| KU4QD |
Rating:  |
2003-01-17 | |
| Interesting radio, limited but a lot of fun |
Time Owned: 0 to 3 months. |
The Mizuho MX-15 is an early, lower power version of their 15m SSB/CW handheld. The later model, the MX-21S is a 2W HT with more features. I've recently added the MX-15 to my collection, but I've had the identical 2, 6, and 10 meter rigs for quite some time, so I feel comfortable reviewing this rig after only limited use.
The rig is VXO controlled with two crystal slots, each crystal providing 50kHz of bandwidth, so you are pretty much limited to 100kHz. This is no different than the later model, but the MX-15 has which one feature which is different from any other of Mizuho's Pico series HF HTs: it has the option of using an external VXO (model VX-15) to cover more of the band. For someone who doesn't want to be limited to two 50kHz band segments and is willing to buy the additional crystals this option makes the MX-15 perhaps a better choice than the succeeding radio. Of course,it's an extra little box to carry around.
Optional crystals are still available directly from Mizuho on a special order basis. Expect to spend about US$23 per crystal to add/change band segments. Don't even think about domestic crystals: I don't know what Mizuho does, but US made crystals almost never give the full 50kHz of bandwidth, and often give much, much less.
The MX-15 puts out all of 300mW. When the band is open it is possible to make contacts with less than a third of a watt, even on SSB. Unlike the later MX-21S, this rig has no S/RF meter, no RIT, no attenuator, and no charging circuit. Otherwise, performance and operation are similar to the later model.
The receiver is hot and has a low noise floor. The receive audio is pleasant, and can be appreciated better through a larger, external speaker. Transmitted audio quality is OK, and very good indeed if you have the speaker/mic.
The rig is best on SSB. On CW there is no QSK and no sidetone, and the CW-2S unit for the MX-xxS series rigs does not work with the older rigs. The good news is that the PTT button latches, so sending, either with the little push button on top of the rig or (better yet) with an external key isn't quite as annoying as on the later rigs. Still, I miss the reassurance of hearing the code I'm sending. Considering that at 300mW CW is probably the mode that makes the most sense I think I'd really prefer to have a Mizuho P-21DX CW only portable rather than this rig. The MX-15 is what I could find, though.
I should also point out that other MX series accessories commonly found for the later rigs don't work with an MX-15, and finding the right accessories is, well... difficult. They included the M-4 speaker/mic., M-3 soft case, and the PL-15 linear amplifier: 300mW in for a 10W out. There was also a PR-1 mounting bracket which turned the radio, amp, and external VXO into a mini base or mobile station.
The radio runs on six AAA batteries. Operating voltage is critical and really must remain over 8.4V, so rechargable batteries are really not an option with this rig. The good news is that the battery (or batteries) last a very long time. The rig only draws 40mA on receive, and a whole 180mA when transmitting.
The MX-15 is the same size as all the other Mizuho HTs: 1 1/2"(D) x 2 5/8"(W) x 5 5/8"(H), and weighs in at just over a pound, making it an ideal lightweight travel companion. The telescopic antenna offered works after a fashion, but really requires a counterpoise. I've never made a contact without a counterpoise, but I can hear fine that way. Really, at these power levels, a bigger, outside antenna is required for any hope of regularly making contacts, especially on SSB.
The MX-15 was offered as a kit in the U.S. by Ace Communications back in the early '80s. If they were put together well, they're fine. If not... Wired and tested units were sold by Mizuho in Japan. I should also point out that these rigs are 20 or more years old now, so some parts may be aging out.
There really isn't anything "wrong" with an MX-15, and within its limitations it performs quite well. There isn't much difference in resale price between the more common and newer MX-21S and the MX-15, so unless you are a die-hard Mizuho collector who has to have every last model or are particularly interested in milliwatting, this rig may not make a whole lot of sense. OTOH, if you find one with the VX-15 VXO and some extra rocks the additional versatility may make this rig worth considering. I don't have the VXO, but I do have the amp and mic. I do collect Mizuho, and I wanted to see what I could do with 300mW, so I don't regret the purchase. I just wanted to point out that this rig certainly isn't for everyone. It is a rig you can have a lot of fun with. |
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