[Elecraft] Question for Wayne about your OCF Dipole

[marvwheeler at nwlink.com]

Thanks for your reply. I am going to put something up similar and will comment about my results.

Again, thank and love my K3S=KPA500. I am waiting on UPS to deliver a used KX3 this afternoon.

Thanks for Elecraft support.

73
Marv

-----Original Message-----
From: Wayne Burdick [mailto:n6kr at elecraft.com] 
Sent: Monday, September 18, 2017 3:02 PM
To: marvwheeler at nwlink.com
Cc: Elecraft Reflector <Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Question for Wayne about your OCF Dipole

Hi Marv,

I didn’t measure the legs. My best guess, standing here by the shack window using an antique brass monocular, is 55’ on one side, 35’ on the other. This is the most satisfying thing about off-center-fed dipoles: length generally isn’t critical. Close your eyes and clip, knowing that, most likely, the ATU will do the rest. 

The installation was opportunistic, taking advantage of a back yard gazebo, a Home Depot telescoping pool-cleaning pole, and a huge white oak. Height at each end was determined by how high my son was able to climb without the neighbors noticing.

The experimental feedline, running under the house for half its length, was more deliberate if not justified in the literature. At first I was using 300 ohm mystery twin-lead scavenged from an installation of yore. But given all the RFI sources I decided to try two lengths of LMR-400, taped together every few feet, forming a sortof-balanced-shielded feed. Purists I consulted ahead of time continue to be shocked at how well this works. At the mast, the grounds are left unterminated. In the shack, the two center conductors go to an Elecraft BL2 balun. The shields are soldered together and connected to the BL2’s ground lug.

There you have it: Wide tuning range, low noise, low-loss, and theory-free. How it works is left as an exercise for the reader.

Wayne
N6KR 



> On Sep 18, 2017, at 2:31 PM, <marvwheeler at nwlink.com> <marvwheeler at nwlink.com> wrote:
> 
> Wayne:
> 
> 
> 
> In a previous post you mentioned your 90 feet long OCF dipole. Would 
> you please elaborate on your antenna? Balun, leg lengths, how fed?
> 
> 
> 
> Thanks,
> 
> Marv
> 
> KG7V