Thanks Tom,
Yes I am aware of the balanced/unbalanced feedline, and have coiled the
feedline directly below the antenna, and have done my share of Googling!

But what I want to know is how the Arrow manages to match the antenna to the
50 ohm feed.

I am thinking its in the spacing of the two elements?

Cheers
VK2KC


"tom" wrote in message
et...
On 11/10/2010 7:40 PM, VK2KC Gmail wrote:
Hello,
I have just built a J pole antenna for the local our local Emergency
Service
centred on 410 Mhz for their field/portable use.

I note that the Arrow antenna feeds the 1/4 w/l element directly, but the
standard J pole feed is on each element.

What works best? The standard J pole feed or the way Arrow feeds theirs?

Cheers John
VK2KC



I could reply as one here does and say -

YES

And then he would leave it there and scold you for not knowing how.

Neither feed is superior. The issue you need to address is that this is a
balanced antenna fed by an unbalanced feedline.

So your mission is to lessen the current on the outside of the coax. This
involves a choke, which could be ferrite based or coiling the thing up
based. I won't get into it beyond this since it's all out there with
google search and google news search.

tom
K0TAR