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Reviews For: Mizuho DC-7X

Category: QRP Radios (5 watts or less)

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Review Summary For : Mizuho DC-7X
Reviews: 1MSRP:
Description:
Mid '70s 1 watt SSB/CW 40M transceiver
Product is in production
More Info: http://
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0014
KU4QD Rating: 2002-03-14
Decent CW rig, could use narrower filtering Time Owned: 0 to 3 months.
I've had my DC-7X for about a month now, and I've used it exclusively for 40m CW during that time, so I think I have a pretty good persepctive on the rig's strengths and weaknesses.

The DC-7X was a kit, put out by Mizuho in the late 1970's. I didn't build mine, but rather found it on the used market. It puts out 2W CW, drawing 550mA on transmit, and only 55ma on receive, so it is stingy on power consumption. This isn't a small Mizuho handheld: it actually is quite large (7.95"W x 6.81"D x 2.55"H) and weighs in at 4.2 lbs. Still, Mizuho allowed for a battery pack (9 AA cells), so they did have portable operation at least somewhat in mind. Operating from out on the deck on a nice sunny day isn't a bad idea, come to think of it.

The rig has an analog VFO which is quite smooth and has a fine enough tuning rate for 40 CW. The rig is supposed to cover 7.0-7.125 MHz, but the dial is actually calibrated up to 7.135, and there is overshoot as well. Mine does cover the entire US CW band. The rig is simple and straightforward and has the usual spartan look typical of Mizuho. In addition to the large main tuning knob, you have a power/vol control, an RIT knob, and a receiver pre tune knob. There are also two switches: one to turn the RIT on and off, and one for the RF Attenuator. An analog S/RF meter, a power LED, and jacks for headphones and a key also grace the front panel. That's the sum of all the controls.

On the air the rig is fairly pleasant to operate. It's typical Japanese semi-QSK. The sidetone is pleasant (unlike the horrible noise produced by a Mizuho CW-2S) and the construction feels solid.

Receiver sensitivity seems very good indeed, and selectivity is certainly better than their handhelds. Still, if I have a complaint, it's with the 600Hz bandwidth for CW. Narrower filtering would have been a very good idea. There is plenty of space under the hood, so I suppose adding a crystal filter is entirely possible, though I am loathe to modify a rare rig.

I got my DC-7X for $125 from an American ham in Japan. The rig is listed as "rare" even on the one Japanese web site I found showing a picture of the rig. I collect Mizuho, so the price was right for me. I suspect, though, that there are smaller, newer, less expensive, better choices (i.e.: a Ten Tec T-Kit 1340) that do the same things this rig does. I guess my conclusion would be that the DC-7X is fine if you want a conversation piece on the air and can actually find one. (I have seen one other available recently.) It's certainly not best in class, especially 24 years later, but there is nothing terribly wrong with it either.