[Elecraft] KAT-500 (was: K3-Twin with Remoterig)

[Jim Bennett]

I can attest to what Vic says. I have an 88-foot long doublet, hung about 45 feet up, fed with 85 feet of 600-ohm ladder line. At the shack end I have a 1:1 balun, and then about six feet of RG/8X running to the K3. The K3's tuner likes the combination. I tried replacing the 1:1 balun with a 4:1 from the same manufacturer. The K3 was quite unhappy with the change in components. The 4:1 went back on the shelf, the 1:1 went back inline. YMMV

Jim / W6JHB

On   Thursday, Dec 8, 2011, at  Thursday, 9:14 AM, Vic K2VCO wrote:

> It is a common misconception that a 4:1 balun is the best choice to feed a tuned balanced 
> line. The assumption is often made that this is appropriate because the characteristic 
> impedance of ladder line or open-wire line is higher than the 50-ohm coax that's connected 
> to the balun's input.
> 
> Actually, since the tuned line is being operated at a high SWR, the impedance seen by the 
> balun will vary all over the map. It may be very high or very low. This is a very tough 
> job for the balun, and in some circumstances it can be quite lossy. This is why a real 
> balanced tuner is better than an unbalanced tuner followed by a balun.
> 
> A 1:1 balun is likely to have lower losses in this application, although there might be 
> combinations of frequency and line length where a 4:1 is better. I hope that Elecraft is 
> planning to make their balun either 1:1 or switchable.