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Old October 18th 07, 12:12 AM posted to rec.radio.amateur.antenna
Tam/WB2TT Tam/WB2TT is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 125
Default Question on dipole SWR problem


"Ed G" wrote in message
.81...


The feedline is doing more than transporting energy to the dipole
centre, it almost certainly carries a significant common mode current
and in that case is just as much a part of the radiating system as the
dipole itself.

So, isn't the coax and control line to the SG237 carrying current mode
RF current, ie contibuting to radiation.

Inch by inch, the detail unfolds.


Yeah, inch by inch. I hate to fill up the post with too many
details as some people grab something insignifcant and go off on a
tangent.... however, the devil may be in the details.....


You are right here. I have a feeling some people think you are running
ladder line to the radio.


You're right on the current in the shield. We have a choke balun,
currently located 85' down the coax toward the transmitter. I have it
scheduled, when it stops raining, to move it up to the input of the SG-
237 coupler unit.


This has got to be a step in the right direction.

Tam/WB2TT

The Choke balun is homemade, 6" diamter, about 11
turns of RG-8X coax. Does that sound sufficient? I didn't make it or
provide it. There is no control line for the SGC coupler unit. It only
requires 12VDC @ 300ma and we are providing that by using a couple MFJ
DC adapter units to feed the 12VDC up the coax.


Ed