Radio Update - QRP etc

After setting up a basic station in the small “office” - just one rig and my keys - I decided to make a “real” hamshack with more radios, some tools, test equipment etc.

I added two shelves above the desk to hold radios, PSUs, 'scope, tools etc. I've now got a “one-desk shack” that can be used for operating on air and building & repairing equipment (on a small scale)

I found that the stock mic for my FT891 was faulty - the mic element is open-circuit - so I bought a Heil HMM fist mic and spent some time setting up the EQ for a reasonable “communications” quality audio. I'm not naturally a 'phone operator, so I'll not be having lots of “ragchew” QSOs, and “communications quality” is all I'm aiming for - to be audible - not quite as extreme as a Clansman but with enough HF emphasis, and enough compression to cut through the noise.

I though briefly about limiting myself to SSB for a few months, to get used to talking on the radio, but that's NEVER going to happen.

Then I found a box with an unbuilt QRPLabs "QMX" kit! I'd bought it in August 2023, and hadn't built it. I have a QCX-mini for 40m and it's a great little radio, and I thought the QMX would be the next obvious step. Then I forgot about it.

So, on Saturday I got the box, opened it. Printed out the Assembly Manual. Watched Hans's You Tube video highlighting the pitfalls. And got started.

The first thing was to check if my early (Rev 1) board has the “Power Board Short” issue - and it did - so I got out my hot-air station and moved the MOSFET a mm or two to remove the short.

Then down to business…. building.

I did it all in one day, with the occasional break for food, dog walk, etc….. The most challenging thing was winding the 2 binocular ferrite transformers - the PA output transformer and the SWR brigge transformer. The “normal” toroid cores were all straightforward.

I built it for 9V operation (this determines the form of the PA output transformer).

I worked first time. Which is amazing given the small size and relatively dense component layout.

On a PSU set for 9V I get at least 5W on all bands. I made a string of 4 x 1N4001 diodes to drop ~2.4V and powered it from the normal shack supply. And used the handy config option “Limit PA Volts” to set a limit of 9.5V. This gives a comfortable 5W on all bands without any risk of overheating the finals etc.

I've used it on WSPR - both via WSJT-X and using the internal standalone WSPR Beacon mode.

I upgraded to the current beta firmware 1_04_002 and the main change seems to be the removal of the Beacon mode and its replacement with “Virtual U3S” - a mimic of the functionality of the U3S multi-function beacon TX. Currently only WSPR is supported - but the other modes will follow. This works well - and allows a “schedule” to change frequency / Mode etc on sequential TX periods.

Then I had to try it on CW.

My first CW QSO was on 30m with Rob, OK7SX, on Wednesday 29th.

Last night I had 3 x CW QSOs : F/FK8IK (Mic nr Vichy), IK3/UY7LA (Alex, nr Venice) on 30m and the icing on the cake was a chat with Will GM0HKS on 40m.

Will was using a K2 at 5W, but did mention that he still has the “wee K1” - that's my old K1 that I built back in 2003. I sold it (and deeply regret doing so) and it ended up in Will's care. We've had a few QSOs over the years and he never fails to mention the “wee K1”.

I've been thinking about where I want to go with radio recently.

What actually gives me pleasure?

What can I do to avoid the aspects of the hobby that spoil it for me?

Building and using the QMX reminded me of the fun I got with I first built the “wee K1” in 2003.

I hadn't been active in the hobby for many years, my log book shows a couple of FM contacts in 2002 with locals on the repeater, and prior to that I was using Packet Radio in 1994, while still living in Huddersfield and working at Holme Moss. The last time I'd actually been on HF CW was while I was at UMIST, in 1985 using the club station.

I built the K1 in 2003 and went CW crazy!

The basic chronology :

• pre-2003
  • 1983 - first licensed as G4SLV, still at school. Used 10mFM and 2m CW before going away to University in 1984
  • 1984 - 1988 - at UMIST, and active in the Radio Society. Used club station for HF CW, as well as 70cm ATV and “other” things
  • 1988 - 1995 - not much radio - some Packet on 2m
  • 1995 - moved to Wick. Some HF SWL using my old AR88D. No “ham” radio
  • 1999 - moved to Shetland. Some 2m activity on local repeater. Some HF SWL with AR88D and AR7030.
• August 2003 - K1 - 2 bands - 40m / 20m - lots of QSOs. A very active phase on the hobby on-the-air.
• Some time in 2004 - K1 - added 4 band board & concentrated on 40/30/20
• Some time in 2004 - IC706MK2G - all bands - 100W - K1 use still frequent - but the lure of 100W was strong for a while - plus digimodes (PSK31 etc)
• November 2004 - 60m use began - mostly SSB - K1 still in use for QRP CW
• 2007 - K2 added to the shack
• July 2007 - Start of 500kHz “experiment”. All HF working stopped and lots of time spent with MF - Sold K1 & K2 and IC706. Bought IC718
• Jan 2009 - Back to HF, mix of QRO and QRP. Mostly CW, Some SSB and digimodes
• Nov 2010 - Back to 500kHz, with some HF mixed in.
• Jan 2011 - Back to HF

At some point during the MF phase I sold the K1 and K2.

From 2012 I spent most of my time on 60m using digimodes, mostly Olivia. I still dabbled on HF CW. Mostly QRO. Bought IC7200 to add to the Shack.

The three main phases were

• QRP CW on 40m/20m with K1
• 500kHz CW (and some WSPR etc)
• 60m Digimodes

Looking at my logbooks I can tell that I really delved deeply into QRP CW with the K1. I worked many, many people in many, many places and had a lot of fun with such a simple little radio.

The K2 was fun to build, but it got little use - I remember preferring the “wee K1” to its big brother. The 500kHz experiment in 2007 intervened and pushed the QRP HF rigs to the side and they were sold to fund “more important” items.

On 60m I had a lot of fun, learning a lot about the propagation on the band, and about the different behaviour of the various digimodes.

I came back to HF CW a few times - but nothing sparked joy like those early times with the K1.

Building the QMX has shown me that it's possible to have fun building and then have more fun using simple QRP radios. And this might be the push I need to get back into QRP.

It's more challenging these days - as most people in urban environments have raised noise levels and struggle to hear “normal weak signals” - but there are still people actively using QRP, and only QRP, to fully enjoy the hobby.

If I can't work someone due to my weak signal, then so be it… move on… there'll always be someone else to work.

One area I've never tried is QRP SSB. So I've turned the power on my FT891 (the “SSB rig”) down to 10 watts. I'll give it a try some time. But once more my focus is back to CW. And now with an additional slant - QRP, and only QRP.

I'll write more as I explore.

My G-QRP Club membership number is 2377, dating back to around 1984…. so I've been at it a long time, in fits and starts.