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Japan Castles On The Air (JACOTA)

Planning and Preparation for a JACOTA Castle visit

Greg Cook, JO3SLK

This month’s Japan Castles On The Air (JACOTA) article is going to be different, due to the State of Emergency and the Covid19 pandemic circumstances. In this article I will introduce you to the website I use to find castles to operate from, the one I use to check the weather, and the antenna systems I use.

Finding the Castles


I use a website called “Jcastle” to find the castles that I want to operate from. It is a super tool, and anyone wanting to operate ham radio from a castle, or just want to know everything there about castles in Japan, should check out.All the following screenshots are thanks to Jcastle.

You can search for details on the nearly 900 castles on Jcastle

Main search page

Below is a sample search I made.

Search by criteria: Castle type = Flatland, Designations = National Historic Site, Historical Period = Pre Edo period

You can also search for castles in various prefectures. The site returns a map with the castle marked with the type of castle structures that you can see at the site. Note the color of the marks, and what they represent.

Hyogo Map with castle type

The main page of Sonobe castle, the first castle I operated from, is shown below.

Without Jcastle, I would not have known about Sonobe castle, which in not that far from my home. And, I would not have had such a great time visiting and operating there in the middle of the Autumn leaf color turning season. See the January 1 issue of FB News for the article on operating at Sonobe castle. I will be using Jcastle in selecting all the castles for the JACOTA project.

Checking the Weather

Knowing what the weather will be like when you visit a castle can influence whether you will be able to successfully, and comfortably, operate there. is a great site to check the weather in any part of Japan. You can really zoom in and get a lot of detailed weather information, over several days. There are too many features to show here, so check out their website and the pages for your area.

Screenshot thanks to

Antenna Systems

There are lots of antennas that you can use for castle operation. Dipoles, verticals, loops, mobile whips, and simple long wire antennas can be assembled and used to make contacts. Whatever system you decide to use, learn to assemble it, and tune it for optimal performance, before you take it to a castle to operate.

Icom AL-705 Loop Antenna

I will be using the AH-705 Loop antenna during my scouting visits to castles. The AL-705 will enable me to check for the best location to operate from, and to check for RF noise at the castle.

Buddipole© Antenna System

I mainly construct antennas for my actual castle operation using the Buddipole© antenna system. Pictures of the antennas are in my JACOTA articles in FB News.

Operating with a horizontal dipole configuration antenna. Picture thanks to Buddipole© Inc.

This is my basic portable antenna system.

I use it to build horizontal and vertical dipole antennas.

Choosing an Antenna Configuration

There are lots of optional accessories that you can get to build various configurations. There are even components for compact antennas that are great for limited spaces at castles, or when somewhat of a “stealth” antenna is best for popular castle operation. I really like to operate on 40 meters, so I bought extra antenna arms and a longer whip to make the antenna physically longer, but I use it in a vertical configuration, so it doesn’t extend out like a horizontal dipole.

A great book by Scott Anderson, NE1ED, explains about the Buddipole© system, and also has “Cookbooks” on various antenna configurations, including required components, construction diagrams and tuning notes. It is an invaluable tool in deciding what antenna parts to take to your next castle location. I downloaded it from the Buddipole© website.

“Buddipole In The Field” book

Configuration for a 40 meter vertical antenna as described in Scott’s book

Antenna Analyzer

Every portable ham operator should have a good antenna analyzer and learn how to use it...learn what the readings mean for the best antenna performance, in the operating configuration and environment. There are many good manufacturers, and the NanoVNA is also becoming very popular. Look for more information on it in a future FB News article.

My RigExpert AA-230Pro analyzer

Tuning the Antenna

When a loading coil is used, the electrical length of the aluminum element is adjusted by placing clips at the correct point on the coil. Cables from the feed point are then connected to the clips through a banana plug.

Coil on a vertical antenna

Another critical part of the antenna is the elevated wire radial. Once I assemble the components for the antenna, set the coils in the proper location in the coil, I attach the wire radial to the VersaTee© unit and extend out to the proper length. Then, using my analyzer, I fine tune the length of the radial for the best readings on my analyzer.

Picture thanks to Buddipole© Inc.

Castle Yagi

With a few accessory components, I can make 2 and even 3 element Yagi antennas between 10 and 2 meters. The Yagi construction is also explained in the “Buddipole in the Field” book.

A 3 element 2 meter Yagi diagram and list of needed components.

2 element Yagi antennas for 10, 6 and 2 meters...especially 6 and 2, are good for castle operation. I can setup in a corner of the castle and then contact stations without a large antenna getting in the way of other visitors.

This is a 2 element, 6 meter Yagi antenna I used at Mt. Myoken

Getting My Gear To the Castle

When you are going to a castle that is relatively flat, but covers a large area or, .... if the castle is in a location where you have to walk up a steep slope (not stairs), a cart can be a handy tool to haul your equipment. You can also take a small table, small folding chair, an umbrella, and a larger camera bag.

Cart with the IC-705 in the LC-192 backpack

The cart carried a lot of needed bags for the operation at Fukuchiyama castle.

Everything you see here was packed into the cart

However, since operating at a castle is a portable operation, try to refine your needs and condense your antenna components down so they will fit in a small bag.

This contains everything I need and is light enough to carry even up castle steps.

So, before you head out for your next castle operation, check with the Jcastle website, or other website in your operating location. Check the weather not only at the castle, but between your home and the castle. Decide what antenna you are going to use, and the components you will need. Then pack everything, including your antenna, analyzer, camera and radios ..... and enjoy!

Which Castle is Next?

Hopefully in a short time the State of Emergency will be lifted, and the weather will be nice, and I can operate from one of the castles that I have visited before. I have permission to operate from two of them, and I think I can get permission from the third castle without any problems. Do you know the name of any of the castles below?

Japan Castles On The Air (JACOTA) backnumber

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