Storm damage

Underdog · 3-Sep-2014, 12:22 PM

Hello again. Thanks to this site we have been enjoying OTA TV for a couple years now. First my setup is a large antenna on the roof of my garage where the dish was. Coax run is about 100ft total to the two TVs in the house and one on the porch. There is an amp mounted directly on the antenna mast but I forget the make or model. The power supply and inserter are inside the garage directly below the antenna. I do have it all grounded.

This has worked fine until last night. We had a bad thunderstorm with some really close lightning strikes. One strike even made our power snap off and back on. Now I only have 5 channels, the rest say no signal. I suspect the amplifier got fried. The red led is still on so the power supply must be working. I would assume if the coax was burned, I wouldn't get any channels at all.

Is there any test I could do? Any recommendations for a replacement? Would I be able to use one mounted inside this time? I'm not too good climbing on roofs.

Thanks

ADTech · 3-Sep-2014, 12:31 PM

Odds are, the amp and/or the balun on the antenna are fried.

Best thing to do is to assume any part is bad until you can prove it isn't. Once you get to a part that you cannot prove is good, then you've probably found the pad part.

The red light just means the power supply is still working, nothing more. Bypass the amplifier at the antenna and at the inserter and see if some measure of signal improves. If it does, the amp is a goner.

Stereocraig · 3-Sep-2014, 4:45 PM

Bypassing the amp and power inserter, is indeed a sure fire way to determine the condition of the amp.
Although I would expect it to be blocking all signals if it's dead, I suppose it's possible to have been only partially damaged.

Another little known trouble spot, is the grounding block.
If there is even the slightest moisture, or oxidation inside it, or the F connectors, it will be susceptible to arcing.
Carbon arcing can't be cleaned, so anything that has them, will need to be replaced.
Spider and cobwebs, will attract overvoltages, too.

GroundUrMast · 3-Sep-2014, 6:10 PM

To bypass the amplifier, consider purchacing a test cable, just a factory built coax assembly that's 50' long. You can use it to bypass suspected amps, and coax runs.

ADTech · 3-Sep-2014, 6:11 PM

Dead and unpowered amps usually become ~30 dB attenuators which allow only the strongest stations to make it through. However, since we don't know what the local signal conditions might be, it's speculation. He didn't post a TVFool plot or identify specific stations.

Underdog · 3-Sep-2014, 9:17 PM

Thanks for the help. Yeah, I forgot to post the link.

http://www.tvfool.com/?option=com_wr...d24366873ca6b1

I'm basically getting only the PBS stations WQED 13 and one other I don't recall. 13 accounts for 4 of the 5 stations I'm getting and they are from the same tower.

I didn't get a chance to go up on the roof yet. Back to my other questions, what would be a good unit and can I get one that mounts inside this time ( a distance of about 8 ft below the antenna) ?

ADTech · 3-Sep-2014, 9:56 PM

Yes, you can mount the amp in a location for better serviceability at a slight penalty in the system noise figure. 8' of coax equals about 1/2 dB additional loss before the amp. I had to do something very similar. I put my pre-amp at the bottom of the 10' gable-mounted mast so I can swap it (something I do for testing purposes) without having to bring down the 10' mast with an 11' long stretched 91XG on it.

As far as an amp, first need to know if that nearby low power (UHF 40) is on the air or not, also what antenna do you have and which way is it pointing?

Underdog · 8-Sep-2014, 10:19 PM

Ok, I was away over the weekend and didn't want to announce that on the internet. Just got done eliminating the pre-amp with cable connectors. I now have CBS (KDKA) and ABC (WTAE) back in addition to WQED. So the amp is fried. What I had was a Winegard 8700 mast mounted that is now discontinued. Spec are 17db VHF and 19db UHF with 2.8 noise on both. I don't remember the exact antenna but it looks like a Winegard HD 7698. I believe it is aimed approximately 350deg.

With the amp I had, NBC 11 and Fox 53 were not always reliable on the set furthest away. So I'm inclined to go with a little more amplification on the replacement.

GroundUrMast · 9-Sep-2014, 3:08 AM

The RCA TVPRAMP1R has about 5 dB more gain, and is tolerant of strong signals. It's also relatively inexpensive.

Underdog · 9-Sep-2014, 12:35 PM

Thanks, I ordered one. I'll report how it works.

Underdog · 11-Sep-2014, 9:51 PM

Got it installed and so far works great. Maybe my imagination but I swear the picture looks much sharper.

One little tip. DO NOT rely on the instructions that describe the default setting on the two dip switches. It says they are set with FM filter on and VHF UHF antenna input combined. Something told me to pull the little rubber plugs and look. Sure enough both switches were set the opposite of the stated default setting.

Thanks for the advise and support. Worse part is climbing up on the roof.