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How to hang wire over asphalt roof?

338_MtRushmore

Sr. Member
Jun 17, 2012
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The Dakotas
I put radio on the back burner over the winter, mainly because I couldn't figure out how to run an endfed wire across the top of the roof. Looking to run about 50' along a ridge cap. I'd like to play with an amp also, preferably without burning my house down. Any ideas?
 
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Just lay it on top? Or find plumbing vents and use them as a stand-off with an insulator of some sort? You could use hose clamps and some black PVC for the standoff.
 
I often use the PVC vent pipes already sticking out of my roof to mount light antennas on.
Like this person did with their homebrew TV antenna.

Screenshot_20180812-215333_Chrome.jpg
 
If laying it in contact with the roof is an acceptable option, I have no problems with that. I dont have foil or metal up there, other than the eves, but crossing those perpendicular hopefully wont be an issue.
 
I read somewhere, i think the arrl handbook that high rf power can be a fire hazard if the antenna is in contact with a wood frame structure. ????, you Might wanna look into that
 
I know you can have 600+ volts at the end of a dipole @100 watts, and well over 6,000 volts at legal limit. I'm guessing most problems occur at the bare end of the antenna, but even then the voltage shouldn't be the highest at the end of a random length. It is decent quality wire so I'd guess there wouldn't be much problem if the insulation wasn't damaged at a high voltage section. I guess you just take your chances.
 
I read somewhere, i think the arrl handbook that high rf power can be a fire hazard if the antenna is in contact with a wood frame structure. ????, you Might wanna look into that
Ok i remember now, it was in the handbook, but it was talking about how you can load up your rain gutter on your house and use it as a loop antenna on 20m/40m. But to be safe, power levels need to be kept at 100w or less do to the chances of rf heating and starting a fire. I would think the same applies to an antenna touching the house as well
 
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I have a random length endfed wire antenna I run. The 9:1 transformer is mounted to my wood sided chimney. It goes from there out to a pushup pole and on ... the counterpoise just lays across the shingles. I run 100w maximum and the house don't burn down.
 
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I can't even find a voltage rating for any antenna specific wire that is being sold by reputable ham dealers. I'd think we would all be well aware if running legal power could cause arc through the insulation, but maybe not.

I guess I'm not certain if I should be worried or not, but I'm leaning strongly to not.
 
At what wattage would a guy need to start worrying? Thay is the question.
1kw thru insulated wire no problem. The issue is why have the antenna just draped over the roof when there are better options? Also i bet at even 100w your gonna have serious antenna tuning issues, reflect etc. Also your radiation pattern and angle are gonna be terrible. I urge you to explore the many different alternatives
 

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