Old Analog TV Antenna?

[nvanw27]

Hi, everyone!
A few months ago, my family bought 20 acres of land that came with a little hunting cabin. On the cabin was an old analog TV antenna. It’s one of those gigantic ones that takes up half the roof. It’s got a coaxial connector on it. I spent a while on the roof getting it down, and now it’s just sitting there.
Would it be possible to use this as a scanner antenna? It’s analog - I tried using it on our Digital TV and it didn’t pick anything up in multiple configurations. I wouldn’t be transmitting through it - I don’t have any licenses and both of my Baofengs have PTT disabled through the software. I’d probably use it to monitor VHF stuff with an occasional venture into UHF.
Is it possible to do this, and what would I need to make it happen? If I can’t, I’m sure I could find something else to do with it, or sell it on Craigslist or something.
Thanks!

 

[doctordialtone]

On the cabin was an old analog TV antenna.

There's no such thing as an "Analog" or "Digital" antenna. A radio or TV signal is a signal.

Chances are out of all of that metal,there is a single set of elements - usually in the middle.

The rest of the radials are either directors or reflectors - designed to aim the signal at the active elements.

Since the antenna is designed for TV frequencies, it's not going to do much good on other frequencies.

You can give it a try, but you'd probably be better off with an antenna specifically designed for the job.

Good luck!

 

[jaspence]

Depending on what you are trying to receive, you may be able to cut the elements to the length for a usable antenna frequency, but it will take some time and calculations with no guarantee it is worth the effort.

 

[mmckenna]

Chances are out of all of that metal,there is a single set of elements - usually in the middle.
The rest of the radials are either directors or reflectors - designed to aim the signal at the active elements

Traditionally, TV antennas have been a Log Periodic design where all the elements are driven.

@nvanw27
TV antennas are designed to be horizontally polarized, so to make it work as a scanner antenna, you'd need to turn it 90º on it's axis. That may require drilling new holes for the U bolt.

TV signals were often low band (just above 54MHz/6 meter ham band), VHF up above the traditional vhf LMR band, and UHF, above the UHF lmr band on up to 800MHz.
You can try hooking it up to your scanner, and it will probably work well enough. Often people would hook FM receivers to their TV antennas and it worked well. It's directional, so it's going to need to point at the transmitter to work best.

 

[wtp]

just hook it up, it can't hurt.
any piece of metal receives radio waves, some better some worse.

 

[Ubbe]

I had a UHF TV antenna 470-700MHz and it worked really well from 400MHz and upwards but it was also good in the 250Mhz band to receive the satellite communications, better than any 1/4 wave GP. Also VHF air where better on that antenna than a standard 1/4 wave antenna tuned for airband.

Can you post a picture of the antenna? If all elements are gigantic it must be a low-vhf single band antenna for the 50MHz band. If you use it in its horisontal position the signal strenght could be down 10 times or worse. Try to use it vertically and it should have a connection box where you connect a coax cable. Use RG6 CATV coax with connectors on it and cut one end and splice and connect in the antenna box and get an adapter from F to BNC or whatever your scanner needs. It will probably work better than any indoor antenna you might use now.

/Ubbe

 

[popnokick]

TV antennas work quite well for scanners. Most of them are both VHF and UHF. As suggested, you will need to turn the elements so they are vertically oriented with respect to the earth (90 degree angle). Here is MUCH more on this... scroll down to the post originally made by Bill Cheek - TV antenna for scanning?

 

[krokus]

Also make sure there is not a pre-amp installed. If there is, and no power is supplied to it, there is little chance of signal making it to the coax. (Assuming the amp would still be functional.)

 

[Ubbe]

Also make sure there is not a pre-amp installed. If there is, and no power is supplied to it, there is little chance of signal making it to the coax. (Assuming the amp would still be functional.)

I haven't seen any low-vhf tv antenna with an inbuilt amplifier, but have seen several UHF types. Some are bypassing the amp when power are removed. I guess a low-vhf antenna can only pick up a couple of channels and have to be used together with another hi-vhf and/or uhf antenna and will then need an external amp with input for each antennas frequency band.

/Ubbe

 

[WB9YBM]

Hi, everyone!
On the cabin was an old analog TV antenna. It’s one of those gigantic ones that takes up half the roof. It’s got a coaxial connector on it. I spent a while on the roof getting it down, and now it’s just sitting there.
Would it be possible to use this as a scanner antenna?

Short answer: "yes". Long answer: since the old analog channels were scattered over a very wide range of frequencies and the antenna (presumably) is designed to "hear" all of that, it should do the same for a wide scattering of scanner signals. The only glitch I see is that TV antennas are designed to have a 75 ohm feed, while scanner antennas are 50 ohms. That slight mis-match may cause some signal degradation. Transformers are (or at least were) available so that stereos could also be hooked up to TV antennas; you might want to check that out. Also, the larger the beam antenna, the smaller the window it will "see" in any one direction (that's so it sees further in the direction it's pointed) so you won't be able to hear as much off the sides as with smaller beam antennas.

 

[mmisk]

See attached picture.
At the top of my tower below my 2m antenna, is the UHF section from a large TV antenna.
I cut it off from the rest of the antenna, mounted it vertically, fed it with LMR 400.
Well, it makes a fantastic scanner antenna and at no cost except for the coax.
Really wide band coverage.

 

[krokus]

I haven't seen any low-vhf tv antenna with an inbuilt amplifier, but have seen several UHF types. Some are bypassing the amp when power are removed. I guess a low-vhf antenna can only pick up a couple of channels and have to be used together with another hi-vhf and/or uhf antenna and will then need an external amp with input for each antennas frequency band.

/Ubbe

The Channel Master model 1162, and related models, had a compartment where the 300 Ohm screw terminals were. You could use a balun there, or the company had amplifiers that fit in the space. (Various combinations of amplification and pass-through were available.)

 

[Ubbe]

The Channel Master model 1162, and related models, had a compartment where the 300 Ohm screw terminals were. You could use a balun there, or the company had amplifiers that fit in the space. (Various combinations of amplification and pass-through were available.)

That's exactly what I ment to say. Amplifiers are only used with higher frequencies, not low-vhf.

/Ubbe

 

[p1879]

I know you said you did not get any tv channels with it, but maybe some new cable could fix that. Free over-the-air-tv can be fun and you might be surprised at what you get, if you persevere. The fact the previous people had a big antenna tells us you might be a long haul from the stations, though. Check your possibilities on rabbitears.info site. You may be an equally long distance to desired radio traffic too; many people have gotten good directional scanner reception with a Vertical-oriented tv antenna, like the folks said.

The comment on amplifying lo-band tv signals: could you expand on that, please? Is the noise level down there counter-productive with an amp? Perhaps I misunderstood.

A friend just failed to get a weak real tv channel 2 signal using a very low noise Kitztech amp., while returning to his 12$ Wal mart On brand antenna restored the station, which is a big challenge to receive in this area. Each signal micro-ecosystem is different, though.

 

[p1879]

pardon, should have said "12$ Walmart On brand antenna booster", as antenna amps were being compared.
p1879

 

[Ubbe]

Television sets doesn't use high perfomance receivers. They use 99cent receiver chips the same as are used in Unidens SDS scanners. If you use a 22dB amp it will totally destroy reception. The Walmart one probably had less gain or could be adjusted to a lower gain value that suited better to the TVs receiver performance. The Kitztech amps seems to have a 0,9dB noise figure and should receive a weak station much better than the Walmart amp. Always use a variable attenuator when dealing with antenna amplifiers to check and adjust to an optimum system gain level, that will be different for each unique loacation and equipment used.

I know that some sat receivers years ago where overloaded by a normal signal from a dish LNB and had to install a resistor to the input of the receiver module to reduce the signal some 6dB or it would produce bit errors in the picture.

/Ubbe

 

[krokus]

That's exactly what I ment to say. Amplifiers are only used with higher frequencies, not low-vhf.

/Ubbe

Not true. The amp we sold most often had three different gain levels listed: low band VHF, high band VHF, and UHF. On most models the VHF low band had the lowest gain, but not all of them. We would suggest different models of amp, based on their location, and desired stations. (We were on the edge of the Detroit Market, but could easily receive three other markets, too.)

 

[scanmanmi]

Ditto on the polarization, you'll have to rotate it 90 degrees. Can't find a good video I saw but here's one.