[TowerTalk] Auto tuners, Baluns and open wire feeders

[Wes Stewart]

If your open wire is short, why bother?  Replace it with low loss coax, put a 
decent common-mode choke at the feedpoint and tune it.  Sometimes the effort to 
use open wire simply isn't worth it.

Wes  N7WS


On 7/17/2018 10:43 AM, Mark Spencer via TowerTalk wrote:
> Hi:
>
> I spent some time trying out various wire antennas at the summer cottage and have more or less settled upon a dipole antenna fed with a short length of open wire feeder that runs from the antenna feed point to slightly above ground level, the open wire feeder is in turn connected to a Johnson match box (a tuner with a balanced line connection), which in turn feeds a coaxial cable that runs to the radio.  The tuner sat on top of a short step ladder during my tests.
>
> The coaxial cable had various mix 31 and mix 43 ferrite chokes applied.  It all more or less worked as I expected it would on various bands.
>
> Moving forwards I'd like to replace the Johnson Matchbox with an auto tuner.  At this point I'm leaning towards purchasing a suitable Balun from DX engineering, connecting that to the output of my SGC231 tuner and replacing the Johnson Match box with the Balun and the auto tuner.   I'll have to do some modelling (to figure out the likely range of feed point impedances  for the dipole antenna at various frequencies) before deciding on what ratio Balun to buy.   I expect I'll install the auto tuner and Balun on top of a wooden pole perhaps 10 feet or so from the ground.
>
> I am curious if anyone else has done something along these lines and if there are any issues with doing so ?  Any comments would be welcome.
>
> I'd like to move away from using a commercially made trap dipole at that location.   (The appearance, lower weight and wind loading of a simple wire dipole with a short open wire feeder is attractive to me, plus I need to use a tuner to match the existing trap dipole.)
>
> 73
>
> Mark S
> VE7AFZ
> mspencer12345 at yahoo.ca
>
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