Antenna Kohjinsha KA1-406S

Antennas

Dynamic Antenna HF 50 to 7 Mhz - Kohjinsha Mod. KA1-406S

Good Morning to all, after what happened the night between 21/22 December 2023 where an atmospheric event of exceptional magnitude, Foehn winds that reached a speed of 220 km per hour (140 miles) and destroyed my Antenna system that I was very fond of, see Antenna Disaster, consequently forced cessation of activity in Radio, I found myself having to decide what to do, which antenna to put to resume my activity in Radio, because it is clear, that for me the activity in Radio is so rooted that no one and nothing in this world will ever be able to make me give up continuing this wonderful and rewarding hobby. How to restore my Antenna park to the same level as the Quad 5 el. multiband + the two Yagi Antennas 3 elements in 30 and 40 m.? which is not exactly easy .... my choice was a careful and prudent choice on what the international market offers in terms of Antennas, to have the maximum performance in my opinion there are two choices, the first is to orient yourself towards monoband antennas or at most dual-band antennas, but the cost increases a lot considering that there are many bands (from 6 to 40 m.) and to do an excellent job you would need at least 2 Towers if not 3, to conveniently space all the Antennas, something to be excluded for me given the costs; so in my opinion there is only one solution left: the new Dynamic Antennas. There are many companies that produce them, see the American SteppIR, the Japanese Versa Beam by Kohjinsha, the Italian AD Antenna Dinamica and Ultrabeam. After a careful selection of the various models and based on my needs, my choice fell on the Japanese Kohjinsha Versa Beam, in the KA1-406S model. This antenna has a 10 meter long boom, 5 elements from 6 to 20 m. plus 3 elements in 30 and 40 m., at 6 m. I also added the kit of 2 passive elements which brings to 7 elements on this band, I hope I have made a good choice, I trust in Japanese products and from research done with several Versa Beam owners, the opinions that emerged on these Antennas were very very good, the Antenna arrives by air at the Turin / Caselle airport in the first ten days of September, after I will assemble it and test it, stay tuned, as soon as possible i will publish all details/install of this new Antenna KA1-406S, I hope I have chosen the best, Many Thanks Hiro San

Added Note September 16 / 2024

From September 10, 2024 to the resumption of my Radio activity, waiting for the new Kohjinsha KA1-406S Antenna to arrive, I installed a Rybakov vertical (fishing rod) length of 7.60 m. with 4 radials inclined at about 45 degrees, feed with a 300 Homs window line, tuned in the station with the Palstar AT2K, the antenna is placed on a mast about 7 meters from the ground and I must say that it works surprisingly well, I tune it from 50 Mhz to 5.357 Mhz, in 6 days of testing to date, I have made 340 QSOs all in FT8 on all bands, with excellent results, QSO with all the continents including the Pacific, well stay tuned guys, for now 73' and Good DX

Added Note October 17 /2024

Finally the antenna has arrived, after having completed all the customs procedures at the Turin/Caselle airport, the courier in charge delivered the antenna to me this morning at 08 AM, I immediately completed the unpacking operation of the 6 packages, all the pieces making up the antenna were very well packed in sturdy cardboard boxes, including the boom and the fiberglass rods, all the details such as brackets, screws supplied, supports etc. well divided and marked, the material used seems to be of excellent quality, now all that remains is to proceed with the assembly, but I want to do things slowly, so as to obtain the maximum without leaving anything to chance, it is my intention to brace the boom not only from above but also from below and laterally, and I will also see if it is the case to brace the fiberglass rods, you can never be too careful given the previous disaster of my antenna last December .........

I must say however that given the advanced season I do not think I will be able to install it before the weather conditions will no longer allow working outdoors, however as I said before there is no rush, considering the fact that I am about to make radical changes to my tower, such as automating it with a radio control in the ascent/descent of the antenna trolley, and proceeding to block the same trolley once it has risen in position where it will be blocked with mechanical pistons, so as to avoid my climbing to the top to bolt it to the tower (I am at an age that it is no longer the case to climb hi hi), for now this is everything, as the work progresses I will take care of informing you in detail with photos and explanations of everything, thanks for reading me, greetings to all and ... Good DX from Enrico IK1MNJ

Kohji nsha KA1-406S - Details

All Dynamic Antenna Models by Kohjinsha

Details of Dynamic Antenna Models by Kohjinsha

Kohjinsha some of the Antenna Owners