From the MIZUHO history…

If there is one Mizuho radio most QRPers are familiar with it's probably the MX series SSB/CW HF handhelds, though not everyone knows them by that name. The two watt HF and one watt VHF versions introduced in 1983 are still in production. The series celebrated it's 20th anniversary in 2001, making the Mizuho MX series handhelds probably the rigs which lasted longest on the market of any ham transceivers ever produced, and they are still going strong. If you don't know them under the Mizuho name, perhaps you've seen them as the AEA DX-Handy, or with the Pico brand name, or with Santec's JIM nameplate. Models have been made for every band from 80m up through 2m including 12m and 17m. Only 30m has been excluded. The MX series remain popular with QRPers the world over.

The first of the series released was the MX-6 a 250mW 6M SSB/CW transceiver which ran on a single nine volt battery, was released in Japan in October of 1981. In August, 1982, an improved version, the MX-6Z, was released, and was quickly followed by a 200mW 2M version (model MX-2) and a 300mW 15M version (model MX-15): the first Mizuho HF handheld - MX-6. 10 meters was added to this series in August of 1983 with the 300mW MX-10Z. Note that all the models after the MX-6 added a noise blanker and replaced the second antenna jack and the phone jack with a more traditional speaker/mic. arrangement. The MX-10Z and later production MX-6Zs also used six AAA batteries in place of the nine volt batteries. The milliwatt Mizuho handhelds were successful despite the miniscule power output. They, like most Mizuho products, were sold both as kits and as built and tested radios. The 200-300mW Mizuho rigs, along with the better known one and two watt rigs, were initially distributed in the United States by Ace Communications or Irvine, CA. Accessories for the early versions of the MX series rigs are now hard to come by. Many of the accessories currently made simply do not fit or work with the early rigs.

In May, 1983 Mizuho broke new ground for the series with the release of the MX-6S. This radio has been in production ever since, and almost all subsequent Mizuho HTs are based on this model. The MX-6S spoted many new features: a full watt of output power, an S/RF meter, RIT, a charging circuit for NiCad (or later NiMH) batteries, and later an RF attenuator was added as well. The volume control was moved to the top of the rig as another rotary knob, and the latching PTT switch found on the milliwatt versions of the rigs was replaced by a more conventional momentary switch. The mode switch was shifted to the bottom of the rig. The MX-6S proved immensely popular, and was quickly joined by the MX-7S for 40 meters and the MX-21S for 15 meters. Mizuho now had handhelds for the three Japanese novice bands.

The line was gradually expanded to include models for all the remaining HF bands except 30 meters. Additionally, Mizuho introduced a number of accessories, including the CW-2S sidetone/QSK unit and a series of 10 watt amplifiers. A mounting bracket to contain the entire "system" and, in effect, create a mini mobile monoband HF station was released.

In the mid '80s Ace Communications sold most of the Mizuho line in the United States under the Mizuho name. After they disappeared, AEA picked up the MX-6S and MX-28S (2 watts on 10 meters) and marketed them as the AEA DX-Handy. By 1993 jCom had picked up the line and sold the MX series as their Pico transceivers. When jCom went out of business Ramsey Electronics bought out and sold off their remaining stock but did not continue to import Mizuho products. Mizuho equipment has not been distributed or sold commercially in the United States or Canada since the mid 1990s.

(Thanks to Caitlyn Martin, KU4QD)
All rights reserved to Caitlyn / K9NI and Mr.Takada, JA1AMH Mizuho founder