Tv antenna help

Head Sail · Oct 11, 2015

Do you have line of sight to the broadcast antenna?

Boomer54 · Oct 11, 2015

Do you have the source on the TV set to antenna?

Boomer54 · Oct 11, 2015

On my setup, I have a "gain" reostat and I have it turned up all the way. Obviously not sure how yours is set up

Rick D · Oct 11, 2015

I'd try a cheap rabbit ear with a coax to see if its the TV or the antenna. I suspect you were using the antenna just fine before, so it's odd that it would now be it....

Dan_Y · Oct 11, 2015

I have a version of this antenna (UFO) from 2008 and fortunately still works very well. The ICOM circuit board is a power inserter that places a capacitivley coupled dc voltage on the coax up to the antenna to power a preamp in the antenna. This is '60s or 70s technology, but cool none the less. The received TV signals are AC signals that simply ride on the DC back down the coax where the DC is blocked by capacitors but the ac rides thru the caps and is sent to the TV output coax of the circuit board, probably after some conditioning and filtering. Not sure what DC voltage you would read on the antenna coax though to see if the power inserter was working. 0 VDC between the center conductor and shield doesn't sound correct. Also, the connection of the coax at the antenna may have leaked and is too corroded to work. If the power inserter I dead, then there may be a weak, or no signal out of the antenna, depending on how it's amplified. Your ohm meter reads resistance, not impedance, so you would measure the total resistance of the coax (a few ohms maybe) and what ever its connected to in the antenna. It may show open circuit. It could show a short if the antenna amp is dead. If the center conductor of the antenna coax shows continuity to ships ground, there is probably problem in the antenna. I don't have any schematics of this system, but the company is still producing new models ands may be of some help.
http://www.majestic-global.us/previous-models/19-ufo-power-boat-mount.html

Rich Stidger · Oct 11, 2015

I had one of these "UFO" antennas until I replaced it this Spring. This antenna has a red LED on the bottom that you can see from the deck after dusk. Is it showing on your antenna? If not, then you are not getting power to the antenna.

The poor reception that I had last year and that was the reason I replace it this Spring was probably a very bad coax connection at the antenna. I still had the red LED light, but the antenna performance was poor. Since I had already bought the new antenna, I went ahead and installed it. But if I had discovered the bad connection I probably could have saved myself some effort and money.

seadaddler · Oct 12, 2015

I would get another TV ant and try again,some thing is bad like circuit board or coax or even ant and before going nuts as I did long ago had a bad ant.
I have a very good marine power ant off my davits and most times does very good job with reception.
Nick

Rich Stidger · Oct 12, 2015

planoron,

I have my original UFO antenna and the power/signal box if you would like to try it for T/S purposes. Send me a PM if this appeals to you.

pateco · Oct 12, 2015

I do TV and satellite antennae work all day. it is most likely the connection at the Antennae. A little moisture along with 12v DC will corrode that thing in no time. Cut it off and replace with a quality compression fitting dielectric grease and new weather boot. Should fix the problem.

Mark Maulden · Oct 12, 2015

planoron said:
Actually I have never had a tv hooked up to this. This what the PO had set up. So should I be able to see 75 ohm between the center wire and shield on the tv input with 0v?

Do NOT under any circumstance put an ohmmeter across an active rf circuit. An ohmmeter induces a voltage which is how it determines a reading. That voltage could be harmful to the circuit....

McIntoshUSA · Oct 12, 2015

Can you temporary (for testing) bypass the circuit board you have and connect the coax cable coming down from the antenna straight to the TV to test to see if perhaps the circuit board is the culprit?

Dan_Y · Oct 12, 2015

Good point Mark. I was assuming he was just doing a continuity check of the antenna coax while it was disconnected from the power injector. Not sure if the level of ohm meter DC voltage would hurt a good rf amp at the antenna.

Pateco, what voltage do the power injectors typically drive to the antenna amp?

Rich Stidger · Oct 12, 2015

Without power going to the antenna the signal coming down will be practically non-existent. In other words, you can't bypass the power injector board to test the antenna. You can test this statement by simply shutting off the power to the antenna and see the result on the TV- with a working system of course.

pateco · Oct 13, 2015

Dan_Y said:
Good point Mark. I was assuming he was just doing a continuity check of the antenna coax while it was disconnected from the power injector. Not sure if the level of ohm meter DC voltage would hurt a good rf amp at the antenna.

Pateco, what voltage do the power injectors typically drive to the antenna amp?

I have not worked with this particular antenna, but most of the powered off air antennae I have worked with are used to add off air to a DIRETV or Dishnetwork Satellite TV systems. Those made by Channel Master, Weinguard, etc. all were designed to work with anything from 12 to 18 volts., and shipped with a 12 volt power inserter.

Benny17441 · Oct 13, 2015

You have a $150 problem. Between possible corroded connectors, fouled cables or a non-working amplifier or antenna itself at best you are looking at a few trips up the mast and a few replacement parts after diagnosing the cause. Sounds to me like purchasing a new antenna with cables and fixtures and going once up the mast to replace the old one would be the way to go. After all life is too short to be dealing with aggravation rather than watching a ball game.

Tv antenna help

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