sees" as though it were looking through a tube pointed in the direction of the transmitting antenna. Gain is increased approximately 4 to 5 dB over that of a single antenna.
GENERAL TECHNIQUES
Before you start putting up an array, you should be aware of the following basic considerations which apply to dual and quad stacking of antennas:
1. Stack only identical antennas.
2. Maintain approximately one wavelength spacing (at lowest channel frequency) between antennas.
3. Cut phasing lines or connecting cables to equal lengths.
4. Length and phase of twin-lead interconnecting harnesses is critical.
5. Horizontal supports should be nonmetallic.
6. Avoid running interconnecting cables horizontally.
Vertical stacking is easier than horizontal stacking simply because in vertical stacks the antennas mount on a common vertical mast and spacing is easily adjusted.
However, with the excellent gain and high directivity of most Yagis today, vertical stacking is seldom necessary. If additional gain is needed, two vertically stacked identical antennas spaced more than ‘/2 wavelength apart will increase signal power by 3dB compared to that of one antenna. However, part of the increased gain will be lost in the connecting cables and the coupler.
Horizontally stacked antennas also must be spaced so that their booms are separated by a distance equal to more than ‘/2 wavelength of the lowest channel frequency. This spacing is needed to prevent the tips of the longest reflector elements from touching. Also, the horizontal supports must be nonmetallic; redwood or cedar 2’ x 4’ s are commonly used.
The severe ghosts caused by high-rise buildings, water towers and mountains can be reduced or eliminated by horizontally stacking two Yagis. However, the wavelength of a channel 2 signal exceeds 17 feet, making such an array for channel 2 unwieldy, heavy and subject to damage from ice and/or high wind. Fortunately, ghosting is more of a problem at high-band channels, and high-band antenna dimensions are significantly smaller. For these reasons, usually only high-band Yagis are stacked horizontally.
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( 3.1 / 291 )Another good source for information on REAL LIFE reception of DTV signals is the Worldwide TV FM DX Club.
This group of people have real hands-on experience in the equipment and the reception techniques.
I have reviewed their web site and found it to be 100% accurate.
BTW, they also have reviews on converter boxes!
Web site: www.wtfda.org
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( 3 / 231 )The following is from the CGC Communicator, an on-line engineering magazine. There are comments from readers...
BEWARE OF SIGNAL SPLITTERS THAT ALSO ACT AS RF FILTERS
Early in the DTV days, I ran into someone with a reception problem that was traced to a splitter that rolled off the high end of the UHF band. Remember the world revolves around cable TV, and some cable systems move the UHF stations to lower frequencies. So, a splitter intended for cable use may be worthless when used with an antenna.
Also beware of coax from a certain national chain of stores. I ran into a roll in which the shield wasn't braided -- it was just wound around the center conductor and they improperly called it RG-6.
Roy Trumbull, roy547 (at) msn.com
VANISHING DTV COUPONS
While RV traveling, I ordered DTV converter coupons. When they shipped in March, I had forwarding activated from my home address to a private mailbox handling our mail while we were away.
I waited and checked the Internet, then called the toll free number and was told that since I had my mail forwarded, the coupons would have been returned... and, no, I couldn't order replacements!
I was told I could appeal to DTV 2009 Coupon Program Comments in Portland, OR. I wrote. So far, no response! If my experience is typical, there will be a LOT of upset former viewers!
Raymond Voss, KG0DK
Retired Broadcaster, Edina, Minnesota
RayVoss (at) aol.com
One additional mention...
I have been receiving called from viewers who have purchased SO CALLED digital antennas such as an amplified pair of rabbit ears claiming to be 45dB gain.
These viewers live within ten miles of the station and claim that they can't get WLIO. I believe them, but it's not the TV stations fault. The problem is that they have been sold a product which looks good, but doesn't work worth a darn.
Please! Be aware that there are people out there profiting from folks being sold products that are defective and misrepresented! As the Romans would say - Buyer Beware!!
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( 2.9 / 210 )From the C.G.C. Communicator....
DTV RECEPTION REALITIES START TO SINK IN
As government officials campaign to offer the facts about DTV reception, millions of over-the-air viewers are going to be faced next February with a harsh reality: install a sophisticated new outdoor antenna or subscribe to a pay-TV service:
Broadcast Engineering Story
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( 3 / 225 )If you have thought about purchasing an antenna, you know that specifications can be hard to interpret. This is why the WLIO engineering department has been testing antennas to see if they meet the claims.
Quoting one of our engineers:
“Harry and I tested the Winegard HD-7694P. The most interesting results for this High-band VHF and UHF antenna that we tested on ch10, then ch11 (in order to get away from local interference from our own ch8 digital signal).
This antenna shows very good attenuation of the side-lobes, around 25dB, and a front/back ratio of about the same amount, 24 to 27db.
It has a very sharp forward beamwidth that we have yet to measure, but I suspect it to be around 20 degrees (+/- 10 degrees) at the 3dB points.
We will take another look at it next week when we have more time, along with any other antennas you would like us to look at.
Dick Knowles, N8IJ
WLIO Engineering”
This antenna seems to be a rather good pick for a simple "in town" to medium fringe signal.
Later we will mount this antenna on the side of our tower to see how it does with a little height.
The "related" link will take you to a site to buy one, but as always.... shop around for best results and deals!
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( 3 / 219 )If you are looking for more information on DTV, the Federal Communications Commission has several publications that are good reading.
A simple guide to the Digital Television Transition
A one pager on the basics of the Digital Transition
The DTV Transition and Over-the-Air Viewers Along U.S. Borders
Helpful if you live near Lake Erie and watch Canadian TV
Setting Up Your Digital-to-Analog Converter Box
Antennas and Digital Television
DTV Transition, Cable Systems to Switch to Digital
DTV: What Every Consumer Should Know
DTV Fact Sheet
Buying the Right TV: What Every Consumer Should Know
Closed Captioning for Digital Television
Closed Captioning and Digital-to-Analog Converter Boxes
Compatibility of Cable TV and Digital TV Receivers/"Plug-and-Play"
FCC web page
DTV Tip Sheet
DTV Shoppers Guide
The documents below are notices that any television sold after June 1st, that receives analog only must be disclosed to the buyer BEFORE the sale.
Advisory on Mandatory Labeling of Consumer Electronics Products with Only Analog Broadcast TV Tuners.
Advisory on Mandatory Labeling of Analog Tuners
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( 3 / 280 )This appears to be the FINAL DTV tables for the area. The list shows the stations in our immediate area, based on the viewer from Henry County to the north, Van Wert to the west, Miami to the south, and Marion county to the east.
Ease of receiving these stations is based on location, viewer antenna height, type of antenna, and performance of receiver. For example, a viewer in Putnam County with a 40-foot antenna, having a gain of ten, properly installed, would see Angola, Ft Wayne, Bowling Green, Lima and Toledo, (possibly S. Bend and Ann Arbor, Detroit)
NTSC = Analog channel they are on.
DTV Chan = Their new channel after 2/17/2009
DTV ERP = Effective radiated power in kilowatts
DTV HAAT = Their antenna high above average terrain.
DTV Area = Coverage in square miles.
DTV Pop = Population served by signal (in thousands)
St City NTSC DTV DTV DTV DTV DTV
Chan Chan ERP HAAT Area Pop.
IN ANGOLA 63 12 16.5 132 17294 874
IN FORT WAYNE 33 19 285.0 239 19941 1027
IN FORT WAYNE 21 24 335.0 224 20240 1052
IN FORT WAYNE 15 31 1000.0 242 21871 1106
IN FORT WAYNE 55 36 1000.0 219 19630 1048
IN FORT WAYNE 39 40 90.0 221 16043 835
IN INDIANAPOLIS 8 9 19.5 284 26105 2488
IN INDIANAPOLIS 13 13 15.1 299 26707 2510
IN INDIANAPOLIS 40 16 225.0 284 19773 2154
IN INDIANAPOLIS 20 21 200.0 236 16842 1912
IN INDIANAPOLIS 6 25 898.0 294 29516 2604
IN INDIANAPOLIS 69 44 215.0 167 14297 1830
IN INDIANAPOLIS 59 45 700.0 285 24873 2432
IN MUNCIE 49 23 79.1 246 17374 1494
IN RICHMOND 43 39 500.0 281 20981 3107
IN SOUTH BEND 22 22 192.0 332 24663 1521
IN SOUTH BEND 34 35 50.0 333 18549 1202
IN SOUTH BEND 16 42 695.0 299 26344 1633
IN SOUTH BEND 46 48 300.0 295 20015 1214
MI ANN ARBOR 31 31 106.0 328 18881 4073
MI DETROIT 2 7 11.2 305 24569 5547
MI DETROIT 50 14 50.0 293 18484 5122
MI DETROIT 20 21 500.0 324 25252 5597
MI DETROIT 7 41 1000.0 305 27193 5767
MI DETROIT 56 43 200.0 318 22343 5247
MI DETROIT 62 44 345.0 323 22657 5131
MI DETROIT 4 45 973.0 281 22741 5397
MI EAST LANSING 23 40 50.0 296 16787 1481
MI JACKSON 18 34 130.0 299 18640 1398
MI LANSING 6 36 663.0 288 25555 3054
MI LANSING 47 38 1000.0 281 20865 1458
MI LANSING 53 51 900.0 300 24069 1807
MI MOUNT CLEMENS 38 39 1000.0 170 16235 4698
OH BOWLING GREEN 27 27 110.0 320 21416 1313
OH CINCINNATI 9 10 15.4 305 27029 3082
OH CINCINNATI 12 12 15.6 305 26169 3013
OH CINCINNATI 64 33 500.0 337 24994 3100
OH CINCINNATI 48 34 400.0 326 23378 2979
OH CINCINNATI 5 35 1000.0 311 29790 3176
OH CLEVELAND 8 8 15.7 305 27926 3964
OH CLEVELAND 5 15 1000.0 311 31477 4147
OH CLEVELAND 3 17 1000.0 296 30387 4263
OH CLEVELAND 25 26 100.0 313 18860 3498
OH CLEVELAND 61 34 525.0 334 25232 3931
OH COLUMBUS 6 13 59.0 286 26405 2526
OH COLUMBUS 4 14 902.0 264 28164 2467
OH COLUMBUS 10 21 1000.0 279 28074 2497
OH COLUMBUS 28 36 1000.0 271 25893 2312
OH COLUMBUS 34 38 250.0 291 21605 2191
OH DAYTON 16 16 126.0 320 21274 3118
OH DAYTON 45 30 425.0 351 22696 2885
OH DAYTON 7 41 1000.0 290 24364 3196
OH DAYTON 2 50 1000.0 323 29198 3497
OH DAYTON 22 51 138.0 351 21345 3050
OH LIMA 35 8 27.5 148 22513 995
OH LIMA 44 44 47.4 207 14071 556
OH MANSFIELD 68 12 14.0 180 19484 1109
OH OXFORD 14 28 400.0 268 20730 2781
OH SANDUSKY 52 42 700.0 213 18330 1542
OH SPRINGFIELD 26 26 50.0 291 15181 2003
OH TOLEDO 40 5 10.0 155 18262 2235
OH TOLEDO 11 11 13.1 263 22521 2387
OH TOLEDO 13 13 14.6 305 22715 2547
OH TOLEDO 30 29 50.0 314 18428 2208
OH TOLEDO 36 46 110.0 356 18875 2041
OH TOLEDO 24 49 59.0 409 18182 1915
Source: FCC's 8th Report & Order.
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