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YAGI-UDA ANTENNA 100th Anniversary

1926-2026

Division 25 - YAGI100 SPECIAL EVENT & WORLDWIDE FRIENDS!

In memory of 25AT102 Ken

 25AT016 Mr. Hideki - former 25AT357, old guard, former JA coordinator

 25AT019 Mr. Masami - Staff Member

 25AT021 Mr. Toshi - OnAir Operator (25AT/YAGI100HQ) 

 25AT025 Mr. Nobu - OnAir Operator (25AT/UDA100)

 25AT099 Mr. Sam - OnAir Operator (25AT/YAGI100)

 25AT105 Mr. Mori - OnAir Operator (25AT/TU100)

JA Special Guests:

 25SD019 Mr. Katsu - OnAir Operator (25UDA100)

 25EK101 Mr. Tetsu - OnAir Operator (25EK/YAGI100)

 25EK111 Mr. Shin (25EK/UDA100)

 25EK141 Mr. Jin (25EK/TU100)  

21 & 22 March 2026 (48 hours)

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 A Yagi–Uda antenna, or simply Yagi antenna, is a directional antenna consisting of two or more parallel resonant antenna elements in an end-fire array; these elements are most often metal rods (or discs) acting as half-wave dipoles. Yagi–Uda antennas consist of a single driven element connected to a radio transmitter or receiver (or both) through a transmission line, and additional passive radiators with no electrical connection, usually including one so-called reflector and any number of directors. It was invented in 1926 by Shintaro Uda of Tohoku Imperial University, Japan, with a lesser role played by his boss Hidetsugu Yagi.

 Yagi100 Alfa Tango Activator's Photo Gallery {reserved for approved AT activators} Under Construction {currently contains pre-event pics}

The final photo gallery will likely be split after the event-QRT into three funny different sections: "Alien" with at least six resonant yagi elements, "Human" with four or five resonant yagi elements and "Little Pistol" with two or three resonant yagi elements!

~ @Enjoy!

It is mandatory for the all activators to activate with a YAGI antenna!

 Rules of the 2026 Yagi100 event

Participation: The event will take place 21 to 22 March 2026, full weekend, 48 hours in total (from 00.00 UTC on Saturday to 23.59 UTC on Sunday) and is open to all 11m operators and for the hunters prior registration and final log sending is not required. Instead, operators who wish to become YAGI STATION must make a request only to This email address is being protected from spambots. You need JavaScript enabled to view it. sending along with the e-mail application for enrollment at least three high-resolution photos of the antenna system used for activation no later than February, 28 - 2026:

 A photo of the antenna

 A photo of the antenna support

 An overall view of the full antenna system

The HQ will assign a special callsign "Yagi addicted" to all approved requests and it will be the AT President himself, assisted by the event Ideator/VicePresident, to review and approve all the requests.

Important ~ Read carefully: Note that only Yagi  antenna users are accepted to activate during the Yagi100 event and should your application be approved by HQ the pics of your antenna will be displayed in the event's Photo Gallery. Remember that by submitting your application you accept that it may or may not be approved. 

Those who have already sent their application and their photos do not need to resubmit anything!

Band and bandplan: Activity must take place on 11m band. The section of the band between .500 and .600 included (so called DX part) cannot be used for QSO.

 Scoring:

 Basic scoring valid for only countries (excluding Japan) with four active "Y-A-G-I" stations: Each worked country adds a multiplier + 25 points for every worked station and the bonus of an extra multiplier activates only when the word YAGI is fully completed (25x4=100). 

 Special scoring valid for only Japan's activators (special guest included): 100 (one-hundred) points per QSO with japanese activators (special guests included).

 Each worked country will be a multiplier.

The main goals is to do "ein plein" with QSO on the four stations to complete the word 'Y-A-G-I'. {upon completion of the word 'Y-A-G-I' (1) multiplier is assigned!} and to do QSO with all japanese activators (special guests included).

 Attention: for Japanese activating stations there is NO "ein-plein" for the "Y-A-G-I" stations but an additional multiplier will be obtained after completing four different QSO with the following AT stations: 25AT/YAGI100; 25AT/UDA100; 25AT/TU100; 25AT/YAGI100HQ

{the special guests are separate by it and their value will always be 100 points}

 All stations (excluding Japan) will have the same value = 25 points each.

Even in countries with fewer than 25/30 AT it is possible to have the four stations that make up the word YAGI: for example: 329AT/Y100HQ - 329AT/A100HQ - 329AT/G100HQ - 329AT/I100HQ

All divisional coordinators can contact us via This email address is being protected from spambots. You need JavaScript enabled to view it. to establish these important steps. In the countries where there will be many candidate stations it may be necessary to do order by making some variant. Our suggestion is to submit all your applications as soon as possible! 

 Rankings; Certificate Download and Prize for the first Hunter: Please remember that this is not a contest but it is confirmed that a general ranking will be established by 1AT074 Max. Additionally, a digital participation certificate will be available for download for all hunters.

 The first ranked hunter will receive a 4-element monoband Yagi by Smartech! 

 The 4el Yagi antenna is reserved for the first of the "pure" hunters, meaning that even the activators (e.g. of the multi...) can make some QSO as hunter on their spare time but they cannot compete of course for the antenna up for grabs!

Logs - {but for  Internal Use only, for AT activators only}: Logs must be sent no later than April 15, 2026. Only logs created by ATLOGGER are accepted according to the software instructions. At the end of the YAGI 100Y event, activators are required to send the log via ATLogger’s SEND LOG button. Paper logs or logs created by different software will NOT be accepted. {No logs for hunters}

expired: This rules may be amended at least until the deadline (28/02/2026) for the submission of activator applications.

Hey! Yagi 100 Anniversary is coming and don't forget to check propagation!

Credits: {GRI Alfa Tango}

1AT10 Roberto, 1AT58 Alex, 1AT74 Max 

~  This email address is being protected from spambots. You need JavaScript enabled to view it. 

 The Yagi-Uda antenna's design will be commemorated in 2026 marking 100 years since its creation by Shintaro Uda and Hidetsugu Yagi in 1926. While Uda and Yagi developed the concept it was only Yagi who secured the patent. Initially developed for uses like radar systems in World War II the Yagi-Uda antenna remains relevant today across multiple areas including the high directivity and high gain needed for satellite communications and amateur radio operations.

 History of the creation

Creators: Shintaro Uda and Hidetsugu Yagi of Tohoku Imperial University, Sendai, Japan.

Design year: 1926

Patent: A few years later, Hidetsugu Yagi secured the patent for the invention and transferred it to the Marconi Company.

Original intent: Uda's initial contributions revolved around the theoretical aspects, whereas Yagi assisted in spreading it worldwide! 

 Blast from the 11m past!!  

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 HUNTERS Category

The event will take place from March 21 to 22 2026 (full weekend, 48 hours, from 00:00z on Saturday to 23:59z on Sunday) and is open to all operators of 11m.

No prior registration or log submission is required for hunters.

The goal for hunters: to make QSO with as many Yagi100 stations as possible.

The database containing all Yagi100 stations will remain active (for free consultation) and shortly before the start of the event, Francesco 1AT051 will design and release a checklist to be printed and used as a "paper log."

 No paper QSL to be requested.
 No log to be sent for hunters.
 No donation to be made.

...Just power-on the radio to do QSO with as many "tagged" YAGI100 AT stations as possible!

Have fun ~ This email address is being protected from spambots. You need JavaScript enabled to view it.

Stay please on the cluster to follow the Yagi100 stations

   Yagi100 - italian corner

  Yagi100 - Chasseurs

  Yagi100 - JA hunters 

 Yagi100 - Cazadores

 Yagi100 - Caçadores  

 NO LOG FOR HUNTERS 

ATLOGGER is available for Activators only!

ActivatorsRoster

 Rankings; Certificate Download and Prize for the first Hunter:

Please remember that this is not a contest but it is confirmed that a general ranking will be established by 1AT074 Max. Additionally, a digital participation certificate will be available for download for all hunters.

 The first ranked hunter will receive a 4-element monoband Yagi by Smartech!

 The 4el Yagi antenna is reserved for the first of the "pure" hunters, meaning that even the activators (e.g. of the multi...) can make some QSO as hunter on their spare time but they cannot compete of course for the antenna up for grabs!

Attachments:

Yagi100

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