Author Topic: Who wants to walk me through troubleshooting a TV Antenna?  (Read 552 times)

Le Poisson

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Who wants to walk me through troubleshooting a TV Antenna?
« on: July 06, 2018, 10:17:57 AM »
About a year ago I put a square grid digital antenna on our roof. Like this one:

https://bit.ly/2zifDhc

We ran about 50' of coax down to the basement and to the TV and were instantly rewarded with about 20 channels. Then, over the following months, the channels dropped off one by one, and today we get no TV at all.

I'd like to get some TV back - we don't watch it much, but the news is good and so is HNIC.

Being that I know nothing about electronics and even less about testing signal strength etc. I've done nothing with this apart from turning the antenna this way and that trying to find signal. Re-aiming has not been a success.

Anyone up to the chore of guiding the blind to the light here?

Cromacster

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #1 on: July 06, 2018, 10:22:04 AM »
rats/mice/squirrels/raccoon chew through the wire?

Also assuming your TV has a digital tuner...

FIRE@50

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #2 on: July 06, 2018, 10:43:58 AM »
That is strange that the channels are dropping off. I've been on an antenna for over 6 years and we've steadily increased the number of channels that we get. Are you able to get your TV to scan for stations? Check the menu/settings options.

Also, I've noticed that sometimes a channel will randomly drop and I've discovered that they have alternate channels. When I punch in the "alternate" channel on my remote, it will find the original one again. I don't know why it happens but is can be annoying.

Le Poisson

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #3 on: July 06, 2018, 10:48:31 AM »
rats/mice/squirrels/raccoon chew through the wire?

Also assuming your TV has a digital tuner...

Nope - wire still good, and I've looked at the connections. They all look good. In an online forum I was reading old messages and loads of folks were talking about beluns - what's a belun? Do I need one?

That is strange that the channels are dropping off. I've been on an antenna for over 6 years and we've steadily increased the number of channels that we get. Are you able to get your TV to scan for stations? Check the menu/settings options.

Also, I've noticed that sometimes a channel will randomly drop and I've discovered that they have alternate channels. When I punch in the "alternate" channel on my remote, it will find the original one again. I don't know why it happens but is can be annoying.

We've done channel scans. I'll do another one right now and see what I get.


{ETA: 0 Digital and 0 Analogue channels found. According to TV Fool I should have 8 channels with indoor "bunny ears" and about another 45 channels with a rooftop setup.}
« Last Edit: July 06, 2018, 11:07:07 AM by Prospector »

[a]bort

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #4 on: July 06, 2018, 12:54:15 PM »
I'm guessing you're in Canada where OTA has been digital for some time so that shouldn't be the problem.

During your re-aiming did you inspect the antenna for physical damage? The shape/size/position of each limb is important for functionality. You mentioned that your coax appears undamaged, but if you have any overly tight bends it could cause attenuation, as well as if it was previously pinched/kinked it may have damaged the conductor or shield permanently but looks fine from the outside.

Maybe you could contact your local HAM radio club about having someone stop by with a Time Domain Reflectometer and a VSWR tester
« Last Edit: July 06, 2018, 01:01:23 PM by [a]bort »

NathanP

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #5 on: July 06, 2018, 01:01:23 PM »
(Assuming that the antenna, cable and TV are ok) Has there been new construction in your area? Perhaps new homes and trees have slowly degraded your ability to receive the TV transmission. It is also possible that the broadcasters have changed which frequencies they use, so it may be a simple matter of asking the TV to search for channels.

Cadman

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #6 on: July 06, 2018, 01:50:16 PM »
Is your rooftop antenna active or passive? If active, it will have its own power supply and onboard electronics which can eventually fail. If passive, there's not much to go wrong other than corrosion where the cable meets the actual antenna element.

I've seen DTV tuner/converter boxes "forget" a station at random; sometimes several. Usually unplugging, waiting half an hour, then performing a channel scan will fix the problem.

You shouldn't need a balun. That's used to match impedance, usually between 300-ohm twin-lead and a 75-ohm coax input. Not real common on new installations.

sokoloff

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #7 on: July 06, 2018, 02:06:55 PM »
Sounds like you may have corrosion in the coax or connectors. There are outdoor-rated connectors and gel-filled coax, both of which are very helpful to avoid corrosion in the field. (The gel-filled cable is nasty to work with, but really works.)

If it's just the connectors that have corroded, re-terminate the line with fresh connectors, use a dielectric grease on the connections, and leave drip loops on the cable to prevent corrosion of the new connections.


Le Poisson

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #8 on: July 06, 2018, 02:12:48 PM »
Sounds like you may have corrosion in the coax or connectors. There are outdoor-rated connectors and gel-filled coax, both of which are very helpful to avoid corrosion in the field. (The gel-filled cable is nasty to work with, but really works.)

If it's just the connectors that have corroded, re-terminate the line with fresh connectors, use a dielectric grease on the connections, and leave drip loops on the cable to prevent corrosion of the new connections.



I suspect this. There is a connection at the antenna, and another at the foundation where the cable enters the house. Anything I should look for if I open them up? I just ordered new barrel connectors online ($0.50 ea, free shipping) and I have some dielectric grease kicking around.  Should I worry about whether the coax is interior/exterior? I think I just grabbed whatever was onhand when I installed the antenna.

sokoloff

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Re: Who wants to walk me through troubleshooting a TV Antenna?
« Reply #9 on: July 06, 2018, 02:15:21 PM »
Interior coax (provided the conductors are copper and not the copper-clad-aluminum [aka pure garbage]) should last longer than a year outside, as long as you keep the water out.

I'd cut the old connector off and have a look at how the cable looks. If it looks fairly "virgin", re-use it. If it looks all corroded, replace it. If replacing it, I'd replace with an outdoor (likely gel-filled) cable.