I also read W2FMI's book and I would have to agree that something isn't
right about the W2DU type Balun. I experienced heating and a rise in SWR
when using a KW and an under 2:1 SWR but not flat. It would heat up and the
standing wave would rise over 2:1. This is not to say that all bead Baluns
are bad. I had heard good things about the Force 12 version. Perhaps it
uses a different ferrite material.
I built several of the W1JR type of Baluns and have had no problem with
heating. I have had a problem finding an inexpensive enclosure. I have
tried using 3" PVC caps and plugs and have about $5 in the enclosure.
However, I created another problem. Weight of the enclosure and the
core/coax with connectors is a bit much for a dipole. An inverted V or
mounting on a beam is not a problem.
I have also had excellent success with a coil of coax. When ur lighting
every florescent tube within a block at 2 AM while on 80m with a flat SWR.
This will cure it.
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