balun for portable VHF dipole 2M to 6M

[Richard Ferryman]

I have constructed a simple telescopic dipole for 2M to 6M to use with my
FT-817ND. This works fairly well but it is prone to RF on the feeder and
some noise pickup. This is almost certainly the result of feeding a
balanced antenna with unbalanced coax. As I need a wideband balun I can't
use traditional VHF tuned baluns. Question is which type of balun can I
scale up (down?) to VHF from HF and maintain efficiency? Toroidal balun?
Ferrite choke? Coiled coax? If ferrites or iron dust cores are involved
then what mix?
Any ideas?
Dick G4BBH

[RUKi...@nospam.net]

I've used about 8 - 9 inches of #43 beads on RG303 coax for a choke
balun on VHF/UHF with success.
RUK

[Bob Miller]

On Wed, 25 Feb 2009 10:21:45 -0000, "Richard Ferryman"
<richard...@btinternet.com> wrote:

I have a 6-meter wire dipole fed with RG8X that was getting about 79
watts forward, 20 watts reverse. A coil of coax, four turns about 5
inches across just below the feedpoint, gave me 100 watts forward. How
this would work on 2 meters, I don't know, but it would be easy to
try.

bob
k5qwg

[Owen Duffy]

"Richard Ferryman" <richard...@btinternet.com> wrote in
news:DYydncl8a7wnhjjU...@bt.com:

Here is a design: http://www.vk1od.net/balun/G1-1-FT140-61/index.htm .

There are many alternatives.

Owen

> Any ideas?
> Dick G4BBH
>
>