Base Jay's I-10K - 5/8 wave model using taper

[bob85]

i am much happier with the astroplane now i know vswr is low where its supposed to be Eddie,
with the radio playing up it was higher than 1.5:1 everywhere,
it would be ideal if minimum vswr was on 27.500,

Bear in mind i am using 200ft+ of rg213 so vswr bandwidth will look a little better at the radio than at the antenna end of the coax,

with min vswr on 27.025 it makes we think maybe avanti never changed the the mk2 astroplane tuning to better suite 40ch rigs.

 

[Marconi]

it would be ideal if minimum vswr was on 27.500,

I'll look closer at my new A/P model regarding the frequency, and I'll check it compared to what you report below. I'll set the top hat to make 27.500 happen and let you know the dimension I get...so you can try cutting your radials. Personally, I would make some heavy copper replacements to temporally test for the correct length first.

Bear in mind i am using 200ft+ of rg213 so vswr bandwidth will look a little better at the radio than at the antenna end of the coax,

I agree.

with min vswr on 27.025 it makes we think maybe avanti never changed the the mk2 astroplane tuning to better suite 40ch rigs.

Again you could be right. I'm curious to see what my new model shows in this regard.

 

[bob85]

Did you use the correct tube diameters for the astroplane model Eddie,

hat 1/8"
upper element 5/8"
1/4waves 1/2"
hoop 3/8"

my mast inside the basket is 1.5" diameter with mast & coax isolated about 1/4wave below the hoop,
tip height is very close to the same as the i-10k mounted on the same isolator.

 

[Marconi]

Bob I made a new thread showing the A/P with your dimensions at 27.205 and 26.900 MHz.