Ok, what is the consensus on grounding the braid of the coax, on the
xcvr side of any feed point balun ?? I see that W8JI uses solenoid
type HF yagi bauns... with 10-20 turns of 213-U..wound in a solenoid
fashion...on a 4 inch ID. He also immediately bonds the braid to the
boom... on the xcvr side of the solenoid balun. If it was a monobander,
ideally you would want to bond the braid a physical quarter wave back
from the feedpoint. That’s not always practical, and a lot of folks use
multiband yagis. So what about bonding the braid, either just on the xcvr
side of the balun.... or within a few feet of the balun ? The idea here is
then the bonding point is well less than a quarter wave away from the
feedpoint.... and CM should be reduced somewhat.
Steve, G3TXQ depicts CM current on a 20m dipole... with and without
a balun... for various coax lengths. But his range is just 20-70 feet. A
qtr wave on 20m is 17.5 feet.....so CM would be nothing. Its also nothing
at 3 x qtr waves..or 52.7 feet. Ok, what happens when LESS than a qtr wave
is used.....or if braid is bonded to boom..within 0-.25 wavelengths of the
xcvr side of the balun ??
Jim VE7RF
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