antenna restrictians
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| Aug 20th 2011, 00:11 | |
N2BFD-2Total Topics: 0 Total Posts: 0 |
Does the local antenna restrictians impead amateurs in their emergency air ability because the amateurs cannot get experience in operating a HF station? Also, do these restrictians prevent people from becomming hams because they cannot get on the air? |
| Aug 22nd 2011, 12:27 | |
WB1GCMSuper Moderator Total Topics: 0 Total Posts: 0 |
The person who chooses to live in a antenna restricted area has a few options. One very practical one is to go mobile. Having a ham station in a car is very useful during emergencies. If the roads are not blocked by fallen trees, the mobile ham can get to an emergency situation and assist, if needed. After a hurricane, the first stations that get on the air from the damage zone are mobile stations. I have a friend who lives in a small apartment, on the first floor of a steel and brick building. Inside antennas are out as well as outside antennas. However, next to one of his windows, outside, is a aluminum downspout, attached to the metal gutter on the roof. With one thin hidden wire attached to it and a few buried ground radials, he can get on all ham bands, 160 through 6 meters. It even works well when it's raining; so I called it, "the hydropole". I have another friend who lives in a condo. No outside antennas are allowed. His solution was to put up a loop of wire around the ceiling of his master bedroom on the second floor and run coax down to the basement. His first contact was East Timor on 40 meters. Usually places that restrict antennas usually allow flag poles. The restricted ham can put up a flag pole vertical, bury radials and place an auto-tuner at it's base. You can either plant scrubs around the tuner or hide it with a plastic rock. Yet another ham I talked to on 20 meters takes out his aluminum extension ladder, which is placed on a piece of plywood, and loads up into that for an antenna. The neighbors think he's working on the house. And there's also stealth antennas. A very thin wire can be used, which is very hard to see when it is oxidized. The answer to your question is antenna restrictions do not necessarily stop hams from getting on the air; there is usually a way of putting up an antenna of finding something to load into. People who wish to get into the hobby can consider the above options, though I left one out: go portable. You can set up at a park or beach, which is very similar to setting up at emergencies. Bob Allison WB1GCM ARRL Test Engineer |
| Sep 1st 2011, 00:23 | |
W1RFIAdminTotal Topics: 0 Total Posts: 0 |
First, a word of caution: Don't try loading the downspout with any more than QRP operating levels. The metal junctions between the sections are not necessarily well bonded, and at higher RF levels, sparking can occur. If leaves are in the downspout, this may not go well. Also, at the high-impedance points on the antenna, RF voltages can get very high and if people or pets contact the downspout at that point, they can get an RF burn. For some of the antennas that Bob described, hams should also do some evaluation of the RF exposure potential of the antenna, although this is not required by the FCC rules at lower power levels. I, too, have done a lot of stealth antenna work. With an antenna tuner, any random wire, loop or dipole can be loaded up, even in an apartment. With 100 watts of power, even with "poor" antennas, I've made plenty of contacts. Even at 5 watts, on CW or digital modes, a poor antenna can still be used to make contacts. I have run wires out windows, ran wires up trees, feeding against an earth ground rod at the base of the tree. In an apartment where my sister lived, I snuck onto the roof and put up a nice dipole. (She was moving anyway...) My favorite "stealth" antenna, though, was in an apartment building. After trying various antennas, one day, the tree surgeons were there to do some trimming on two 80-foot trees. I bribed them with pizza and beer and they put up a 40-meter dipole about 70 feet in the air. Man, did that baby sing! I made DX contacts every night, and loaded it up on 20 and higher to good effect. One night, I came home and loaded up my transmitter and sppppttttzzz... the SWR was about a million to one. I went outside and found the coax neatly cut and cut again about arms reach up the tree. Bummer! So, at night, I climbed the tree, soldering iron in tow, with a small plastic box painted bark grey and put in an SO-239, about 15 feet up the tree. Every night, after dark, I opened my window, tossed a coaxial cable outside, ran around and hoisted the end up the tree, getting back on the air. This worked for months. One night, I drove home, only to see that both huge trees were simply gone, along with my antenna, feed line and the little box. A month later, the antenna showed up in the yard, but there was, of course, no place to put it up, as there were now no trees in the yard more than 20 feet in the air. I moved to Andover, CT some months later, where I put up an inverted vee at about 40 feet and once again made contacts. Still, that 70-foot high dipole was maybe the best wire antenna I've used. :-) I know one other ham that had woods about 300 feet from his apartment, so he put up an antenna and buried a feed line, running 300 feet to the woods. Others have simply asked their landlord and secured permission for a modest, but effective antenna. 73, Ed Hare, W1RFI ARRL Lab Technical forums moderator |
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