On Mon, Jun 11, 2012 at 10:31 PM, Hal Murray <[email protected]> wrote: > > [email protected] said: >> But you know what? If you simply place an automotive "puck" type GPS >> antenna on your roof you have to do the same thing. It must be grounded the >> same way, same lightening protection and so on. So in the end you may as >> well put up a professional looking and permanent steel mast. It is not >> that much more work. > > What about putting a skylight high on the roof and putting the antenna up in > it? > > What's magic about inside vs outside the roof/skylight envelope?
If the skylight is transparent to radio frequency then it might work. But many times low emisivity glass (tat means the modern energy savings type) has metallic coatings that attenuate radio signals. Also from inside the skylight can you see the horizon all around for 360 dregs. for that to happen the skylight must be taller than the peak of the roof. That would be an unusual skylight > > ----------- > > I have a large pine tree out front. It's roughly 3x the height of my (one > story) house. What are the chances of any lightning hitting my house rather > than the tree? A direct strick is not required. What if the lightening hit a power pole down the block? there would still be a huge electric field and the potential between the antenna and ground would be huge and there would be current. If the lightening hit the antenna there is nothing you can do, grounding will not help. What he prepared for is the much more likely chance of a nearby strike. Here is "The Book" http://members.rennlist.org/warren/LightningProtectionAndGrounding.pdf What if I put an antenna on the top of my house so the tree > is only 2x the height of my antenna? > > Of course, that depends on how far the tree is from my house. Not far. Call > it 45 degrees from the back of my house to the top of the tree. An antenna > on the top of my house would probably be below that sight line. > > Is there a good book or URL on lightning vs antennas? Again, I'm interested > in both the technical issues as well as the local zoning/legal issues. The local building code almost always reads "do what NEC says". In other words few cities will invest the time and $$$ to write their own code and will defer to the Nation Electric Code. Technically the most sites papers are all for universities in Florida. > > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
