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Reviews Categories | QRP Radios (5 watts or less) | Mizuho P-21DX Help

Reviews Summary for Mizuho P-21DX
Mizuho P-21DX Reviews: 1 Average rating: 5.0/5 MSRP: $about $200 kit, $255 factory bui
Description: 15m CW QRP transceiver
Product is in production.
More info: http://
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KU4QD Rating: 5/5 May 6, 2003 01:56 Send this review to a friend
Brilliant, tiny 15 meter CW QRP rig  Time owned: 0 to 3 months
Two or three months ago a friend in Japan put me in touch with another Japanese ham who had a P-21DX for sale. I tend to collect and enjoy Mizuho gear, and the gentleman offered me what his wife called a "YL price", so I jumped at the opportunity to try out this rig, which is rare outside of Japan. What a find it turned out to be!

I have already reviewed the somewhat more common 40 meter version, the P-7DX. There are some differences between the rigs, so I thought a separate review was in order.

Like the P-7DX, the P-21DX is very small and very compact Later ones run on 6 AA cells. My early unit had a blank space where the battery holder normally fits. I'll probably add one soon. Fortunately, it can also be used with an external 9.5V supply (the Mizuho PS-2 is the matching unit) or with a 13.8V supply using the optional PM-1 DC to DC converter. The rig is beautifully made and solidly built. It's spartan, but does feature RIT and an RF attenuator. An optional audio peak filter kit, model PF-1A, is available. I have one in my P-7DX and I don't think much of that filter. My P-21DX doesn't have one, and on the less crowded 15 meter CW band I don't miss it much. Later versions of this rig, which was made until 1999, have a very tiny internal speaker. Mine is an earlier unit, so I have to use it with headphones or an external speaker. Again, having heard what the little speaker sounds like I don't feel I am missing much.

The radio is VXO controlled and can cover any 50kHz in the 15m band. The default crystal from the factory covers 21.100-21.150, which is in the old novice band in the U.S. I found activity there to be almost nil, so I quickly ordered a rock for 21.000-21.050. which added $23 to the cost of the radio for a genuine Mizuho crystal. Mizuho crystals use a proprietary cut and any I've gotten from a third party were either off frequency or didn't give me full range. I had this experience with my MX-21S 15m SSB/CW handheld, and the P-21DX uses the same crystals as that radio. Fortunately the Mizuho crystal came from Japan quickly and was right on the money. I plugged it in and my radio was accurately calibrated without any adjustment.

Tuning is smooth and the tuning rate is quite comfortable. The received audio is excellent through headphones or an external speaker.

I had no problems making contacts with the rig through a dipole around 30 feet (10 meters) up in the air, and the receiver is very sensitive and compares well with bigger rigs. The radio draws only 75mA on receive, 280mA transmitting at half a watt out, so batteries should last a good long time. This rig is an excellent choice for backpacking or field operation.

I heartily recommend the P-21DX for the CW QRP enthusiast, though given a choice I'd probably start with the 40 meter version. I'm lucky enough to have both. The combination of small size, solid construction, and decent performance make this one a winner. It's a pity nobody every commercially imported these rigs into the U.S. The P-21DX is quite hard to find, so if you do find it don't miss the chance to buy it.

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