Home Brewed Construction of an End Fed Tuner (EFT).This is to enable me to use any antenna with any transceiver.
Chuck Carpenter (W5USJ) should probably get the credit or blame for my attempt at this.

Here is my working schematic.


I picked a sheet of doubled sided substrate that is 4 1/16" x 7 1/8" then sanded each side with a 100 grit sanding block.
Then applied a light coat of clear acrylic to both sides to retard tarnishing.

Laid out the substrate for drilling then drilled it.

Finished the lay out and mounted the substrate on standoffs to allow access to either side.

Top and bottom views of mounted DPDT switches. The switches will allow seven values of inductance to be added to the antenna.

Now let's add the needed inductors.


L1 is 8T on a T37-2 toroid for 0.249uh and is mounted in the 1st position.


L2 is 12T on a T37-2 toroid for 0.484uh and is mounted in the 2nd position.


L3 is 16T on a T37-2 toroid for 1.057uh and is mounted in the 3rd position.


L4 is 22T on a T37-2 toroid for 1.900uh and is mounted in the 4th position.


L5 is 32T on a T37-2 toroid for 4.121uh and is mounted in the 5th position.


L6 is 40T on a T50-2 toroid for 7.944uh and is mounted in the 6th position.


L7 is 40T on a T50-2 toroid for 7.866uh and is mounted in the 7th position.

I measured the total inductance that can be added to an EFLW antenna and it was 24.5uh.


Wired all the switches so the inductors can be switched in or out.


Added the "TUNE" portion of D1, T1, R1, R2, R3 & R4.

I installed the LED (D2) and the varicap (C1).

Now to build a case.

I decided to put the binding posts and the BNC connector on the back instead of on the ends.
As I looked at the "INSULATED BINDING POST" I decided that they were not insulated. So to fix it
took a nylon nut and using a Dremel Drill and reshaped it to fit a larger hole.

Installed connectors on back panel.

Installed back and front panels.

Installed left and right side panels.

Finished the wiring.

Finished.

Here is a 71 mb video clip on the inductors.

And here is a 46 mb video clip on the varicapacitor.

Now to test it.

It did not WORK! UGH!!!
It would tune the antenna, but the LED would not DIM?

After much checking and frustration and rebuilding T1. The issue was solved.I had reversed
the SWR circuit feed from the TUNE/OPERATE switch. Swapping the leads cured the issue.

The ultimate test was October's CQWWDX contest.
Using the EFLW tuner with a 61' active element with a 25' counterpoise
with an above ground height of barely 10'and my Elecraft K3 running 5 watts.
Contest results: 119 POINTS; 65 contacts on 5 bands (80-10m) 15 zones 25 countries.
OUTSTANDING