Thursday, June 26, 2014

Threemile Mountain and the LNR Precision End Fed Trail Friendly Antenna

We made a last minute decision to head up Threemile Mountain last weekend. Lynn and I both had a good weekend of spending time with her students on a summer school trip to Bents Fort near La Junta Colorado and also have been cleaning out closets and generally downsizing.

It was a nice break to get out to a summit and do a little radio. Since I did a video report of our activation I will talk a little about the LNR End Fed antenna.

Here is the video of the activation:

I had no intentions of buying the LNR Precision EF Trail Friendly antenna but after meeting the LNR Precision staff at Dayton and seeing the display antenna I decided to give it a whirl. I ordered it at the hamfest and it was on my doorstep shortly thereafter. Here is the writeup from the LNR web site:


EFT-10/20/40 Trail Friendly
EFT-10/20/40 Trail Friendly
LNR Precision also offers the NEW “Trail Friendly” version of the popular Multi-band QRP 10/20/40 EndfedZ antenna. The new “EFT-10/20/40 Trail Friendly” is an enhancement of the EF-10/20/40 MKII offering a lightweight but strong 26G polystealth wire (opposed to 18G).  The matchbox (BNC connection) is much smaller and the total weight of the antenna comes in at an amazing 3.5OZ. The overall storage dimensions is 5.25″ x 2″ x 2.5″ and is perfect for your mobile needs. Also it is the first of our EndfedZ antennas to come with our “rewind” storage bar for easy deployment/storage. More details will be coming (along with specs and pictures) but we are already taking orders on our purchase page and units will ship just a few days upon order placement. The EFT-10/20/40 Trail Friendly offers the same superb quality you have come to expect with all of our EndFedZ antennas and we know you will be pleased. Be the first in your club to show off this hot new antenna!  

I found the antenna to be everything they advertise it to be.

Small and light weight (perfect)
This thing is small and well built. The only weak point is in the antenna radiator which attaches to the matching network without any strain relief. That would not normally be a problem and do not think it would be an issue with normal use. However, I am pretty brutal on antennas and sometimes break things trying to get deployed fast on a SOTA summit. This was no different and I promptly broke the lug that attaches the radiator to the matching network during its first use. No matter, I just stripped the wire, tied it in a knot and reattached it. Now it has a little strain relief.

Antenna wire reattached
Here you can see the wire and 40 meter coil deployed on a SOTA summit
The other end in an old snag with 15 feet of RG-174
Since I did not tune the antenna before bringing it out I decided to check it to make sure. It was a little long so I trimmed it a bit and it was spot on. I tuned it for 40 meters first (this is probably backwards) as I figured it would be a little narrow on that band and broader on 20. It is now resonate for 40 meters CW and is resonate across the entire 20 and 10 meter band.

Easy to tune, light weight, no tuner required and easy to deploy..... almost perfect.

This antenna will be easy to modify for other bands such as 17 meters (maybe 15 meters) but I really need 30 meters. I think that a 30 meter stub after the 40 meter coil may work and I plan to experiment with that this summer.

The winding system is unique and I think ingenious. However, I have my own method of winding end feds and will probably remove the winder in favor of my hand winding method that I showed in my Aspen Ridge video on my youtube channel. (search for KA4JQZ then look for the Aspen Ridge video or look for my post on Aspen Ridge).

In order to remove the winder I will have to find another way to provide strain relief for the coil section but I have some ideas. I will post updates as I modify this antenna.

Overall I am very pleased with this antenna and impressed with the folks at LNR Precision.

I look forward to their re-release of the FX4 as I think they build a quality product.

Please feel free to ask any questions.



  1. Thanks for the write up on the LNR End Fed. I will be interested in your quest to add 30. As you know I only operate 20, 30, 40 from the summit and the unavailability of 30 is what kept me from buying the antenna. Now I have plenty of wires laying around that I am not sure that I need another one! Also, I want you to know that I have got rid of all my "winders" and now use your wire wrapping method. Love it. Thanks again.

    1. Matt, thanks for posting a comment. I really wish I had antenna modeling experience but will do it the old fashion way. Cool that you learned how to wrap wire without using a winder. Actually I am very impressed with the LNR winder and how it is incorporated into the coil. The key to effeciency is making one thing do several task and they have done it. That being said it takes me a lot longer to wind the wire using their method vice mine. With the addition of 30 meters this antenna would be perfect for me!

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