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Reviews For: Mizuho QX-21

Category: QRP Radios (5 watts or less)

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Review Summary For : Mizuho QX-21
Reviews: 1MSRP:
Description:
15 meter monoband SSB/CW transceiver, 5W out on high power, 500mW on low power
Product is in production
More Info: http://www.mizuhoradio.com
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0014
K7VO Rating: 2003-07-31
Neat little monoband QRP rig Time Owned: 3 to 6 months.
The QX-21U was a kit offered briefly by Mizuho sometime around 1998. When combined with the NC-1 knob and case kit you ended up with a very nice, complete 15 meter monoband QRP rig. The radio offers some of the best features of the P-21DX CW portable transceiver and the MX-21S 15m SSB/CW handheld. It puts out 5W on high power and 500mW on low power. The PF-1A CW audio peak filter kit can be installed inside this rig, much like the P-21DX.

Features include an effective noise blanker, RIT, and an RF attenuator. The rig is VXO controlled, with each crystal providing 50kHz of frequency coverage. While the P-21DX can take just one crystal internally and the MX-21S can accommodate two, the QX-21 has four crystal slots, so it can cover 200kHz of the 15 meter band. The rig can be powered by 13.8V DC external power, 10 AA NiMH or NiCad rechargable batteries, or 9 AA alkaline batteries with the provided dummy battery.

I bought mine built and working on the used market so I can't comment on how the rig goes together as a kit. I do know that I need to clean up the original owner's wiring a little. It does work fine the way it is.

The rig is only slightly bigger than the P-21DX, so it is quite small, but it's still a bit bigger than a Yeasu FT-817 in volume and it only covers the one band. OTOH, it is pretty miserly in terms of battery consumption, something an FT-817 simply cannot claim. Rated power consumption is just 75mA on receive, 500mA for 500mW output, and 1.2A for 5W output.

The first time I used this rig seriously was on the top of Spokane Mountain on a contest weekend. My first QSO was with W1AW on SSB at 5W. Not too bad. The nice thing about this test was that I was using the rig under some fairly demanding conditions. What I found then, and in using the rig since, is that receiver sensitivity is excellent but selectivity leaves something to be desired. On CW in particular some sort of additional filtering really is needed, so I can only give the rig a "4". My review of the PF-1A in my P-7DX was less than stellar, but I sure wish I had another one to install in the rig. Using it on the base with an outboard filter, like my Mizuho AP-1D, the results are pretty decent.

The QX-21U/NC-1 combo has the usual Mizuho spartan look and rugged design. One oddity is the antenna connector: a BNC on the right hand side of the rig. I much prefer the SO-239 in the back as was used in the P-21DX. The back panel of the rig is totally blank.

The NC-1 kit comes with stickers not only for the QX-21, but also the QX-7 and QX-6 40m and 6m versions. I've corresponded with ham friends in Japan who enjoy Mizuho gear and none has ever seen or heard of the other versions. The QX-21 itself seems to be quite rare.

Can I reccommend this rig? Within it's limitations, yes, I can, and not just as a curiosity. It is fun to use on the air. It just isn't perfect, and I've come to expect an awful lot from Mizuho gear.