March 5, 2021

Hans, PA3CCX, was intrigued by the BALUN! Would this unit still work ? Well, the only way to find out is to measure. And the impedance was not 50 Ohm, the SWR was not 1:1. Basically it was bad,........

So, he took it apart, which is also a challenge. It would be nice if we can reuse the housing !

Well, it was also quite shocking. Filled with water, the foam was soaked and shrunk. It was very well understandable that this BALUN was not going to work. So, Hans cleaned and dried the housing, and the SWR was suddenly MUCH better.

Look at the Smith Chart after cleaning. Not to bad I would say.

The question now is what to do. The housing could be closed again with proper glue, or we could replace the BALUN with a new one based on a 240/43 ferrite core with teflon coax (18 wnds). Hans is reflecting on this issue, and will come up with a wise decision,..........more to come,....

The housing is not looking very healthy right ?

The idea was to print a new housing with UV-resistant material. Let's wait what the final idea will be.

23-03-2021

OK, Hans has build a new balun in the old housing. The housing is glued together with outdoor kit, and we hope that it never has to be opened again,...

Look at the pictures how it is build together inside now.

At the output two resistors in series are added to facilitate leakage of any build up voltages. The core is a new FT240/43. The coax is thin teflon high quality coax.

Measurements:

The Smith chart:

The current attenuation:

A new bracket is made to connect the balun to the mast. It is changed to make sure no water is running in the balun.