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#1
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I have done some reading about balun transformers and how I can connect
my existing flat antena cable to 75 ohm cable. However, my questions is this... what if I replace the 30 year old flat cable all the way to the antenna. Will this yield better reception? (It is pretty good as it is.) The exiting flat cable is starting to fall apart at some places. Currently I just have it directly wired to my coax cable (just before it enters the house) with out any type of transformer. The coax is properly grounded (to the circuit breaker box.) So my questions are these: 1. How do I connect the coax directly to the antenna? Or should I? Do I still need a balun transformer? 2. If I need a balun transformer, does anyone know of a heavy duty outdoor one? (Or should I build my own.) 3. Will reception improve? Thanx to all who reply. jg |
#2
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On 9 Feb 2006 00:54:33 -0800, "jg" wrote:
Thanx, I'll try it this weekend. I have some high end coax cable ready for the job. Only one more question... should I worry about the quality of the balun transformer? The ones I have seen at Home Depot/Lowes/Radio Shack look pretty flimsy. I know there is probably nothing inside that should not get wet, but I still wonder... jg I'm not sure what to tell you about the quality of them. I'd guess they are all made by the same company anyhow, but who knows? Use the boot that comes with them, and I tend to wrap electrical tape around that to be sure it stays dry at the coax connector. If water gets inside the balun, it's cracked and bad from the start. They are sealed. As another posted said, replace the screws and nuts on the antenna with brass ones if they are real rusted or corroded. Mark |
#3
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jg wrote:
Thanx, I'll try it this weekend. I have some high end coax cable ready for the job. Only one more question... should I worry about the quality of the balun transformer? The ones I have seen at Home Depot/Lowes/Radio Shack look pretty flimsy. I know there is probably nothing inside that should not get wet, but I still wonder... jg The outdoor TV antenna baluns are sealed better to prevent moisture from getting inside and degrading the components. They also have a rubber boot to cover the coax connector. Here are two URL's for Radio Shack TV antenna baluns. The second one has gold plated connectors which should make it more reliable for outside use. http://tinyurl.com/9codd http://tinyurl.com/dnmxd |
#4
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Twinlead has less signal loss than coax so it's
preferred in reception areas where signal strengths are low. Should I be worried about this? Currently the twinlead only runs from the top of the antenna to where it enters my house. About 40 ft. Then I have coax in my crawl space for another 80 feet or so. 30 ft of which is just coiled and wasted. Reception for local (Sacramento) stations is pretty good. Reception for San Francisco stations is too grainy to watch at times. My zip code is 95682. (So I should not expect too much from San Francisco.) If need be I can replace the existing twinlead with new twinlead. Should I look into this? jg |
#5
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While you are at it, you may wish to replace the antenna as well. If you do
be sure to get one with good UHF reception. Once the US switches to digital TV, I believe in 2009, all TV signals will be in the UHF band. "jg" wrote in message ups.com... I have done some reading about balun transformers and how I can connect my existing flat antena cable to 75 ohm cable. However, my questions is this... what if I replace the 30 year old flat cable all the way to the antenna. Will this yield better reception? (It is pretty good as it is.) The exiting flat cable is starting to fall apart at some places. Currently I just have it directly wired to my coax cable (just before it enters the house) with out any type of transformer. The coax is properly grounded (to the circuit breaker box.) So my questions are these: 1. How do I connect the coax directly to the antenna? Or should I? Do I still need a balun transformer? 2. If I need a balun transformer, does anyone know of a heavy duty outdoor one? (Or should I build my own.) 3. Will reception improve? Thanx to all who reply. jg |
#6
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On Thu, 09 Feb 2006 19:03:47 GMT, "Jeff" wrote:
While you are at it, you may wish to replace the antenna as well. If you do be sure to get one with good UHF reception. Once the US switches to digital TV, I believe in 2009, all TV signals will be in the UHF band. That's not true. VHF High Band and UHF. |
#7
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JG,
I agree with everyone here that coax is better but so far noone has mentioned there are two types of coax, 50 ohm and 75 ohm. Make sure that you use the 75 ohm coax. 50 ohm is generally used for communications and you can't tell the difference between the two by the size or thickness of the coax. You can tell by the number stamped on the coax, eg. RG75U, etc. J jg wrote: I have done some reading about balun transformers and how I can connect my existing flat antena cable to 75 ohm cable. However, my questions is this... what if I replace the 30 year old flat cable all the way to the antenna. Will this yield better reception? (It is pretty good as it is.) The exiting flat cable is starting to fall apart at some places. Currently I just have it directly wired to my coax cable (just before it enters the house) with out any type of transformer. The coax is properly grounded (to the circuit breaker box.) So my questions are these: 1. How do I connect the coax directly to the antenna? Or should I? Do I still need a balun transformer? 2. If I need a balun transformer, does anyone know of a heavy duty outdoor one? (Or should I build my own.) 3. Will reception improve? Thanx to all who reply. jg |
#8
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jg wrote:
Twinlead has less signal loss than coax so it's preferred in reception areas where signal strengths are low. Should I be worried about this? Currently the twinlead only runs from the top of the antenna to where it enters my house. About 40 ft. Then I have coax in my crawl space for another 80 feet or so. 30 ft of which is just coiled and wasted. Reception for local (Sacramento) stations is pretty good. Reception for San Francisco stations is too grainy to watch at times. My zip code is 95682. (So I should not expect too much from San Francisco.) If need be I can replace the existing twinlead with new twinlead. Should I look into this? jg If you want the best weak signal reception (San Francisco) either use new twinlead all the way from the antenna to the TV or new coax all the way with an antenna amplifier too. You might want to consider an antenna rotator if the local and distant stations are in different directions. BTW- If you use twinlead, install it with a continuous twist along it's length. Make several twists per yard. I know it's a pain to do this but it helps to reduce the reception of noise from home applicances on the twinlead. |
#9
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On 8 Feb 2006 21:53:31 -0800, "jg" wrote:
I have done some reading about balun transformers and how I can connect my existing flat antena cable to 75 ohm cable. However, my questions is this... what if I replace the 30 year old flat cable all the way to the antenna. Will this yield better reception? Maybe. ![]() (It is pretty good as it is.) The exiting flat cable is starting to fall apart at some places. Currently I just have it directly wired to my coax cable (just before it enters the house) with out any type of transformer. How did you do that? Soldered one wire to the center and the other to the braid? I'm curious, but as others have said, you should redo it, and run straightaway to a tv or a signal splitter, if you want to go to more than one tv. They still sell them for flat lead. I would also pay attention to the way the wire is run now. Flat lead should have stand-offs to keep it away from the pole and the siding, and as someone pointed out, it should be twisted I can imagine that some prior amateur or neat-freak kept the wire untwisted because he thought it looked better. So if they didn't do a good job the last time, your job can be better. (The interference will still try to interfere, but its effect on one part of the flat-lead will be exactly the opposit of its effect on the other part of the wire, so the two effects will cancel each other out. Hence, no interference. This is similar to the reason that wires from burglar alarm sensors use twisted pairs of wires, so that lightening won't generate a voltage spike in the wires that will damage the control panel (or set off the alarm?). The coax is properly grounded (to the circuit breaker box.) So my questions are these: 1. How do I connect the coax directly to the antenna? Or should I? Do I still need a balun transformer? Yes. 2. If I need a balun transformer, does anyone know of a heavy duty outdoor one? (Or should I build my own.) They're not so much heavy duty as they are designed to keep the insides dry, with the rubber cover and all. 3. Will reception improve? Thanx to all who reply. jg Remove NOPSAM to email me. Please let me know if you have posted also. |
#10
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You haven't told us what type of tv antenna you have, and whether or
not you have a rotor. To get San Francisco stations in your area, you must use a rotor as the Sacramento stations and the San Francisco stations are not coming from the same direction. Also, to get the UHF stations from San Francisco, I recommend the Channel Master 8-bay bowtie. It is very common in Sacramento to have separate VHF and UHF antennas as it is fairly easy to get decent reception from San Francisco, Santa Rosa, Concord, Chico, Redding, Reno, and even more, as well as all the local stations. But you MUST have a high-gain antenna with a narrow beamwidth. Otherwise, the local stations will interfere with the distant stations. As in Fresno (where I now live), with a high-gain antenna with a narrow beamwidth, it is possible to get more than one station on the SAME channel, just by turning the antenna. I recommend NOT using any pre-amp at the antenna as the powerful Sacramento stations will wipe out most of the distant stations. Generally speaking, in the Sacramento area good coax cable will work better than twin lead, especially if you are around any electrical interference. Also, even twisted twin line can pick up signals that may interfere with the distant signals. But DON'T have several feet of coax wound up in your attic. Every foot of lead, whether twin lead or coax, adds to signal loss. Generally speaking, the antenna should be mounted as high as possible, although this is not always the case, especially with UHF signals. There is never a guarantee as to what you will receive. As far as using a balum at the antenna (and at the tv if necessary), all balums are NOT created equal. Different samples from the same manufacturer can vary greatly in the amount of signal loss, etc., especially at the UHF frequencies. For the antenna AND balum, I recommend staying away from Radio Shack. In Sacramento, the most popular antennas for picking up San Francisco, are made by Winegard and Channel Master. The BEST UHF antenna you can use is the Channel Master 7-foot parabolic but strong winds can cause problems if the mast is not strong enough. I used the 7-foot parabolic on a 30-ft. mast with rotor and got excellent reception from most of the UHF stations from San Francisco. Second best is the 8-bay bowtie. For more information, read my article in RADIO ELECTRONICS magazine, August 1982, titled HOW TO SELECT THE BEST TV ANTENNA. You should be able to find that issue at a library. |
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