Sirio SY27-4 Beam Install

[N8MJS]

Beam works very well. Use it all of the time skip is in. Someone recorded me out in Mississippi today, and played it back. I was impressed to say the least; conditions being what they were. For just using 50 watts, this beam apparently works better than I anticipated. SO does this radio and mic arrangement.

Yes; you can use a TV rotor with this antenna. But you will need to get a support/thrust bearing for it. This will remove nearly all of the side wind load on the rotor. That will keep it from being damaged and give it a longer life. Doesn't cost that much and is easy to install too.

Channel Master Rotors 9521A and TB-105 Support Bearing Used to turn your TV, HDTV or other communication antenna toward the strongest signal

I purchased a new 4 element sirio. I notice the factory lengths of all elements uncut are set for 26.500 mhz.
I don't want to have to cut the ends of each element. The manual gives a cutting chart for 27 mhz, 27.500 mhz, and various 10 meter frequencies.
I was wanting to use this for the CB channels and possibly up to 27.555.
Will post pictures of new manual. The one on Google was pre tunned for 27.200 mhz. Totally different than mine.
I'm going to build it and not cut anything and see what happens,
then go from there.

 

[Robb]

Easiest way is to purchase a tape measure that is scaled to m/cm/mm from your local large chain hardware store for about $6 (think that is what I paid for it anyway).

Used it on assembling the SIrio Vector 4000 vertical I put up too.
Made assembly a cakewalk.

 

[N8MJS]

Easiest way is to purchase a tape measure that is scaled to m/cm/mm from your local large chain hardware store for about $6 (think that is what I paid for it anyway).

Used it on assembling the SIrio Vector 4000 vertical I put up too.
Made assembly a cakewalk.

I have the metric tape measure.
so cutting elements is a must then?

 

[firerunner]

Just push them inside if you can don't cut them.

 

[firerunner]

you can slit the ends with a hacksaw and just use small hose clamps to tighten them in place.

 

[N8MJS]

I was able to adjust my gamma match for a very low swr on 27.385 via a 3 ft jumper and my antenna analyzer.
No cutting of any elements. At 6 ft off ground I got a swr of under 1.4 on all 40 channels.
I then adjusted for lowest swr at 27.385.
I then raised the antenna to approx 8ft off the ground.
Ran 75ft of rg8x from beam to shack.
Still seeing very low swr on all 40 cb channels. Even low swr from 27.405 to 27.725.
My hope is once its on top my tower things stay pretty close to what i have now.
Not sure why i would want to cut
Element lengths at this point.

 

[357magnum]

Thanks for all this info , I've had one in the box in my garage for almost 2 years now with no help to get it up . I'm not afraid of heights as it will be over 30' to the base @ the peak of my house , but I had a Gran Moll seizer a while back and I'm not suppose to be doing things like that by myself . I still go up there on occasion but try and not spend much time up there . Hopefully I'll get it up before the next " Good " cycle . 73 and God Bless , Leo

 

[The DB]

Not sure why i would want to cut
Element lengths at this point.

The reason they want you to cut has nothing to do with the antenna's ability to be tuned via the gamma match. The reason they tell you to cut is because different frequencies work better with different lengths, especially when working with yagi antennas.

The antenna will still function as a yagi, however, either gain, the front to back ratio, or more than likely both, will not be up to spec unless said elements are cut to length.


The DB

 

[N8MJS]

The reason they want you to cut has nothing to do with the antenna's ability to be tuned via the gamma match. The reason they tell you to cut is because different frequencies work better with different lengths, especially when working with yagi antennas.

The antenna will still function as a yagi, however, either gain, the front to back ratio, or more than likely both, will not be up to spec unless said elements are cut to length.


The DB

Very good point. I went back and cut each element to the specifications for 27.500 MHZ per the manual.
With my antenna approximately 8 feet off the ground horizontally polarized I'm seeing my resonance point at 27.500 exactly.
I did Notice by cutting the elements it did make my standing wave at 26.965 mhz come up to a 1.9 SWR.
At 26.925 mhz I get a 2.0 swr.
At 28.420 I get a 2.0 swr.
I'm temporarily using 75 ft of rg8x made by DX engineering.
The antenna will be placed at approximately 45 foot off the ground on my tower and be fed with 75 ft of LMR 400.
I have a IMAX 2000 at the top of my tower.
The Sirio will be placed just below that.

 

[Shadetree Mechanic]

Just dug this up, thinking about getting a 27-4 just to get something going without spending a lot of money.

 

[357magnum]

Every one by now knows I have one , sitting in the box through Walmart , Free Shipping $159 delivered . Maybe I'll get help & get it up !

 

[firerunner]

Hahaha, yea Leo I will believe when you post a picture of it up!

 

[firerunner]

Shadetree it's a decent antenna for the money and mine worked pretty good. It's not super heavy duty but not too bad. Good luck!!

 

[357magnum]

Capt , I can post a pic of it sitting on the Garage floor in the un-opened box !

 

[firerunner]

Leo I was talking about up in the air!