OK Experts... TV Antenna question

[goldfinger]

I know there are alot of smart people here and hopefully one of you will have the answer to my non-oil related question.

I have a friend who is unable to get cable and will not get satellite, so he's stuck with a plain old VHF/UHF antenna to get local channels. He recently had to purchase a new antenna because his old one got blown away in a storm.

For some reason the replacement antenna's performance isn't nearly as good as the old one. Just a slight movement in the antenna and he loses some channels completly. He bought the highest priced antenna he could find at a local store. Same place the first one came from.

He does have a 27db gain amplifier on it which was also used on the old antenna. Any tips that might bring the performance up? Or something to check that might be incorrectly installed?

Also, what is the possibility of boosting the signal twice? IE once on the pole, and again before it goes into the TV. Is that even possible? Without the booster he doesn't pick up ANYTHING at all.


Thanks

 

[keith]

The "more expensive" antenna is perhaps more directional than the old antenna. That means that when the antenna is directly pointed to the trasmitting tower, it has higher gain than the old. But, move the antenna a little and the gain drops off rapidly. The cheapest "omnidirectional" antennas receive signals equally well (or poorly) in all directions.

Go to antennaweb to find out the direction of the tramsmitters and recommended antenna for any US location.

Keith.

 

[goldfinger]

Thanks Keith. That link was really helpful. Looks like all the stations but 2 recommend the Large Directional w/ Pre-Amp, the other 2 recommend medium. The one he got has a 160" boom which is the largest they had and he's using the same pre-amp.

Looks like what's he's got is the best he can get. :/

 

[XS650]

An antenna mounted amplifer can do some real good with weak signals. But once you have an antenna mounted amp, about all a second amp on the set end is amplify the noise with no better signal.

The exception would be if he has more than a couple of sets hooked to the antenna, then adistribution amplifier will mainten the same signal level to as many sets as the amplifier is designed for.

The comments about the new antenna being more directional than the old one are right on, but something still sounds a bit strange. When the antenna is aimed correctly at one of the weaker stations, does it work better than the old antenna did? If not, then there is probably an installation problem.

He will probably need a rotator if the stations aren't all from very near the same direction.

 

[brianl703]

Very often, when stations are not all in the same direction, a smaller antenna (with an amplifier, if needed) works better than a larger one (amplifier or not).

A larger antenna has more gain (provides a stronger signal to the TV) but it is also more directional. It works like a magnifying glass...the magnifying glass makes an object appear larger, but you can't see all of that object at once without moving the magnifying glass around. More powerful magnifying glass? Even less of the object can be seen at once.

And so it is with antennas. A smaller antenna that is aimed between two stations may well get an acceptable signal from both, but a larger antenna that is aimed betwen two stations may well get an acceptable signal from NEITHER station.

Is he aiming the TV antenna by turning it VERY slowly while watching a TV connected to it?

Guesstimation of aim works fine with smaller antennas, but not so with larger ones. Chances are that the antenna aim is slightly off enough that he won't get a viewable signal without a booster. This is especially true if it is aimed in-between stations so as to pick up more than one.

[ July 16, 2004, 12:25 AM: Message edited by: brianl703 ]

 

[JohnnyO]

Do they still make those rotators? I remember my grandparents had one in the days before cable. Still, I live in town and whacked the (lousy Adelphia) cable for (cheaper) Direct TV and I only pay $39.95 a month.

 

[brianl703]

Radio Shack still sells them. I am also pretty sure that Lowe's and/or Home Depot has them.

And if you can't find them there, try http://www.starkelectronic.com

 

[motorguy222]

What kind of wire is hooked to the antenna? Is it co-ax or regular antenna wire.The co-ax costs a little more but is worth it.The co-ax does much better and is shielded to help keep out interference and it gives a far better picture that regular antenna wire does.

 

[motorguy222]

What kind of wire is hooked to the antenna? Is it co-ax or regular antenna wire.The co-ax costs a little more but is worth it.The co-ax does much better and is shielded to help keep out interference and it gives a far better picture that regular antenna wire does.

 

[labman]

When I went through this about 25 years ago, I was told twin lead would give a stronger signal. My antenna was set up for twin lead and had to be converted. I used coax because it is easier to run going through walls and so forth. Twin lean needs to be in the open.

Coax did not prevent problems when I had a radio opperator next door. Likely he was a bad apple in that barrel and violating the law.

 

[motorguy222]

I have used twin lead(regular wire) and co-ax on the same TV,antenna combination and the co-ax has always been the better choice.The picture is much better,while it may not keep out the interference from a CB/HAM radio base station,it does help keep out interference.The closest TV station to where I live is 40+ miles away,the co-ax gives me much better reception.


Sorry for the double post above,my computer must be having a bad day.

 

[The_Jeff]

If you use coax, use RG-6 over the cheaper RG-59. Home depot has it in 100' rolls for $12; crimp the end connectors on with any old pair of pliers.

 

[MolaKule]

A medium gain antenna with an "on-antenna" boost pre-amplifier is the best set-up, IMHO. Use a 27 to 30 dB preamp and RG-6 coax.

Do not use two amps in series; each amp has a certain amount of noise that will show up as speckles, since the second amp will amplify the first amp's noise.

Also, make sure you use a coax lightning arrester and ground the arrestor using 10-12 guage solid wire.

 

[brianl703]

quote:

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Originally posted by eljefino:
crimp the end connectors on with any old pair of pliers.

---

I wouldn't recommend that when the proper crimping tool is all of $10, and the connector installation cannot be done correctly with a pair of pliers.

(Unless you're talking about the connectors with a separate ferrule..I haven't seen those for sale in years, and I've never seen them for RG-6)

As far as cable goes, make sure that it is suitable for in-wall installation by looking for the wording "UL CATV" or "UL CATVX" printed on it.

Cable without these markings does not comply with building code regulations for in-wall installation. You might not care, but your insurance company likely does......

 

[seotaji]

I would reccomend calling a professional installer to come take a look at it and adjust if necessary.

I had a friend get an OTA HDTV antenna and the first installer put it in a decent spot, but the pro he called afterwards (free since the place he got it from makes sure their customers are satisfied) did the most work and put the antenna in a place where it got the best reception.