Tag: QMX

The Tiny Paddle Mic Hack for the QMX

Do you think cables suck? Do you think both the N6ARA Tiny Paddle and the K6ARK mini mic just are just too bulky or lacking in functionality? Well then this hack is for you! Joking aside I love both of these amazing creations by Ara and Adam. I like to have separate kits for each of my radios and you can bet that if the radio can do sideband Adam’s mini mic is going to be in that kit. If the rig does CW you can bet that Ara’s tiny paddle is stashed in the kit as either the backup key or the primary key.

Since SSB has been added to the QMX, I have been thinking about doing the 1lb POTA challenge. The 1lb POTA challenge is activating a park (10 contacts) with at least 1 digital, 1 voice and 1 CW QSO as part of those 10. The radio, antenna, battery, mic, key and cabling all have to come in under a pound.

Tiny Mic Paddle
The Tiny Paddle Mic Hack

With the QMX using the paddle jack as the mic jack when in SSB mode, I had an idea. That idea lead to me doing a thing!

The recommended microphone element for use with the QMX radio (the one used for the development of the SSB firmware) is Digi-Key part number 668-AOM-5024L-HD-F-R-ND. It turns out that the solder connection point spacing of this mic element and the same spacing as the solder points for NA6ARA’s tiny paddle plug edition. Soldering the negative terminal of the mic to the sleeve post (closest to the plug) and the positive terminal to the ring of the plug results in the same wiring as the K6ARK mini mic with the addition of a second switch in parallel with the mic element.

K6ARK mini mic wiring
The K6ARK Mini Mic wiring for the QMX

In operation, the QMX ignores the microphone element when in CW mode. When in SSB mode the DIT side of the paddle is the PTT. Speak into the microphone as you normally would very close to the your lips. The one thing to watch out for is that you only press the DIT side. If you press the DAH side down as well you will bypass the mic so audio is feed to the radio resulting in no output power. The radio is no worse for wear should you do that. I have found that there is just enough room to rest you thumb on the edge of the PCB which allows for easy press of the DIT side to activate PTT.

Is this mod the most comfortable way to operate the QMX? For me, it is not, but its pretty darn cool and if you are a gram counter you might just like it. Adding the mic will not allow for the use Ara’s QMX adaptor for the tiny paddle. It will need to tweaking to allow for the microphone. I’m gonna drag my feet attempting that and hope someone else does that before I give it a try.

Its time to go play radio!

Enhance Your QMX Radio: Touch Keying & Band Modifications

A while back I did a touch keying modification to my QMX radio using one of K6ARK’s touch keying PCB. Here is a demo of it.

The project was quite a fun shoe-horning in another PCB into the QMX case, but I did it….and it worked! Here is a PDF of my notes on the process.

QMX Touch Key Mod – N6MTB Notes REV 1.4Download

Another modification I did to my QMX was to change the band support to make it work on 40-10 meters. I had previously modified this radio for 60-15 meters (this was before QRP-Labs offered a kit for those bands). Dan, AI6XG, came up with a better mod for use on 40-10 and latter further modified my rig for 40-10 using Dan’s notes.

Here is a quick short showing off both the band mod and the touch keying mod.

Since then I have updated to the firmware that supports SSB and all is well with that and my mods. I’m currently using and End Fed Random Wire with a T-1 tuner to cover all those bands. My next project with this rig is to make a trapped/linked end fed half wave antenna to eliminate the use of the tuner.