RaDAR – Meet TUD the QCX

My QCX 40m CW only transciever built from a kit, nickname “TUD” – The Ugly Duckling.

I had a few challenges building this rig and it almost became a …. beacon, but hey, it can still be, quite handy if I want it to be!

T1 – everyone’s nightmare but mines working now …. I think. Not such a big issue peaking the band pass filter. The biggest problem was the audio that gradually got worse but this was the cause ……… an intermittent short circuit on the earphone socket. The socket was a mission to fit I recall but at first all was OK!

So I moved C51 and soldered a new socket to the 49er “daughter board” introduced as a audio output work around a while back. Now I have TWO audio outputs, the HiFi QCX output and the LM386 output. The one can be used to feed a MP3 recorder for recording CW QSO’s!!!

I have now completed my journey and can get on with my ….. ham ….. life!!! 🙂

Hoping for a QSO or two later today ……… 🙂

73 de Eddie ZS6BNE




RaDAR – 49er vs QCX vs HB1A

I had all three rigs at my disposal this weekend and it was a good test. I made a few QSO’s and here is an extract from the log.

It tells a story. I had just repaired T1 on the QCX the night before, or at least found a workaround for it. It worked as expected and although I must still peak the band pass filter by removing a few turns from T1 again, it worked well.

The QCX Pro’s

It has a good CW receiver with 200 Hz audio filtering and a good Class E transmitter. It has an automatic facility for sending pre-programmed messages although it needs a firmware upgrade because mine only sends the first of sixteen choices – not serious though. The on board micro switch can be used as a hand key. The rig is VFO controlled adjustable to a resolution of 10Hz. Power consumption appears to be acceptable.

It has a built in keyer.

Advanced technology design. Low cost (Kit) in the region of R950.00

The QCX Con’s

It’s very difficult to make changes once built. If you’re lucky enough to have everything working perfectly and you don’t need to touch it then it’s fine. I wanted to rewind T1 and caused slight damage to a track or two on the PCB and had to find a workaround so mine no longer looks so pretty but fortunately still works! If you can build it, you can repair it!

I had audio problems and built in an external LM386 audio amp. It alleviates the only problems I ever had. The possibility of further PCB damage trying to fix the audio is just too great. My “Ugly duckling” will stay an ugly duckling for the time being, at least my duck is still kicking!!!

There is a CW decoder which is quite nice but if you’re going to rely on it you’re going to lose one QSO after another as it sometimes decides to go deaf when you most need it …. that missed comment! Your brain is still the best morse coder reader there is 🙂

The biggest con ……. The QCX is a CW ONLY rig. It cannot be used to listen to SSB transmissions without some innovative intervention like I did with the audio amp.


No container.

40m Only.

The 49er is a fun rig but certainly stands it’s ground against the competition! It’s a straightforward no nonsense radio.

49er Pro’s

Very good power consumption for it’s odd 1.3 Watts output. Very easy to repair if you must and uses standard components. Simple analogue design using easy to get components. It has a good receiver with sufficient CRYSTAL filtering.

Low cost, in the region of R130.00 An IDEAL entry level radio.

49er Con’s

Single frequency, 7.023 MHz for receiving and transmitting. This frequency is not a “watering hole” either and skeds are usually made to meet at appropriate times. The audio side tone is great but there is “thumping” at times, exaggerated by using cell phone earphones. It can be unpleasant sometimes while sending.

No AGC and no volume control 🙂 You need to adjust the distance of your earphones from your ears, more than enough audio though!

No container.

40m Only.

The HB1A. I had to repair this one but it’s also a reasonably straightforward design but does have some firmware much like the QCX. A lot of the components are surface mounted.

HB1A Pro’s

Well it has a sturdy container. An overkill really 🙂 Power consumption is acceptable. Very good audio and side tone with volume control. It has four levels of filtering for CW and SSB. Yes it can receive SSB transmissions and is also capable of cross mode (CW / SSB)  QSO’s. It also receives AM stations with reasonable audio quality.

It has a built in keyer.

This particular model can operate on 40m, 30m and 20m

Price unknown as I swopped it for my immaculate 50W 2m FM Alinco DR135 with optional built in APRS / Packet TNC but like I said it needed a simple repair on the LCD display.

HB1A Con’s

I can’t think of any? It is a CW only transmitter but all three under discussion are. Power output the same as the QCX at around 3W.

Overall comments.

Obviously all options are lightweight if one needed to take a radio with you on the trail. Certainly you don’t want to limit your contact base to CW only. There may be a SSB station in range and the operator able to send and receive morse code. VFO control is a must when doing some serious amateur radio communications.

This brings the HB1A to the top of the list, the QCX second and the 49er third. The QCX even with it’s modern design has only an advantage over the 49er with a little more power out (Typically 3W) and is VFO controlled. If they were to be used only on 7.023 MHz then the filtering may be an advantage with the QCX but the 49er’s receiver is surprisingly good!

So, my CW only trail friendly radio I’d take with me on serious hikes would definitely be the YouKits HB1A.

About a year ago, I bought a Rossi battery and it has proved to be an absolute gem as far as a power supply is concerned! It serves as a decent torch too and if you really needed to, a cell phone charger although I’d steer away from that option from past experiences!!!

I have an end fed antenna which is adjustable to a certain extent for working on 40m, 30m and 20m (Pushing it). I have a tuning indicator which has proved invaluable for peaking the capacitor setting once deployed and the deployment of an end fed is usually the fastest and easiest of all antennas. Use a tree branch and if there are no trees then certainly the RaDAR Painters pole mast is the optimum solution. This one has a one meter length “counterpoise” but simply used to tie down the rig end of the antenna.


73 de Eddie ZS6BNE


RaDAR – QCX Recovery

The QCX is an awesome kit using modern technologies to achieve it’s excellent results. Mine was successfully built but had an audio problem and comments on the QRP Lab forum led me to believe the problems may lie around the receive transformer T1.

The QCX’s PC Board is very finely designed and doesn’t easily stand up to anything more than the initial soldering of components. Removing T1 for a rewind was a recipe for disaster which became reality. My rig was reduced to that of an intelligent QRP beacon … the transmitter still worked.

I built up the courage over a week or two to make a plan to wire in an alternative transformer. I used a T80-2 and even then winding the four coils was a mission. I used veroboard and soldered the coil’s four start’s and finishes in a sequence I could implement within the remaining PCB contact points …. those that weren’t damaged through removal of T1.

I had to connect directly to a Surface Mounted IC, pin 7, in one case. I actually used the wire itself as an extension to my soldering iron bit by strippinng the wire, soldering leaving a little excess solder, touching the IC pin with the wire and heating the wire till the blob of solder at the end melted and flowed between the wire and the IC pin.

Success …………

Peaking of the Band Pass Filter – C1. Also presently fully un-meshed at the peak which requires removal of a few turns on T1 but easier to do now ….. next week’s task but peaked sufficiently I think to use this weekend!

I simply tucked the receive coil under the chopping board and fixed it in place with double sided tape. The QCX was saved.

I still have a bug in the QCX’s audio section but I at this stage don’t want to try desoldering again causing inevitable damage to the PC board so I’m still using my workaround by connecting a 49er board’s audio section to the QCX’s volume control. It works well enough.

Looking forward to making some new contacts with the QCX again this weekend!!!

73 de Eddie ZS6BNE

RaDAR – The reality

That’s one thing about these RaDAR challenges. They are not easy. There are many things to contend with, logistics, propagation, weather, participation. If you try the movements that adds a whole new set of challenges, fitness, working against time, and each deployment is a new puzzle especially if you’re in a place you haven’t been to before.

Then it’s grid determination, good voice procedures to get the info sent and received without errors. Safety in unknown environments against man and beast. Food, hydration and protection against the cold and rain.

Then try to make 5 QSO’s from each position. In South Africa we don’t have extreme weather but certainly a challenge to get sufficient QSO’s. RaDAR even makes provision for participants to sit in their shacks listening for the RaDAR stations out there but sadly that doesn’t often happen.

RaDAR also puts the operator into a real world scenario where all these things are a daily reality. If you’re out there alone and you need to communicate with someone quickly using what you have (Hopefully regularly practised) then you will come up against these obstacles too but RaDAR operators will know how to handle it … through experience

73 de Eddie ZS6BNE

Over forty two years ago …..

RaDAR – November the 4th challenge

I’ve just been browsing Google+ and reading the respectable RaDAR Challenge participant’s feedback. I feel proud to be part of such a group of radio amateurs willing to go the extra mile in doing something a little different. RaDAR is “Daring to be different” a phrase suggested by Lucy M6ECG who was active too braving the cold and strong winds.

My friend Stephen ZS6SVJ has now migrated to snowy Canada and his recent comments were if he wanted it easy he’d use WhatsApp or Skype. He embraces the challenge and all it stands for.

My challenge started off with a challenge of a different kind, spending the day in Potchefstroom with my XYL and grandson Eduan where he took part in Karate championships for his age group. The plan was to be in the RaDAR Ops area before 16:00 local after a 350km drive. I made it back in time.

The RaDAR challenge for me started setting up as a field station initially from where I could do some on foot deployments. A suitable pass for the AO-7 satellite was exactly at that time frame and I set up quickly at grid KG34ac19pa. I made contact with Kieth ZS6TW in KG44bd, Andre ZS2BK in KF26sa and Rickus ZS4A in KG41ds. Success!!! Hadn’t been on AO-7 in ages.

I had modified my ZS6BKW antenna after talking to Brian ex ZS6BKW via email. Mine wasn’t tested but I had built the top section according the Brian’s specifications. It still needed to be tuned though. It was resonating nicely on the lower portions of 40m and 10m but not on 20m ….. that was my planned DX band for later.

I got it up high amongst the blue gum trees. Then I broadcast my intentions to make a contact or two on Facebook before starting the on foot deployments.

I made no QSO’s ….. then later checked the RBN ….. I was transmitting using 5W.


V51YJ in Namibia reported hearing me via the RBN pretty well. This was on my pack’s FT-817. I knew from experience that in this case local NVIS comms would be impossible. Forty meters had gone skip!!!!! That meant it would be a waste of time going for a walk. That certainly put a damper on my challenge. I was even hoping for a 49er contact! It was not to be …..

Forty meters was out for me ….. twenty meters needed a tuned antenna …. I wasn’t sure. There were contests on all over the place and fatigue from a long day started to set in ….. I missed the last planned FO-29 pass. Could’ve got another two or three QSO’s there …. darkness set in and I called it a day returning on the Sunday morning, yesterday.

Sunday – Tuning the ZS6BKW 

I had left the antenna in the trees but before I took it down I made a few adjustments including cutting the feed line shorter, around 200mm at a time. This brought the lowest SWR point to around 7.1 MHz (Midband) and 28.460 MHz. On twenty meters there was no sign of an SWR dip. I know I may still have to trim some more but decided to talk to Brian first …. I’ll be back!

The new design’s flat top itself is a little shorter but the ends hang down. Ideal to fit into smaller spaces if you can get it up around 10 meters high.

Sunday morning on 40m and NVIS conditions were EXCELLENT. I made QSO’s with Marinus ZS6MAW, Author ZS5DUV and Theo ZS6TVB. Theo created the termination connector for my ladder line using his 3D Printer a few moths back.

Signals were 59 PLUS all over!

I had a CW QSO with Wally ZS6BCI and Pierre ZS6A. Wally made a joke that he thought I was using a kilowatt! I’m almost always QRP and we talk often! During my QSO with Pierre I switched over to the 49er pushing only 1.3W and Pierre gave me a real 579. He also said the 49er’s frequency is around 7.02315 to be exact.


I’d misplaced my other hand key but luckily found this one I keep with the HB1A in it’s carry bag.

Would have been great to have had such fantastic conditions during the RaDAR Challenge on Saturday but it was not meant to be …




73 de Eddie ZS6BNE





RaDAR – QCX Audio

I think I have sorted out all the QCX alignments which are quite simple to do and appear to be correct. I feel I did a good job during the build process and have used the little rig a few times trying to get the feel of it.

I’ve made peace with the fact that it is a well designed modern receiver that is filtered to the maximum (200 Hz). It does receive signals but the purpose of this Blog is to share my experience of the audio. My QSO with Z21GC last night was a good example.

I have tried various headphones but the audio is not sufficient to drive them to a comfortable level. I’ve used my cell phone earphone with limited success. I also used a PC’s shoX powered speaker and that is what I used to complete my QSO with Brian last night. I held the speaker close to my ear, constantly adjusting the volume control as the signal had deep QSB. The audio amp can be easily over driven and the distortion can be heard almost sounding like a 555 oscillator. If you cut back on the audio it sounds more pure but then it’s a battle to hear properly.

It appears there is no AGC (Automatic Gain Control) so there is a constant fiddling with the volume control to prevent overdrive. Certainly a lot went into the design of the QCX. It’s a modern style rig and the TX is really awesome …. Oh that reminds me …. I noticed, on key down, the sidetone audio level gradually gets less, the signal indication gets less which appears to be essentially an audio level indicator in it’s standard configuration.

I checked my supply voltage and it’s reasonably constant. I put my home brew dummy load / QRP Power meter on the output and it stays constant but as explained above, the sidetone audio levels gradually get lower. You don’t notice it while sending CW only on key down for a few seconds.

A lot has gone into the design of this rig but the audio falls short of my expectations which builds up frustration. But, I’m a “die hard” I’ll be back hoping there is something I can do about it.

I have a spare 49er board which I may use for the audio section only and hook that up to the QCX.

                                                                   The QCX’s Audio output stage


It will be a simple task to wire the 49ers LM386 audio amp via the volume control pot. The 49er doesn’t have a volume control either! Then wire the power supply in parallel with the QCX’s


           The 49er’s Audio output stage


Update 2017-10-27

I built the audio and power supply sections on the 49er board and did the tests.

The LM386 isn’t the quietest audio amplifier you could ever use which probably explains why Hans didn’t use it in his design but I can hear what I need to hear now even if it’s mixed with the LM386’s “Hiss”. The headphones I use now have sufficient drive for comfortable listening and I simply still use the QCX’s volume control for comfortable listening level.

Without wanting to be invasive I used the standard QCX audio output and fed that into the LM386’s input. No RFI …. there is sufficient filtering on the 49er circuit.

So, I’ll make this a permanent solution to my QCX problem for the time being.

Update 2017-10-31

Last night I wired the 49er audio section to the volume control of the QCX which is just before the QCX’s audio section. The audio is lively!!! More than enough. So it appears that there may be a fault in the region of IC10 on the QCX board as reports worldwide say that the QCX has quite sufficient audio to drive headsets or whatever you use to play the sound.

It wasn’t a waste of time doing this for once I do manage to find and fix the fault I have an alternate audio port for recording or even for a public address facility!

I am still concerned about T1 and the band pass filter peaking. I get a peak but don’t see the peak drop while turning C1 before it’s unmeshed again. I may have to further reduce the turns on the toroid one turn at a time. Maybe I’m close to resonance but not exactly there. I doubt it though that that be the cause of the audio levels of the QCX. The 49er addon proved that I think???

73 de Eddie ZS6BNE