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Linked endfed halvewave with DG1JAN XOTA

This page was last updated : 21-Oct-24 17:05:47

With the DG1JAN XOTA now build and tested, I wanted to make a linked wire set, which by closing and opening links, can be configured for the amateur radio bands from 10m to 20m.

The idea is simple:

1. Cut a piece of wire longer then normaly would be resonant to 10m.
2. Make a loop on both ends, and mount one end to the XOTA PCB.
3. While keeping a loop at the open end, trim the wire to be resonant on 10m.
4. Add some kind of connector to the wire end
5. Take a new piece of wire longer then 1/2 the difference between 12 and 10m (so a bit longer then 1m)
6. Add connector to wire add connector compatible with the connector of step 4
7. Make a loop on both ends, connect connector and place S-biner to prevent pull on the wires.
8. While keeping a loop at the open end, trim the wire to be resonant on 12.
9. Repeat steps 5..8 for 15, 17 and 20m.

And when all done, you should have a 20m resonant endfed.

Now check the different wires by openening every link from the 20, 17, 15, 12 when everything is ok, all bands should be the same as before. If not . . . well somethings have changed during the assembly. Sometimes you can re-adjust the resonance a bit my shortening or lengthing the loops.

TODO : measure my wire set and note lengths for reference.

A closed link with the S-biner. For testing I used  faston terminals (m/v) but they will be replaced with 4mm Gold Bullet Banana Connector Plug which are normaly used for RC Lipo Battery.

Vertical configuration

For trimming the wires I used a vertical configuration using a 12.5m long glass fiber pole.

 

Kind of close up of the XOTA PCB.

Some SWR measurements I made on this vertical setup (10..20m).

10m 

12m

15m

17m

20m 

I have tested it a few times and everytime the SWR matches.  

 

Horizontal configuration 

With this wire set I was curiouse if the set could also be used for a horizontal setup, located aprx 4.5m above ground.

I used the glass fiber pole to make a horizontal setup for a 10..17m wire set. At this location I can't extend the wire set for 20m unless I want to make a slooper.

Close up of the open links making the horizontal 10..17m wire set a endfed halvewave for 10m.

 Some SWR measurements I made on this horizontal setup (10..17m).

10m 

12m

15m

17m

Again 17m is a little high, but nothing a simple tuner can't pull to 1:1.

 

Next experiment (when the weather allows it), going out in the field to give a propper RX/TX test.

 

To be continued. . . . . 

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