[TenTec] OT: Openwire Balanced Antenna Tuners (QST Test)

[Steve Hunt]

I was responding specifically to the comment from K4TAX:

"I'll take an air-wound inductor over a toroidal inductor any day, space 
available.  The typical loss in an air-wound inductor is IR loss where a 
toroidal has IR loss plus eddy current loss."

I didn't read that comment as applying specifically to balanced tuner 
operation.

If you are asking what is my preference in tuners for twin feedline, it 
would be an unbalanced L-match with a good 1:1 balun at the output. If 
that L-match needed to be automated and use fixed value inductors, I'd 
happily take iron-powder-cored inductors in place or air-cored inductors.

73,
Steve G3TXQ

On 20/02/2013 21:36, Rick - DJ0IP / NJ0IP wrote:
> Steve, this thread seems to have taken two paths:  1) "balanced tuners"
> (which is what it was initially about) and 2) "Toroids vs. air-core coils in
> general."
>
> Focusing on the original topic, balanced tuners, my preference is clearly
> link-coupled air-core coils, as used in couplers such as the Johnson Viking
> KW Matchbox, and the Annecke Symmetrical Koppler.
>
> Are you saying you would prefer to have a matchbox for tuning openwire fed
> antennas built with toroid coils instead of air-core coils?
>
> The application here is a general matchbox, say from 80m thru 10m, and
> should be able to match pretty much anything you throw at it.
> If you choose a toroid, it's going to have to cover 3.5 to 30 MHz, unless
> you have a separate set of coils for the high bands than for the low bands.
>
> IMO, the Air-core coil is better in this specific application.
> If there is a better way, I will be happy to learn about it.
>
> For bandpass filters, where each band has its own coil(s), then I agree,
> toroids are the way to go.  There you will use a different mix for different
> bands.
>
> 73
> Rick, DJ0IP
>
>