help with screwdriver antenna

[WR3143]

Anyone seen this or know who built it?
I own it, came with a radio I bought. I'm familiar with how they work, etc. except I've never seen one with these coil taps at the bottom.
Any Ideas?

 

[w9cll]

Looks home made to me

 

[Road Squawker]

Hard to tell from the pic,.... is the motor lead running through the center of the matching coil?

also,... that single wrap around the ferrite is not nearly enuf.

 

[WR3143]

Yes, homemade.
It's a DK3 design but I'm pretty sure it's not one of his builds.

The lead with the choke on it is the drive motor power. It does work. I can wrap more loops.

Looking for info on the coil taps in the pic as I have not seen them on one of these antennas yet.
Thanks

 

[WR3143]

Hard to tell from the pic,.... is the motor lead running through the center of the matching coil?

also,... that single wrap around the ferrite is not nearly enuf.

No. The power lead enters the tube above the coil. It had mini Anderson connectors on it.
I powered it and the antenna goes up and down as it should.

How many wraps on the ferrite coil should it have?

 

[Road Squawker]

...
How many wraps on the ferrite coil should it have?

Well,assuming it is a mix 31 ferrite,... and NOT a 43 then 13 turns is correct.

good info here: http://www.k0bg.com/choke.html

 

[WR3143]

Well,assuming it is a mix 31 ferrite,... and NOT a 43 then 13 turns is correct.

good info here: http://www.k0bg.com/choke.html

Ok. Cool. Thanks for the link. I'll follow those instructions...
and the choke can go on the vehicle side of the Anderson connectors, right?

 

[Obed]

if it is indeed the motor drive that goes through the core...tarheel says to wrap their power lead thru theirs at least 3 times...

 

[Road Squawker]

... the choke can go on the vehicle side of the Anderson connectors, right?

if it is indeed the motor drive that goes through the core...tarheel says to wrap their power lead thru theirs at least 3 times...

any wire before the feedpoint will act as an antenna, get the feedline choke as close to the feedpoint as possible.

I have a Tarheel, the ferrite they provided is in my junque box.

My mix 31 3/4 inch ferrite has 13 wraps on the motor lead. same on the feedline.

this is not my install photo, but mine is very similar, except mine is mounted as high as possible to get as much coil above the roofline as possible.
notice both the feedline and the motor leads are on separate chokes

 

[Obed]

agreed...every mobile antenna i have ever installed, i either made a choke balun or installed cores on the line...I have used 4 different brands of screwdrivers over the years and made one of my own...if you do not use the core (or some kind of core) on the drive line, as was stated it will act as part of the antenna and can affect your tuning on some, if not all of the bands.
I just bought two tarheel antennas that I have not installed yet...
a little tarheelhp to put on the wifes ranger and a 100 to put on one of my truck...thanks for the heads up on their core, I will check that out and see how it goes.
I plan to do the wifes install this weekend... will be another week or two before I get around to doing my truck.

 

[WR3143]

Hard to tell from the pic,.... is the motor lead running through the center of the matching coil?

also,... that single wrap around the ferrite is not nearly enuf.

Here's a better pic....

 

[WR3143]

Here's the bottom. No threads.
Not sure how this supposed to mount.