The W3DZZ Top band Inverted L is a great antenna if you want to get on
top band but never thought it possible because you are limited to a small garden. It
doesn’t have to be in a straight line, you can bend to your garden shape and it
should still work pretty well.
The lengths are divided up in to 9.9 metres
followed by the 7MHz trap and then 6.55 metres to the 3.5MHz trap and then
another 8.54 metres. A good earth is needed with a ground rod, but preferably some ground radials would be even better.
As usual the higher the better for the
antenna, but it will work at 15 or 20 feet if limited with height.
The traps
are the simple coax fed, divided up to 20 turns for the 80 meter and 11 turns for the
40 meter on a 40 mm PVC water pipe former with simple solder connections as
shown in the diagram.
Below are my traps which took about an hour to build.
Forty
Eighty
The top band length shown will give a 1:5:1 SWR at around
1.9MHz. If you are limited with height try to put in more ground radials if you
can.
The picture below shows it going over original designer’s
house, but as I said before you can bend it to how you want. I’m lucky enough
to have it as a straight dipole, but last year I had it up as a horizontal L
shape round the corner of the garden and it worked well.
Do experiment with this antenna, especially now it's summer and you can get it ready for those dark nights when top band and eighty start coming in to their own. Once set up correctly to your particular situation it will work really well for those lower bands!
Forgive the quality of the camera work, but hopefully you get the idea with the W3DZZ about 10 meters up!
This shows where the coax is split to the shack and the earth goes to the ground radials from the DX Commander
No comments:
Post a Comment