New style astro plane

[Cat Driver]

Anybody tried this antenna yet? If so, do you hafta mess with it a lot to set the swr on it or is it fixed at the factory? I know the old one was a good antenna and I was needing something to put at the wifes shop for her to jabber on. Found the new style ones for $50 here an there.

Ronnie

 

[freecell]

all of the information you're looking for is contained in the patent.

http://www.firecommunications.com/patents/astroplane/

the two vertical skirt elements (and the spacing between them) as well as the material used (and length) for the supporting mast and the length of the vertical portion of the top hat element are all critical to the vswr, input impedance and the takeoff angle.

 

[Cat Driver]

all of the information you're looking for is contained in the patent.

http://www.firecommunications.com/patents/astroplane/

the two vertical skirt elements (and the spacing between them) as well as the material used (and length) for the supporting mast and the length of the vertical portion of the top hat element are all critical to the vswr, input impedance and the takeoff angle.

Looks like a P.I.T.A. to me.... I think I'll try the starduster style or something else. Its just for the wifes shop, so she'll have something to listen to an yak on.......

Thanx,
Ronnie

 

[Marconi]

Larry, the AP is fixed tuned and does not need anything but a little assembly if you are going to work 11 meters. It is not designed to be tunable and generally works very well. If you want a more or less failsafe and easy to install CB antenna, get her an A99 instead of the M-400 knockoff.

 

[Cat Driver]

Larry, the AP is fixed tuned and does not need anything but a little assembly if you are going to work 11 meters. It is not designed to be tunable and generally works very well. If you want a more or less failsafe and easy to install CB antenna, get her an A99 instead of the M-400 knockoff.

Yeah, I guess thats what I'll hafta end up with. I just hate them noisy ass fiberglass antennas, other than that I don't mind'em to much.

Ronnie

 

[freecell]

if you re-read the patent you will find that all the parameters i mentioned previously are able to be controlled by the adjustment of the particular sections and the mast length that i detailed and referred to. the manufacturer does more or less guarantee a minimum of 1.4:1 in its properly assembled form across the cb band. whether more complicated than most adjustment procedures or not, the astro plane antenna is adjustable in every sense of the word. impedance, resonance, pattern, takeoff angle and vswr are all able to be adjusted and manipulated.

get your tiff reader here........

http://www.alternatiff.com

note to bob85, if you're reading this i have the tuning procedure you requested to synchronize the occurrance of both minimum vswr and resonance at any operating frequency you choose for the I10K. you know what to do.

 

[bob85]

if im reading the patent correctly they claim the optimum t/a is when the supporting pole or coax outer shield extends about 1/4wave below the ring,
if thats right then just throwing them up on any old pole will greatly effect how the antenna performs,

even if you used a conductive pole that extended only 1/4wave below the ring do you still have the coax effecting takeoff angle??

could a resonance breaker be used to effectively make the antenna see only 1/4wave below the ring or other lengths to controll takeoff angle both isolating the support mast and feedline at the optimum distance below the ring for your particular needs????

 

[Cat Driver]

If I'd get the astro plane I was gonna use 2 -10 ft TV antenna masts together stuck in a 3-5ft tripod. That would probably be wrong too...

Ronnie

 

[Marconi]

Bob, I read that to mean this lenght of the support and/or feedline below the bottom hoop needs to be at least 1/4 wavelength or more for optimum effective TO angle. It can be more, but not less. If less, then the TO angle will rise up dramatically. To a degree I think most other antenna act about the same in this regard.

 

[freecell]

"even if you used a conductive pole that extended only 1/4 wave below the ring do you still have the coax effecting takeoff angle??"

i'm trying to decide whether to answer that question or to let you check it out for yourself and tell me. why should i have all the fun?

"could a resonance breaker be used to effectively make the antenna see only 1/4 wave below the ring or other lengths to control takeoff angle both isolating the support mast and feedline at the optimum distance below the ring for your particular needs????"

there's no doubt that the support mast would have to be insulated from the main structure @ + or - 1/4 wavelength below the ring depending on the results desired. it appears that the mast section decouples the feedline from the feedpoint to the degree that outer shield CMC is no longer an issue. that should tell you something in reference to your first question.

 

[W5LZ]

Marconi,
"To a degree I think most other antenna act about the same in this regard."
And they do, in general, sort of. Another one of the reasons for the recommended antenna minimum height thingy, usually more associated with input impedances, but still affects everything, TOA included.
A conductive/nonconductive support does make 'some' difference but not enough to worry about. Keeping that 1/4 section of feed line straight as possible does help. 'Straight' meaning no 90 degree turns in it, slight turns or bends aren't gonna make much difference.


Bob,
Could a "resonance breaker" be used? Sure, but it would depend on just what that "resonance breaker" consisted of. In most cases it be a little impractical cuz the average person wouldn't know what the thingy was to start with. Another aspect of that is that any 'resonance breaker' will introduce some amount of 'loss'. That's one word NO antenna manufacturer wants in their advertisement - lol. Antennas are a lot like cats. There's always more than one way of 'skinning' them (pun intended).
- 'Doc

 

[loosecannon]

cat driver,
dont let 'em confuse ya.

they are all correct in their comments about the antenna, but i think they are getting a bit off point of your original intention.

i currently own and run this antenna as my main CB/11m antenna.
its called the "top one".

this is the antenna you want for your application.
it will outperform the A99 on the same 20' mast.

i also own an antron, and this antenna is definitely quieter on receive, and i dont mean it has less "ears".

it takes a bit of time to put together, but it is not any more difficult than any other alum. cb antenna.

the hardware is kinda cheap. you might want to upgrade to stainless steel bolts and nylon insert nuts.
really helps keep things tight in the wind.

here are the main things to remember about this antenna:

1. you must support the hoop against the mast by using UV resistant rope, or cable ties at four points.

2. you must have a good metal to metal connection from the top mounting bracket of the antenna to the mast, and from one mast section to the other. might have to scrape some paint.

3. the mast must run down past the hoop for 8 feet minimum.
the antenna is just over 7 feet without the top element, so this will be fine with your setup.

4. the coax must run down the mast all the way down past the hoop for at least 8 feet.
best to keep it secured to the mast all the way to the bottom.


thats it. mine works VERY well. i have it on a 50' pole, but i have operated it 10' off the ground with great results too.

one tip: when screwing the various elements to the mounting bracket, the rubber insulators can make threading them in quite difficult.
coating the threaded end of the element with some automotive tune up grease will greatly ease the installation and assure a tight fit while maintaining conductivity.
dont use too much, just a light coating.

follow these instructions, and you will have a very low SWR with no fuss.
best of luck,
loosecannon

 

[freecell]

"it be a little impractical cuz the average person wouldn't know what the thingy was to start with........"

just a dielectric material with a high enough "k" constant to prevent the remaining conductive support structure from resonating at out of band frequencies with respect to the target frequency of the array. teflon works well and can be found in the necessary dimensions.

loosecannon, good post. the top one here is matched for Z=50 / X=0 @ 27.385 where we have established the AZHO link between arizona and idaho. almost every time without fail the top one responds to band openings long before the A99 does at the other end of the path. it will get signal out over the tops of the hills surrounding the town here where end fed verticals just can't cut it. the top one even outperforms our vintage hygain clr golden penetrator by a noticable margin. the mast section is exactly 16' terminated with teflon and conductively separated from the 50' push up. i fabricated a 4 element mast mounted and insulated spider hub fashioned after the starduster radial element support hub to maintain the concentricity of the loop.

the local terrain here makes it the fixed omni antenna of choice.

 

[Cat Driver]

LC, I think I'll go ahead an try it for the $50 it cost. I've wasted that much on less before.LOL

But I'll be sure an keep yer post where I can come back to refer to it.

Thanx Again,
Ronnie

 

[loosecannon]

very cool freecell!

interesting about insulating the pushup pole from the 16' of mast.

i was under the impression that as long as it had the 1/4 wavelength below the hoop, that more didnt matter.

do you think i am affecting my take off angle or anything else by having roughly 25-27 feet of mast below the hoop?

cool idea on the hoop support too!

i cant believe that the manufacturer hasnt added some sort of support for the hoop to the antenna.

it is the clear weak point!
i'll bet there are plenty out there who badmouth this antenna because it eventually snapped from the constant shaking of the hoop in the wind.

now, to really flame the fires;
what kind of antenna is it? LOL

i say 1/4 wave folded dipole.

what say you? (im really kinda kidding, as i know this is a source of endless debate, and i dont want to hijack this thread for that purpose)

dont do it marconi!!!
dont do it!!!LOL

great thread,
loosecannon
loosecannon