Here's the old trade-off between radiating efficiency and ease of
matching for an end fed wire. The EFHW is more efficient, because little
power goes into the ground system, but its high impedance is harder to
match. A wire of a different length may be easier to match, but more
power goes into the ground system, where it doesn't radiate much. Both
will work but, I believe, on average the EFHW will be a bit better. Is
it worth the trouble? Who knows?
Antenna discussions have long had a tendency to focus on SWR. Low SWR
does not necessarily mean an antenna is effective. There's an old
saying, "The SWR of a dummy load is 1:1."
73,
Scott K9MA
On 2/10/2017 09:56, Don Wilhelm wrote:
Brian,
If your end fed antenna is actually a halfwave (which is what EFHW
means), the answer is no.
The solution for portable work is to use a length that is not a
halfwave - 58 feet is known to work well for 40 thru 10 meters when
used with a 13 foot counterpoise. Double the lengths if you want 80
meters.
With that antenna and counterpoise length, dispense with the balun for
portable operations, and use a BNC to Binding post adapter instead (no
coax).
If you need to use a short length of coax, you can put the balun at
the end of the coax, and you can try both the 1:1 and 4:1 positions to
see which provides the better match.
73,
Don W3FPR
On 2/10/2017 10:36 AM, Brian Pietrzyk wrote:
Speaking of baluns or un-un's... I'm about to assemble a BL2 which is
a 4:1. Will that be enough to bring an End Fed Half Wave (EFHW)
within tuning range of my KX3 ATU?
I'm going to be ve3bwp/hi9 QRP week after next and hoping to try a
couple of different length end feds into one of the trees near the
beach. I'll be trying Phone and psk31/JT65/CW an afternoon or two
that week. Anyone interested in a sked email me direct.
_
--
Scott K9MA
k...@sdellington.us
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