Dan, for QRP work, a balun is not that necessary. A balun helps
greatly in reducing common-mode current that can be created on your
feedline as a result of feeding a balanced antenna (dipole) with an
unbalanced line (coax) or from other factors such as uneven dipole leg
lengths, proximity of the antenna to metal objects in the environment,
etc. If you would be connecting a transceiver with 100w output to the
antenna system this common-mode current can become severe enough to
cause "RF bite" burns on your mic, CW key or equipment cabinets,
disruption of computer operations, burglar alarms and other equipment
in your home, etc.; below 10w this is much less of a problem. You can
build or buy a 1:1 balun to connect dipoles to 50-ohm coax. You can
also create a "common-mode choke" for no money which reduces
common-mode current the same way a balun will, by winding a portion of
your coax feedline into an even coil; there is tons of info on
"common-mode chokes" if you Google that.
-- Rich WB2GXM<div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br />
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On 9/8/18, gonewiththeego@... <gonewiththeego@...> wrote:
Oh, thanks! I'm looking for an SWR-meter meanwhile. And about the balun ? Is
it a "MUST HAVE" ?
