Topband: Aluminium roof vs antenna performance

[Jim Bennett]

Rik -

Last year we replaced the 20+ year old roof on our house. It was made of treated cedar "shake boards", with simple tar paper and plywood underneath. My antennas consist of (1) 26.8 meter long doublet fed with 450 ohm ladder line, (2) 80 meter Inverted L, (3) 160 meter Inverted L, (4) 5/4 wave 2 meter vertical. 

The choice we had was to go with either concrete tiles or powder coated steel from Gerard . At first I was hesitant to do this, but the dollar difference made the decision for us - we had the powder coated steel installed. From what I can tell, it made almost zero difference in the performance of my antennas. Perhaps if I were to take the time (and a long time it would be) to model it in EZNEC, I might see a change in radiation pattern. However, I am still able to work the same amount of DX and stateside station as before. In addition, my antenna tuner apparently did not have to "re-learn" settings for that doublet. My suggestion is to go with whatever is best for you, either in cost or insulating efficiency.

Jim / W6JHB

p.s. - the roof we had installed looks exactly like the one here: http://www.gerardusa.com/steel-metal-roofing/products/barrel-vault


On   Friday, Oct 18, 2013, at  Friday, 9:26 AM, Riccardo Negro wrote:

> Hi all,
> tomorrow I must decide which type of insulating system to be used under the
> tiles of my new roof. Roof's structure is classic wooden and total surface
> is 220 square meters.
> Since there will be several antennas for 80 / 160 sorrounding the house I
> am wondering if using insulating panels (polystyrene) covered with a foil
> of ALUMINIUM (to reflect heath) could become a nightmare for antenna
> resonance, pattern, etc.
> The point is: better to have or not to have a roof with aluminium under the
> tiles ?
> Many thanks for your kind advice !
> 73 de Rik, IK2CAW
> _________________
> Topband Reflector