Just wanted to share some easy swap-in replacement backs for the QMX enclosure I posted on Printables. Just remove the four bottom screws to swap in a larger back to accommodate various mods.
I added three sizes of varying depth. Good way to try a few things without needing to commit to taking a Dremmel to the stock case.
Used the small size to add 3 LiPo cells, BMS, speaker, and battery charge port to the back of one of mine. Makes for a super tidy setup where I just need to connect a key and an antenna. I have did the 10W mod and limit the voltage with the QMX firmware so the 3S LiPo configuration with 1000mah cells gives me a nice power boost and enough runtime without external power. Connected un-amplified 32ohm speaker directly to the jack pads on the bottom of the PCB so it disconnects the speaker when headphones are attached. It is loud enough for quiet environments and headphones are always an option. Same deal with the DC power jack, Connecting an external power source disconnects the internal battery. Really like the setup.
Hope some of you find it useful and look forward to seeing if anyone does some nifty mods. Up next I’m going to add batteries, speaker, mic, and touch key to my other QMX…
Chris, that’s seriously cool, when I remember coming across it months ago and admiring it!
Just had a look again and am now curious about the Fuchs Kreis you added.
I’ve been using my modded QMX(2xPA 10W mod, Battery, Speaker built in @ 268g) with my tightly packed mini ZM-2 clone.Was toying with adding a tuner along with a few other options when I mod my other QMX. Would be great to be able to directly connect at EHFW wire and counterpoise, or a 1/4 vertical with a tuner disengagement switch perhaps. Wonder if the Fuchs might be a good fit for a light and compact integrated tuning solution? The Z-Match is awesome but the torroid and two polyvaricons take app a fair bit of space. Not huge but shaving more weight and volume would be a plus if I’m at it. Will do the double PA FET mod so want it be be able to handle up to 10W if I have the power cranked up…
Here about as small as I could scrunch up my ZM-2 Clone. 151g, 69x82x38mm including BNCs. Bet I could get away with 1/4 weight and volume with your config. Hmm…
Your ZM-2 close looks great! The Fuchs tuner is really only one polyvaricon less than a Z-match, still needs a poly, a toroid, and the switches and connectors plus box. A minimalist Fuchs tuner (poly, toroid, switch) can be built at 50g and works great. Downside for multiband operation is that you need an antenna with links or traps. Take a look at AA5TB - 40m to 17m EFHW Coupler .
Thanks Peter. Was checking out the link, I think I’m going to whip together an ugly prototype to try out. Sure like the idea of having the transformer and a little bit of tuning leeway. Curious to see what sort of haphazard efhw wire drapery I can get away with.
