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ASTROPLANE best vertical antenna ever?
- Thread starter nosepc
- Start date
I didnt use a hat so I just extend or retract the upper stinger. Theres only so much you can adjust on these things unless you get creative. I'm thinking of getting creative though by making it where you can extend or retract the two lower legs but keep the hoop the same dia. If the numbers hold right then you could go into 20 meter band I'm thinkin. But im still thinking
Looks like Dan is building a copy, his site has some interesting babble going on about it.
http://mrcoilycom1.ipower.com/id36....94I2N8PU9MS2xoFnl9aR5hsRZcY4vcckLO0yrzHN_m04w
73
Jeff
http://mrcoilycom1.ipower.com/id36....94I2N8PU9MS2xoFnl9aR5hsRZcY4vcckLO0yrzHN_m04w
73
Jeff
the astroplane antenna is a vertically polarized, off center shunt fed, end loaded and extended 3/4 wave dipole antenna, matched at level A using a full size quarter wave matching section. it is not colinear and it only functions as described above (and according to the manufacturers specifications) when element 14 (the "mast" section) approximates a half wavelength at the operating frequency or frequencies in question and only when any conducting support structure is insulated or isolated from the "mast" section.
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He clearly hasn't read the studies on this forum mostly by @bob85 and @Marconi with additional contributions from a few others on this forum, or it is possible that he read raid studies and didn't understand them, certain aspects of how this antenna actually functions take a certain understanding that goes far beyond the average technician. There are things happening with this antenna that I haven't seen happen in any other antenna out there such as the current distribution on the mast, or the part of the mounting bracket that is right next to the feed point yet appears at first glance to have no currents flowing on it in spite of the fact that there are peak currents flowing on both sides of said conductor. I can go on here.
This really is a fascinating antenna, and I haven't seen very many people give an explanation that even understands that quirks and oddities even exist with this antenna, much less take any of them into account when describing how this antenna actually works. Typically, people just put this antenna into whatever category they feel it looks like or whatever info is found online that looks good at first glance, and go with that.
I want to credit @bob85 and @Marconi specifically, as well as a few others, who have done a lot of work trying to figure out what is actually going on with this antenna design. I don't think they exactly agree with each other, but their opinions are going to be among the best out there.
The DB
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I’m a believer. Been a long time since I had one, but I seem to remember isolating mine using electrical tape and seeing an improvement in both receive and transmit.
That said, I think the same holds true for any antenna. Seems to me a metal mast simply becomes a radial of some undetermined length which designers have no way to account for. Hence, it should not be allowed to become part of the antenna.
the matching section aside, two thirds of the antenna wasn't in the box when you bought it. element 14 is the 1/2 wl. end of the dipole (below level A) and above level A is the other 1/4 wl. element forming the extended 3/4 wl. dipole, top loaded or not.
Interesting take on this. Perhaps someone will compare it to other 3/4ƛ antennas.
they're all vertically polarized, off center, shunt fed (or not) and extended full wave dipole antennas, except for any real 7/8 wave models, which would be 1.125 wavelengths, all extended dipoles. an extended dipole for the sake of this discussion is any dipole in which one or both 1/4 wave elements are longer than a 1/4 wavelength, such as 1/2 wl, 3/4 wl., etc..
https://www.worldwidedx.com/threads...ernative-view-point.31799/page-44#post-758740
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Are there any members that make and sell Astroplane copies? I picked up a Targa BT-101 (Astroplane) and the parts quality is not all that great. That being said comparing my Gainmaster at tip height of 57' and the Targa tip height of 35' I see a difference on both rx and tx of about 1.5 S units with the Tagra being weaker. I know the 22' height difference will definitely affect the Targas performance compared to the GM. Long term plans are to get the Astroplane up to the 50'+ range but if there is someone that builds them with quality parts I would like to go that route before putting it up 50+'.
Thanks in advance,
Harry
Thanks in advance,
Harry
