It worked for many months.
Wired for 12 V supply. ATU said it put out 4-5 W.
Then after a storm or three, it stopped transmitting. Might have been static zapped by storm. Might have transmitted in bad SWR as vertical antenna flexed in storm.
It still receives, the microcontroller talks on USB serial, I put a 50 ohm dummy load on the BNC port, and can tell it to test transmit, but hear nothing on a nearby KX3.
BS170s are now hot while idle. A short?
I need to find the fault.
My effort to replace the four BS-170 transistors and to add protective zener diodes failed.
The microcontroller still works. Over USB it's possible to "screen /dev/ttyACM0" and get to the diagnostics, to trigger a test transmit into a 50 ohm load.
But no signal comes out.
Worse, even idle, the PA transistors and output transformer are hot. They shouldn't be!
Stare at schematic, thinking.
Might be time to write it up, bag it up, set it aside, buy replacement.
Got a little QDX radio that isn't working.
Connects via USB, just looks like a sound card and a serial port.
It works like a penny whistle!
You blow on the end of the USB cable, and it measures the zero-crossings of the audio waveform, figures out the frequency, adds maybe 7 or 14 million to the number, then squeaks out a 4 Watt RF whistle to the antenna.
Except the BS-170 N-channel MOSFETs probably popped from high voltages from momentary bad SWR.
So no happy whistling.
Meshtastic, APRS, D-Star, QDX and getting back into radio
Ham radio is a cyclical hobby for me, and when the interest comes it comes fast and strong. And so it did several weeks ago…
It started with a trip to Wabeno, WI to help support the Wisconsin Dual Sport Riders annual Ride 4 Research. It’s a dual-sport motorcycle event held in the backwoods, where there is very spotty cell coverage. It’s one of the only (maybe the only) events of it’s […]
#AmateurRadio #APRS #DStar #H2T #HamRadio #Icom #ID50a #ID5100 #LilyGo #Meshtastic #MuziWorks #QDX #QRPLabs #Yaesu
Muro deGrizeco
K9CUF
Jim "Ham on a Bike"
DG1JAN 🇪🇺
Steve Duncan
Venya (he/him/dude) 🇺🇦
Steve Duncan