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Posted by: K5OX Posted On: 12/27/01 Subject: Re: antennas Message Posted: In Reply to: antennas posted by kg4pai on 10/28/01 It really depends on several factors. If the antenna is short and loaded then large tubing would increase efficiency -- example a base loaded vertical with counterpoise radials. If you have space for the dipole #22 insulated hookup wire will work fine but larger #14/12 electrical wire as mentioned already will be easier to match requiring less critical trimming and more broadband. If you are running high power, be careful with arcs at ends of antenna -- the voltage (RF) can get high and in extremely rare cases start a fire. But I would not worry -- just keep the ends away from anything that could conceivably conduct and start some arcing. Also as crazy as it seems -- use the usual lightning protection. I've had my TV antenna take a stay hit after a nearby tree was hit by lightning and lost everything plugged in the house. Depending on how your house is made the roof may not be all that high -- my one story Texas slab house is only 14 feet at the roof ridge. Although temporary I'm using a 20 meter dipole with #22 green hookup wire using tie wraps for insulators and aligator clips to change from 20 to 10 meters along the back eaves of the house. Running 5 watts QRP and do excellent on 10 with DX -- so so on 20 becuase height is only 9 feet high. Another warning from practical experience. My Texas house has all power wiring in the attic. It is a RFI/TVI nightmare 'cuz the antenna just a few feet from the power wiring. Running 100 watts not practical -- even trip mine and neighbors GFI breakers. QRP no problem. Over about 25 watts -- trouble. I would really suggest you consider small "invisible wire" right angles to the house. I live in a restricted neighborhood and if it is not obvious from the front of the house, chances are no-one will notice it. Now that Satellite Dishes are premitted under reasonable acommodations mandate by the FCC, the no antenna neighborhood attitude has eased just a little. Just don't make it easy to see from the front of the house assuming you are in a single family dwelling. Maybe I'm anti attic cuz I just find it hard to work up there. Good luck, Frank |
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