In Remembrance of Radio Pioneers
by Philip Neidlinger, PE
Hidetsugu Yagi & Shintaro Uda
-Photos from the internet in the public domain.
As eleven (11) years have passed since I last besmirched the memory of a Dude, I expect to be cut a lot of slack from you boys and girls with respect to the quality of this essay. I’m a bit out of practice and may inadvertently inject an occasional comma splice or syntax error. Additionally, I may accidentally convert someone’s pet sacred cow into a pile of tasty USDA prime ribeye steaks. If the calls for my lynching do not reach a fever pitch, then I may churn out another inflammatory article in less than eleven years hence.
Now that the preliminaries are out of the way…It’s good to be visiting with you again! Some may remember when my 19th and last Dead Electrical Dude, Lev Terman, appeared here on 10 October 2005. A lot has transpired and I shan’t bore you with the details. Let’s just say I’ve been busy raising children and keeping the local sheriff from evicting K4SMN and I from the Neidlinger Estate and Country Club (NEC2). Memories tend to be short and I figured it was high time to give my reputation a booster kick back into the gutter where it so deservedly belongs.
How many of you have cursed when the gears of your Armstrong Super Rotator 2 have ground themselves into smooth metal disks as the large skyhook beam came to a screeching, bank account emptying halt? Or, used a homebrew, handheld beam antenna to hunt down and skin alive an offending barbarian who has the utter gall to interfere with your local repeater group’s weekly “Aches and Pains Net”? Have you decorated your brand-spanking new pick-em-up truck/SUV/POV/VAN/Hummer with a minimum of 10 directional antennas in a holy quest to be anointed the highest-scoring rover in a VHF/UHF contest (Note: A good rule of thumb dictates that a rover antenna installation isn’t worthwhile unless your gas mileage is reduced, via increased air drag, a minimum of 34.9%)? If you answer “yes” to one or more of the preceding questions, then the likelihood that a Yagi-Uda antenna was part of the mix is indeed high. If you
answer “no” to any of the aforementioned questions, then you’re poor, like I am, or don’t’ get out very often.
Examples of common verbiage when hams refer to their parasitic directional antenna arrays may read something like:
“My Yagi was busted up real bad when the twister went through the back 40 last night!”
“The HOA thinks my Yagi and kids are ugly and will destroy their property values”.
“The XYL says it’s her or the Yagi.”
“I can’t have an effective station without a Yagi on a 150’ tower and a 5 KW equalizer.”
Lots of techo-jargon, slang, and half-truths pertaining to Yagi-Uda antennas are floating around out there in the ether. Turn on your radio, spin the dial, and someone, somewhere is bound to be talking about their favorite Yagi-Uda and why it is the best thing since sliced bread. I venture that most never mention, much less know about, Mr. Shintaro Uda. Who in the blazes is Uda? Shintaro’s last name rhymes with “Barracuda”—which can be either a mean, toothy type of carnivorous sea fish or a neat and cool Plymouth from the halcyon years of my golden, lost youth. In order to help the kind reader avoid possible confusion, please note the following figures:
Yagi-Uda for 160/80/40m belonging to my friend Dave, G0EVY with crane rotor. The massive array is homebrew and tips the scales at over 1000 pounds! Photo by Dave, G0EVY.
1970 Plymouth Barracuda. Public doman photo by AlfvanBeem from Wikipedia.
This is what a typical Yagi-Uda sorta looks like.
Sketch by the Author.
Figure 3 is a generic version of the Yagi-Uda beam. This particular one has one reflector on the left, a driven element where RF is applied, and two directors. For those who are really new at this, you point the right hand side towards the station with which you wish to communicate. Regardless of the operating frequency, it’s really not a great idea to stand in front of the “business” end while the RF is coming out, especially if you are squeezing a whole lot of it into the sucker from the transmitter. Yeah, I know, it MAYbe okay, but once you get into the mid-HF to low-VHF and above range (someone please check me on this), things get dicey. Remember, the first thing to get cooked is the aqueous humor of your eyeballs in a manner similar to boiling an egg. YUCK!!!
The electric field polarization (there is also a magnetic H component oriented 90 degrees catty-wampus to the other field) is which way the elements are oriented in relation to terra firma; horizontal elements = horizontal polarization while vertical elements = vertical polarization. This orientation sometimes doesn’t mean a whole lot since once your “CQ!” bounces off one of those Kennelly-Heaviside layers (er….ionosphere), all bets are off. I think I read somewhere in Terman’s Radio Engineers Handbook (1943) that the reflected polarization is elliptical. I’m not in the mood to look this up at the moment so the possibility exists I’m dead wrong.
There are more variations of the Yagi-Uda beam antenna than Carter has pills. The total size is generally dictated by the operating frequency, number of elements, mounting provisions, desired forward gain, and how much money you can afford to blow. Finally, I am not going to dwell on the dense technical theory pertaining to the Yagi-Uda as that would definitely kill the mood I am trying to create. Search the internet and I am sure you will find something you can build that fits your needs. I can’t do all the work on this end!
Now that you have a pretty good idea of what a Yagi-Uda antenna looks like, let’s get back to my original question of the exact relationship of Mr. Yagi and Mr. Uda. Here is what I have dredged up from the internet. Both worked together at Tohoku Imperial University with regards to the antenna’s theoretical background, testing, and publishing of the test results in 1926. Both of their names were also on the documentation.
Additionally, an English language article was published by Yagi in 1928. Somehow, Uda’s name was omitted in the translation. Perhaps this is why English readers only knew about the antenna by the name at the top of the article.
The outbreak of the Second World War wasn’t that far way when the inventors’ paper was published. The following is likely apocryphal and I am unable to verify it’s veracity: the Allies and Germans all used the Yagi-Uda antenna for various communications devices and weapons systems. The Imperial Japanese High Command was unaware of the antenna’s existence until some Allied communications equipment was captured. One of the antennas was weird looking and had the word “YAGI” engraved on one of the elements: an “AHA” moment followed. Interesting!
Well, that about wraps up this combo special. I hope you have enjoyed this essay and it motivates you to do some research on your own. If you find any blatant errors, then please be kind in any subsequent criticism.
Philip Neidlinger, PE, KA4KOE
Post Script: For those newbies who wonder why the two Dudes described herein are numbered 20 and 21, there are 19 more articles lurking in the Eham archives. Since I am a fairly decent sort, I’ve included the links below:
Enjoy and Let’s Be Careful Out There!
All material Copyright 2016
Via Creative Commons
Dashtoons thanks KA4KOE, for his continuing series of fascinating and fun profiles of those who made it possible to play ham radio and exchange inflated signal reports with operators in many lands.
Philip's extensive engineering background and mad lab skills give him a uniquely informed perspective, for a cool spin on the magic technology that created us radio monsters.
In real life, Herr Neidlinger is no Doctor Strangelove, but rather an Extra Class amateur radio licensee and senior electrical engineer with the Defense Department. He has written articles published by QST, CQ and Electric Radio magazines. What's more, besides playing the Theremin rather well, Philip really looks a bit more like a responsible adult. No surprise then, he's married to Sheri Neidlinger, Doctor of Genetics and Public Health with whom he's raising two children and hopefully not insisting they all get ham tickets and wear identical sweaters. No, not Philip, you can trust him, he's not like the others. But somehow, you probably inferred that already.