Metal Roof and Wave Propagation... Will it Help or Hinder...? Yes or No...?

[BaoFeng_Blogger]

Hi All...

Am replacing my homes asphalt shingle roof. Have option of either the same (asphalt shingles), or a metal roof.

The front faces the entrance to our cul-de-sac @ 240* SW, having a "hip" roof at that end. The rear is @ 60* NE and has a "gable" roof.

Presently hold Tech, but will be taking Gen at beginning of year... and considering, I hope (expect?) to pass.

Will be using a dual-band VHF/UHF vertical as my base, seeing two VHF repeater towers (K4LKL/R and K4LKW/R) are about a dozen miles away... and NI4CE/R which is just a few miles from my house.

Haven't decided which antenna to get when I become a Gen., but of course... that depends, somewhat, on my roof situation.

So the question is... Am I better off with, or without, a metal roof when it comes to being a Ham?

Thanks to those who answered.

73...

BaoFeng Blogger KN4OTS

 

[popnokick]

Metal roofs make GREAT ground planes for VHF / UHF antennas... and for HF verticals! So if you are planning on mounting all your antennas on the roof.... preferably near the center of the largest masses of metal... you'll be in good shape. Indoor antennas you say? Fuhgeddabouit. Not gonna work with a metal roof. Oh... and don't plan any wire antennas near the metal roof... stick with verticals and mount them on the roof. If you are doing wire antennas they should be far away from large masses of metal (like a metal roof).

 

[JoshuaHufford]

Like how mine is mounted?

 

[k6cpo]

My first HF contact was made between San Diego, Ca and Florida on ten meters using a mag mount CB antenna placed on the roof of a metal storage shed. Yeah, metal roofs can help.

 

[BaoFeng_Blogger]

Thanks guys...

Boy oh boy, going to have fun...
Metal roof, here I come.

73 to ya...

BaoFeng Blogger KN4OTS

 

[DJ11DLN]

Not a Ham but back when I messed with CB my antenna was a quarter-wave whip mounted in the middle of the peak on a metal barn roof, about 35' up. I was constantly accused of running power, though I never did, talked all over the country and to several other countries on a stock SSB rig. That should tell you what I think of your idea! Have fun.

 

[prcguy]

For HF verticals a metal roof is the best thing possible. For VHF/UHF it may actually degrade performance slightly by pushing the signal upwards slightly above the horizon compared to the same antenna above a non conductive roof. I would compare this to the pattern of an HF vertical mounted to an "infinite ground plane" with the best low angle radiation vs mounting it some close but random height above ground like 3/4 wavelengths where it will push the pattern up above the horizon.

To make the best of the metal roof with a VHF/UHF antenna you may have to remove its ground radials and plant it down in the roof so the roof starts where the original radials did to make an infinite ground plane. I also think any little improvement you might get from this might be easily out done by raising the VHF/UHF antenna up higher on a non conductive roof.

A quick check with an antenna analyzer program will tell you more about this. If you choose to put up a horizontal wire HF antenna in the future I think the metal roof will cause more complications.

 

[KK4JUG]

Besides a better quality radio signal, the metal roof will last longer and if you have trees over the house, it will provide better protection. Definitely, metal over asphalt shingles. It'll pay for itself over the years.

 

[Spec]

I have what is called "TECHSHEILD" roofing. It is standard plywood with a coating of aluminum on the inside portion. After I erected my vhf/uhf vertical it increased my range in certain directions depending on height. My ant is on a mast next to the house. Simplex range is approx. 200 miles to the west and 75 to the east.

 

[captainmax1]

Go with the metal roof for strength and endurance. Will enhance outdoor antenna's but will kill any reception in your home. No indoor scanning and bad cell phone reception with the metal roof. I changed from shingles to a metal roof 2 years ago.

 

[RFI-EMI-GUY]

Metal roof. Not only better life, you will shield the noise generated in the house from getting to the antenna. I would also ground the roof using stainlees or bronze clamps (depending on materials). Put wire antennas away from, higher than and perpendicular to the house.

 

[JoshuaHufford]

For HF verticals a metal roof is the best thing possible. For VHF/UHF it may actually degrade performance slightly by pushing the signal upwards slightly above the horizon compared to the same antenna above a non conductive roof. I would compare this to the pattern of an HF vertical mounted to an "infinite ground plane" with the best low angle radiation vs mounting it some close but random height above ground like 3/4 wavelengths where it will push the pattern up above the horizon.

To make the best of the metal roof with a VHF/UHF antenna you may have to remove its ground radials and plant it down in the roof so the roof starts where the original radials did to make an infinite ground plane. I also think any little improvement you might get from this might be easily out done by raising the VHF/UHF antenna up higher on a non conductive roof.

A quick check with an antenna analyzer program will tell you more about this. If you choose to put up a horizontal wire HF antenna in the future I think the metal roof will cause more complications.

How high would you suggest raising the antenna above the roof?

 

[prcguy]

At least several wavelengths and the higher the better is a general rule for VHF/UHF. I would consider a VHF/UHF antenna over a huge metal roof ground plane similar to an HF antenna over earth ground. When its lower than a few wavelengths and at multiples of 1/4 wavelength like 1/4, 3/4, etc, the pattern of a vertical antenna can be pushed upward and away from the horizon a bit, lowering its gain at the horizon. The problem diminishes as you get higher and its got the least impact at 1/2 wavelengths above ground like 1/2, 1, 1 1/2, etc.

Usually a VHF/UHF antenna is on a mast or non metallic roof many wavelengths off the ground and there is no real problem of ground influence. Get the VHF/UHF antenna at least 15-20ft (about 3 wavelengths) above or away from the metal roof and I would not expect any problems.

How high would you suggest raising the antenna above the roof?