I want to run about 50ft of antenna feeder cable for FM radio. The feeder cable will be attached to an exterior wall beneath vinyl siding.
Which cable should I use, coax or flat twin feeder? I suspect the answer is coax but I would like to use flat wire because I have 50ft of that. Also flat feeder would be easier to hide inside the house.
Peter.
Have Googled FM Antenna Design? Lots of info on what type of wire to use and how to determine the correct length and placement based on what your goal is - full band vs. specific stations, etc.
For a quickie FM feed, flat twin should be fine, but not for analog TV, but... Since over the air analog TV will be phased out in a few short years you wont have to worry about that anyway. That is unless you want to one day receive over the air high definition digital signals which will be available. In that case you may want to just get yourself set up with a digital HDTV antenna and proper coax downfeed, rotator, mast, and preamp. But if you are just looking to get a better FM signal then twin should be fine for that. If you go whole hog and want a proper digital exterior TV antenna then Frys electronics has them, unfortunately Radio Shack seems to have turned into a cell phone store (what a shame), Best Buy I think sells digital antenna parts too. If you go with coax then I like RG6 quad shield the best, but you have to get good at terminating them with the Thomas Betts (sp?) waterproof F connectors and their snap crimping tool.
300 ohm twinlead is not shielded so it picks up interference more easily than coax. Also, wet weather and running it next to metal can affect the impedance of the wire pair causing signal mismatch. Usually these things don't happen, however. When installed properly, it is usually less lossy than coax.
There is no such thing as a "digital HDTV antenna". It's a myth to get more money out of people. Any decent antenna will work with digital and HDTV.
There's no such thing as a digital antenna.
Same thing happened years ago with color TV. Companies were advertising "color TV" antennas.
What is recommended by OEM for that particular Radio Long wire, 300 ohm, 75 ohm, or 50 then you need to decide what to use, whatever you use in order to get good reception Antenna and feeder line/coax must match ohms impedance of your radio in must cases any TV antenna will do good job but remember that TV antenna is directional and it must be impedance match to you radio. KA2AYS
Kuskokwim wrote in news:127l1c8evj8b7$. snipped-for-privacy@40tude.net:
I think I remember seeing a can of "Color TV Tuner Cleaner" at Radio Shack once. I didn't see B&W cleaner next to it. They must have been out of it.
Just so I start off annoying, flat lead is not cable. I guess because it is not round, but I don't thin I was alive when these things were named.
You can use flat wire, but like cable, it has to match the imepedance of what it is connected to. at each end. Your tv and your antenna may have two screws the right distance apart for flat wire**, they may have a coaxial connector, and they may have both. Whether you use cable or flat line, if the connector on the tv or antenna doesn't match physcially, you have to use an "impedance matching transformer".
You see one kind of these all the time, with a female cable connection at one end of usually white cylinder about 2 inches long, with a shortpiece of flat lead coming out the other end, with some metal forks on the end for mounting under the screws.
The inverse is available too, but less common, with a male cable connection, a cylinder with the transformer inside, and two screws to attach the flat lead too. This kind is less commmon because all new tvs for the last 20 years or more have cable connections on them, and probably all new antennas.
If you have one kind of connector at the tv, or splitter, or vcr, or dvr, and the other kind at the antenna, that tends to give you the easy ability to use either flat lead or cable, but you should know that there is a small amount of signal loss whenever a impedance matching transformer is used, so using one at both ends, when you could use a different "wire" and use none at either end, seems like a mistake.
Although another factor would be where you live. If you're close to the antennas you want to receive from, your signal strength might be so high that losses don't matter. In my case, I want Baltimore stations, but I also want DC stations. DC is 40 miles away and some antennas might be farther than that. But to add another factor, I had to buy an amplified antenna (or one could buy a signal amplifier designed for antenna signals) because some of the DC stations were so weak I wouldn't be able to get them at all otherwise.
When I lived right in Brooklyn, all the NYC stations were strong, and Connecticut and Philadelphia stations there was no chance of getting or I just didn't want them.
BTW, if you use flat lead, you have to twist it a little, so that it rotates on its axis a half turn every two feet or so (I forget if there is a distance suggested). If you;re a neat freak like I can be, and run the wire so it has no twists, you'll end up picking up static from nearby cars, lawnmowers, transmitters if any, lightning, and all kinds of sources of electronic radiation. By twisting the wire, whatever is picked up at one section of wire is counteracted and neutralized by the opposite signal induced in the part of the wire that is flipped.
You also have to use stand-offs to keep the wire away from your house. You can find "antenna stand-offs" for "flat lead" (probably called flat lead or flatlead, on Google, to see what I mean. I don't know the details about this, but I'm pretty sure if there is rain sticking between the wire and the house, you'll have plenty of signal loss. Probalby other reasons too.
Looking back at your original plan: I don't know if one can be succssful putting it *beneath* vinyl siding. Never heard of that and never heard the question asked. Ask on sci.electronics.repair . Make your question simple and don't be too distracted by answers you can't understand. I don't understand a lot of their answers either, but you can either reread what they say until you do, or wait until someone replies in English, or ask again.
They make special tubes for putting flat-lead through a wall, but I don't know if they are needed or not. They have an insulating support at each end and are empty in the middle. I guess this is all about avoiding signal loss. Although we had an outdoor antenna with flat lead when I was little. My father had enough money and would have hired a pro and done things right, and I don't remember ever seeing a tube like that. When I lived in a 6-story Brooklyn apartment, I found a flat lead hanging down from a roof-top antenna and saw that it wasn't being used at the other end, so I just spliced in and ran my flatlead between the window and the sill, and everything was fine. Like I say, the signals were strong, so any loss there was in excess signal strength (the tv has amplifiers in it. It's only when the signal strengh for a given station is near or below a minimum that a little more signal loss will cause a probelm
I don't think the flat lead was twisted either, but it was only 21 feet from the antenna to my window sill. I was 40 feet up and 40 feet back from the traffic, and maybe lightning did cause static. That's to be expected, even if it can be avoided. :)
Another variable is that coax has more impedance (bad) per foot than flat lead, but it is more isolated from interferance. I don't know if that is still true if the flat lead is twisted as recommended. BTW, the wires to burglar alarm sensors, like door and window switches, should also be twisted. You can buy twisted pair, already twisted, and you should use it here, because lightning will induce voltages in the wires to the sensors and burn out your alarm control panel if the wire isn't twisted. When twisted, each half turn neutralizes the unturned part.
The price for ignoring the rules is varying amounts of signal loss for each one. They all add up.
By not violating them, I get all 6 TV stations in DC, and maybe with a
2nd amplifer I could get Lancaster Pa.You could start off by putting flat lead under the siding, and if it isn't great, comparing it with flat lead just handging away from the wall (don't put in standoffs unless it is better and you want it to be permanent, and maybe only have to put in one standoff at the edge of the roof, and one at the bottom. Or comparing with cable, which has the center wire shielded by a saparate metal braid, and isn't fussy where it is put.
**BTW, if you see teeth pointing down on the washers for the flatlead, it is designed so you don't have to strip the wire, and the teeth will cut into the insulation. However, I always imagine that the wire I have has new super-duper insulation that the teeth can't penetrate, and end up stripping the wire. Does anyone know if these teeth are reliable or not? Flat lead does come in lots of different qualities, indoor and outdoor for example.Why do you say not analog? All TV has been analog since the 1940's until recently, and flat twin has been used all these years. For 25 years, plus or minus, there was no cable, and it wasn't common for another decade or two.
P&Mailed to OP. Please reply by post.
Everything in my previous post still applies but I see you were aksing about radio. Radios don't have that stupid feature so many tvs have these days that turns the picture and sound off if the signal is not strong enough.
And they can often take a really weak signal and still get good reception out of it, especially if there isn't a nearby frequency that is stronger.
I only have one FM radio connected to an attic antenna. In other rooms I rely on the built-in, and there is a tremendous difference from one radio to another.
It doesn't seem to be based on price. Right now, my best radio is cheap Sylvania clock radio from the 60's or 70's with an analog clock but not even a sleep switch, in my kitchen and it gets WAMU and WCSP well. Another one that works well is also cheap plastic.
OTOH, I don't get really good results with some fancy black "receivers" (matching in shape to black vcrs).
Antenna is very important, and where the AC cord is the antenna, I sometimes have to move the AC cord around to get good reception. That should go away with an outdoor antenna.
I go to flea markets, yard sales, and hamfests, and I often buy table radios. A dollar or two.
Reception comes and goes also. Maybe they are fiddling with their signal, which aiui can be very tailored to specific directions, not just a big circle.
I have a digital display, AM-FM clock radio with two alarms (each with buzzer, radio, or both in sequence) from 1973 that used to get WAMU,
88.5, in DC and now doesn't get it. It used to get WCSP, 101.9 in DC, then got it badly for about 4 months, and now it's back to getting it well.OTOH, another radio, expensive in a wood cabinet ($150?), with a separate left speaker, whose AM tuner is terrible, gets both DC FM stations well. Yet it can't get well anymore 88.1, WYPR, right in Baltimore. I have to call the local station and ask them to fix their signal. I think that can work sometimes. But I can get that local station without static on my 15 dollar clock radio with the 1.5 inch speaker. The sound isn't very good though because the speaker is cheap.
I went to a demonstration of the expensive one they advertise at night sometimes. The demo was five miles farther from DC than my house is, and their cheap model (500 dollars) didn't gget the stations I wanted. Their thousand dollar model did, fairly well, and might have worked better at home, but it was 1000 dolllars. I think because they insisted they would give me back my money, I bought the cheaper one, and it did NOT work better at my hosue, and I sent it back and they gave me back my money.
P&M, reply by post.
That reminds me of something I read once, about a way to save money on computer supplies. Using a simple 5-step procedure you could convert all of your printer paper to double-sided paper.
You're right it is misleading, if the antenna says "digital" then it only means it has good UHF and possibly only UHF reception, but rabbit ears and old VHF/FM only antennas wont work adequately for DTV. If the OP only has an old VHF/FM antenna for the radio, then twinlead is fine but might be problematic for VHF TV unless you use standoffs and not jam it behind the siding, etc. For FM anything you do is better than the power cord antenna, even if you just split the twinlead and staple it to the back of some funiture. I probably should have left it at that.
Many thanks for your very informative answer. My focus is on FM radio reception from local stations. We live in a condo (stand alone residence) which is supplied with cable TV/telephone/Internet, etc.
My reason for running the exterior cable under the vinyl siding is that, being a condo, there shall be no change to the external appearance of the unit. As a result standoffs are not an option. I am hoping that the space beneath the vinyl siding will remain dry so perhaps the flat feeder may not be unacceptably lossy. I think I shall try the twin feeder before buying coax.
One thing that surprises me is that I have heard or read several times that flat feeder is OK where the signal is below 30 MHz. Also I have been advised that flat feeder is OK to use for FM radio reception. Now, as I recall, FM broadcasts, are between 88 and 108 MHz. I guess I am confused.
Peter.
If the cable TV feed is analog then there might be FM available there too, older analog cable systems did not brickwall filter out the lower FM frequencies, (but they would never advertise that fact). I used my old analog cable TV feed as my FM antenna for years. Its worth a try, may need a small splitter and xformer.
They used to sell a square punch that would make a second notch in the side of 5" floppy disk, so that you could flip it over and put it in the floppy drive upside down, so that you could use the other side of the disk. I think the cover already had head access holes on both sides. A friend had a punch like this and used it.
Yeah I saw that later and you probably saw my second answer at the end of the thread.
I dont know about this, but the sound in tv is also FM, and our first tv didn't have detent tuning by channel. It had continuous tuning from channel 2 through 13, with indicators on the dial where each channel was, and a tuning eye to make it easy to fine tune. Oh, yeah, it had two concentric knobs, one that changed frequency quickly and one on top of it that changed slowly for fine tuning.
And between channeds 7 and 8, I think it was, was FM radio. It's in the same place still, and maybe one can tell with one of those FM-TV radios. And there was a switch to turn off the video when one was listening to FM radio. Of course there were no FM radio stations then, where I lived and almost everywhere else.
and the picture is AM.
I never saw one that old, but I have seen one without UHF and then one where the UHF tuning was continuous (it went to channel 83 too).
FM is just slightly above channel 6. I used to know of people in a nearby town getting channel 6 on their radios (with analog tuning).
Cable TV puts channel numbers 14 through 22 (that's cable, which is different from UHF above 13) in the gap between FM and channel 7.
BTW, there is also a small gap between channels 4 and 5. Some older cable systems would squeeze in a channel 1 here.
Not so much annoying as wrong. Of course twinlead is cable.
Hmm, How about your TV antenna then? Twin lead has typical impedance of 300 Ohms vs. coax. which has 50 Ohm or 75 Ohnm typical. There is also balun transformer to splice them together.
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