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Technical Topics => Equipment => Topic started by: flexoman61 on October 09, 2015, 1616 UTC

Title: Dipole on rooftop, SNOW?
Post by: flexoman61 on October 09, 2015, 1616 UTC

This weekend I was planning on putting up a dipole antenna laying flat on my rooftop. One thing I almost forgot to consider
is the snow cover and how it will affect the antenna performance. I'm thinking it will completely screw it up since the snow
must be somewhat conductive.

I think I will wait for replies on this before I go ahead with installation.

Thanks

Title: Re: Dipole on rooftop, SNOW?
Post by: ChrisSmolinski on October 14, 2015, 1411 UTC

That's an excellent question!

My first guess was to assume that it would cause a lot of attenuation. I looked around for data on attenuation of HF signals due to snow/ice, and could not really find much.  The closest thing I could find was this paper about attenuation of VHF signals through the Ross Ice Shelf in Antarctica: http://arxiv.org/pdf/1011.0477v3.pdf

If I am interpreting the results correctly, VHF signals were able to get through several hundred meters of solid ice, and there was less attenuation at lower frequencies. If so, a few inches of snow may not really be an issue for shortwave signals. 

Title: Re: Dipole on rooftop, SNOW?
Post by: John Poet on October 29, 2015, 2129 UTC

Just make sure to use insulated wire and it shouldn't make much difference in receiving.

If you were to transmit with it, the presence of snow or even rain would change the SWR somewhat, but usually not seriously.