Yagi antennas for under $5

[kf4lne]

Right, no other element has any electrical connection to it.

 

[KC2GVX]

I made one today!

Well, I took to the shop and put one together today. Granted, this is my first and has some bugs, but the next one I will make will be weather-proof. I mounted this one on a 8' piece of PVC pipe and am using an outdoor umbrella stand for portable testing. Below is the picture of my model, as followed by the directions laid out above. I tested outside here in Toms River, NJ and was able to get Burlington County TRS, Manchester TRS, & Jackson TRS all with 99% decode on the PRO 96. I was able to also get the Ft. Dix/Mc Guire TRS CC on 408.95. This antenna is excellent, and the next one I make will be more "professional" I am still testing the reception, and so far I was able to pick up Brick Township input on 458.050, which I never did before.

 

[kf4lne]

Good to see another one built and put to use! I hope you guys get a lot of good use from this.

 

[richrowl]

Yagi construction hint

Drilling hoes in the boom keeping all the elements in a vertical line can be tricky.
To keep all of them in a perfect line try this:

Lay out the spacings on the boom and mark the centers for the holes.
Get a piece of wood the length of the boom, furring strip, 1X4 or whatever is available.
Drill one hole for the reflector.
Using this hole attach it to the piece of wood with a nail, screw etc.
This will hold the boom in a secure position and all the other holes can be
drilled perfectly verticle.
Remove the nail/screw and attach the elements and you should have something
professional and proud to look at.

 

[ka3jjz]

Dan this is exactly the sort of stuff the Wiki can pretty easily capture. Your description and pic in the beginning of this thread are very good indeed. If he formula for the director/reflector and spacing are included, it would be nearly ideal. 73s Mike

 

[kf4lne]

I am working on getting more pics to show the details of construction and will be adding it to the wiki soon

 

[ka3jjz]

VG Dan. We have a section on the Scanner Antennas wiki for homebrew projects - once you've got your page set up, be sure to link to it there. We don't want to have another orphan page. Be sure to include the forumlae for the director, reflector, spacing and so on - that's a critical piece of the puzzle.
Thanks for putting this in the wiki. It's much appreciated. 73s Mike

 

[srt1026]

if not too worried about weather proofing, try using a yard stick as your boom. hot glue the elements to it--keeps them vertical, and the measurments are right there for you . drill 2 holes behind the reflector for a 'U' clamp to a mast, or a hole in each end to hang with string in the attic.

 

[TeRayCodA]

Hi,
I made several of these out of 7/8 " aluminum tubing with 3/16" welding rods for the elements.I used "pushnuts" to keep the elements in place on the boom.
A gamma match was then built for the tuning.
A drill press can can work wonders for building these and getting them straight.
I made mine for GMRS band.
Keep in mind,that any constuction built from wood(when it gets wet)could change your impedence.Why not use some inexpensive PVC pipe for the boom?
I had some plans for these from a Rat-Shack antenna book.I deviated a little from their plans to add the gamma match.They work well.
See mine at:

 

[TeRayCodA]

The gamma match I made is from a SO-239 antenna "feedthrough" connector,drilled/tapped for a 8/32 S/S screw,to attach the gamma rod.
I would suggest using a " N" type connector instead,if I had to do it over again.That is what I had handy at the time.But,it still works great.
The driven element is 1/2" aluminum tubing,the shorting strap is made from some scrap aluminum.I bought most everything at Lowe's for this project.

 

[TeRayCodA]

And,if you build one of these,they are DC grounded through the support pipe.

 

[trainman111]

I have built a 3 element yagi tuned to 161.000 Mhz. using instructions from http://www.alabamarailfan.com/scanner.php. The directions didn't say anything about having to cut the driven element in half. It did say however that it does look like an electrical short-circuit but also that "it behaves very differently to the radio frequency signals we are trying to capture" (being the railroad band). Is this true to most all other bands or should the elements be cut in half if I were to make another yagi for a different band?

Nick

 

[TeRayCodA]

I have built a 3 element yagi tuned to 161.000 Mhz. using instructions from http://www.alabamarailfan.com/scanner.php. The directions didn't say anything about having to cut the driven element in half. It did say however that it does look like an electrical short-circuit

Yes, that is what I have seen also,but I adapted a gamma,after looking at a yagi where I work,and noticed how easy it would be to build one.

 

[joetnymedic]

I built one. came out pretty good. doesn't look like junk. Works ok too. The Fed dipole I made works great. Pulls in stations in VHF from miles away. At this point I'm guessing 60-70 miles. I love the thing. Kokomo turned me on to it. I have to paint it and put it a bit higher but even where it is now I'm doing awesome. I'm thinking of doing a UHF and 800 mhz version with the leftovers. Just not sure which yet. I'd entertain making them and shipping as long as they were paid for. Gives me something to do. Relieved alot of stress this last few days.

Joe

 

[cnmsales]

Possible to add more step by step pictures to the PDF? Thanks in advance.

 

[ocscan]

The gamma match I made is from a SO-239 antenna "feedthrough" connector,drilled/tapped for a 8/32 S/S screw,to attach the gamma rod.
I would suggest using a " N" type connector instead,if I had to do it over again.That is what I had handy at the time.But,it still works great.
The driven element is 1/2" aluminum tubing,the shorting strap is made from some scrap aluminum.I bought most everything at Lowe's for this project.

What is the purpose of a gamma match and can you break down its constuction a little more...will be constructing an 800mhz model this weekend.

 

[ka3jjz]

Dan, have you considered putting that PDF document on a file server somewhere? I'd like to link it in the Wiki. Homebrew projects such as this are always a welcome addition.

73s and thanx...Mike

 

[kb2vxa]

Hey Dan, now you'll have to tell them how to build an Armstrong rotor to turn the beams.

 

[ocscan]

I will be using this Antenna indoors so I will use the MKI, Model I manuel rotor....

 

[kyguy]

UHF & 800mhz

What would be really sweeeeeeet is if someone could figure out a way to connect the UHF + 800mhz to feed off of one coax !! Regardless, these plans look pretty cool - give me something to try AFTER all my honey-do jobs are done (?)