Trying a home made yagi

[HomerBB]

I have begun to assemble a home made 3 element yagi.
I've started with the basic parts, and will be putting it all together in the next couple of days when I get time off from work.

Some photos of the start is here:

HomeBrew Yagi

In fairness regarding the construction materials, The pipe is all EMT (electrical conduit), for now, not aluminum. If the antenna proves worthy, I'll look into upgrading the cost to aluminum.

The PVC is to help with attachment to the top fence rail boom, and for easy adjustment of spacing. The radials can be slid in and out on the boom like a trombone movement to get my best performance.

I've looked at several matching methods, and am leaning toward this one:

The DK7ZB

Any ideas forthcoming from you fellows will be discussed and considered.

Thanks,
Homer

 

[Mr Clean]

DX Engineering has everything for a Yagi if needing anything. I am going to build one sometime. Getting ready to pour concrete for a Tower myself. 5 element should be up in a month or so. Going wih a H/V Maco but if it dont handle the weather a Yagi built with DX parts will be going up

 

[HomerBB]

DX Engineering has everything for a Yagi if needing anything. I am going to build one sometime. Getting ready to pour concrete for a Tower myself. 5 element should be up in a month or so. Going wih a H/V Maco but if it dont handle the weather a Yagi built with DX parts will be going up

Sounds like you are going for the long haul.

I am at simply experimenting at this stage, but may be doing something more permanent if all goes well.

Thanks for the tip on parts.

 

[HomerBB]

Got the elements cut and set to the spacings. Have it set to a 45* angle and just need to get the matching system made and mounted, raise it up higher and begin to test it.

Photos:

Yagi Update

 

[HomerBB]

Added my version of the match system.

Tested SWR:

ch 01 1:7

ch 19 1:4

ch 40 1:2

with no further tuning than the match on the antenna as shown.

All the time I had to fool with it so far. Will try to get better reports than truck drivers saying, "It's workin' driver"

I'll try to get a few field strength numbers, too. I need to get it up into the air a little.

photos:

update02

 

[W5LZ]

About the only thing that I see as not exactly optimal is the 45 degree tilt thingy. 'Course, that's just an opinion that really shouldn't affect you much till you try it to see the results. May not make any difference then either!
Which matching system? Whichever is most practical for you. Sure there are some differences but if done at least half way right most of them will work just dandy.
I think you're doing just fine so far. Keep going!
- 'Doc

 

[HomerBB]

Thanks, Doc.

I'm not high enough to let it all the way vertical, and DX is so poor I am not going to run it horizontal. Gotta figure out how to get it higher soon.

The photos were here http://www.cirilo.net/cac/yagi/update02/album/index.html

 

[BJ radionut]

Great Effort!

BB; I have been following your effort...Looks cool!
The "tilt" will get you kinda the best of both worlds...kinda Vertazonical...or is it Horavertical? Run it...till you can make the change...may surprise you that way.
Your SWR measurements tell me the driver is a little short or you may have it setup for a little "up the band"...either way it will work FB...enjoy GL with your new RADIOFUN toy!
All the Best
BJ

PS: Just a personal note here...I was always and equal spacing kind of a guy. I always thought it gave me the best of both worlds...gain and rejection and easiest to balance the weight on the boom...but HEY...that's me
Good Job...
BJ

 

[RickC.]

I was going to ask you how you planned to match it and was guessing a Beta match since the DE looked to be insulated. Parallell coax Q-section.... Well, why not?

What are the element spacings?

Good stuff!


Rick

 

[HomerBB]

I was going to ask you how you planned to match it and was guessing a Beta match since the DE looked to be insulated. Parallell coax Q-section.... Well, why not?

What are the element spacings?

Good stuff!


Rick

The boom is chain link top rail, 1 1/4" galvanized steel.

The dimensions I am starting with will be these (in the photo no elements are cut to length, yet):

Frequency = 27.185
Reflector length = !8' 1 3/8"
Driver length = 17' 2 1/2"
Director length = 16' 6 5/8"

Spacing:

Reflector to driver 7" 3"

driver to director 3' 7.5"


One reason for the 1 1/4" pvc nipples on boom holding the elements was so I could adjust the distances between all the elements by simply sliding them in and out.

 

[BJ radionut]

Beam specs

BB: Just curious to how you calculated the element lengths and element spacing your using,
Thanks
All the Best
BJ

 

[Marconi]

HomerBB, I agree with BJ radionut regarding the advantages of more balanced spacing vs. optimized spacing. I have tried some of the optimized spacing ideas with my Wilson 4 element yagi that Maco and others suggest. But, I always end up back with a more balanced spacing across the boom. I even find field strength readings were better with my more balanced construction. I would be interested to see some of your FS comparisons though.

I have also noticed that my yagi is much more responsive when I am able to keep the boom straight and all the elements lined up evenly, including the sag. The reflector often droops the most, and I was suprised at the ill-effects that a bad alinement caused with my rejection, both back and to the side.

Your measurements seem a bit short based on your CB bandwidth results and your expected center at 27.185. I don't know how your element diameter compares to Maco 103C either, but their elements are also a few inches longer. I think you are using 1/2" conduit, so the element size should not be a big factor when comparing to the Maco.

Your work look nice and neat. Get it up a bit more and keep us posted on your success.

Just curious what make the boom look black in the pictures?

 

[HomerBB]

BB: Just curious to how you calculated the element lengths and element spacing your using,
BJ

I used this program, QY4 for my current layout. I found it by searching Google. Since receiving these inquiries and suggestions after posting, I've gone back to it looking for other possible arrangements without increasing the overall size too dramatically.

This is one possibility,

Not only do I need the size to remain within certain limits, but I don't want to have to change the match up too much.

 

[HomerBB]

HomerBB, I agree with BJ radionut regarding the advantages of more balanced spacing vs. optimized spacing. I have tried some of the optimized spacing ideas with my Wilson 4 element yagi that Maco and others suggest. But, I always end up back with a more balanced spacing across the boom.

Your measurements seem a bit short based on your CB bandwidth results and your expected center at 27.185.

Just curious what make the boom look black in the pictures?

To answer the last first, the color is a combination of shadowing, and the age of the boom. The top rail is several years old.

You are correct that the diameter is 1/2".

I tried the equal spacing in the program I'm using and the results are different as to the anticipated F/B and Gain, within the program. The plot feature, F3, offers a peek at the theorized results graphically.

I agree the DE length is short for the frequency I want, so back to that for correction.

I'll keep working on it.