Sunday, December 25, 2022

JD1BMH on MX-21S worked from central EU...what a DX !

Jul, OK1SP worked JD1BMH using my Mizuho, MX-21S handheld transceiver by amazing Mr.Takada, JA1AMH. 

Output power: 1.9W 
Band: 21MHz 
Antenna: 5el. beam at 30m (yes, it helped a lot) NB: OFF 
Powered: inside AA size battery cells 
Key: RM-31 Czech military key (1961) 

Setup simplified, so no CW-2S unit used for T/R switching and side tone with CW keying. 

Watch this amazing QSO here:


73 - Petr, OK1RP
--
B: http://goo.gl/Fd2JhJ

What could be easier..?  ¯‍∖‍_‍(‍ツ‍)‍_‍/‍¯

Wednesday, August 10, 2022

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