Hello Everyone....
Once, I suggested to a "Mom and Pop" antenna company that they build a
6M yagi for rovers. The idea came when I was walking by their booth and
saw that they had a huge pile of the chrome(?) telescoping type antennas
that used to be found on the cheap transistor radios. These had a
threaded base so that they would screw into something.
Here was my idea....build a yagi of 3 or 4 elements. The center part of
the elements would be made out of (say) 1/2" solid Al. Then drill and
tap the end of the elements so that you could screw in one of the
telescoping antennas. Clearly, other construction methods could be
used. The length of the little telescoping antennas was about 2ft...so
you would have elements that would be 2ft of telescoping antenna +
center section of 1/2 AL + 2ft of telescoping antenna. If you made the
1/2" centers just the right length, then you could use the same
telescoping antennas for every element. You would need 6 of them for a
3el yagi and 8 of them for a 4el antenna.
The point of all this is that full sized 6M yagi elements are less than
10ft....if you removed the chrome telescoping element "tips" you would
have a center section of 1/2" Al that was less than 6ft across....this
is street legal!!! This would mean that the center section of the
reflector would be longer than the center section of the director(s), so
that when you added the length of the telescoping "ends" you would end
up with a correct length element. Whoever built one of these would have
to spend some time figuring out the lengths of the center sections so
that the tuning would work out right considering the different diameters
of the element material. I think that it is important that you have the
center of the elements just the right length that you just pull the
telescoping tips out all the way for each element. No measuring--just
pull it all the way out.
When the rover arrives at his location, he just screws in the 6 or 8
element tips and voila!!! a 3el or 4el full size yagi. When you are
ready to leave, just screw them out. If you forgot, drove down the road
a bit, and something hit one of the little telescoping antennas and
ruined it, the antenna company could sell replacements. Any sane rover
crew would have several of these replacements along in case of "emergency".
You could mount this on your normal rover mount or mast(whatever you
use). You could screw in the telescoping tips and then operate OR if
you mast is the type that can be raised, raise the mast and operate.
This would give the rover a full size 3el or 4el beam when on location.
Clearly, you cannot drive down the highway with this, but while parked
it should beat the dickens out of the typical 6M loop or squalo type
antenna. Setup time would be very minimal, which is very important.
ASIDE: Somewhere, there are pics of us driving down US67 just north of
Presido, TX in DL79 with a full sized 6M5X on the top of our van!!!
Eighteen wheelers slowed down and moved way over on the shoulder as they
approached us.....
If any antenna manufacturer likes this idea, feel free to steal it and
go into production. Just send me the first 3 or 4 that come off the
production line as my "royalty"......
Comments?? Suggestions??
73 Marshall K5QE
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