435MHz (70cm) 6 Element Yagi Antenna - August 2023
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- Опубліковано 3 жов 2024
- Design, modelling, construction, and testing of a 70cm Yagi Antenna, including antenna gain range test using a NanoVNA.
The 6 Element Yagi-Uda antenna has a 10MHz bandwidth from 430MHz to 440MHz.
Antenna construction details: vk6ysf.com/yag...
Yagi dimensions modelled with: www.changpuak.... JavaScript Version 12.01.2014, based on Rothammel / DL6WU
The 70cm band is an ideal frequency range for experimenting with various antenna design types. Tolerances are not overly critical, as is the case with the 23cm band and higher frequencies, nor is it as cumbersome for construction as the 2m band (144 - 148MHz) and lower frequencies.
Excellent presentation Peter. 👍👍
To bend the tube you can fill it with silver sand that you use for a bird cage, tape the end of the tube, fill it, tape the other end and bend it.
Thanks for making this video, Peter. May have a go at making one of these myself. I'm new to radio, and some of the more technical bits were a bit over my head. But, no worries, you gave all the sizes, so if I just use those I'll be fine.
The main design feature is the element attachment method, allowing the elements to be adjusted for the best SWR and Gain. This is my second attempt at a Yagi antenna, and I found that it is much more forgiving than I once thought. If you build the antenna, let me know how it goes. I am also keen to see some photos
beautiful !
Thanks for the great antenna website!
Thank you for the video Awesome beam 73
I love the idea of being able to adjust all parts of the antenna.
It's also easy to breakdown for portability. Nice build, I have
always wondered about the use of a folded dipole for a driven
element. Gary KF6EWO
Thank's Gary, I'm making another for portable work. I didn't think of that at time, however another strength of this approach. Cheers
Thx for showing the Design Calculator functions....Why you Deviate so Much from the Folded dipole Calculator Rod/tube Diameter (2.3mm) & Radius R (20.2 mm) dimensions ?? ...Your Rod/tube Dia (10mm) & Radius R (74mm) Both seem significantly Modified from Calc'd dimensions for some reason...
I'm rebuilding a 18ele 440mhz homebrew yagi. I'm not fully seasoned on this, but I'm using a high grade of RG6 here to feed most of my antennas here..HF/VHF and UHF with no problems. Question is how would using 75 ohm coax effect the length of the coax matching stub....assuming it's still needed? I appreciate your video....shows me much I needed to see, for my driven element is needing complete restoration, and it's director is gone. Thanks.
My understanding is that you need to have approximately 1 wavelength (per the video) of a different impedance coax. 125 ohm coax is commonly used however in my case and in some commercial folded dipoles 75 ohm is sufficient in a 50 ohm system.
Also I have an alternate 'J' dipole driven element that I have used on the 5 element Yagi that may be of interest.
See: ua-cam.com/video/Ks5ZaZlLxgQ/v-deo.htmlsi=zLFmS4h47eKxC4rF
And web page: vk6ysf.com/yagi_J_Driven_Element_20250715.html
ENJOYED YOUR VIDEO HOW LONG WAS THE 75 OHM BALUN FOR 435 MHZ. I AM BUILDING THIS YAGI
It is 690mm for 435MHz and the method to calculate this is at about 12min into the video.
Keen to hear about your build results.
Great video, but please don't use the mic built into the camera.
Thanks, will look at audio quality for future videos.
Sir give me measure ment of your antenna
See details: vk6ysf.com/yagi_435mhz_6el_20230201.htm