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Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters

Created by on 2022-07-10

 
Wire homebrew Yagis can perform with the better commercial aluminum Yagis.  After over 60 years as an amateur with many home-built antennas I have concluded that the wire Yagi is the best performing 40-meter antennas one can construct and maintain provided one has trees or other means to support the wire elements for a Yagi. No matching device required as the impedance will be about 50 ohms at a height of about 50 ft. or more above ground. I use RG8X for up to 1500 watts SSB.
 


It seems that many amateurs old and new shy away from wire beams because of the complicated presentations in articles on the internet with models, and complicated formulas involving math beyond many, myself included. If interested in a 3 or 4 element wire Yagi for 40 meters, just remember 369. Someone years ago, designed a 40-meter antenna named the 369 for 40 meters. Impedance was about 50 ohms. Gain at a 50 ft height and an element spacing of about 27 ft would be around 11dBi with about 14 front to back. 27 ft is about .20 wave spacing for 7.2 MHz. .15 to .25 spacing between elements will give about 50 ohms imp. close enough to match 50 ohm coax of your choice. back to the radio.
 


For those of us who do not model or have a lot of math capabilities it is not a problem. I think many amateurs, new and old, shy away from wire Yagis because of the complicated presentations one is able to find on the internet. Therefore, I am passing on my experience in this article to those who are looking for simple antennas that will hang in there with the better aluminum Yagis. 
 


Here is why: (1.) A wire Yagi properly spaced will not need a matching device for 50-ohm coax. 

(2.) For mono band operation, RG 8X, the less expensive coax, will do just fine for runs up to 150 ft in my experience for power levels of up to 1500 watts SSB. I normally run 1200 watts with an occasional 1500 watts SSB for DX contacts and have experienced no failures with RG8X of good quality from DXE and The Wireman. 

(3.) My wire Yagi antennas are all mono band so that keeps the design simple, Resonant frequency, and SWR adjustments are simple to monitor and adjust with an antenna analyzer such as a Rig Expert AA35 Zoom and others. 

(4.) Here are simple design parameters by others proven over the years to work for me. A wire Yagi is simply a dipole driven element, with a Reflector and one or more directors. I have found that the old 369 antenna designed by someone years ago works great today for 40 meters. Make the Director 63 ft, the driven element 66 ft. and the Reflector 69 ft. Spacing for 50 ohms impedance is about 27 ft. This represents about .20 wave length spacing at the center frequency of 7.20 MHz . Spacing of .25 wave also works for 3 or 4 elements to give about 50 ohms impedance feed point impedance at 50 ft height above ground. 
 


My 4-element wire Yagis at 60 ft send some power with 1200 watts SSB. If you want to design a wire Yagi for other bands keep it simple. Use the dipole formula for the driven element- 468 divided by the frequency. 
Make the director 5% shorter than the driven element. Make the reflector 5% longer than the driven element. Space at .15 to .25 ft wave. .20 will give around 50 ohms feed for a 3 or 4 element wire Yagi using #14 stranded copper THHN from Lowes or Home Depot. 


Get the wire Yagi as high as possible although lower heights will work well depending on your soil. When you are shooting supports up over trees for a wire Yagi, nothing is exact in feet and inches so there is no way one can do an exact model installation. Rounding off and keeping all the directors the same lengths has worked well for me over many years. 
 


It works great from my experience. Hope to hear you on the bands with a great signal from a wire Yagi.


 
Good Luck and enjoy the hobby.
Frank, K4RVN
 

 

KW9E2022-12-15
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Great article Frank. We’ve discussed these on 40m. I could only squeeze in a reflector and my 40 meter dipole is part of a home brew fan dipole (30, 40, 80). Not sure if the reflector is doing much but it’s only up about a quarter wavelength. Get about the same reports from Bill ZS1CCY

73 and keep up the good work

Pete KW9E
K4RVN2022-08-10
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
I find that today with the cost of wire, insulators, coax,
support cords, and connectors plus a 1 to1 balun that a 3 element 40 meter, 3 element wire yagi has a cost of about 200 bucks and change. Still a great antenna for the money in my view.
Frank
Reply to a comment by : W4VR on 2022-08-09

I've been using wire yagi antennas on 40 meters for the past 50 years. they work well and cost nothing...but you have to have the trees or poles to support them.
W4VR2022-08-09
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
I've been using wire yagi antennas on 40 meters for the past 50 years. they work well and cost nothing...but you have to have the trees or poles to support them.
KB3MKD2022-08-02
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Thank you!
Reply to a comment by : K4RVN on 2022-07-31

Yes you may, and thanks for your interest. Frank
Reply to a comment by : KB3MKD on 2022-07-30

May I use this article in our club newsletter?
K4RVN2022-07-31
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Yes you may, and thanks for your interest.

Frank
Reply to a comment by : KB3MKD on 2022-07-30

May I use this article in our club newsletter?
KB3MKD2022-07-30
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
May I use this article in our club newsletter?
K4RVN2022-07-26
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
John,
Thanks for your nice comments on my article. I have plans this coming fall to make a 4 element 20 meter wire Yagi
to replace one that a storm took down. It is too hot here now to work outside.
73,
Frank
Reply to a comment by : G4YDM on 2022-07-25

Thank you for your article, great to know someone else uses the wire beam technique, they work very well, I have them on ten meters and six meters, unfortunately, I do not have the real estate for twenty meters, the height being a problem, however, I have tried using yagi aerials in the vertical plane a few feet above the ground with patience you can achieve a good match. 73 to all de John G4YDM
G4YDM2022-07-25
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Thank you for your article, great to know someone else uses the wire beam technique, they work very well, I have them on ten meters and six meters, unfortunately, I do not have the real estate for twenty meters, the height being a problem, however, I have tried using yagi aerials in the vertical plane a few feet above the ground with patience you can achieve a good match. 73 to all de John G4YDM
K4RVN2022-07-20
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Took a look at your site. Nice looking wire beam.
It looks pretty high and spaced well. Nice looking station and locations.
Frank
Reply to a comment by : W4VR on 2022-07-18

I've been using wire yagi antennas for the past 40 years on 40....sure beats putting up a tower.
K4RVN2022-07-20
Re: Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Thanks for nice comments Edward.

Frank
Reply to a comment by : VE3CUI on 2022-07-12

Frank, a most inspiring article, indeed, that MORE than a few Amateurs of to-day --- who are otherwise dissuaded-discoraged from cutting wire & melting solder by the likes of EZNEC, & other computer modelling --- should take very seriously to heart... Personally for me, THE overall best performing 40-meter DX antenna was a 3-element inverted Bobtail array that the trees here supported some 30 years ago, or so, & was featured in an earlier volume of ARRL's "Antenna Compendium". That relatively simple antenna opened-up the path to Europe for me literally HOURS before the band was expected to open, & it was just a "killer" set-up for the "JA" crowd, too, on 7-MHz. Think "...classic Bobtail", only flipped upside down, & fed at the point where the centre vertical meets the horizontal wire linking all 3 elements together. So very easy --- yet, so very effective. One 40-meter antenna that I was just dying to make --- but could never come up with the height required --- was a vertical 2-element "gossamer" yagi, made of wire (driven element, plus director) & light wood spreaders, pulled tight, & made rotatable by way of a rotor sitting on the ground. I did just this exact same set-up back 40 years ago, but for the 20-meter band. That rotatable affair opened-up an entirely new world of DX'ing possibilities for me on 14-MJz. It worked so well in fact, that "CQ" published a construction article that I wrote about it in 1982: "A Tree-Mounted Vertical Yagi Array", I believe I called it. Imagine having a towerless rotating-directional array on 7-MHz, for practically pennies like that...?! It's all within the realm of reality, limited only by the height that's available for you to raise it, & the confines of your own imagination... Computer antenna modelling be damned...!!! :o)
W4VR2022-07-18
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
I've been using wire yagi antennas for the past 40 years on 40....sure beats putting up a tower.
VE3CUI2022-07-12
Wire Yagi Antennas are Simple to Construct and Maintain for 40 Meters
Frank, a most inspiring article, indeed, that MORE than a few Amateurs of to-day --- who are otherwise dissuaded-discoraged from cutting wire & melting solder by the likes of EZNEC, & other computer modelling --- should take very seriously to heart...

Personally for me, THE overall best performing 40-meter DX antenna was a 3-element inverted Bobtail array that the trees here supported some 30 years ago, or so, & was featured in an earlier volume of ARRL's "Antenna Compendium". That relatively simple antenna opened-up the path to Europe for me literally HOURS before the band was expected to open, & it was just a "killer" set-up for the "JA" crowd, too, on 7-MHz.

Think "...classic Bobtail", only flipped upside down, & fed at the point where the centre vertical meets the horizontal wire linking all 3 elements together. So very easy --- yet, so very effective.

One 40-meter antenna that I was just dying to make --- but could never come up with the height required --- was a vertical 2-element "gossamer" yagi, made of wire (driven element, plus director) & light wood spreaders, pulled tight, & made rotatable by way of a rotor sitting on the ground. I did just this exact same set-up back 40 years ago, but for the 20-meter band.

That rotatable affair opened-up an entirely new world of DX'ing possibilities for me on 14-MJz. It worked so well in fact, that "CQ" published a construction article that I wrote about it in 1982: "A Tree-Mounted Vertical Yagi Array", I believe I called it.

Imagine having a towerless rotating-directional array on 7-MHz, for practically pennies like that...?! It's all within the realm of reality, limited only by the height that's available for you to raise it, & the confines of your own imagination...

Computer antenna modelling be damned...!!!

:o)