The real power output of MX-21S measured...!

Hello all,

as I read several articles about the Mizuho MX-xxS series radios where owners doubt about its real RF output power and some of them measured (no explained how and what test equipment has been used in their case) the power at around 1W only instead of 2W specification I decided to measure one of my own MX-21S radios.

I arranged the test equipment which consisting the BNC-N adapter > N-N cable > R&S NAS Directional Power Meter calibrated by National Metrology Authority, CMI > N-N cable > Palstar, DL2K dummy load.

BNC-N adapter: 0.02dB attenuation at 50MHz

N-N cable: 0.06dB attenuation at 50MHz

Total attenuation inserted: 0.08dB

Battery powered MX-21S / Ubat: 8.4V

Measured power

Xtal A / 21.025MHz: 1.9W

Xtal B / 21.225MHz: 1.9W

Combined uncertainty: +/-5% calculated for k=2

So total RF power output including the inserted attenuation at the test setup is 1.9 x 1.018 = 1.935W (0.08dB total attenuation converted to power ratio)

MX-21S total RF power output measured at 8.4V Ubat: 1.935W +/- 80mW

73 - Petr, OK1RP