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#21
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Cecil Moore wrote:
Gordon wrote: Well, I got an improvement, probably in spite of myself. The setup gives better signal strength, and is less suseptable to interfearence (people walking aroung the room) than just a single bowtie. A mismatch can cause ghosting in an analog TV. What does ghosting do to a digital TV signal? If its bad enough it will wreck the reception. But the latest processors can tolerate multipath that is only 1 db down. They are getting better as they try to debug HDTV for mobile reception. -Bill |
#22
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On Jun 1, 4:49*am, Cecil Moore wrote:
Gordon wrote: Well, I got an improvement, probably in spite of myself. *The setup gives better signal strength, and is less suseptable to interfearence (people walking aroung the room) than just a single bowtie. A mismatch can cause ghosting in an analog TV. What does ghosting do to a digital TV signal? -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com It puts 'ripples' into the passband. The ripples happen because of phase cancelations. The ATI HDTV Wonder cards can handle variations to around 8-10 dB. After that it just freezes up. Near the bottom of the page in the link there is an example of the ATSC spectrum. Add random dips into it. http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html G² |
#23
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On Mon, 01 Jun 2009 06:49:20 -0500, Cecil Moore
wrote: A mismatch can cause ghosting in an analog TV. What does ghosting do to a digital TV signal? Your worst nightmare. From 10 years ago: http://www.businessweek.com/bwdaily/dnflash/aug1999/nf90826b.htm (Note the sales predictions, which were totally wrong). All DTV chipsets now have ghost elimination circuitry, which does a good job of reducing multipath problems. There's a spec for it but I'm too lazy to look. Here's the patent: http://www.google.com/patents?id=XNp3AAAAEBAJ&dq=7038732 with references to others in citations. I won't pretend to understand how it works. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#24
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Jeff Liebermann wrote:
I must say at the outset that I am hesitant to buy an antenna based on its form-factor, but I'm forced by the local code to not display bare-element type antennae on the mast. As others have mentioned, this is mostly incorrect. The problem is in the interpretation of the word "unreasonable", which might be interpreted in a variety of ways. Without details on your situation, I can't comment on this. The FCC website has quite a bit of info on interpretation (from various regulatory and legal actions) of what is and isn't unreasonable. Paint color: reasonable, restrictions on location: unreasonable, restrictions on form of antenna: unreasonable. I do like the panel style for the reason that I can arrange 3 around a common mast, aimed at remote cities, and join the outputs for increased coverage. Mast? Welcome to "unreasonable". The FCC 47.1.4000 clause that limits antenna installation has nothing to say about the supporting structure. While the HOA may not be able to prevent you from installing an antenna, they most certainly will have something to say about the design and construction of the supporting structure. They may also demand that it be installed by a licensed and insured installer to protect themselves against subsequent litigation. I know you don't want to hear about all this, but methinks you should at least be warned before blundering onward. Hah.. go look at the case of Stanley and Vera Holliday.. 5 masts 30 ft high, multiple dishes and antenans... http://www.fcc.gov/Bureaus/Cable/Ord...9/da992132.txt an analysis at http://dirt.umkc.edu//dd99/DD991025.htm |
#25
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On Mon, 01 Jun 2009 06:49:20 -0500, Cecil Moore
wrote: Gordon wrote: Well, I got an improvement, probably in spite of myself. The setup gives better signal strength, and is less suseptable to interfearence (people walking aroung the room) than just a single bowtie. A mismatch can cause ghosting in an analog TV. What does ghosting do to a digital TV signal? In countries using COFDM (DVB-T), the symbol time is about 1000 us (8k) or 250 us (2k), so in the worst case with minimal guard intervals, you can still use mismatched coaxial cables longer than 1 km without problems :-). With ATSC 8VSB it depends how well the equalizer is capable of detecting the characteristics of the radio and coaxial path with a known signal pattern. Paul OH3LWR |
#26
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Elmo P. Shagnasty wrote:
In article .net, Usual Suspect wrote: I must say at the outset that I am hesitant to buy an antenna based on its form-factor, but I'm forced by the local code to not display bare-element type antennae on the mast. I don't believe the local code has any say in the matter. But if you want to give up your rights... This is true to a point. Local codes no problem, BUT in HOA territory these rules do not necessarily apply. In most cases the HOAs have modified their rules. The small direct satellite lobby started the trend. Allowing these dishes they really had to include other TV antennas. |
#27
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"Elmo P. Shagnasty" wrote:
In article m, Radioguy wrote: I don't believe the local code has any say in the matter. But if you want to give up your rights... This is true to a point. Local codes no problem, BUT in HOA territory these rules do not necessarily apply. In most cases the HOAs have modified their rules. The FCC is the entity here, not local communities. And neither HOA nor local communities can override FCC in this matter. You SHOULD know better, Elmo. There are some restrictions an HOA can place on a homeowner, but they are few. Here is a link to the FCC site: http://www.fcc.gov/mb/facts/otard.html -- -------------------- http://NewsReader.Com/ -------------------- Usenet Newsgroup Service $9.95/Month 30GB |
#28
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Radioguy wrote:
Elmo P. Shagnasty wrote: In article .net, Usual Suspect wrote: I must say at the outset that I am hesitant to buy an antenna based on its form-factor, but I'm forced by the local code to not display bare-element type antennae on the mast. I don't believe the local code has any say in the matter. But if you want to give up your rights... This is true to a point. Local codes no problem, BUT in HOA territory these rules do not necessarily apply. In most cases the HOAs have modified their rules. The small direct satellite lobby started the trend. Allowing these dishes they really had to include other TV antennas. the FCC premption (aka OTARD rules) is the key thing here.. The HOA can't really do anything if it fits in the FCC guidelines.. dishes 1 meter, OTA TV any size. |
#29
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On Jun 2, 3:23*pm, Jim Lux wrote:
trend. *Allowing these dishes they really had to include other TV antennas. * the FCC premption (aka OTARD rules) is the key thing here.. The HOA can't really do anything if it fits in the FCC guidelines.. dishes 1 meter, OTA TV any size. Nice thing about the Winegard SquareShooter is it resembles a dish though my neighbors might think I don't have a clue how to aim it. It's opposite where all the little dishes are aimed. They would have laughed if they had seen the spectrum analyzer on the driveway next to the car. I was on the roof with binoculars to see the screen. G² |
#30
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Sal M. Onella wrote:
"Usual Suspect" wrote in message obal.net... snip I do like the panel style for the reason that I can arrange 3 around a common mast, aimed at remote cities, and join the outputs for increased coverage. You may encounter some undesired affects from joining antennas. If it works, fine, but if it doesn't, consider switching among the three at the TV set(s). The problem is that the prime signal will be "contaminated" by signal pickup from the other antenna(s). The degree of contamination may or not affect reception. Good luck. It will suffer phase distortion. In the good old days we called that "ghosting", now it will be signal drop outs! -- Joe Leikhim K4SAT "The RFI-EMI-GUY"© "Use only Genuine Interocitor Parts" Tom Servo ;-P |
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