[Mldxcc] Question about 40M inverted V dipoles

[Alan Maenchen]

Emily,

It sounds perfect!
I have a similar antenna here: 40 meter inv Vee with apex at 45ft.

The antenna works fine at 7 and 21 MHz. that's the fundamental, and all odd
harmonics.
Even harmonics should give you a very high SWR (20 and 10 meters).

Yes, your tuner will make the radio think the antenna works well on 20, and
you can make QSOs that way. However, your signal will be about 10dB lower
than if you had a 20 meter inv Vee at the same height. The proof of that is
my performance in the IARU contest last month. While 40 and 15 worked well,
I had far fewer contacts on 20 even though everyone else thought 20 was the
"money band".

In fact, today's project is to add a 20 meter set of wires to the 40 and
make it a "fan dipole".

Aloha, Alan  AD6E  /  KH6RR






On Thu, Aug 14, 2014 at 8:02 AM, Emily Clarke <n1did at comcast.net> wrote:

> So at W1RH Bob's suggestion I decided to get my butt in gear and built a
> 40M dipole.  It's an inverted V so it fits on my lot with a center mast
> currently 27 feet up at the center - 10 feet up at the ends.  It has a 1:1
> balun that I had for a while from LG.
>
> I tuned it to 7.1 MHz the logic being:
>
> 7.1 = 14.2 (x2) = 21.3(x3) = 28.4(x4)
>
> So I used my antenna analyzer and trimmed it up to 1.1 to 1 at 7.1 and it
> dips to 1.2 at 21.6 (odd).  The antenna analyzer doesn't show any dip at
> 14.xxx or 28.xxx.  This I don't understand.
>
> However I get a perfect 1:1 match on the rig with it's tuner all across
> all of those bands which I guess is somewhat expected.  It also tunes flat
> at 17m and 12m.
>
> Does this sound right/safe?
>
> Emily
>
>
>
>
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