Without modeling it, I would guess that it will actually narrow the matched BW
and it makes it a single band antenna at the same time.
My Drake L4-B would drive anything. When I decided I needed a new challenge
(9BDXCC) I wanted to get on 160. Of course the Drake didn't cover 160 and my
then K3, now K3S doesn't have a tuner. So I added some wire to the ends of the
80-meter inverted V. This meant that I didn't have an 80-meter antenna but the
Drake would drive it anyway. Currently, with a KPA500 and KAT500 I have modest
power on 160 but the KAT500 chokes on 80 at above 200-300 Watts.
Hence the new vertical for next season.
On 4/21/2017 11:10 AM, j...@kk9a.com wrote:
It is very easy to put a hairpin coil on your top band vertical and bring
the resonant SWR to 1:1. This should give you much more usable SWR
bandwidth for the KPA1500. Many commercial tube amplifiers will only
tolerate 2:1 SWR.
John KK9A
>From Wes Stewart n7ws
Fri Apr 21 13:11:12 EDT 2017
I'm not necessarily defining a personal situation. But almost any 80 or 160
antenna will suffice as an example.
I am currently constructing a vertical for those bands. The model shows
2:1 on
160 at resonance and >3:1 just 60 KHz away and this is with considerable
ground
loss. Less loss would equal lower BW. With quarter wave resonance on 80
at 3.6
MHz it exceeds 3:1 at 3.8 MHz and is nearly 7:1 at 4.0.
Transmission line loss is a non-issue with 7/8" Heliax.
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