Question: Outdoor antenna mounting problems?

MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#1
I will be putting the antenna on the roof soon (now in the attic) and I have a few questions for those whoe antennas are outside-

Do you have problems with reception in high winds?

Or if your antenna ices over?

Other than the obvious problem of shortned lifespan for the outdoor components, is there any other problems with outdoor / rooftop mounting?

Thanks.
 

n2rj

Moderator
Staff member
#2
I will be putting the antenna on the roof soon (now in the attic) and I have a few questions for those whoe antennas are outside-

Do you have problems with reception in high winds?
Yes, only because of that #^%$@@ Hickory tree that creates multipath galore. But only on channel 44 (5.1).

Or if your antenna ices over?
Been there done that. Icing over kills reception for a bit but it comes back in a day or so. Extreme icing can bring the antenna down but it also brought down a lot of things around here. Utility poles, trees and power entry masts come to mind.

Other than the obvious problem of shortned lifespan for the outdoor components, is there any other problems with outdoor / rooftop mounting?

Thanks.
Damage to your roof if you don't use a good mount or don't seal it off properly or the risk of the antenna falling on powerlines if it's too close. Both of these can of course be avoided.

Also there is lightning, but even NASA can't prevent lightning from striking everything.
 

MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#3
Yes, only because of that #^%$@@ Hickory tree that creates multipath galore. But only on channel 44 (5.1).

<I was thinking more of the antenna itself moving in high winds, vibrations, etc>

Been there done that. Icing over kills reception for a bit but it comes back in a day or so. Extreme icing can bring the antenna down but it also brought down a lot of things around here. Utility poles, trees and power entry masts come to mind.

<I don't actually expect much icing, back in Upstate NY we had some ice storms that put 2 inches of ice on everything. But we do have frost buildup here that gets pretty heavy at night.>

Damage to your roof if you don't use a good mount or don't seal it off properly or the risk of the antenna falling on powerlines if it's too close. Both of these can of course be avoided.

Also there is lightning, but even NASA can't prevent lightning from striking everything.
Its only going to be on a 5 ft mast, and yea, I suppose I'll have to ground it too! Also, there's no trees or power lines close enough to fall on it.
 
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Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#4
Pogi,

What kind of support are you planning to use to hold your mast? If you have a chimney (assuming it is in good condition) Radio Shack has a mount for masts that uses stainless steel strapping that goes around the chimney and they hold an antenna mast very solidly. I'll add a photo of a setup I did last summer using a chimney mount to this thread, later ...

* Here it is:


This photo was taken during the initial setup, before guy wires were added below the VHF high-band Yagi.

In my situation, I use wall brackets with lag screws on the siding of the house for two different masts, one with two sections of 10' tubing and the other is a 30' telescopic mast. These require guy wires. I'm not particularly fond of tripod mounts that are screwed thru the roofing material do to potential water leaks.

I have trees all around me and I haven't had any problems with reception even in major windstorms. I can't speak to the icing question because we had a very mild winter, but in years past with VHF and heavy snow and ice, we had no problems, except twice my antenna rotor 'froze' until the weather moderated. I realize regarding icing, my past Analog VHF experience is not a very good comparison to UHF and Digital.

Regarding a shortened lifespan, until the Digital change took place, the last time I worked on the VHF and UHF antenna array on my 40' (at the time) mast was when I installed them in 1985. When I took them down last summer everything was in reasonably good condition. Some of the 'U' bolts were very rusty and the rivets holding the elements on my VHF antenna were weakened via electrolysis to the extent I was able to remove all the elements by hand! It literally disassembled itself.

The reason the works stayed up and functional was my liberal use of RTV (room temperature vulcanizing silicone rubber) on all the threads and coax connectors, Scotch electrical tape (not a cheap off-name brand) to hold the coax to the masts as well as proper guy wires. Usually, I prefer to use tape rather than zip-ties on coax because the ties tend to crush the coax. I hope this helps!

Jim

PS Thanks for the assist posting the photo, n2rj
 
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n2rj

Moderator
Staff member
#5
Agreed with all Jim has to say.

If the antenna is properly secured, it will not come down in most wind situations nor will reception be affected.

But by code even commercial towers are in many cases only required to withstand 70mph. Beyond that you're probably going to lose a lot more than your antenna so I wouldn't be too worried.
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#6
Pogi,

One thing I forgot to write, is you really should ground your mast to a grounding rod or a cold water pipe for protection from lightning.

Jim
 

n2rj

Moderator
Staff member
#7
I would recommend a cold water pipe only if you can verify that it is metal below ground. These days with so much PVC and PEX out there it is hard to tell.

An 8 foot copper clad spike is probably best.

Also remember the NEC requires all grounds be bonded to the house service ground. Potential difference between grounds is a bad thing. That's called a ground loop and guess where lightning will travel to get from one ground point to another... that's right, through your equipment!

Article 810 - Radio and Television Equipment
 

MrPogi

Moderator, , Webmaster of Cache Free TV
Staff member
#8
Thanks

I was planning to use a ground rod... There's just too much plastic in my house to take chances. Where my pipe enters the building its metal, then all pex and PVC.
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#9
I would recommend a cold water pipe only if you can verify that it is metal below ground. These days with so much PVC and PEX out there it is hard to tell.

An 8 foot copper clad spike is probably best.

Also remember the NEC requires all grounds be bonded to the house service ground. Potential difference between grounds is a bad thing. That's called a ground loop and guess where lightning will travel to get from one ground point to another... that's right, through your equipment!

Article 810 - Radio and Television Equipment
n2rj,

Thanks for the reminder: I always forget about 'modern' plastic piping and three-wire AC. My house was built in during The Great Depression with iron and steel pipes and about half of it still has knob and tube two-wire AC. No doubt, somewhere there's lead based paint under latex, too.

Jim
 

Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#10
re: Ground Loops

Potential difference between grounds is a bad thing. That's called a ground loop and guess where lightning will travel to get from one ground point to another... that's right, through your equipment!

Article 810 - Radio and Television Equipment
n2rj,

You are the only one in some time that has referred to Ground Loops and I have some knowledge about them having personally experienced problems between a turntable, a real-to-real tape deck, a tuner and an amplifier many years ago. Using what I learned, I have 'come to the rescue' of many others with "bizarre" componant audio problems. hmmmmmmmmmmmmmmmmmmmmmmmmmm

My question to you: I currently have three different antenna masts in the air and in my case (per an earlier post) all three are grounded to a common cold water pipe that runs hundreds of feet (horizontally) underground.

However ... what if someone has multiple antenna masts and they chose to drive seperate grounding rods into the Earth for each one ... wouldn't they tend to offer different levels of 'earthing' and potentially create Ground Loops? My thought is to ground or 'earth' everything to the same place. What say you?

Thanks in advance,

Jim
 
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#11
My question; I currently have three different antenna masts in the air and in my case (per an earlier post) all three are grounded to a common cold water pipe that runs hundreds of feet (horizontally) underground.

However ... what if someone has multiple antenna masts and they chose to drive seperate grounding rods into the Earth for each one ... wouldn't they tend to offer different levels of 'earthing' and potentially create Ground Loops? My thought is to ground or 'earth' everything to the same place. What say you?

Thanks in advance,

Jim
I agree.

There are two ways that a ground loop can hurt you.

A ground loop in an antenna installation can cause lightning surges to travel through your equipment. The solution is to ground all antennas at the same point, and connect them to the power ground directly from that point. This technique is often referred to as a STAR ground.

A ground loop in a power system occurs when the ground wire and neutral wires are connected in more than one location. This causes neutral current to flow in the ground wire which creates a small voltage offset between equipment that is plugged into different circuits. The current tries to balance itself by flowing through the audio and video cables. That is the source of the hmmmmmm. This tends to happen in homes or businesses with multiple power panels. The sub-panels must have the neutral isolated from the ground with a special insulated neutral buss. It can also happen with a short in romex or a mis-wired 220 volt appliance.
 
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Fringe Reception

Super Moderator, Chief Content Editor
Staff member
#12
Tower Guy,

You are verifying my (until recently, completely forgotton) 'suspicions' from 40 years ago when I had 10, 15 and 40 meter band long-wire antennas in the air ... BUT ... I didn't use a common grounding (earthing) at the time and I had no clue why there was an AC potential between them (I could feel it when I touched any of the antennas).

So: since I currently have a TV antenna mast (literally) in my back yard facing west to receive 9 channels (including subs) ... BUT ... my main mast is about 60 feet away on the north end of my home (my test mast is adjacent to it) I suspect ALL THREE of them should be grounded at exactly the same spot. That way, there should be no 'voltage' potential between them and no "LOOP" issues. True?

Thanks in advance,

Jim
 
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FOX TV

Contributor
#13
I will be putting the antenna on the roof soon (now in the attic) and I have a few questions for those whoe antennas are outside-

Do you have problems with reception in high winds?

Or if your antenna ices over?

Other than the obvious problem of shortned lifespan for the outdoor components, is there any other problems with outdoor / rooftop mounting?

Thanks.
High winds can cause problems, so mount it as rigid as possible (rigid mounting can help with ice issues too). I have never lost signal due to antenna icing, but I have had antenna damage due to ice. Be sure to seal all coax connections, and please follow the National Electrical Code on proper grounding. A coaxial cable grounding block is not adequate protection, as all it does is ground the shielded outer braid and has no ability to re-direct a lightning strike to ground for the center conductor.

For that purpose you will need some type of antenna discharge unit, and the best ones use a plasma gas which becomes conductive in the presence of high voltage, and directs any voltage seen on the center conductor to ground. You also need a separate grounding conductor for the mast itself, which may be tied back into the electrical panel ground, or can be run to a separate ground rod.

Proper grounding techniques are rarely discussed on here, and it is an important issue that almost everyone overlooks. The cost of properly grounding an antenna is much less than the replacement of an expensive HDTV.

And yes, I do eat Meat !! Burgers, steak, sausage, bacon, Pork Chops (Sorry Piggie), chicken.....It's all good !
 
#14
I suspect ALL THREE of them should be grounded at exactly the same spot. That way, there should be no 'voltage' potential between them and no "LOOP" issues. True?

Thanks in advance,

Jim
Yes, that's right.

Also 40 years ago a typical receiver or transmitter had a two prong plug and a pair of bypass capacitors from each side of the power wires to ground. This created a 60 volt potential (at very low current) on the chassis of the equipment. You had the ground the equipment yourself using the wing nut ground on the back of the transmitter.
 

FOX TV

Contributor
#15
Outdoor antenna mounting tips

I will be putting the antenna on the roof soon (now in the attic) and I have a few questions for those whoe antennas are outside-

Do you have problems with reception in high winds?

Or if your antenna ices over?

Other than the obvious problem of shortned lifespan for the outdoor components, is there any other problems with outdoor / rooftop mounting?

Thanks.
High winds can cause problems with antennas that are not mounted rigid enough to have excess movement in high winds. Rigid mounting can also prevent ice damage to some extent. icing of a receive antenna will not normally cause issues unless the ice physically damages the antenna, and I have never lost a signal due to icing of the antenna itself.

Exhaust from heating sources can cause premature aging of the metals, ( Usually Aluminum) that the antenna is made from. Oil heat exhaust is very bad for aluminum antennas, and can eat away at the aluminum, but it takes many years to do so.

Proper antenna grounding is a big issue that no one on here seems to mention very often, but it is an extremely important issue that needs more attention paid to it when advising people on outdoor antenna installations. If someone needs the help of this forum to receive DTV signals, then it is a high probability that they do not know the first thing about proper antenna grounding techniques and its importance.

A coaxial grounding block IS NOT ADEQUATE PROTECTION from voltage spikes or surges. All this device does is ground the outer braid or shield of the coax, but does nothing to protect the center conductor of the coax from voltage spikes due to lightning surges. The only real way to protect the equipment hooked to this antenna from lightning damage is to disconnect it when you are away or during a storm.

Grounding the lead-in antenna cables and the support mast pole helps prevent voltage surges caused by static discharge from nearby lightning strikes from reaching the center conductor of the coaxial cable. Nothing can prevent damage from a direct lightning strike, but grounding with proper surge protection can help reduce damage to HDTV, and FM receivers / tuners from nearby lightning strikes.

A common grounding point is recommended to avoid different grounding potentials, and the electrical service grounding system is the best choice. If using different grounding points for multiple antennas, it is possible to check the soil resistance with a Ground Megger. This device checks the conductivity of the soil by sending a relatively high voltage through the ground to two or more return ground rods, and it then calculates the resistance of the soil by the amount of return voltage the ground rods receive.

This device is used by electrical utility and radio / TV tower installation teams to find the specific resistance of the soil, and 10 ohms is normally the number used by the electrical industry, and that provides the best path to ground for the electrical industry. The lower the soil resistance, the better your ground system can reduce the potential for static or voltage surges caused by nearby lightning strikes.

See image attachment for a diagram of proper antenna grounding, and the antenna discharge unit is the MOST IMPORTANT item in the diagram.
 

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