[Elecraft] Horizontal Loop question

[Don Wilhelm]

Terry,

I do not really intend to answer your questions about the switching the 
feedline, that is up to you  In the old days, we did that with a knife 
switch, or more 'rich and sophisticated' hams used a DPDT relay.

For the balun, the impedance at the shack end will determine whether a 
4:1 or a 1:1 will be a better choice.  Measure the impedance on all 
bands of interest with an antenna analyzer and use the results to figure 
out which will be the better compromise.
The antenna feedpoint impedance will change from band to band, and the 
length of the feedline will transform that impedance to something else.
If you have trouble matching it on any one band, try adding or 
subtracting 1/8 wavelength of feedline for that particular band and 
measure again.

73,
Don W3FPR

On 11/29/2015 10:17 PM, n7tb wrote:
> I currently have a horizontal loop at my QTH being matched by an Icom AH-4
> Tuner.  It is interfaced with my Icom 756.  I will be running a new-to-me K2
> with the auto tuner installed.  Right now, the loop is connected at its end
> points to 450 ohm ladder that has one leg attached to the tuner's antenna
> connector and the other leg to the ground lug.  Coax comes from the tuner to
> my rig and works great on my Icom 756.  Now for the several questions.
>
> 1.  the AH-4 interfaces with the 756 via a four conductor molex connector.
> Is there some way to take those 4 wires and interface them to my K2 and let
> the AH-4 tune the loop instead of the internal K2 tuner?
>
> 2.  I presume it possible to take the coax feed from the A-4 off my 756, or
> have an antenna switch do that, and attach the loop coax feed to my K2, then
> turn on the 756 to the same frequency that I want to transmit on the K2, and
> press the tune button on the 756 to tune the loop?
>
> 3.  I could manually take 450 ohm loop antenna connection off the Ah4,
> attach it to a balun attached to another length of coax that attaches to the
> K2, but this is very cumbersome.  Perhaps an antenna switch is available
> that has two balanced feedpoints and a coax feedpoint that would allow me to
> switch remotely?  Does anyone know of such a thing?
>
> 4. If I decide to feed the 450 ohm twin lead to coax to my rig, what type of
> balun do I need? 4:1 or 1:1?
>
>