The Big Ugly Balun (BUB)
 

Big & kinda ugly.  That describes me  :-)  -- and it describes the big ugly balun as well.  Thankfully, we (both me & the BUB) work pretty good.

If you use a vertical for HF, or if you use a coax-fed dipole of some sort without a balun, you'll want to consider this.

I'm not going to reproduce all the technical why's -- others can do that much better than I can -- see the links below.  But I do want to show can a BUB can be built and used from a practical perspective.

You'll need:

• 23-25' good quality coax (such as LMR-400)
• a form to wrap it on (such as 4" PVC, about 1' long)
• 10 or so black plastic tie wraps (10-14" long)
• you'll probably want to put PL-259 on one or both ends
• when completed, you may wish to wrap the whole thing in good electrical tape (Scotch 33 or 88), depending on how well you did the tie wraps
• drill and drill bit the diameter of your plastic tie wraps

Steps:

• cut coax to length (23-25')
• (it may be useful to have a 2nd pair of hands for the wrapping of the coax)
• starting near the bottom of the PVC, drill single hole for plastic tie wrap
• put tie wrap in hole
• put 1 or 2 turns of coax on bottom of PVC -- it is probably helpful to turn the PVC, not twist the coax
• carefully drill 2nd hole above the top of the coax
• put tie wrap through 2nd hole, holding coax snug, tighten tie wrap
• make some more turns of coax, drilling hole after 3 to 5 turns, installing tie wraps as needed
• a little over halfway through, the tie wraps will no longer be long enough, so you'll start them halfway up
• after 20-21' is on the PVC, add any more tie wraps if needed
• wrap with electrical tape if needed
• install PL-259 end(s) if desired
• if it will be for a dipole, add dipole PVC and/or hooks if desired -- see http://www.hamuniverse.com/aa4cvfandipoleIMG_22a.jpg
• drill any support holes at the top, if needed
• install -- keep the BUB away from direct contact with metal -- keep it at least a few inches away from any metal tower/pipe/support
•  

Here is my BUB under my full-1/4-wave 40m vertical, held up by some dacron/poly rope:

Good links:

Ham Universe on the BUB (very good explanation, lots of pictures)
Ham Universe with a BUB under a multi-wire dipole support 
 

73, Dave, N0RQ

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