PDA

View Full Version : dam santa



VE7MGF
12-26-2012, 06:22 PM
the wire antenna came down Christmas night so i get to build a new one
my thinking is to build a shortened 160m dipole
the apex is about 40 ft with a leg of 62ft
going to feed it with 450 ohm and a tuner
there is no way to put up a full size dipole
so if i insert a loading coil in the middle of the leg to make up the shortage in length
is this a reasonable solution to getting an antenna that will go from 160m to 6m
and yes i downloaded antenna modeling software couldn't figure how to run it
i know there are people on here that have much more knowledge than i do on this topic
thanks for any info supplied

KG4CGC
12-26-2012, 06:28 PM
If you dam Santa, he'll explode of toxic sewage build up.

VE7MGF
12-26-2012, 07:21 PM
ya well next time i guess reindeer are in season all year:hyper:

W3WN
12-26-2012, 08:26 PM
If you dam Santa, he'll explode of toxic sewage build up.I thought it would be an explosion due to an overdose of milk; word is he's lactose intolerant. (At least Scott Calvin is, or was)

KG4CGC
12-26-2012, 10:15 PM
So, I wish I was more helpful with the antenna.

VE7MGF
12-26-2012, 10:21 PM
i figured that if i let the wisecracks go for awhile before i try to get back to the topic posted

NQ6U
12-26-2012, 11:25 PM
To clarify things a bit, are you proposing to stick a loading coil on just one side of the dipole?

N8YX
12-27-2012, 09:38 AM
If you're planning to use it on all bands from 160 through 6, such a construct - when fed with ladder line - must be a half-wavelength long at 80M. This length is subtracted from the total linear space available then the remainder is halved and used as the approximate length of the two end stubs. Once you have that figure, you can plug the main dipole and stub lengths into one of a number of online loaded-dipole calculators and get your coil dimensions.

You don't need traps with this approach...just loading coils.

VE7MGF
12-27-2012, 09:42 AM
i want to put a loading coil (wraps of magnet wire on a plastic pipe ) on each leg about 3/4 of the way to the ends
to make the dipole electrically 1/4 wavelength long per leg

N8YX
12-27-2012, 09:45 AM
If this comes out like I want it:

--0--------[==]----------------------(++)----------------------[==]--------0--

Insulator, stub, coil, 1/4w (@80M) wire, center insulator/connection to ladderline...repeat for the other side.

N8YX
12-27-2012, 09:55 AM
I would also use at a minimum #14 solid for the coil turns...maybe even #12 or a 2KW-rated piece of Air-Dux coil, suitably strain-relieved and shielded from the weather by a non-metallic, lightweight enclosure.

KK4AMI
12-27-2012, 10:34 AM
I would be interested in what brought your wire down? I always heard that there is a downside to antenna coils as far as droop and weight stress on your wire. That is if you are not looking to trip Santa up anytime in the near future.:irked:

K7SGJ
12-27-2012, 12:52 PM
I would be interested in what brought your wire down? I always heard that there is a downside to antenna coils as far as droop and weight stress on your wire. That is if you are not looking to trip Santa up anytime in the near future.:irked:

Put it in the chimney if you really want to fuck with him.