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Discussion in 'CB Antennas' started by Charlie Brown, Apr 18, 2011.
Avanti AV-150 "Astro-Beam"
Never knew of this antenna. Anyone try one?
No PSM, I have never had one of these, but I have tried to study the design using the instructions. Most reports I've heard from owners suggest that the beam is very effective, but I have no idea what characteristics were consider.
My ideas on this one is that it uses a AstroPlane as a driven element, and that supports my idea that the A/P is a 1/2 wave radiator. If there are any advantages to using this in a beam, the benefits might be the same as I suspect helps the A/P work so well as an 11 meter vertical antenna. This idea has to do with the very large foot print that the A/P antenna design makes. The capture area is not long, but it is very fat...and thus IMO, this may be how it is able to be so short, compared to a yagi styled 1/2 wave element, and work so well. I don't know for sure about the gain, and I don't think that is the advantage realized, but I do think it probably has very good ears, and if so that distinction could be very noticeable working on-air.
In my personal experience using several A/P verticals I tend to see this RX advantage, with only a very slightly less signal than other antennas that are much longer and mounted much higher at the tip. I can't claim this advantage is like a night vs. day difference, but it is detectable in many instances.
I think the AstroBeam is very much like the A/P and the electrical continuity in the assembled antenna needs to be followed exactly to the T for it to work as intended.
I used to run one of these back in the 80`s had as much vertical gain as my moonraker 4 and just as good side and rear rejection too...... if all you needed was vertical it was a super antenna in a small package.......hope this helps you out
I use one for 1 1/2 yrs or so and it worked rather well. Excellent back door rejection.
They were around a long time ago and worked quite well. The beam version did actually use the Astroplane as the driven element.
I ran one back in the mid 70's for a while with the boom mounted at 74 feet.
With 5 watts I could talk to and hear barefoot mobiles 50 miles away while at the same time completely blocking out a loud female on a Browning station that was only 2 miles from me.
Being it's so short in length it has a very tight null on the back corners that will block out just about anything including your loudest and closest neighbor.
My Moonraker 4 wont even do that.
The nice thing about such a small antenna is that it can be mounted on a pole with a small rotor unlike a 4 element dual polarity beam that requires a tower and heavy duty rotor.
They are a very quiet antenna as they are DC Ground
I'm surprised there weren't more of them sold back in the day but I think the popularity of the small dual polarity PDL-II for just a few dollars more was more appealing to most at the time.
Both being small and can be mounted on a pole using the same small rotor the PDL-II won out and I think the name of the PDL-II was a major part of that, sounds more catchy than an Astro-Beam.
I still have a couple of them and have entertained the idea of cophasing and running both of them.
I bet that will make Marconi's head swim with new ideas about just how to accomplish that.
I've got a real good idea as to how to do just that.
Maybe some day when I get ambitious with lots of free time.
This design is a great idea if it works as it should.
Tuning a vertical yagi mounted on a metal mast can be quite frustrating.
just spotted one of these across town still up on a tower, looked to be in very nice condition... I may have to stop and ask about it
Camaro 1, if you decide to get it...keep us posted...
If so, and before you take it apart if you can I have questions.
Does it use the short coax transformer at the feed point?
What is the length of the top radiator?
I know Greg, RT2020 used to run one of these and loved it. I have heard all the same happy reports on the Astrobeam... short boomlenth, good forward gain, good rejection, light enought to turn with a TV rotor, etc. I think KomaToast is dead on about price vs. the PDLII being the main reason there weren't a ton of them in the air.
im going to stop over there maybe this weekend if I get time,,, I know its not in use for cb anyways,, I would have heard them on it as im only about 5 miles away(straight line). it caught my eye as I never seen one before.
If it is not for CB, then don't bother with the questions I asked.
I just meant that they are not using it,, as I would have heard them sometime,,, ill let ya know what I find out about it
stopped and checked out the astro beam,,,, the guy doesnt use it anymore and doesnt want to get rid of it..