Hi folks,? Greg KI4NVX here.
Finished the build of my QMX Rev3, firmware 1_00_017 yesterday afternoon.
Since I bungered my BNC connector during a brain cramp episode, I soldered in a BNC connector with a short piece of RG-316 so I could move forward with checkouts and testing.
Used the following:
Dakota Lithium 10A battery
Decent, 214 W Buck/Boost controller in constant V mode. It also shows current and seems reasonably well calibrated.?
QRP-Guys SWR/PWR meter for basic Power Out measurements on all 5 bands into a dummy load? before going live.
WSJT-X to 'drive' transmit? running on my 6 year old, still decent HP Envy convertible laptop.
Live, on-air testing was done on 20M into a Chelegance MC-75- ground mounted 1/4 wave vertical tweaked to 1:1 SWR as measured on the QRP-Guys meter and my Elecraft K2.?
Everything I checked and twiddled so far have worked perfect. I used WSJT-X for successful FT8 receive checks and completed a couple of full QSOs.
Then switched to WSPR mode and made some 'relative' temperature checks on the output transistors.
I've also attached a snippet of the WSPR map for who heard? 'ME' transmitting at 2034 GMT.
I estimated that my output RF was approximately 3.7 watts out of the QMX.?
For the curious:
My temperature checks were made with a nothing special DMM with a thermocouple wire bead, insulated all the way up to the bead and then squeezed in between the two, outside edge twer transistors right down next to the mounting screw shaft of the hold down washer/heatsink. So ... I'm not saying these temps are lab-grade accurate but I did get a sense of relative changes.
These checks were made (in a 78 degree room with no extra airflow? - QMX NOT in its enclosure.
Idle current is approx 0.112 A
Idle Temp:? ? approx 30C??
XMT Temp: 20M - approx.. 3.7 A output RF power into dummy load and 1.1SWR antenna-? 50C
XMT Temp: 17M into a dummy load - approx 5.46 A output RF power? -? 63C (gonna have to think about that ! )?
Both cooled down to the idle temp of 30C in about 4 minutes.
Very Happy Camper Here.
73? Greg? KI4NVX?
