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Discussion in 'CB Antennas' started by AudioShockwav, Jan 15, 2020.
I looked.. and?
Astro plane copy.
Plans are widely available, so why not to produce it.
I remember first Astroplane - called "Top One" in Poland I saw in 1989 and it was Midland/Alan production.
One big difference, Jeff.
If I remember right, the Astroplane was about 12' in length, wasn't it?
This thing is nearly 22'.
They are calling it a 5/8 wave antenna.
Thought this would be a interesting one to talk about.
I LOVED my Astroplane when I had it. I only stopped using it because they came out with the Astrobeam. Back when I was a young fella.
I like mine.
My order has been in "stand-by" mode for two weeks until I decide if I want to spend that much ($253.00) money. I had the Astroplane antenna in the seventies and eighties and it worked well for me.
Astroplane looks like it's nothing more than a 1/4 wave vertical but with a proper ground plane.
The bt-101 is tagra's version of an astroplane, same size as the original astroplane and all the other copies,
the size quoted in the download sounds like total height when you add the 1/2wave 1.5" pole it ideally should me mounted on,
avanti also called it a 5/8wave but i only see a hat loaded efficiently matched 1/2wave with 5/8+ performance when installed at the same tip height,
i have no plans to take my astroplane down just yet.
If anyone would like to diy there it is: https://www.worldwidedx.com/threads/homebrew-astroplane-build.34985/
Ah! Good to know.
Much prefer a 12 footer to one that's 22.
Thanks for sharing!
Good to see you're still kicking.
When Jeff posted the link to the Tagra Website and I saw it listed BT-101 as 22' length I was amazed. So, I emailed them and asked some questions.
I got the idea maybe they made their antenna a true 5/8 instead of a 1/2 wave, so I did a model scaled to 5/8. I used a 1.25:1 ratio. I fixed everything but the loop. To many small wires. After I tweaked the match I redid the ratio and I came of with a 1.28:1 conversion ratio.
It didn't work out the be 22' feet long. So, you may be right, thinking maybe they included the 1/2 wave mast inside of the A/P antenna.
I started with an old model I made that was my attempt to duplicate DB's idea for the feed point location on the A/P. I will post his model too and use it to compare results as an overlay. I did loose some bandwidth in this new model.
Bob, I also noticed the model showed more gain that Tagra published. They show less gain than Avanti did back in the days. However, the DB model shows the gain at just about what Avanti published...as best as I can tell.
I also heard somewhere...maybe in this thread that this antenna cost over $200.