I recently purchased the Cobra Extra Light Jr., a 70 foot dipole, fed with
ladder-line, for use while camping. There are different ways that I can use
it. I have been connecting the antenna to an SGC-tuner (SG-231) for use
with a K-2/100. On 80 meters with 100 watts, there was a lot of stray RF,
getting into the audio, and giving rf bites when touching the mic. I spoke
with one ham on the air who noted the distortion of my signal, and said the
SGC tuners are really only for long wires or whips; I needed to use a
balanced, link-coupled antenna tuner (Maybe like the MFJ?).
I've also read much of the DX Engineering web page, which is very
comprehansive. There, they say one needs a 1:1 current balun (as opposed to
a voltage balun), but their linear-loaded antenna uses a 4:1 balun; I am
assuming that a linear-loaded dipole has a higher impedance relative to a
standard dipole?
I have the W9INN 4:1 balun, but after searching the web, I cannot find any
information about whether it is a current or voltage balun. How does one
tell the difference? I also have tried the small LDG baluns, but the SWR
changes rather dramatically - might be due to heating up of the balun
perhaps - they are very small. I've tried the baluns with the Elecraft
external tuner, but it seems to be very sensitive to stray RF (it is
difficult to get a good ground while camping), which was the reason for
trying the SGC tuner.
My question is what opinions people might have concerning a link-coupled,
balanced tuner - would that be the most efficient (in terms of loss and band
coverage) in this situation? I wouldn't be adverse to using a manual tuner.
Or, would a balun (like the DX Engineering current balun), used with a
typical external tuner like LDG or Elecraft be more efficient and work well
on more bands? If so, would I use a 4:1 balun like used on the DX
Engineering linear-loaded antenna? Thanks in advance for any guidance. Tom
W6EIJ
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