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Sirio 4 element putting toether

cowboytta

Member
Feb 26, 2019
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I don’t know anything about beams. Got a Sirio 4 element I’m trying to put together. For example the instructions say for 27.0MHz… A (reflector) is 760 mm. My question is that 760 for each side of the element or half of 760 for each side….making 760 total. Thanks
 

I don’t know anything about beams. Got a Sirio 4 element I’m trying to put together. For example the instructions say for 27.0MHz… A (reflector) is 760 mm. My question is that 760 for each side of the element or half of 760 for each side….making 760 total. Thanks
Just pulled up my SY 27-4 pdf. where it's showing the end tuning element length of 690mm; yes that's each 1/4λ side. That's a big jump, 690-760mm? I suspect 690mm is for the lower range of full potential of the antenna (chasms of 12M), not just 26.9-27.5mHz. The table you're looking at, I have somewhere as well, though mine is for the the SY-3, the 3 element version. I did a little math and found the length for 27.200mHz, calculating figures given for 27.0 and 27.5mHz. I did that for each of the 3 elements. Look to cbjunkies; "Sirio SY-3 or SY27-3" Can't say whether those figures will jive with your calculations; perhaps use as a check.

Good luck with the Gamma Matching.

Remember, it's not self explanatory if you still have a question. Ask the question and ignore Igor. There is a difference between one individual's help and Shinola.





 
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Thanks 98,338 and AL Buckeye...most the time I try to ignore people like the other guy....they seem to forget everyone starts at the bottom at one point in time.
I adjusted the mm starting at 728 for the reflector....got do some fine tuning but the beam is working good.
Again, thanks
 
Thanks 98,338 and AL Buckeye...most the time I try to ignore people like the other guy....they seem to forget everyone starts at the bottom at one point in time.
I adjusted the mm starting at 728 for the reflector....got do some fine tuning but the beam is working good.
Again, thanks
I can't relate to 728mm. But by referring to an Average from a small handful of calculators for 27.205mHz yagi element lengths, I can give full length for 3 of the 4 elements. The 2nd Reflector (4th element) will be shorter than the first ;) that's all I can say on that.
Ref: 18'3.24"
DRVN: 17'3.72"
Dir: 16'3.36"
Notice the 1' differences. That's 6" per 1/4 wave side. Does the 4th element follow the pattern, heliphino?

Do you mean the "Director" is working good; you've gotten the Gamma Matching down to 2:1 or less thus the entire beam is working good? Hot Damn you're good! The entire rig is a Yagi-Uda Beam, quite commonly referred to as simply Yagi or Beam, interchangeably.

My Sirio SY-3 is my first beam antenna. Based on experience with a SD27, same as Driven element as SY-3 and SY-4 I was sure tuning the SY-3 would be a breeze, not so.

I've read, unlike a vertical monopole, with horizontal dipole you should be prepared for an upset, to a degree, IF you move forward and raise the antenna up to 1/2 wavelength height. You're likely find an SWR change. Hopefully better than 1:1, if such is possible, but likely not. I've heard most recently, 1.2:1 is better that 1:1. I'm not educated on the why details. Something about more cushion for the pushing.

I'm still in the 12' tuning stage with my SY-3. I'm very slow. I plan on raising it in stages. I've a 25' mast anchored at 15' that lowers very easily by rope and pulleys. I'll be much quicker during this stage. 15#s, w/ antenna and rotor, swinging in the wind that last 10' of fence top rail; not wise. That is my 2nd stage of tuning before pushing it up it to it's final 36' resting stage. Whatever the SWR then, I live with.
 
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728 mite be kind of an oddball but I use the upper end of 11meters so kinda centered on 27.3050. SWR, I got down to 1.3 but going for down a little more. Right now I only got it at 10' but will end up at 30' with vector 4000 on top of it or may put on my other tower which is 56'. I know very well about slow...I'm in my mid 70's....slow is the only speed I got.
 
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Vector 4000 just above the SY-4 you say?
I had thought to mount my monopole Imax 2000 above the SY-3; the several inquiries I made into the feasibility of function was met with negatives.
But you know better? That's encouraging.

Yep, 1.3:1 does indicate "working good". Congrats.
It's not too late for you and likely never needed by me; I applied aluminum anti-seize to element sections. Should it ever become necessary to disassemble.
The sections fit snuggly together and corrosion is sure to occur.

I too frequent that end of the band. But tune for the breath 1-40. I get 1.05:1 (digital SWR) through out for 5/8 monopole. Trying to get the SY-3 close.

What do you have on the tower?
 
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Vector 4000! 27.8' 7/8λ, was unaware of them. How many sections? How well does it stand up to winds? That is how upright does it remain during storm winds?
The Imax 2000, nearly all fiber glass does take to leaning considerably, 20-30d, but bounces right back; it is only 3 sections. Extra freight costs. I also triple waxed my second one with Carnauba before putting it up to ward off fiberglass breakdown. My first one was up about 7 years before it battled with oak tree branches during tropical storm winds. Can't say the Carnauba wax helped it any. It was splintered from one end to the other.

I'm not a nit picker though I'm inclined to check details; to broaden my education. And validate my negativity towards advertising. The 7/8λ in this case; a spectacular advertising gimmick aimed at CBers. It is pretty close to 7/8λ for a 10M band; but closer to 6/8λ for 11M. Having said all that, what are your SWR readings for 27.305MHz.

I'm curious because of the controversy between the value of 5/8λ over 1/2λ for 11M. Some, and perhaps more opinions are that the 1/2λ is superior. Opinions be damned, how is the performance of the Vector 4000. Plenty on the receive and TX? Do you use foot warmers or heavy wool socks?
 
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Really? Why cant you just answer my question instead of trying to make me look dumb.
sp5it is trying to get you to STOP LOOK N THINK.
kinda like when id try to teach newbies to drive a big truck,think what you gonna do when im not with you? and if i direct you backing in every dock your never gonna learn. i only show you a few times n expect you to use your mind. sp5it n i see the same on many things
 
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sp5it is trying to get you to STOP LOOK N THINK.
kinda like when id try to teach newbies to drive a big truck,think what you gonna do when im not with you? and if i direct you backing in every dock your never gonna learn. i only show you a few times n expect you to use your mind. sp5it n i see the same on many things


Amen to that. Waaaaay back in grade five I had a teacher that EVERY time you asked him how to spell a word, regardless of what word it was he would always spell out d-i-c-t-i-o-n-a-r-y. It was his way of getting us to learn for ourselves and not simply rely on someone else. With the amount of information we have available at our fingertips today, combined with a little common sense, you can pretty much find ANYTHING yourself. I cannot remember the last time I actually asked someone how to do something. Youtube has been a blessing for how-to projects.
 

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