[TowerTalk] Choke on feed point of dipole

[Tom Hellem]

Jeff-
Assuming your comments pertain to a wire dipole. Mine is made of aluminum
tubing, a repurposed DE from a 20 meter yagi, modified
somewhat to put bigger diameter tubing at the bottom half. Intention is to
use it for portable setups, like POTA, etc., and constructed in such a way
as to facilitate quick and easy deployment. 100 watts max.
Knowing this, would your recommendations still apply?

Tnx , 73
Tom
K0SN

On Tue, Jan 13, 2026 at 11:37 AM Jeff Blaine <KeepWalking188 at ac0c.com>
wrote:

> I would not hesitate to put up a vertical dipole.
>
> In fact my 30m beam is so directional I'm thinking of putting up one
> here just to cut down on rotor wear & tear.  Assuming you have the
> height, It's much simpler physically than doing a vertical as you don't
> have the ground system to worry about.  And it gets the important
> current maximum quite a way off the ground.
>
> The "easy" way to do this is to build the dipole as normal. **NO** choke
> at the feepoint in this case.  The **GROUND** leg of the dipole runs
> down to ground, next to the coax with the two secured together so they
> are not blowing around separately.
>
> The important part is to put a serious coax choke at the end of the
> dipole tip, on the ground side.  That means multiple turns through a
> couple of type-31 ferrites.
>
> Antenna resonance is trimmed with the tip length at the top assuming you
> have a pulley to pull it up.
>
> 73/jeff/ac0c
> alpha-charlie-zero-charlie
> www.ac0c.com
>
> On 1/13/2026 4:02 AM, Brian Beezley wrote:
> > Tom Hellem wrote:
> >
> > "I think the reasonable conclusion is that a center fed vertical
> > dipole is a very difficult thing to make work..."
> >
> > Tom, at my last QTH I dropped a 40m dipole vertically from a tall
> > eucalyptus. I fed it directly with RG-58 (no choke). The feedline ran
> > roughly horizontal for tens of feet. (The tree was slightly down the
> > slope of a hill from the shack.) SWR was fine. I remember generating
> > pileups during Field Day as a 500 watt home station, but otherwise I
> > was not that impressed with its performance.
> >
> > The gain and elevation pattern of a vertical antenna are quite
> > sensitive to ground quality. Unless you have really good ground, a
> > horizontal antenna may perform better, even at low angles, if you can
> > put it at a decent height. "Decent" might not be that difficult at 14
> > MHz and above, but it may be a problem below.
> >
> > When modeling a vertical antenna, these generic ground constants are
> > much more appropriate than those your antenna analysis program offers:
> >
> > https://k6sti.neocities.org/hfgc
> >
> > Brian
> >
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