Mobile (Roofmount) Antennaes - Safe Distances

[KQ4AHE]

Thanks to your previous suggestions I purchased (from Antenna Farm & HRO) a roof mount and dual-band antenna (both Larsen) for the Yaesu FT-7900 I have the use of. I thought by buying a roof mount I could use it in the car and inside the house. I was reading the Yaesu manual and they mention the importance of not being too close to the antenna when transmitting. The roof mount has a 12 foot lead. When inside the house I have it setting on a 16" aluminum baking pan for a ground plane. I'm wondering if you're setting about 8' to 12' away, from the antenna, which is at table top height, when transmitting if that's considered ok? I believe this Yaesu has 50W at 144MHz and 45W at 430MHz at high power. The antenna is rated at 200W if that's a factor. Thanks in advance for any help or opinions on this matter or for pointing out any concerns I'm not knowledgeable enough to consider.
Regards,
George

 

[mmckenna]

RF Exposure Calculator

The American Radio Relay League (ARRL) is the national association for amateur radio, connecting hams around the U.S. with news, information and resources.

www.arrl.org

Using that calculator and the specs for a Larsen NMO-2/70, you'd need about 4.6 feet separation between a person and the antenna if running 50 watts on the 2 meter band. You'll need about 4.25 feet on the 70 centimeter band at 45 watts.
In a vehicle, you are a bit safer because you have the roof between you and the antenna. If you have it mounted on the trunk, you need to consider exposure to passengers sitting back there.

 

[KQ4AHE]

Thank you! I wasn't yet aware of that calculator and appreciate the link to it. Very useful! There's a lot to this antenna business as I'm finding out. Very perplexing. Still boggles my mind how a "field" can generate an electromagnetic wave. Thanks again for the reply!

 

[tunnelmot]

If you have it mounted on the trunk, you need to consider exposure to passengers sitting back there.

Memphis PD used to mount quarter waves INSIDE on the rear window package tray with the 6" uhf spike poking through the carpet. On what I'm sure was full power Syntors.