Any Astro Plane Fans ?

[bob85]

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.

 

[HomerBB]

The bracket is 2.55906" x 9". The distance from center-to-center of the skirt-like lower elements on the top bracket is 6".

in the photo most of the metric dimensions are translated to inches noted in smaller print near the metric number.

A good conversion URL. - World Wide Metric

 

[Marconi]

Wow...that is new looking Bob. My old stuff looks like crap compared to that.

My new top one is close, but a little different.

Thanks for these details.

 

[Marconi]

Thanks for the image Homer. I have that one too, but I was never really sure even though it looked exactly like I figure the original looks.

As I recall you have or had an original once too. My old Top One is coming loose at the tips of the radiator where it attaches to the mounting bracket and the top hat. I drilled these spots and inserted bolts, to fix the problem, but I've never put it back up again since.

Like I said somewhere earlier...I have never worked one of these during DX until this past weekend. I wish I could have gotten the bottom hoop up as high as the GM to the feed point and then I think the signals would have been a different story.

 

[bob85]

that is my buddy goldfingers hub eddie, its old but cleaned up ok,
he took that pic about the time you sent me the cte hub and i wanted to know how the spacing compared,

i looked through my discs & memory sticks for the other measurement pics for you but i can't find them, they will turn up when im not looking for them,

how far away from your models are the sizes i posted from the avanti user manual parts list?

 

[Marconi]

I see a little difference Bob, but this whole antenna is basically act like a big tuner to me. The differences don't look like much, but the model can go to heck in a hand basket it seems in just a minute...if something it wrong with a dimension. You can also see this if something on the antenna comes loose, so I caution to get things tight without overdoing it.

I'll get my model that I posted the other day that I called "Astro P Specs 32'" and show you how a little difference can matter if I didn't already delete it. This shows how much detail it takes with modeling an antenna...and IMO we can't just put some wires together, do things with the software that are out in left field, and expect the model to work like we would expect. IMO, such off the wall efforts can only result in the limitations you caution me about. Any model you see in Eznec that does not look almost exactly like the real thing...is not going to show you good results IMO. As a general rule the results show to be mostly better than a good model should report, but not always.

Just as a note about my models in particular...I always set my models to Eznec's idea for Average Earth, unless I'm doing something special with that feature in particular.

I'm anxious to see if you isolation scheme works to help eliminate some or all of the bad properties I see this antenna to cause.

Below is a PDF file of my old manual for my CTE Top One. I include the spec sheet that likely helped spread some of the CBBS about this antenna. Strange how lots of folks complain about manufactures telling us puffing type lies about their products...but folks still swear by every word claimed as the same time.

This not a 5/8 wave antenna. You can see the full antenna producing a typical 1/2 wave pattern with a few kinks here and there due to making it so short IMO. You can also see the tuning stub leg is out of phase with the mast and thus these two elements show cancellation into the far field...as the NET of this combined current is very near ZERO. Unfortunately due to this lack of balance (symmetry) this antenna can act very bad.

Again I hope your idea for isolation work out.

 

[bob85]

i agree its effectively a 1/2wave eddie,
it is different to your typical cb antenna in how it works imho,

i can't remember the details of my first test years ago but i am sure i did not test it at equal tip height against other antennas and that's the whole point of the antenna, can it do what avanti claim,
its the only reason i want to try one be it homebrew or the avanti,

owning one NOS unopened is a different matter and to do with nostalgia and happy memories,

the very first cber in this area used an astroplane,
as kids mostly on indoor antennas as cb was illegal we all envied him,
all i had was a homebrew dipole made from wire and canes,
another local called grease monkey who left to become a submariner used one and me for a short while,
i never thought id see a genuine one again,

same deal with my BIG-MAC, i only ever spoke to one other guy using one when i had mine up at 73ft to the base and never heard of one since,
i wish id rescued the coils & hubs from my mates dustbin when he smashed it up,
and my starduster m800, nothing special but unique in this area,

im not too worried it will cause tvi if its on a 1/2wave isolated mast at the same tip height as the 10k.

 

[Henry HPSD]

same deal with my BIG-MAC, i only ever spoke to one other guy using one when i had mine up at 73ft to the base and never heard of one since,

R u sure



Joking m8, i know u know..hihi.

Kind regards,

H>

 

[jazzsinger]

Hi Bob. Glad you got an av101 finally sorted out. Wouldn't mind 2 or 3 myself but as you know banned from Tm1, lol. So can't get hold of Mark. I've pm'd Henry. Hopefully he'll be able to help me out, but if not I'll find them somewhere to go with mighty magnums and clr2's I have. Love my old antennas

 

[Marconi]

Hi Bob. Glad you got an av101 finally sorted out. Wouldn't mind 2 or 3 myself but as you know banned from Tm1, lol. So can't get hold of Mark. I've pm'd Henry. Hopefully he'll be able to help me out, but if not I'll find them somewhere to go with mighty magnums and clr2's I have. Love my old antennas

Jazz, I have two, but they are both CTE knockoffs. I won't sell either, and if I had an original Avanti...I would not sell it either.

same deal with my BIG-MAC, i only ever spoke to one other guy using one when i had mine up at 73ft to the base and never heard of one since,

R u sure



Joking m8, i know u know..hihi.

Kind regards,

H>

Henry, can I remind you that if you ever take your Big Mac out of the box...would you please get me all of the necessary dimensions...so I could fix my model. I had to guess.

 

[jazzsinger]

Jazz, I have two, but they are both CTE knockoffs. I won't sell either, and if I had an original Avanti...I would not sell it either.



Henry, can I remind you that if you ever take your Big Mac out of the box...would you please get me all of the necessary dimensions...so I could fix my model. I had to guess.

Yeah I know Eddie but a bundle turned up in the Netherlands. Shipping antenna's from Netherlands is cheap from here. Hopefully there is still a few left.

I want one to play with.

I already have a nib avanti av101, I got from my friend Andre in the Netherlands.

I also have about 10 x Clr2's. 8 x Mighty Magnum 3's. 8 x hygain 418's a couple of cushcraft arx450 and a couple of others.

I really want a sigma 4 nib, but thats proving elusive.lol.

Bit of an antenna magpie

 

[bob85]

Henry, you are a tease lol,
the Netherlands is THE place to be for vintage cb antennas, i have no doubt about that,

the chances of me ever seeing an original again in real life are zero imho, they were so rare here,

my locals would accuse me of ghost talking as they could not hear who i was talking to,
all i know is my BIG-MAC at 73ft to base in a field with no nearfield obstructions worked better than any other antenna i owned, providing it was not too windy,

was it just the height of current maxima or do they make more gain @ low angles with a narrower main-lobe like i think they do,
maybe its just a 7/8wave with high angle radiation like some people tell me,
it can't outperform a 5/8wave hihi

best regards.

 

[jazzsinger]

Its funny we are talking Big Mac. I only recently got in touch with Paul Iceman. He was the only one in Glasgow I ever knew with a Big Mac. Went across the city too see it years ago. I thought my 3 ele beam with mighty magnum 3 and my Sigma 4 were big. But the Big Mac was a monster. He put out one hell of a signal with it.

The Netherlands seems to be where it was at not only for antennas but also export radios too back in the days before the net.

Was also the first country I ever contacted on ukfm too on an Amstrad cb901 thunderpole and b150.

I have had so many good friends in 19 div over the years. Just wish we had the net in the 80's. Lol Loads of stuff there was so hard to get in my city. Jazz

 

[Needle Bender]

I eliminated most of my local TVI/RFI by using 1.25'' diameter solid fiberglass rod to isolate the mast 105" down from the mounting bracket on my Avanti AP, since the mast is the 1/4 wave counterpoise for this folded 3/4 wave GP. I used 5.5 turns of the coax on a 4" diameter former for the cmc choke around the fiberglass.
Remember, you must have a 50 ohm load at this direct-driven feed point, requiring it be either a 1/4 or 3/4 wave antenna. It must also produce maximum current and minimum voltage at the mounting bracket point of contact or it would short the high voltage node to ground, a very bad idea.
Where the bracket meets the longer side of the radiator is the center of the top 1/2 wave of this folded 3/4 wave, with the bottom end fed 1/4 wave folded 180 degrees back into radiating phase with the top 1/2 wave.
The high voltage node is in the loop around the counterpoise, requiring the extra clearance.

 

[Marconi]

Henry, you are a tease lol,
the Netherlands is THE place to be for vintage cb antennas, i have no doubt about that,

the chances of me ever seeing an original again in real life are zero imho, they were so rare here,

my locals would accuse me of ghost talking as they could not hear who i was talking to,
all i know is my BIG-MAC at 73ft to base in a field with no nearfield obstructions worked better than any other antenna i owned, providing it was not too windy,

was it just the height of current maxima or do they make more gain @ low angles with a narrower main-lobe like i think they do,
maybe its just a 7/8wave with high angle radiation like some people tell me,
it can't outperform a 5/8wave hihi

best regards.

Bob, if it had been me and that Big Mac did that good...I would have never let it get out of my possession for any amount. Here is the model I made, but I had to guess at much of it.