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Fasttrack
04-15-2013, 05:14 PM
Been looking at this rusty old TV antenna on my house and thinking about trying to use it to pick up some basic stations. I noticed that there are two 1/8" braided steel cables that stretch across the roof. They appear to be tied - as in square knot - to the antenna pole and the other ends are tied to bits of scrap metal to keep the wire from blowing in the wind. They just lay flat over the surface of the roof.

What is the purpose of these? I seem to recall seeing something on another roof with an antenna but my Google searching hasn't availed me.

Jim B
04-15-2013, 05:25 PM
You would do better to replace the old antenna.

The new HD channels are all over the place. Channel 2 in you area may not be at 56 MHz it could be at 500 MHz. When HD came along many stations moved frequencies. The new TV's know haw to remap the ID channel, some times called Virtual channels but without a lot of work you wont know where they are.
You need an antenna the covers both VHF and UHF and the UHF portion should have a built in amplifier.

hitnmiss
04-15-2013, 05:31 PM
My house was built in the late 60's and has an old antenna laying up in the attic. I hooked up to that and get great digital channel reception...

Fasttrack
04-15-2013, 06:00 PM
The new TV's know haw to remap the ID channel, some times called Virtual channels but without a lot of work you wont know where they are.
You need an antenna the covers both VHF and UHF and the UHF portion should have a built in amplifier.

I'm not opposed to getting a new one, but my TV is new and this antenna does have a preamp but I don't know if it still works. I can pick up 7-8 channels but I'd like to do better. Of course, the channels I get are all independent/shopping channels. I want to get PBS and CBS, which, according to TVFool, should be possible.

Paul Alciatore
04-15-2013, 10:57 PM
I am a retired TV engineer and can not think of any reason for the steel cables you have described as they are now. Perhaps they were previously used as guy wires and some previous person just left them on the roof when they broke loose or were removed for some reason. If they are fastened to the pole/tower at a higher point, that would tend to confirm this.

As for the old antenna, it is probably not the best choice for a new installation. If nothing else, there is probably some corrosion that will make it less than 100% efficient. A new antenna will not cost that much and I would not put in the necessary work to use the old one. Get a new cable for the down-lead too.

Fasttrack
04-15-2013, 11:36 PM
I wonder if the cables were for some sort of rotation gimmick. I found the remnants of plastic pulleys on the tower...


So, if I buy a new antenna, where is a good place to get one on the cheap? I found this place but it seems like a pig-in-a-poke type website...

http://antennadeals.com/HD2605.html

lakeside53
04-15-2013, 11:42 PM
Around here all the channels moved to UHF and from horizontal to vertical polarization An old VHF antenna won't do me any good, and the new UHF is a fraction of the size.

JoeLee
04-15-2013, 11:43 PM
Could be the braided cable was intended to be some sort of ground radial for the antenna. The remnants of plastic pulleys may have been for a long wire antenna that at one time was tied off to a tree.

JL..................

doorknob
04-16-2013, 01:26 AM
These guys are well known:

http://www.solidsignal.com/cview.asp?mc=03&d=over-the-air-tv-antennas-supplies&c=TV%20Antennas

A.K. Boomer
04-16-2013, 09:49 AM
I'm not opposed to getting a new one, but my TV is new and this antenna does have a preamp but I don't know if it still works. I can pick up 7-8 channels but I'd like to do better. Of course, the channels I get are all independent/shopping channels. I want to get PBS and CBS, which, according to TVFool, should be possible.

I went through allot trying to get PBS here, I had it - then moved only about 6 blocks away never to receive it again.
Evan even helped me design a Yagi that was supposed to pick it up and wouldn't - not a loss because the thing works great for other stations and is "stylin"

anyways FT - Im sure you know you can get PBS on line, and it's on demand for whatever you want to watch,,, thats what I do now, just run a cable from your pc to your tv - if your not on dial up...

edit; it almost sounds as if those cables were once supports and the center ring slid down the mast?

brian Rupnow
04-16-2013, 10:57 AM
I once seen an old farmhouse that had a rig for turning the TV antenna manually. Someone had set up a pair of bicycle pedals and sprocket with about 48" of chain and a 1/8" steel cable that attached to both ends of the bicycle chain, ran through a series of small pulleys, and wrapped around the TV antenna. By turning the bicyle pedals by hand in one direction or the other, it would pull the steel cable in one direction or the other and turn the antenna.

Paul Alciatore
04-16-2013, 01:26 PM
Around here all the channels moved to UHF and from horizontal to vertical polarization An old VHF antenna won't do me any good, and the new UHF is a fraction of the size.

UHF and VHF do have very different requirements for an antenna. UHF antennae are a lot smaller.

As for vertical vs horizontal polarization, you can just turn the antenna 90 degrees. It may not be designed to mount that way, but a simple horizontal boom would fix that.

In fact a pair of antennae that were intended for horizontal polarization on opposite sides of a horizontal boom would make a nice phased array. This would space them out from the main pole/tower to avoid any interaction. It would also give you higher gain in the forward direction and increased rejection to the sides. The distance separating the two would control that rejection - some math required. A phasing harness would be needed to connect them. A splitter could be used backwards with EQUAL length leads going to each of the antennae and the "input" jack of that splitter going to the TV.

jason.weir
04-16-2013, 02:38 PM
maybe lightening arresters?

bob_s
04-16-2013, 05:53 PM
Just go to

http://www.digitalhome.ca/ota/superantenna/design.htm

And grab a copy of the plans for a Gray Hoverman antenna.

Good for a couple of hours of shop time. Then enjoy HD tv with better resolution than the cable company supplies.