Rooftop masts

[Napalm]

Hey gang.

I have my antennas in the attic space of my two storey typical American wood construction.

It's a newer (2018) house but there's no metal backed insulation in the roof space.

I'm itching to get them out of the attic and into free space. I don't fancy bolting them to the eaves, so would a roof top tripod work? Or maybe a couple?

I have a discone, a DPD Omni X (mil) and a 300MHz dipole. As with most places in the Midwest we do get frequent lightning which concerns me. I'm gone for 10 hours of the day and I have to sleep at some.point. Disconnecting antennas when it storms isn't practical.

I thought about a freestanding mast/tower next to the house but my house is already 30/40ft high so I'd be wasting money imho.

Any thoughts?

Dave

 

[mmckenna]

I have a discone, a DPD Omni X (mil) and a 300MHz dipole. As with most places in the Midwest we do get frequent lightning which concerns me. I'm gone for 10 hours of the day and I have to sleep at some.point. Disconnecting antennas when it storms isn't practical.

A wooden roof doesn't magically stop lightning. Lightning can still hit your antennas, even in the attic.
And a direct strike should not be your only concern. Nearby strikes can induce enough energy into your antenna or feedline to do damage.

I'm itching to get them out of the attic and into free space. I don't fancy bolting them to the eaves, so would a roof top tripod work? Or maybe a couple?

A long time ago I had a neighbor that had two tripods at either end of his roof with a 10 foot mast on each one. Should work just fine if that's what you want.

Proper grounding should be done either way.

 

[Napalm]

A wooden roof doesn't magically stop lightning. Lightning can still hit your antennas, even in the attic.
And a direct strike should not be your only concern. Nearby strikes can induce enough energy into your antenna or feedline to do damage.



A long time ago I had a neighbor that had two tripods at either end of his roof with a 10 foot mast on each one. Should work just fine if that's what you want.

Proper grounding should be done either way.

Yeah I understand about the induced currents. My radio room is on the second floor so grounding would involve a 20ft ground strap to a real ground.

Aside from relocating to the basement, what can I do?

 

[mmckenna]

Aside from relocating to the basement, what can I do?

You answered that yourself:

My radio room is on the second floor so grounding would involve a 20ft ground strap to a real ground.

If you put masts/antennas on the roof, you still need to ground those. That'll be some copper coming down to your ground rod.

 

[Napalm]

Revisiting this thread.

Commercial installations (cell phone, LMR, Public safety etc) obviously take direct strikes and are okay.

Is that even feasible for the home user?

 

[mmckenna]

Revisiting this thread.

Commercial installations (cell phone, LMR, Public safety etc) obviously take direct strikes and are okay.

Not always, but well designed sites can absolutely take hits and stay on the air.

Is that even feasible for the home user?

Budget is usually the challenge. If you look at documents like Motorola R56, and follow that, a hobbyist might do OK. But rarely do they want to put much money into properly grounding things. Homes just are not set up for that.

There's a lot of people that do absolutely zero grounding and survive. But confusing luck with skill is usually a bad thing. As I said above, a roof does not magically stop that much energy. Neither does wrapping things in layers of electrical tape.

 

[Napalm]

Not always, but well designed sites can absolutely take hits and stay on the air.



Budget is usually the challenge. If you look at documents like Motorola R56, and follow that, a hobbyist might do OK. But rarely do they want to put much money into properly grounding things. Homes just are not set up for that.

There's a lot of people that do absolutely zero grounding and survive. But confusing luck with skill is usually a bad thing. As I said above, a roof does not magically stop that much energy. Neither does wrapping things in layers of electrical tape.

I get it... I do. The chances of a direct strike with the antennas in the air are obviously higher. I don't want a lightning strike to fry my radios LOL.

I'm gone for 10 + hours a day and can't always be here to unplug radios when it storms. *shrug*. Just at a loss as to what to do.

 

[paulears]

People are correct, its about money. Im in the UK, so nobody cares about lightning, but do you folks not have insurance for this kind of thing? If the price of copper in the US is similar to here, you could be better off buying normal radios, and taking the risk of them dying, and not buy a mega expensive flashy one. Then take the chance?

 

[FKimble]

Another little problem with roof mounted antennas without proper grounding is the lightning may decide to set the house on fire!

Frank

 

[Napalm]

People are correct, its about money. Im in the UK, so nobody cares about lightning, but do you folks not have insurance for this kind of thing? If the price of copper in the US is similar to here, you could be better off buying normal radios, and taking the risk of them dying, and not buy a mega expensive flashy one. Then take the chance?

I buy expensive flashy radios because I want to enjoy my hobby and I work hard for my money LOL. I haven't looked into house insurance but I still would rather try to mitigate it.

Lightning is just as prevalent in the UK as it is here - I'm a british Ex Pat who moved in 2011.

 

[paulears]

Yes, perhaps, but few people here take any precautions on their antennas. Its just not a ‘thing’ here. Indeed we now have electrical regs that make grounding things within a home rather tricky to do. We have equipotential zones, and a thumpingly chunky copper bond to ground might well be a big problem. Grounded antenna, grounded radio, big spark when you attach the antenna, and possibly quite a bit of current flow. Even a garden shed power supply can be trouble for us Brits now.

 

[Napalm]

Yes, perhaps, but few people here take any precautions on their antennas. Its just not a ‘thing’ here. Indeed we now have electrical regs that make grounding things within a home rather tricky to do. We have equipotential zones, and a thumpingly chunky copper bond to ground might well be a big problem. Grounded antenna, grounded radio, big spark when you attach the antenna, and possibly quite a bit of current flow. Even a garden shed power supply can be trouble for us Brits now.

Geez. And I know for hams there's EM calculations you have to do and submit to OFCOM?

Anyway - I don't want to risk throwing copper in the sky and frying my radios but a direct strike seems really expensive to protect against. I guess I'll just do my best to prevent transients and other static charges building up and make sure my radios are on the home insurance.

 

[paulears]

OFCOM are very proactive on EMF exposure, and all hams were given a calculator to assess their risk. At the low power levels, 99% were safe. THEN this year everyone got an increase in allowable power? Odd!