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Any Astro Plane Fans ?

To my eyes, at least initially, it looks like a dipole (upper vertical element and the mast for both sides of said dipole) and a half wavelength loop (the "radials" and hoop area) in parallel with each other, at least as far as the feedpoint is concerned.

A quick and dirty model with a dipole and a half wavelength loop in the vicinity of the lower element of the vertical dipole shows gain over a center fed dipole. It was, however, very touchy when it comes to impedance, specifically the X variable, a change of 0.1 wavelength (10 millimeters, or about 0.4 inches on a 10 meter antenna) changed the X variable by about 150. I've never seen such a big change from such a small adjustment...

Note, this was a simply a model of the concept of a half wavelength loop in parallel with a center fed dipole. It did not even resemble the astroplane design and was more a proof of concept type model. It wasn't refined in the least.

Thanks for the details Eddie, perhaps I'll get a chance to put them in at some point and play with it...

The DB

I agree with you here, because the Patent shows us that the mast can be extended a 1/4 wave above the mount and the antenna will also work. I've modeled this configuration, but I don't remember if it resulted in any differences. If I can find this model I will post it up as well. In looking at this antenna is is very obvious the bottom is some sort of loop and I call it a feeder that happens to radiate in phase with the top and the mast plays a significant part in how the antenna works...I have said before the A/P looks and acts like a big tuner to me.

I'm getting close to the bewitching hour and I don't know what will happen here, but if you don't see me tomorrow...you will know the devil got me.
 
eddie, the astroplane is safe at my mothers with the NOS saturn, when i open it i will measure it and clear up any confusion,

in the meantime i can tell you the hub spacing is very close to 6" but its not 3" deep, 2.5" is close,

http://i5.photobucket.com/albums/y152/ukmudduck/astroplanehub2.jpg

http://i5.photobucket.com/albums/y152/ukmudduck/astroplanehub.jpg

the down tubes are two piece, 2 x 1/2" x 48" tube minus the depth of the hub, swaged like the sigma hoop at the joint

the upper tube is 5/8" x 48" minus the depth of the hub

the user manual states a 13" spreader rod protruding past the legs 1/4" so 12" center spacing at the spreader,

the hoop is 4 pieces of 3/8" x 24" tube, 29.5" spacing at the hoop will be close,

hat is 4 x 1/8" x 24" stainless steel

the mast needs to be 1-1/4" to 1-3/4" diameter which will effect the impedance,

my mast is 1-1/2" diameter.


Bob, could you get me the dimensions for the top short radiator on your new Avanti A/P?
 
its not here Eddie,
as soon as i have another astroplane on its way i will open it and check actual length against the parts list,

parts list states 48" x 5/8"
 
its not here Eddie,
as soon as i have another astroplane on its way i will open it and check actual length against the parts list,

parts list states 48" x 5/8"

That is fine Bob.

I am currently using 45.7" x .625" inches with the top hat wires at 48" x 1/8", but my model wants me to go shorter a bit. My best tuning on this one is to adjust the top hat shorter, but I want to keep the model to specs...if I can and still see a good match in the middle of CB.

The Internet schematic that Homer and I have referred to shows different specs, but it is a model older that my top one, when this model of the A/P had a single radial element instead of two element. I still used the short SS looking wire Avanti use on the Moonraker and other GP antennas of the time. There dimension looks to be 23" x .25" with a small mounting ring on the end.

My old top one is 46.5" x 11/16" inches from tip to tip, not including the mounting stub.
 
I have a Avanti AV-101 Astroplane 5/8 CB Radio Antenna NOS 1978 coming to me. Should I take down my Hy-Gain SPT-500 PENETRATOR, and put up the AV-101?
 

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haku,

first off, congratulations! an unassembled AV-101?! you must've paid a pretty penny for that one.

i am a big fan of this antenna, and have the sirio version (not the newest one, but the actual astroplane copy) up in the air right now.

while i love the antenna, it will not outperform your super penetrator, and probably has a higher angle of radiation to boot.

if it were me, i would store it away and prize it.

if you are restricted on height however, the fact that the astroplane radiates the signal from the top of the antenna might be an advantage.
LC
 
I gave away my original AstroPlane, after meeting gary wrong, one of the biggest arses I've ever had the sad experience of running into (after a concert) and recalling that line in the song, "Maybe to an astral plane" I couldn't STAND having something which reminded me of that...
moon.gif
 
I gave away my original AstroPlane, after meeting gary wrong, one of the biggest arses I've ever had the sad experience of running into (after a concert) and recalling that line in the song, "Maybe to an astral plane" I couldn't STAND having something which reminded me of that...
moon.gif

Hey NB'r if truth be told, your bad experience probably had more to do with your youthful choice in life meeting "Gary Wright"...than it did over a simple AstroPlane.

 
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No, that's the wrong guy.

Hey, he says it, too! at 1:34

...and it was all the antenna's fault ;)
 
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Eddie,
I finally got to the astroplane, made a fiberglass isolator last night & started assembling it today,

mine is a little different to the instructions, I'm guessing its an A/S era antenna, tube looks and feels like 6061-t6,

the old astroplane afaik had the upper basket tubes expanded to take the lower tubes, mine has straight tubes & the lower tubes swaged to fit inside,
when fully pushed together they measure 94"
the original will be the same since it has about the same overlap,

its a stupid setup mechanically, the lower tubes should fit over the upper tubes & the spreader should clamp onto the lower tubes to support them,

avanti lacked mechanical aptitude in most if not all of their base antennas.

The upper 1/4wave tube is 48"
 
Thanks for the info Bob.

I thought Henry said they were old Avanti A/P antennas?

The antenna did not include a manual?
 
They are old circa early 80's avantis & come with everything i got with my sigma4 & saturn, manual warning stickers warranty card & bag of hardware containing 1980's american air which tells me they were shipped to europe by boat,

i can identify avanti tube at 1000 paces in thick fog,

The manual is the same as the one on cbtricks showing expanded tubes,
at some point they changed from expanded to swaged tube on the basket legs but never changed the manual since it does not effect how you assemble it.
 

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