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Twin X-Mount Dipole Idea

I have a feeling that if you're talking about that circularly polarized antenna, it isn't going to be up very long. They really don't have any benefits on CB, or HF in general.
- 'Doc
 
I have a feeling that if you're talking about that circularly polarized antenna, it isn't going to be up very long. They really don't have any benefits on CB, or HF in general.
- 'Doc

According to the plans I have,it offers 7 db gain. It has a 12' boom. The reflector is .15 wavelength from the driven element. The director is .20 wavelength from the driven element
CBC International - books plans kits modifications repairs for CB radios

P.S. I want to make one just to see what it can do. Again I repeat my request,has anybody made a CP antenna?



P.S. this is two three element yagi's combined in a vertical and horizontal set of beams.
http://www.youtube.com/watch?v=Fu-aYnRkUgg
 
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I have not, but a couple guys about 50 miles from me have the originals in the air and they get back to me very good in the evenings when we do some local talk,
 
According to the plans I have,it offers 7 db gain.

does it specify dBi or dBd or even in this case dBic?
In most cases you will suffer a loss of 3 dB (unless you are talking to another CP antenna of the same rotation). An average of half the signal is "wasted" on polarization angles that aren't used by the linear polarized antenna.
P.S. I want to make one just to see what it can do.
Me to.
I'm just not ready to invest in materials until I'm happier with a design.

If the two dipoles are close together (on the boom) and fed 90 degrees out of phase the axial ratio is ~1.0 even with reflectors and directors.
Looks like a pretty nice design and it can be reversed right vs left handed with a relay.

Physical staggering of the vertical and horizontal elements is what caused the .44 axial ratio (still lost as to why).

Originally Posted by W5LZ View Post
I have a feeling that if you're talking about that circularly polarized antenna, it isn't going to be up very long. They really don't have any benefits on CB, or HF in general.
- 'Doc
I'd like to see some support for that view.
Because it seems like a debated issue not an excepted fact.

RE: DX qualities again debate some sources state increased fade others extol CP and make a dissertation of when, where and at what frequencies the skip signal is right or left handed. (skip of a linear signal can convert it to a circular polarized signal)
There are a couple super scanner models posted along with a four dipole phased array I'd propose as an improvement.
 
I'll have to ask him what gain figures in particular. He had suggested that because I am a noob at antenna building and design,that I could start with a straight up yagi antenna. A three element yagi can be built from these plans. My thoughts for a 3db loss a doubling of output power can be used instead. I got a 22nd edition ARRL antenna handbook ordered.

Note:7db gain the same as a 25 watt transmitter used with a zero gain dipole.
Note:Spreading the coax's center wire and shield apart to hook up to a gamma match and center of a dipole causes inductive reactance
Note:After tuning each antenna while the other and vice versa is connected to a dummy load,slight retuning may be necessary.
Reply from Maco on their gamma matches:
"Our gammas work pretty much on any antenna if its hooked up right and if the antenna is capable of being matched to the 10 and 11 meter bands.

However I am not sure if the air capacitor will work with it or not."
Maco's answer to me asking if their gamma matches have a capacitor built into them:
" http://www.macoantennas.net/accessorypages/4600.html "
If I purchased a couple of Maco gamma matches,I would get the model that includes a SO-239 w/lug.
Note:If possible,the antenna should be tuned at it's operational height.
A sort jumper between the SWR/Analyzer and antenna(under 2 ft.)must be used.



Note:Observe capacitor plate spacing. Use one for the power range you're using.



For inquiries contact: lou2@cbcintl.com

http://www.bellscb.com/products/antennas/Maco/manuals/New/MaCo_4600_6600_install_instructions.pdf
http://www.hyelectronics.com/prodinfo.asp?number=M-4600

A home brew gamma match sounds way cheaper

Just wondering. Since it's a rotating wave,why not mount the elements in a 'X' instead of a '+'.
 
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ghz24,
I think the simplest 'confirmation' is that you don't see many/any used on CB or HF in general. Wouldn't you think that if they were beneficial at all that someone would be selling them? Or at least using them?
I don't have the facts and figures to confirm my opinion, but if you do a little researching I'll bet you could find them. What's the purpose of a circular polarized antenna? Where is it commonly used? That alone should give you an idea of why I don't think it's worth the bother. This circular polarization isn't 'new' by any means, and it's been discussed before.
- 'Doc
 
ghz24,
I think the simplest 'confirmation' is that you don't see many/any used on CB or HF in general. Wouldn't you think that if they were beneficial at all that someone would be selling them? Or at least using them?
I don't have the facts and figures to confirm my opinion, but if you do a little researching I'll bet you could find them. What's the purpose of a circular polarized antenna? Where is it commonly used? That alone should give you an idea of why I don't think it's worth the bother. This circular polarization isn't 'new' by any means, and it's been discussed before.
- 'Doc

I know it sounds like a gimmic but I would like to experience firsthand how this CP Antenna performs. Honestly,have you ever considered such an antenna? At the very least it could be rewired to operate as a vertical/horizontal set of beams. The plans I have are set up for a basic three element beam but in the hands of an experienced antenna designer/builder,one could expand from there using it on different bands. The only benefit I could see by using a CP beam antenna is where DX'ing comes into play. Maybe I'm wanting to make my first home brew antenna to be a spectacular,one of a kind antenna. I do have at least one goal in mind. There's a operator 30 miles from me and I want to see if I can melt his ear wax with it. LOL! Lou at cbcintl.com suggested that for my first antenna that I should start simple and make a three element yagi. The only base antenna I owned was a Rat Shack 3db gain end fed dipole.

The biggest thing is that I'm learning about antennas and how to build them. That in itself is enjoyable.
 
And if you want to see what any particular antenna will do, then by all means do so, give it a shot. I also understand why Lou would tell you to start with something simpler. It would, at the minimum, give you some experience dealing with tubing etc. Give you a 'feel' for what sizes can mean with weather etc.
Good luck.
- 'Doc
 

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