The MTR3B helps reducing the weight of my SOTA gear significantly. It weighs only about 15% of the KX3 in its Go- Box but has still acceptable output power and performance.
Ordered a kit from the latest production batch of LNR Precision and received it within a fortnight. A plug for DC power supply is part of the kit.
Assembly was done in about two hours. Before I actually started, the RCA- jack had been replaced with a BNC- jack. Therefore the mounting hole needed to be increased by 2mm in diameter.
Assembly and soldering went smoothly. However, two screws would not fit into the nuts on the PCB. They seemed to be somewhat different in size. Luckily spare screws from the KX3 were available and fit nicely.
Only after the assembly had been completed I discovered that one of the 3.5mm stereo jacks was defective. As soon as a key was plugged in, the radio started sending dits. This was a bit annoying as I couldn’t find a similar 3.5mm stereo jack in my stock and had to order some for replacement.
Output power and current consumption:
Band/ Voltage 12V 9V 8V 7.2V 6V
40m 6.0W/ 800mA 3.5W/ 620mA 2.9W/ 560mA 2.3W/ 510mA 1.6W/440mA
30m 5.5W/ 750mA 3.0W/ 550mA 2.5W/ 500mA 2.0W/ 450mA 1.3W/ 370mA
20m 6.0W/ 820mA 3.5W/ 660mA 2.9W/ 590mA 2.4W/ 540mA 1.6W/ 450mA
RX current consumption is about 40mA.
The built- in keyer works in iambic- mode A. However, storing CW messages is a bit tricky. So far I did not succeed getting an error- free message in.
All in all the MTR3B is an awesome little radio and I’m looking forward to using it in the fields.