My recently completed mid-band QMX has been working well on the bench and I have chased a few portable operators on CW with good reports, but it hadn’t had a decent test on SSB.
It’s my second QMX kit build - I embarrassingly destroyed my first one by applying a way too high supply voltage. At least the replacement has the latest version mainboard and covers the preferred ‘SOTA’ bands: 40 - 15m.
This afternoon I drove out to my closest summit - Mt Disappointment, VK3/VC-014, 4 points. It’s an easy 15 minute walk from the carpark through tall Mountain Ash forrest to a picnic table near the top that makes a convenient place to set up. The weather was cool and windy with a storm sweeping across the state from the north-west bringing strong QRN, reminding me not to stay too late.
The antenna was a link dipole on a 7m squidpole and power was a 4S LiFePO4 battery via a 12V regulator. I only operated 40m SSB and made nine contacts from the usual eastern states that I would expect to work on that band. My signal reports were good for the 5W PEP power level, mostly R5 and signal strengths from 3 to 8. Comments on the audio quality were good.
A caller at 0451UTC was low down and partly wiped out by static crashes but I made out some of the callsign - ‘5YI’. I asked for repeats and heard F5YI - still not complete under the QRN - more repeats revealed my caller was F5PYI, Larry, near Lyon France! We copied reports, 33 and 44 for me and I was completely amazed, I didn’t expect to work Europe on 40m SSB with 5W in the middle of the afternoon.
Of course, Larry has a very capable station and was doing most of the work with an impressive gain antenna on 40m, and he obliged me with lots of repeats until I got his callsign. Many thanks Larry, it was a very exciting contact and totally unexpected with my tiny, new radio.
Congratulations on the new QMX. And on your debut with a connection to Larry. I know Larry runs a contest station, but that’s not meant to question the QMX’s capabilities in any way.
I’m a little surprised by the size and capacity of your battery. With the theoretical 70Wh, in my experience, you should be able to activate it for 24 hours continuously.
Thanks for your comments, Chris and nice to hear from you as I’ve been following your QMX Carrot build with interest.
You are right - the 13V 5.5Ah battery is way more than the QMX needs, but it is what I had available. I am using an LDO linear regulator to provide a steady 12V to the radio as I’m very nervous about how I power it. It’s an LM1085IT-12 in the module covered with black heatshrink, visible in the selfie photo next to the water bottle. I plan to make up a smaller battery with 18650 cells to better suit portable operation with the QMX.
The QMX is an amazing achievement - so much capability - Hans has produced a tiny marvel and is to be congratulated.
The QMX certainly is a marvel and amazing that it’s effectively a home developed product, not a team of designers in a factory.
I was just thinking that with Hans’ clear intellectual abilities that he could re-design the QMX with built in ATU and power supply (lithium battery + charger) and then he’d have a comparable product to an Elecraft KX2. In fact a QMX with capable ATU would probably be better than a KX2. Imagine my delight when Hans hinted at possibly developing an ATU during his FDIM presentation!
The mic is visible in the selfie photo in front of the water bottle. It consists of the case and PTT switch from an old Motorola lapel speaker mic that I picked up cheaply at a hamfest. The internals were removed and a new electret mic insert from Jaycar (a local hobby parts supplier) was mounted in the centre of the grill.
I used it for a while with an mcHF transceiver, but noticed the mic was sensitive to causing RF feedback if there were power lines on the summit. I reworked it with a lining of copper foil shielding, changed the cable to a better shielded one and fitted a clip-on ferrite suppressor at the radio end. It seems to be fine now.
