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Reviews For: Mizuho SB-8X

Category: QRP Radios (5 watts or less)

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Review Summary For : Mizuho SB-8X
Reviews: 1MSRP: approx 800 in 1981
Description:
6, 15, and 40 meter 10 watt SSB/CW transceiver
Product is in production
More Info: http://www.qsl.net/ku4qd/mizuho
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
0014
K7VO Rating: 2005-11-06
Excellent performer but odd form factor, tuning, and controls Time Owned: 3 to 6 months.
The SB-8X is a triband rig covering 6, 15, and 40 meters SSB/CW at 10W out. It is the only Mizuho rig I've seen with a red LED digital display, albeit with only 1kHz resolution. The digital display can double as a digital clock and the rig has both a sleep timer and an alarm clock function. Those two large buttons in the front are for setting the clock. It's an analog rig and the display is labeled as a counter, which is what it is.

The shape is also odd. Does anyone remember the Drake UV-3 triband mobile? It had a normal sized front panel for an FM mobile but the rig was way long. The SB-8X is like that, as in 62mm high, 165mm wide, but 312mm deep. Not quite as long as a UV-3, but still... The rig was designed for mobile use, with the mobile bracket included when bought new.

The rig is a typical Mizuho VXO design. Each click of the main tuning knob is 20kHz, with the VXO control allowing an excursion of + or - 15kHz (30kHz total) from the center frequency. The tuning is not nearly as coarse an you might expect and is quite comfortable for me. In addition there is a fine tuning control concentric with the VXO control. At the flip of a switch this becomes RIT. My main complaint with this slightly odd tuning scheme is that it is difficult to tune across the band to hear what's out there.

While the rather silly clock controls are prominent on the front panel some very significant controls are way on the back of the rig. Having the mode switch back there (same as the SB-2X/SB-2M and all the HTs) is quite awkward on a rig this long. The switch from frequency display to clock is also back there. These controls would be about impossible to reach in a mobile environment.

As is typical with Mizuho gear there are no bells and whistles. The only other feature is a noise blanker which does work quite well for pulse type ignition noise. There are separate connectors for both an external speaker (mini jack) and headphones (1/4" phono jack), which I do appreciate.

The receiver performance is quite good, as in typical of a later, well thought out analog design. The 2.4kHz filter is fine for SSB but wider than I'd like for CW. There is no CW filter and it appears there is no allowance for one. An external audio filter (DSP or analog) is pretty well essential for CW. There are separate antenna connectors for 6m and HF.

The specs claim the rig covers 7.0-7.1MHz on 40m but the SB-8X actually will tune 800kHz per band. As you approach the top of the American 40m band at 7.300 receiver sensitivity declines somewhat. Output power stays at 10W or very close to it throughout the band. So... it is usable througout 40m.

Specs claim 100Hz drift after 30 min warmup, 500Hz drift before that. It seemed pretty darned stable to me though, as with all analog designs, there is warmup drift.

On SSB the SB-8X receives excellent audio reports with the stock mic. Power consumption for 10W out is 2.5A, which is really excellent. Pity the rig is too long and too heavy for portable work.

Overall, I'd say the SB-8X is a good if odd radio with fairly poor ergonomics. I had a hard time deciding whether to rate it a "3" or a "4" but the receiver performance does warrant the higher rating.