Basic Big Beam Question

[critter]

Hi, so after not radioing for a along time and recently getting the station out of storage I have set out on a long term plan to get back into the DX game, I am a big fan of MACO antenna's as they have served me well over the years, 20 year's ago when I was doing my thing and just starting out and after using several different antennas including the A99 with GP I set up a MACO V-58 and this thing kicked ass IMO, I also learned when you can take a 4watt walky-talky and connect it to a antenna that’s 70 feet in the air on a hill over looking the town like my house and kick the cat wattage aside antenna is everything, so I am definitely going beam and want to go big, but after doing some reading I still have questions flat VS dual polarity for one, I am looking at the maco flat 8 or the laser 500, what is the advantage of running dual and can you run both simultaneously? If I understand correctly it depends on the antenna that your station is talking to ideally vertical-to-vertical or horizontal-to-horizontal, if you were talking to a station that has a vertical omni directional antenna you would want to be running vertical polarity? And also would there be any benefit in running your dual polarity beam with both polarities simultaneously? I'm sure someone here can enlighten me. I intend on running a maco V-58 for local, providing there is any and setting that antenna up first. Thanks Scott

 

[Quiksilver]

What frequency(s) do you to operate? If it's 11 meter DX, you'll be fine with the Maco V5/8. Worldwide antenna for sure!! Anything other freqs., you'll need separate antennas, or possibly a dual/tri-bander beam. As far as dual polarity, you cannot run simultaneously....I believe. Efficiency would be horrible.
I could be wrong though...

http://www.hamuniverse.com/yagibasics.html

 

[Robb]

You can run it in a dual polarity mode. It's called 'circular polarization'. Think that Maco sells a special wiring harness as well, which is needed to make it work that way. But if you are getting a vert and horiz beam; I would just run two separate pieces of coax and an antenna switch. You've got the money . . .

http://www.macoantennas.net/NewProducts.html

 

[W5LZ]

Both of the prior posts are correct. You can run both polarities at the same time. Doing so results in very inefficient operation. There's a difference between 'dual-polarization' and 'circular polarization', each has benefits in particular circumstances. Neither are beneficial in most/all circumstances. I've found that it's often nice to have both polarizations available. When one starts to 'fade out', the other one starts to 'fade in'. It's not 100% reliable though. And then there's the requirement to switch between the two and all that that requires.
I'd advise sitting down and planning from the ground up. There's always something that you wish you'd done or had to start with, so try to anticipate stuff. Whatever antenna you finally decide on, you can almost always bet that it will be the cheapest part of getting the whole mess up and operating.
Good luck.
- 'Doc

 

[Henry HPSD]

Pehaps my answer to Jay in the mojave on another forum migth be of use:
He found it interesting that "his" 5/8 wave was from time to time stronger than his 5el Yagi.



THE ANSWER:
There are a couple reasons why a signal could be stronger..

Propagation which arrives at your location tends to have a circulair polarisation.
If the HF signal penetrates the inosphere the signal gets broken up in 3 parts:
1 the ordinary 2 the extraordianry en the Z component.
Due to the influence of the earth magneticfield each part gets a circulair polarisation.

The stronger the magnetic field (near south/north pole) the stronger the signal will rotate.

From that point of view it has no advantage using either a vertical or horizontal polarisation.
Of course one has to bare in mind the additional ground gain a horizontal antenna brings in.

Now, this is most of the time the case...however there are still many people investigating the thing called "propagation".

It is possible using only propagation as a reason that a signal which is generated horizontal from some part of the world is strong vertical on the opposite part of the world.
Heck it happend to me aswell, i recall when i was in afghanistan a qso with Italy where the italian was mutch stronger on his 5/8 wave then he was on a 5el beam..

Another thing to bare in mind is the take-off angles a yagi produces on the back of the beam at a "elevated" heigth above ground.
Where computer modeling migth show a -40 dB Front to back in a nice azimuth plot at 0 degrees...it can be as low as -12 dB for example at 45 degrees.

That produces only 2 Sunits below a "orientated dipole.
That 45 degrees is for example your average sproadic E propagation
A low placed 5/8 wave with a decent groundplane will have a rather low take-off angle and can show a negative gain at that 45 degrees.

And of course the direct toa.
The 5/8 wave will often have many more "lobbs" with heigth compared to the yagi. There for it has more "spots" where a received signal migth be stronger.

So, all in one...yes it is certainly possible....
But, it is also known that a high place beam will outperform any omnidirectional vertical antenna on real dx in say..at least >95 procent of the time.

End of answer.

THE THING TO REMEMBER:
-1 no "real" bennefit using vertical or horizontal from a propagation point of view
-2 horizontal antennas bring in additional ground gain
-3 the take off angle from a horizontal antennas is better to control.
-4 vertical antennas are stronger on ground wave.

hence: DXing -----horizontal
Local ----- Vertical

Kind regards,

Henry 19SD348
All about antennas

 

[airplane1]

I know one thing for sure, I do not see Ham operators running their beams vert as far as I see around here and there are a lot of hams in my area. They are all running horizontal.So I would go horizontal because all these operators can not be wrong.

 

[wavrider]

I know one thing for sure, I do not see Ham operators running their beams vert as far as I see around here and there are a lot of hams in my area. They are all running horizontal.So I would go horizontal because all these operators can not be wrong.

Good point and Henry all ready explained why, Horizontal the TAO can be controlled and you get ground gain.

On 11 meters most ops use vertical polarization. ( Easy to stick a fishing pole in a tree and get the gain from a splatter box amp). So if wanting 11 meter ops then vertical would be the best for all around use, local and DX.

If just concentrating on DX then horizontal is the way to go and use your vertical for local talking.

It all depends on what you want to operate as, if you want to be a big gunn local then vertical on the yagi.

 

[GnG8d]

I know one thing for sure, I do not see Ham operators running their beams vert as far as I see around here and there are a lot of hams in my area. They are all running horizontal.So I would go horizontal because all these operators can not be wrong.

Of course not

 

[Mr Clean]

Pehaps my answer to Jay in the mojave on another forum migth be of use:
He found it interesting that "his" 5/8 wave was from time to time stronger than his 5el Yagi.



THE ANSWER:
There are a couple reasons why a signal could be stronger..

Propagation which arrives at your location tends to have a circulair polarisation.
If the HF signal penetrates the inosphere the signal gets broken up in 3 parts:
1 the ordinary 2 the extraordianry en the Z component.
Due to the influence of the earth magneticfield each part gets a circulair polarisation.

The stronger the magnetic field (near south/north pole) the stronger the signal will rotate.

From that point of view it has no advantage using either a vertical or horizontal polarisation.
Of course one has to bare in mind the additional ground gain a horizontal antenna brings in.

Now, this is most of the time the case...however there are still many people investigating the thing called "propagation".

It is possible using only propagation as a reason that a signal which is generated horizontal from some part of the world is strong vertical on the opposite part of the world.
Heck it happend to me aswell, i recall when i was in afghanistan a qso with Italy where the italian was mutch stronger on his 5/8 wave then he was on a 5el beam..

Another thing to bare in mind is the take-off angles a yagi produces on the back of the beam at a "elevated" heigth above ground.
Where computer modeling migth show a -40 dB Front to back in a nice azimuth plot at 0 degrees...it can be as low as -12 dB for example at 45 degrees.

That produces only 2 Sunits below a "orientated dipole.
That 45 degrees is for example your average sproadic E propagation
A low placed 5/8 wave with a decent groundplane will have a rather low take-off angle and can show a negative gain at that 45 degrees.

And of course the direct toa.
The 5/8 wave will often have many more "lobbs" with heigth compared to the yagi. There for it has more "spots" where a received signal migth be stronger.

So, all in one...yes it is certainly possible....
But, it is also known that a high place beam will outperform any omnidirectional vertical antenna on real dx in say..at least >95 procent of the time.

End of answer.

THE THING TO REMEMBER:
-1 no "real" bennefit using vertical or horizontal from a propagation point of view
-2 horizontal antennas bring in additional ground gain
-3 the take off angle from a horizontal antennas is better to control.
-4 vertical antennas are stronger on ground wave.

hence: DXing -----horizontal
Local ----- Vertical

Kind regards,

Henry 19SD348
All about antennas

I agree with all this except one thing and that is vert being better for groundwave. It is in most cases if the other station is vert but I can talk farther on the flat side to another flat side antenna groundwave but im sure henry means that most of the time locals are using vert. And yes I know henry knows more about antennas than I ever will lol. Farthest ive talked vert groundwave was about 160 miles. Horz was about 220 miles. And this was with very good groundwave conditions.

 

[Mr Clean]

PS I love having both polarities on a beam.

 

[hookedon6]

ok,................. I start it

there is no "ground wave"propagation on 11 metersop:op:

 

[HomerBB]

Of course not. There is only talking a long long way when no skip is in . . .

 

[Captain Kilowatt]

ok,................. I start it

there is no "ground wave"propagation on 11 metersop:op:

I was going to say that but decided to wait and see who else wanted to jump in. I KNEW someone would. I wish I had a dollar for every time someone called direct wave propagation ground wave. True ground wave propagation is just about non-existent above about 3 MHz.

 

[radioreddz]

one thing for pea picken sure you won't go wrong having a dual polarity antenna one like a maco 5 element maxi beam. screw that wire reflector hog wash. 5 element great gain with a pretty good beam width so you don't have to pin point so much like you do with 7 or 8 elements. also it seems like horizontal is the way to go for long distant ground wave contacts. less noise from man made sources and horzontal to horizontal ur locked in. with Dx on 11 meters cb band either will work depending on how the signal returns to earth. a horizontal signal after hitting what ever propergation layer is active at the time may reach it's target vertical polarized oir vice versa. if you can afford it and have the ways and means and area for it go with the dual polarity beam antenna. with that bein said a 4 element quad or a maco 5 element maxi beam.

 

[Henry HPSD]

Hello Guys,

Regarding that ground wave thing.

For sure propagation is not my best side, and i am hoping to learn.
So just saying...that is wrong....isnt helping me or others.
Olease do take the time to explain why.
And try to teach as i am trying to do.

My findings are based for example on the ARRL antenna book and i quote:

The term ground wave has had several meanings in antenna literature, but it has come to be applied to any wave that stays close to earth. Reaching the receiving point without leaving the earth lower atmosphere. The ground wave could be traveling in actual contact with the ground (as in fig1) where it is called "the surface wave". (end of quote)

So please do explain: why i shouldnt have used the term "ground wave" in reference to 11meter ? It seems to me it is applied for more than one purpose.
To refer to it as "direct wave" would also ask for a explination.
As were talking for example "100 miles and futher away..far beyond the direct line of sigth (including the 1/3 extra distance from the radius pf earth as should be applied accourding the arrl antenna book for direct line of sight.)

The reason i mentioned vertical / horizontal in that aspect is due the following
Vertical polorised waves dont suffer that much from the absorbtion of the earth as horizontal waves are supposed to do . Because the electrical field component is straigth in reference to the earths surface. (there are less earth currents).

We all know the earth is a major factor in absorbing "ground waves" and that this is less on low bands (160/80 etc) and stronger on high bands (like our 11/10 meters) that doesnt mean we do not have any "ground wave..."

The above is by the way based on "behaviour of shortwave signals from H. Molhuizen".

But im also perfectly aware that bookes can be wrong, or the interpertation of the reader is not rigth. Thats why we test all the antennas and all the idea's.

So, do explain why some of you guys are saying 'no" ?
As i havent changed my interpertation yet and i really would like if it is inaccurate.

I have also send a email to my "propagtion-guy" (his job is to predict propagation for world services and defense) hoping he will provide futher insigth aswell.

Kind regards,

Henry HPSD
19SD348