How would you direct feed a quad without issues?
Would it not require some sort of balun for it to radiate correctly?
Would it not require some sort of balun for it to radiate correctly?
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High power 1.1 balun for quad
- Thread starter -=PEAKABOO=-
- Start date
Yes. This is a good solution IF the load is similar to the feedline impedance. Otherwise things get complicated. Force 12, a respected antenna manufacturer among hammy hambones uses this trick on some of their products.
HELLO PEAKABOO, ANY QUAD WITH MORE THAN 2 ELEMENTS CAN BE DIRECT FED AS LONG AS IT IS BULIT CORRECT. I RUN A 4ELEMENT ON 30FT BOOM THAT I BUILT(EZNEC PLUS) DIRECT FED 50OHM COAX NO ISSUES AT ALL. WITH MODERN TECHNOLOGY ALL IT TAKES IS KNOWLWDGE, PATIENCE AND YOU CAN BUILD ALMOST ANYTHING.
Hi,
I did a 35 Kw balun for a 11m band quad.
You can check it here;
Balun EA1DDO para Antena Cubica, Balun EA1DDO, Quad antenna balun, Balun de cuarto de onda por malla, Quarter Wave Sleeve balun, Corrientes de modo comun, Common mode currents, balun, choke antena
73, Maximo - EA1DDO
I did a 35 Kw balun for a 11m band quad.
You can check it here;
Balun EA1DDO para Antena Cubica, Balun EA1DDO, Quad antenna balun, Balun de cuarto de onda por malla, Quarter Wave Sleeve balun, Corrientes de modo comun, Common mode currents, balun, choke antena
73, Maximo - EA1DDO
Just read what Henry HSPD suggested,is the same
I have used the pawsey stub with good results in a 4 element marine vhf quad vertical polarization and 3 element 11 mts. yagi
the question is this:
would the quarter wave sleeve be more efficient and less affected by the nearby mast and pole?
both are easy to construct.
would the quarter wave sleeve be more efficient and less affected by the nearby mast and pole?
both are easy to construct.
Hi,
Gamesetter, yes, it is a quarter wave sleeve system aplied to a quad antenna.
I never seen that before (quad with quarter wave sleeve). I just got the idea because that guy is using really hign power and usual balun did not fit.
This balun is not affected by boom. The one with that issue is the Pawsey stub. Both cables should be equal and are affected by metals around.
We are finishing now this first balun, then I post some pictures.
Thanks
73, Maximo - EA1DDO & HK1H
Gamesetter, yes, it is a quarter wave sleeve system aplied to a quad antenna.
I never seen that before (quad with quarter wave sleeve). I just got the idea because that guy is using really hign power and usual balun did not fit.
This balun is not affected by boom. The one with that issue is the Pawsey stub. Both cables should be equal and are affected by metals around.
We are finishing now this first balun, then I post some pictures.
Thanks
73, Maximo - EA1DDO & HK1H
Hi again,
It is not same.
There are different aproaches to develop a balun using 1/4 and 1/2 wave coax; quarter wave sleeve, pawsey, bazooka, collins, etc.
Those 1:1 then there are some modifications to do same with 4:1 impedance tranformation.
Those kind of balun, are only useful for monband antennas. Once you go for a multiband or even wide band, the balun loss his effect.
Perhaps is the reason because nobody uses them.
It is not same.
There are different aproaches to develop a balun using 1/4 and 1/2 wave coax; quarter wave sleeve, pawsey, bazooka, collins, etc.
Those 1:1 then there are some modifications to do same with 4:1 impedance tranformation.
Those kind of balun, are only useful for monband antennas. Once you go for a multiband or even wide band, the balun loss his effect.
Perhaps is the reason because nobody uses them.
am i reading this article wrong?, the maths don't look right,
he calculates dimention A ( the 1/4wave pipe ) using 66% velocity factor stating that 66% is the coax vf when the coax's own velocity factor has no bearing on dimention A,
remember coax has 3 rf conductors, the outside of the center wire, the inside of the braid and the outside of the braid, your 66% comes from the slowing effect on signals travelling inside coax such as rg213 rg58 ect,
when you add the pipe you effectively create a new FAT concentric coaxial cable formed by the outside of coax braid and inside of the pipe, anything else in the cavity such as your coax outer jacket and any filling you may use will reduce vf ( shorten the pipe for the same elecrical 1/4wavelength )
or looking at it a different way you could have different electrical lengths due to the FAT coax's velocity factor for the same physical pipe length,
its the velocity factor of this new FAT coax you form that determines the correct 1/4wave electrical length of the sleeve balun, not the freespace pipe length or the vf of the coax you use inside it.
he calculates dimention A ( the 1/4wave pipe ) using 66% velocity factor stating that 66% is the coax vf when the coax's own velocity factor has no bearing on dimention A,
remember coax has 3 rf conductors, the outside of the center wire, the inside of the braid and the outside of the braid, your 66% comes from the slowing effect on signals travelling inside coax such as rg213 rg58 ect,
when you add the pipe you effectively create a new FAT concentric coaxial cable formed by the outside of coax braid and inside of the pipe, anything else in the cavity such as your coax outer jacket and any filling you may use will reduce vf ( shorten the pipe for the same elecrical 1/4wavelength )
or looking at it a different way you could have different electrical lengths due to the FAT coax's velocity factor for the same physical pipe length,
its the velocity factor of this new FAT coax you form that determines the correct 1/4wave electrical length of the sleeve balun, not the freespace pipe length or the vf of the coax you use inside it.
If the question is still "High power 1.1 balun for quad" .......... the answer is to directly feed it with the coax.
I know peak doesn't post here anymore, but a 4 element will present a 50 ohm load and a quad has the ability to suppress CMC on it's own because of the magnetic loop.
I know peak doesn't post here anymore, but a 4 element will present a 50 ohm load and a quad has the ability to suppress CMC on it's own because of the magnetic loop.
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