[R-390] Ultimate Antenna (well, up till now at least!)

[Mark Donaldson]

Your intermod reduction is probably due to the antenna
tuner acting as a tuned bandpass filter.


--- Tim Shoppa <shoppa_r390a at trailing-edge.com> wrote:

> Roy knows about some of my antenna adventures this
> fall, but a brief
> summary for those that haven't followed my goals and
> ambitions:
> 
> I figured out that I could hang an 80M dipole (cut
> for the low end as
> I work CW) between two trees at the corners of my
> property. It's
> a rather odd-shaped piece of property, but that's
> fine, because if
> it was more rectangular then I wouldn't have 130
> feet between trees :-).
> 
> I had previously sent lead weights up about 50 feet
> into the trees to
> hang antennas, but wanted to do better this time. So
> I built myself
> a pneumatic tennis ball canon:
> http://www.antennalaunchers.com/
> This gizmo sends tennis balls not into trees, but
> just plain over trees.
> Towing some fishing line from a reel, I hauled my
> antenna up somewhere
> between 90 and 100 feet above the ground.
> 
> First iteration fed the antenna with coax, and I
> tried to cover multiple
> bands with a fan dipole configuration. Worked good
> on 80M, did not do
> well on the other bands at all! Took it down, and
> sent it up with 450
> ohm ladder line. Wow, what a difference a day makes!
> The intermod
> from the local BCB is just gone if I use this
> antenna with a balanced
> tuner or a receiver with a balanced input (ala the
> R-390A).
> 
> Today I built some proper standoffs for bringing the
> wire into the shack
> (before it was just kinda dangling across the side
> of the house and over
> the garage - OK until the ladder line lies on the
> gutter!). Tomorrow,
> a real lightning arrestor built around two spark
> plugs. Gotta get that
> M14x1.25 tap!
> 
> I am so so happy with the results. With the balanced
> feedline it's perfect
> to match into my 390A; with the coax there was awful
> intermod from the BCB's
> down the street but with the ladder line it's just
> clean. The same clean
> that I previously achieved with loops and twinax,
> but with a whole
> lot more height than I could get from my attic. And
> with my
> link-coupled tuner, the thing loads up into my
> vintage transmitters just
> fine on 80M, 40M, 20M, and 15M. Someday I'll have to
> get a rig that
> transmits on the WARC bands too, but not that modern
> yet :-).
> 
> Tim N3QE
>
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