I have just received an MTR4B and would like to share my first impressions and benchtest results. My subjective point of view may be biased a bit due to the successful use of the MTR3B Mountain Toppers in 60 SOTA activations with a total of 3385 QSO.
Subjective point of view
The MTR4B looks all around very clean processed. Dimensions and weight are, as expected, significantly greater than those of the MTR3B.
The front panel with the very well readable display looks fantastic and conveys a touch of luxury. Nothing to complain about the user interface in connection with the display, almost perfectly solved.
The bottom of the case looks virtually indestructible, but this makes it quite heavy.
Overall subjective impression: A masterpiece of technical design - made to love and enjoy it!
Accuracy of voltage display: ok (0.1V@6V … 0.2V@12V below supply voltage)
RX current 30mA@6V (no antenna): ok (31.87mA)
(RX current @6V (no antenna): 23.42mA)
RX current 20mA@12V (no antenna): ok (18.87mA)
Supply voltage range 6-12V in RX and TX mode: ok
Band annunciator: why “9” and not “8” for 80m? (other bands ok)
Power output at supply voltages of 6/9/12V
- Power output 2.5W +/- 250mW@9V: not fulfilled (see above)
- Power output 3-4W@12V and up to 4.5W@12V: not fulfilled (see above)
- Accuracy of op frequency: ok/30-50Hz too low (Reference PFM1300, K3/P3)
- TX signal quality: ok (Reference K3/P3)
- TX/RX Transceive accuracy: ok (Reference K3/P3)
- Sending speed of stored messages: ok (was/is not “perfect” on the MTR3B)
- Direct frequency entry: ok
Technical point of view
My MTR4B fulfills - with the exception of the power output (see above) - its specification/product summary in all tested cases.
From my point of view it is absolutely incomprehensible that the power output is not best matched to the same level on all bands before delivery. BTW, the same applies also for the MTR3B.
Such things unfortunately reduce a specification to an empty marketing phrase.
Another questionable point is the high power output of significantly more than 5W at the maximum permitted operating voltage. This will almost certainly lead to problems under operating conditions with a not perfectly matched portable antenna - also a freshly charged 3S accu will increase this risk even more.
Overall technical impression: The MTR4B is undouptedly a technically high-quality product based on its field-proven MTR predecessors. So it is highly regrettable that such a product is delivered to the customer with the above mentioned deficiencies. Not every customer will have the skills to customize a ready-made device.
Next steps planned
- matching the power output on all bands to the same level
- adjusting the power output to max. 4W@12V
- 80 to 60m conversion, as soon as SW&HW mods are available