W9mbt ham member qrz page.
Ham radio attic antenna safety.
Thanks w9mbt feb 29 2012 3.
First is safety with less than 100 watts what do i need to know about health and fire hazard.
Yes there are high voltages at the ends of the antenna but there is very little current and it would have trouble creating a spark on all but the smallest gap.
Most amateur radio clubs in chicago area that hold training classes for new amateur radio operators.
I ve read some of the hf 10m homebrew constructions and they seem do able for me but.
Attic antennas can be significantly affected by attic wiring and hvac ducting.
It has been known since the early days of radio that rf energy can cause injuries by heating body tissue.
Lots of amateurs in these situations are doing so successfully especially on hf.
Discussion in general technical questions and answers started by w9mbt feb 29 2012.
Yes in the attic.
In extreme cases rf induced heating can cause blindness sterility and other serious health problems.
Again stay away from metal and wires to maintain your pattern.
Have 2 story home with ample attic above for antenna or can put antenna against house and not extending above roof.
Distance gain and duty cycle are the three factors to consider when installing and safely operating an antenna system be it outdoors or in your attic.
Safety of indoor antennas.
Many hams including many of you reading this are limited by hoa or other outdoor antenna restrictions.
Also the height of attic antennas is usually lower than optimum.
If you are mounting the antenna in your attic you d need about 7 10 feet of space between the antenna and the occupants in the house.
A second advantage to mounting the antenna in the attic is that you will be protected from lightning strikes in the event of severe weather.
With time bare copper oxidizes the wood where the wire is tightly stapled to absorbs some of this oxidization and forms a loose yet lossy bond with the wire.
Bare copper antenna wire stapled directly on wood rafters causes loss of rf signal energy.
This is great for the amateur radio operator that is providing net control activities during a skywarn severe weather activation.
Safety and rf exposure are important topics to consider.
On vhf a beam antenna can work well in the attic even a rotator can be used.
That s a good one.
Other than the safety rfi issues discussed here the other important point to remember is that an attic antenna particularly for hf is not in the clear like an outside antenna.
On hf wire beams can be run on the roof supports or the rafters these usually are good for one direction only but can be switched electrically for different coverage.
The house will act as a natural shield and as long as your attic mounted antenna system is independent to the rest of your antennas lightning won t be an issue.
But even if you can t put up an outdoor antenna you can still operate with antennas installed in an accessible attic space.
These heat related health hazards are called thermal effects.
