‰ NOW 40 WPM ‰ TEXT IS FROM SEPTEMBER 2013 QST PAGE 54‰ BACKLIGHT GIVES THE METER A NICE SOFT GLOW IN MY SHACK. AFTER ALL OF THE COMPONENTS ARE INSTALLED, THE ASSEMBLY MANUAL WALKS YOU THROUGH THE INITIAL CHECKOUT AND METER SELF TESTS. THERE IS MUCH MORE DETAIL HERE THAN THERE IS IN THE ACTUAL ASSEMBLY SECTION. FIGURE 7 SHOWS THE VARIOUS CIRCUIT BOARDS AND DISPLAY MODULES DURING THE INITIAL CHECKOUT. FIGURE 8 IS A PEEK INSIDE THE COMPLETED MB 1 CHASSIS. THERE IS PLENTY OF ROOM TO WORK INSIDE THE CABINET. FOR THE FINAL ADJUSTMENTS TUNE MY TRANSMITTER OUTPUT. THEN, WITH THE COUPLER PLUGGED IN TO THE MB 1, I ADJUSTED THE FWD TRIMPOT ON THE SIDE OF THE METER TO SET THE APPROPRIATE POWER READING ON THE MB 1. I HAD TO SWAP THE CABLES FROM THE COUPLER TO THE MB 1 AND ADJUST THE REFL TRIMPOT IN THE SAME WAY. I CHECKED THE SETTINGS FOR SEVERAL TRANSMIT POWER LEVELS, BUT THATS ABOUT IT FOR CALIBRATING THE MB 1. WITH A LAB GRADE CALIBRATED VOLTMETER TO MAKE THOSE MEASUREMENTS, IT MAY BE POSSIBLE TO OBTAIN EVEN BETTER ACCURACY. YOU COULD ALSO PERFORM THE ADJUSTMENT USING A CALIBRATED WATTMETER CONNECTED IN SERIES WITH THE MB 1 COUPLER. OUR TEST ENGINEER WAS QUITE IMPRESSED WITH THE ACCURACY OF THIS METER CONSIDERING THAT I BUILT IT FROM A KIT AND CALIBRATED IT WITH A COMMON VOM SIMILAR TO WHAT MOST AMATEURS MIGHT HAVE AT HOME. OF COURSE WE COULD HAVE ADJUSTED THE MB 1 TO EXACTLY MATCH POWER AND SWR MEASUREMENTS FROM THE LABS TEST SETUP. IN REVIEWING THE LAB NUMBERS AGAIN AS I COMPLETE THIS REVIEW, I WONDER IF WE MIGHT HAVE ACTIVATED THE BAND CORRECTION FEATURE FOR THE 10 METER TEST. INFORMATION FROM THE MANUFACTURER INDICATES THAT THEIR TESTS WITH AN NIST CERTIFIED POWER SENSOR FIRMWARE UPDATES SPEAKING OF THE FUTURE, THE DB 9 CONNECTOR ON THE MB 1S REAR PANEL IS A SERIAL PORT, WHICH YOU CAN CONNECT TO A COMPUTER TO LOAD NEW FIRMWARE AS UPDATES BECOME AVAILABLE. YOU WONT NEED TO CONNECT A COMPUTER TO THE MB 1 FOR ANY OTHER REASON, THOUGH. THERE IS NO COMPUTER CONTROL PROGRAM AND NO INTERFACE TO READ DATA FROM THE MB 1. ARRL LAB TEST RESULTS ARRL TEST ENGINEER BOB ALLISON, WB1GCM, COMPARED THE MB 1 MEASUREMENTS WITH THE TRANSMITTER OUTPUT POWER AS MEASURED BY THE LABS CALIBRATED HP 437B POWER METER WITH APPROPRIATE CALIBRATED POWER ATTENUATOR AND CABLES. RESULTS ARE SHOWN IN TABLE 1. AS YOU CAN SEE, THE WORST MEASURED CASE IS FOR 100 W CONTINUOUS CARRIER ON 28 MHZ, WHERE THE MEASUREMENT IS LOW BY 10 COMPARED TO THE HP 437B. IN ALL OTHER CASES, THE POWER IS WITHIN A FEW PERCENT OF THE VALUE MEASURED BY THE LABS EQUIPMENT. THE MEASURED SWR VALUES ARE ALSO VERY CLOSE TO THE THEORETICAL VALUES USING RESISTIVE LOADS OF 25, 50 AND 100. THE MB HF 1 COUPLER THAT COMES WITH THE MB 1 HAS BEEN CALIBRATED AT THE FACTORY, AND A CALIBRATION TABLE HAS BEEN STORED IN THE MB 1 MEMORY. THE CALIBRATION TABLE USES REFERENCE FREQUENCIES ON 80, 20, 10 AND 6 METERS. TO PERFORM THE INITIAL SETUP OF THE METER, I USED MY DIGITAL VOM TO MEASURE THE OUTPUT VOLTAGE FROM THE COUPLER, AND USED THE CALIBRATION VOLTAGE PRINTED ON THE COUPLER TO FINE ‰ END OF 40 WPM TEXT ‰ QST DE W1AW ƒ