Gable mounted mast for dual band antenna install

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LCRay

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I am planning on installing bracket and mast at the gable end of the house.
Will be attaching a vertical antenna for VHF/UHF

Question is :

Any suggestions as to mounting systems that have worked well for any of you people?
Also any brands to beware of?
Thanks for any suggestions or comments
 

N4GIX

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jim202

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I am planning on installing bracket and mast at the gable end of the house.
Will be attaching a vertical antenna for VHF/UHF

Question is :

Any suggestions as to mounting systems that have worked well for any of you people?
Also any brands to beware of?
Thanks for any suggestions or comments
This has been stated many times on here, but will bring it up again.

Grounding of the antenna mast is a must. To do it correctly, you will need to follow the NEC (National Electrical Code) and maybe contact your home owner's insurance company to get their feedback. Done incorrectly could put you in a position of the insurance company turning down any claim for damages caused by lightning.

No sharp bends in the down wire from the mast to the ground rod. Wire should be at least a number 2 in size. Anything smaller and you can consider it a fuse. Make sure the down wire doesn't come in contact with any other metallic object on the path from the roof to the ground rod. Do not use any metal clips in trying to keep it close and neat to the house. Metal clips act as a choke and lightning doesn't like any restrictions.

The simple guide to follow is to run a good sized ground wire connected to the mast down to earth where you have at least an 8 foot ground rod. Your soil conditions will dictate if it needs to be longer and if multiple ground rods will be needed. Do not place the multiple ground rods near each other if you have to go that route. Space them at least twice their length apart. This takes into account the "cone of influence" around each ground rod. Spacing them closer causes this cone of influence to be overlapped and you loose the full benefit the 2 ground rods will provide.

Do not use the standard water pile clamp on the ground rods. Use the correct ground rod grounding clamp. This is a bronze unit that slips over the rod and has a bolt on the outer edge to tighten the ground wire to the rod.

Ideally your looking for a 5 Ohm resistance to ground or less for your grounding system. Problem is this can only be measured with a low resistance meter designed for this purpose. Normally it takes at least a 3 point measurement system to come up with the measurement. Not all electricians even have this meter.

Use of one of the clamp on meters to measure the resistance will also not work. You don't have a complete circuit to another grounded point to use it with.

Some people will also tell you to connect your ground to the electrical meter ground. I have some reservation on doing this as many of the municipality electrical inspectors don't fully understand section 850 of the NEC. In there, there is a section for communication facilities that allow the ground connection to be bonded to the electrical meter ground rod to provide a common bond between multiple ground systems.

Good luck with your install.
 
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LCRay

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Messages
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LCRay

Member
Joined
Sep 8, 2013
Messages
34
This has been stated many times on here, but will bring it up again.

Grounding of the antenna mast is a must. To do it correctly, you will need to follow the NEC (National Electrical Code) and maybe contact your home owner's insurance company to get their feedback. Done incorrectly could put you in a position of the insurance company turning down any claim for damages caused by lightning.

No sharp bends in the down wire from the mast to the ground rod. Wire should be at least a number 2 in size. Anything smaller and you can consider it a fuse. Make sure the down wire doesn't come in contact with any other metallic object on the path from the roof to the ground rod. Do not use any metal clips in trying to keep it close and neat to the house. Metal clips act as a choke and lightning doesn't like any restrictions.

The simple guide to follow is to run a good sized ground wire connected to the mast down to earth where you have at least an 8 foot ground rod. Your soil conditions will dictate if it needs to be longer and if multiple ground rods will be needed. Do not place the multiple ground rods near each other if you have to go that route. Space them at least twice their length apart. This takes into account the "cone of influence" around each ground rod. Spacing them closer causes this cone of influence to be overlapped and you loose the full benefit the 2 ground rods will provide.

Do not use the standard water pile clamp on the ground rods. Use the correct ground rod grounding clamp. This is a bronze unit that slips over the rod and has a bolt on the outer edge to tighten the ground wire to the rod.

Ideally your looking for a 5 Ohm resistance to ground or less for your grounding system. Problem is this can only be measured with a low resistance meter designed for this purpose. Normally it takes at least a 3 point measurement system to come up with the measurement. Not all electricians even have this meter.

Use of one of the clamp on meters to measure the resistance will also not work. You don't have a complete circuit to another grounded point to use it with.

Some people will also tell you to connect your ground to the electrical meter ground. I have some reservation on doing this as many of the municipality electrical inspectors don't fully understand section 850 of the NEC. In there, there is a section for communication facilities that allow the ground connection to be bonded to the electrical meter ground rod to provide a common bond between multiple ground systems.

Good luck with your install.
No problem, I'm glad you posted this reminder.
As a Safety Professional, earth grounding can't be repeated enough.
Thanks
73
 

prcguy

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For VHF/UHF antennas up to maybe the Comet GP-6 size, a J mast from an old satellite dish works fine. The newer Directv masts are 2" dia and have a very large mounting foot that you can get at least 5 lag bolts in.

Its nice if you have enough flat solid wood on the gable or eaves and you can mount the foot there. Or you can do what the satellite antenna installers do and mount to your roof overhang (this avoids leaks into the house) and make sure some lag bolts go into a rafter.

Ground to NEC as mentioned, but that does not include the discussion of a 5 ohm or less ground potential or using #2 wire, etc. NEC states minimum #10 copper wire for the grounding of an antenna to your house electrical entry box. NEC is concerned with human safety and not necessarily lightning protection, which is way beyond what most people can do to their home. Mountain top repeater sites and cell sites are designed from the ground up to withstand direct lightning hits and to retrofit a residential home to do the same would be wishful thinking at best. Disconnecting your antennas and unplugging your radio when lightning is a approaching is a better way to protect your radios.

Also, insurance companies are not concerned with your antenna grounding and probably don't employ anyone that is up on electrical grounding. Unless your policy specifically states in writing they will not cover damage from a lightning strike because of inadequate antenna grounding, then it falls under the blanket terms and limits for your policy. My wifee managed a large home insurance company overseeing about 20 states and has never heard of antenna grounding mentioned in a lightning claim.
prcguy
 
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LCRay

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For VHF/UHF antennas up to maybe the Comet GP-6 size, a J mast from an old satellite dish works fine. The newer Directv masts are 2" dia and have a very large mounting foot that you can get at least 5 lag bolts in.

Its nice if you have enough flat solid wood on the gable or eaves and you can mount the foot there. Or you can do what the satellite antenna installers do and mount to your roof overhang (this avoids leaks into the house) and make sure some lag bolts go into a rafter.

Ground to NEC as mentioned, but that does not include the discussion of a 5 ohm or less ground potential or using #2 wire, etc. NEC states minimum #10 copper wire for the grounding of an antenna to your house electrical entry box. NEC is concerned with human safety and not necessarily lightning protection, which is way beyond what most people can do to their home. Mountain top repeater sites and cell sites are designed from the ground up to withstand direct lightning hits and to retrofit a residential home to do the same would be wishful thinking at best. Disconnecting your antennas and unplugging your radio when lightning is a approaching is a better way to protect your radios.
prcguy
Thanks prcguy
So, just to clarify, as now I am a little confused, and I tried to read between the lines.
I am looking at the Comet GP-3 (approx. 6 feet, fiberglass Wt. 2lbs, 9ozs.) attached on a roof gable mount.
How would you treat the electrical ground/ earth ground install?
 

prcguy

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Here is a typical 2" dia satellite dish J mast, but they can be had for almost free if you look around: DIRECTV Satellite Dish 2" OD Mast Mount J-PIPE ANTENNA FOOT Roof Porch Balcony | eBay They are plenty strong enough for the GP-3 antenna you are considering. Brackets by Winegard posted by others would work fine also.

For grounding you should follow the National Electrical Code at the very least and if you want to supplement it with additional stuff then that's up to you. Just be aware you will probably never be able to withstand a direct lightning hit to your antenna and have no damage to your radio or much of the electronic items plugged in at your house.

Here is one of many NEC instructional sites that concentrate on Article 810 of the code which deals with antenna grounding: https://www.seapac.org/documents/seminars/2013/2013-Kuhlman-Applying the NEC to Amateur Radio.pdf
prcguy



Thanks prcguy
So, just to clarify, as now I am a little confused, and I tried to read between the lines.
I am looking at the Comet GP-3 (approx. 6 feet, fiberglass Wt. 2lbs, 9ozs.) attached on a roof gable mount.
How would you treat the electrical ground/ earth ground install?
 

LCRay

Member
Joined
Sep 8, 2013
Messages
34
Here is a typical 2" dia satellite dish J mast, but they can be had for almost free if you look around: DIRECTV Satellite Dish 2" OD Mast Mount J-PIPE ANTENNA FOOT Roof Porch Balcony | eBay They are plenty strong enough for the GP-3 antenna you are considering. Brackets by Winegard posted by others would work fine also.

For grounding you should follow the National Electrical Code at the very least and if you want to supplement it with additional stuff then that's up to you. Just be aware you will probably never be able to withstand a direct lightning hit to your antenna and have no damage to your radio or much of the electronic items plugged in at your house.

Here is one of many NEC instructional sites that concentrate on Article 810 of the code which deals with antenna grounding: https://www.seapac.org/documents/seminars/2013/2013-Kuhlman-Applying the NEC to Amateur Radio.pdf
prcguy
Thanks
Good grief ! Read the attached regs.
Got to wonder how many installations are actually to NEC code
 
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lmrtek

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the fiberglass antennas are easily destroyed by lightning and tend to get hit more often than grounded aluminum antennas due to static building up on the fiberglass suddenly discharging upwards to complete the lightning path

and since it will be the highest object, it will be the thing to be hit so grounding it as if it were a lightning rod is imperitive because someday it will be

the only difference is that lightning rods can survive many direct strikes

the diamond antenna will be vaporized after ONE
 
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cmdrwill

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I am going to have to agree with MOTEX, most hammy grade fiberglass antennas are piss poor designs with a small gauge steel wire inside.
 
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