PLJ-1601-C Frequency Counter Manual – English Language Version

This one is long overdue and is a rework of the manual for the PLJ-1601-C frequency counter from the 1-Watter project.

I’ve done the best I can against the original version which you need to have on hand in some places where the translation doesn’t quite make sense



Absolutely no warranty / liability / guarantee etc etc!


Not a Chinese QRP Transceiver #2 – Rockmite][ 40m build

My mid year resolution was to make good on this year’s New Years resolutions and tick a few incomplete or unaccomplished projects from my list. It has to be said that I’m one of the worlds worst at seeing things to conclusion. I’m great at getting things to a point necessary to achieve the task at hand but never realise the full potential of half the things I play with. A bit like successfully building a nuclear reactor out of junk you’ve got laying around in the garden shed, but then only running it at a power setting sufficient to power a single 40W lightbulb rather than powering a whole city. With greater projects afoot for this year (more on that later) I need to get my house in order!

One of the tick list items was to build my Rockmite][ 40m. I got hold of one of these in my post Chinese QRP kit building phase earlier in the year. Unfortunately it got overtaken by the 1 Watter project but in hind sight, that may be a bonus as the learning from the 1 Watter has put me in good stead for any transceiver builds of the future. The Rockmite has achieved a degree of cult status in the QRP circles and in its original incarnation there’s plenty of discussion and documentation surrounding the Small Wonder Labs product. Since Small Wonder Labs closed their doors after years of sterling service to kit builders around the world, the baton has been taken up by Rex Harper at QRPme and this kit is a Rockmite][ 40m, the branding akin to the recent reincarnation of “Geoff Lynne’s ELO” no doubt! Thankfully Kanga Products in the UK supply some of QRPme’s range thereby avoiding another backstreet mugging by the tag team who are The Royal Mail and Border Force for import duty and delivery surcharges. The anticipation, when I discovered that you could still get hold of and build a Rockmite,was similar to saving that really crispy roast potato until last at Sunday lunch (don’t deny you know what I mean!) We’re here, it is now officially Rockmite][ 40m build day!

Now in the run up to this I’ve researched as many resources as possible to ensure this is a painless experience.

Some people have been, in my opinion, unfairly harsh about the level of instruction available for this kit. You can look at that from several perspectives. If you’re a beginner you’ll want/need more support but more seasoned builders may well be happy with what they’ve got available.

QRPme provide a well stocked resource page specific to each iteration of the kit on their documentation page.

In addition Google provides some interesting background reading, including a copy of the Small Wonder Labs build manual which can be read in conjunction with the QRPme literature.

So suitably armed with all of that, a work bench full of test kit and a handful of anticipation it’s time to attack the roast potato!

Every project deserves an unboxing photo


I’d decided on the QRPme custom powder coated and etched enclosure to go alongside this build to give it a professional finish. Thankfully you get everything you need if you go for this option which saves rummaging around in component draws and ordering packs of 50 to get a single much needed component.


The PCB is tiny for this thing and a fraction of the size of the 1 Watter.


That said it’s by no means as complicated in design. In the words of Rex Harper “Be realistic, you’ve got a $40 radio” but at the same time a little piece of nostalgia reinvented!

With a little bit of time and effort you’re rewarded with this.


Now there’s a neat little trick with this kit for allowing the crystals to be swapped out for frequency changes. By using sockets and then adding a grounding pin to the crystal can you get a very nice interchangeable crystal.


It’s another technique worth having in the toolbox! In addition, as there are a lot of hairpin mounted components I wanted to try out a build method suggested by Dave Richards AA7EE in his article on Manhattan build techniques where he suggests forming the bends using round nose pliers (another £1-99 purchase from eBay). Most of my builds to date have been very angular when it comes to bending component legs. Functional, neat, but you’re stressing the leads through 90 degrees. Equally I’ve read a few things recently which say categorically NOT to bend leads on certain components through right angles. Every day’s a school day!

Just for a bit of fun I dug out my now rather rare Altoids tin (I can’t find anyone locally who sells them for some reason!) to see how the Rockmite would fit if I hadn’t bought my nice powder coated enclosure.



There’s definitely something Cold War Spy Thriller about being able to build a fully functional transceiver which can be hidden in a mint tin! Illya Kuryakin and Napoleon Solo eat your hearts out!

Another first for me was the use of MeSQUAREs in the build which are a really neat method of building. It’s something which again Dave Richards champions and utilises frequently in his projects. It’s a good way of getting into Manhattan style construction and something I will be exploring further. Getting hold of them in the UK is easy, the GQRP Club shop stocks them along with other useful goodies!


Here the MeSQUAREs are used to provide attachment points for the speed pot control of the Rockmite][. They also find a use in mounting the power LED to the enclosure. Very neat!

So here we have one finished project.





After a little bit of fiddling with the setup and inbuilt keyer we have a 600mW CW QRP rig all set to go.

I need a bigger project me thinks. Time to broaden my horizons!


Rockmite V3 Builders Guide

Rockmite V3 Builders Help

LED PreWire-1

Rockmite 40 V3 Power Efficiency Mod

Rockmite 425 enclosure Assembly Notes

Rockmite PicoKeyer

Small Wonder Laps Rockmite Assembly Manual

QSB-01 (qrp-tech synchronous buildathon) #7 – Final Details – Custom Case Decals

Having spent a lot of time building my 1 Watter I wanted it to look half decent in its enclosure and had a good look around at my options for labeling up the case with something funky to do it justice.
As big a fan of the old Dymo labeller as I am, I’ve never been 100% happy with the finish I’ve achieved when I’ve used them. Although functional they’ll never win any prizes.

A bit of research unearthed the idea of custom decal printing. This is something I’d never even considered. Bearing in mind the number of Airfix models I built as a kid, it never crossed my mind that things in that department had evolved with the whole IT concept of “print your own”.

My favoured option would have been to use the media which you run through a laser printer to give the most crisp output, but not owning one and in a similar vane to the Dremel bench saw project, I wasn’t about to go and buy one for a single job, so left it in the hands of my Epson Stylus Photo R360 to see what it would do with the ink jet media.


Mr Decal Paper (real name not me being flippant) on eBay supplied the decal sheets and the instructions which made life a bit easier. You need to seal your printed sheet with spray varnish to prevent the immersion in water stage from causing everything to run off the page. A trip around the art section of The Range provided a solvent based product rather than a water based one which would have defeated the whole object.

I designed the decals in a combination of PaintShop Pro, MS Paint and MS Word. The dry run on plain paper was spot on but the actual print on the decal paper was less than polished. I’ve had this before with ink jet inks not wishing to play ball with media other than the massively overpriced product from the manufacturer. As Epson don’t produce a decal paper I’ve got to live with it.

Now despite my anticipation of thunder storms on a Bank Holiday weekend, the weather proved me wrong and in effect was perfect for turning the garden washing line into an impromptu spray bay.


My three coats took seconds to dry in the heat but I still gave it ample drying time between applications to prevent any mishaps.

The next morning brought judgement day along with an assessment of my ability to accurately cut things out with a slide cutter and pair of scissors.
Like the Airfix kits of the 70’s a quick soak in water releases the decal from its backing sheet allowing them to be applied.



Not bad for a first attempt! The instructions suggest a drying time of 24 hours or a spell in a low temperature oven to harden the decals dependent on the surface they’re applied to. I’m not sure my 1Watter would see the funny side of that!

Mountain Topper MTR-5B

Faced with the choice of having to spend Saturday evening watching Britain’s Got Talent (a contradiction in terms if ever there was one) or push pins into my eyes, I chose the third option and built another radio!

Now this was a little forward as I still haven’t put the finishing touches to my 1Watter but given the circumstances I think I’m allowed a little latitude.

When I was hunting around on the internet for ideas of what was small, portable and a potential project I stumbled across several reviews for the Mountain Topper in its earlier guise the MTR3B


Rarer than rocking horse droppings on this side of the atlantic these things get great reviews from people who like yomping up mountains for a bit of SOTA action.

Like everything, these radios evolve and the latest offering is the MTR5B and again even rarer!


When I first saw this I was making noises like the little green aliens out of Toy Story and filed the idea in the back of my brain along with plans for global domination, owning an Aston Martin and having Rihanna’s number on speed dial.

That is until Kanga Products emailed me, offering me the opportunity to own one of these as I’d expressed an interest while perusing their website. It took nano seconds to think that through.

I had to wait a week or two for it to arrive and to be honest there were degrees of reservation as to what was going to be in the box as my original research was on the complete kit which involved a hell of a lot of SMD work.

I like a challenge but there’s a point when you have to admit your limitations and this may have been it. The box yielded this


That’s a bit more like it! So half an hour later we have this




It really is that small and all it wants for optimal performance is a 9V battery.

Now the MTR5B is a five band transceiver so there’s lots of potential out there as you’ve got 40-15 meters to play with.

This evening there’s plenty of activity on the air so the smoke test went something like this

The only word for it is “Awesome”

I wanted a portable solution for sitting in the sun with and it doesn’t get any more portable than this!

You watch the Bank Holiday weekend descend into a wash out just to spite me!

QSB-01 (qrp-tech synchronous buildathon) #6 – And the fat lady sings!

So after several weeks / months of interrupted building we’re there!

Now admittedly it’s not in the enclosure I wanted to build, which was this

Screenshot 2016-03-09 14.41.42

but you can’t have everything! A PCB enclosure requires the ability to cut reasonably straight lines in your medium with repeatable accuracy. To do this I was planning on using a Dremel mounted horizontally in a 3D printed purpose made frame which converts the drill into a bench saw. Unfortunately part way through printing, my good chum Mat’s printer decided it had had enough and requires a bit of rebuild work and maintenance to get it back working. As such I don’t have a completed table/platform for the Dremel holder.

That said, every cloud has a silver lining. A Dremel would have set me back seventy odd quid, plus the additional hardware for the frame. The cheaper solution was an LMB/Heeger CR-442 painted enclosure from Mouser. Even with the duty charges and shipping I was out for less than a third of the cost of the Dremel saw table project and probably got to keep a few more fingertips into the bargain. If I build another 1Watter (and I will) I’ll look to box it in the bespoke built enclosure if the printer is back working.

So (drum roll please), here it is!





If you want to save yourself several hours with a set of calipers and some graph paper trying to work out what will fit where (and it is tighter than the proverbial in there!), here’s a copy of my drilling template. Print it at full size A4 and you’re good to go.


OK, the enclosure needs a bit of artwork to liven it up and to make sense of the controls and connections (separate post for that bit) but the soldering iron is officially cold!

Now on first reveal to those at home, I got a “Ah, isn’t it cute!”

Not what I was expecting! I was trying to build the QRP equivalent of Dr. Heinz Doofenshmirtz’s “Inator’s Inator” here (you have to watch Phineas and Ferb to truly get that one I’m afraid) so people cooing over it is not what your kick-ass QRP radio wants to here. That said it’s a nifty little package.

The best part of a day was spent tinkering with the final setup and alignment as per Chuck’s YouTube video #9.


This one’s a must. I was really surprised to discover how serious the relationship between the adjustment of C24 and C25 was when aligning the transmitter. I was wondering why I was seeing absolutely nothing on my power meter when I was keying until, Boom! The power was rocketing past 1W in a hurry. All good stuff.

As part of the build up to this project I invested in a frequency counter from eBay. The supplied item turns out to be a PLJ-1601-C which comes with absolutely nothing. Google provides you with a manual in one flavour – Chinese. So, with a little bit of effort here’s an English language version I made using Google Translate.

PLJ-1601-C english translation

PLJ_1601A – chinese language

It’s free and comes with no warranty, acceptance of liability etc etc etc. Just be grateful someone made your life easier for you rather than having to attend night school to learn Cantonese!

** Addendum 29/07/16 – Many thanks to Trevor Newstead who has noticed that for some bizarre reason all of the images have disappeared from my english translation version. I will look to redo the document at a later date but in the short term the original Chinese language version has been added for reference. If you look at the two side by side you can see what’s what. Sorry! it’s on the todo list

With the frequency counter attached to the antenna and everything on a dummy load I get a tuning range of 14.055.86 to 14.060.49 MHz.


Unfortunately I still can’t get the hang of my Homebrew oscilloscope to get anything sensible out of the frequency analyser to check the spectral purity during transmission, so that’s a job for another day. That said I have managed to get my DS203 to do something useful. Here we’ve got a nice sine wave on keyup!


The final stage is to design some case graphics, check the output for harmonics and sort out a throw up antenna so I can play outdoors in the sunshine. There’s no point in building a portable rig and sitting indoors when the sun is shining outside is there?

QSB-01 (qrp-tech synchronous buildathon) #5 – transmitter build updated @ 21/05/16

Phase 15 – Final RF Power Amplifier Stage

Commenced 02/05/16  Completed 02/05/16

Phase 15 completed

Completed build requiring fitting in an enclosure, setup and alignment








Phase 14 – Third Driver Stage

Commenced 02/05/16  Completed 02/05/16

Phase 14 testing


Audio file – Phase 14 testing

Phase 14 completed



Phase 13 – Second Driver Stage

Commenced 02/05/16  Completed 02/05/16

Phase 13 assembly work


Phase 13 testing


Audio files Phase 13 testing

Phase 13 completed



Phase 12 – Transmit Band Pass Filter (BPF) & First Driver Stage

Commenced 28/04/16  Completed 02/05/16

Phase 12 assembly work


Phase 12 testing


Audio file – Phase 12 testing

Phase 12 completed




Phase 11 – First Transmit Mixer

Commenced 27/04/16  Completed 28/04/16

Phase 11 assembly work


Phase 11 testing


Video file – test operation of the first mixer stage

This testing stage is clever in that it is using the receiver to test the transmitter in a feedback loop where the output of the first transmit mixer is fed into the antenna input. This comes with a caveat of don’t do this under any other circumstances else risk destroying your creation! In the above video the audio output of the keyer has been switched off by entering the command mode and disabling it. As such the tones which are heard are those being produced by the transmitter. The technique negates the need for any test equipment which is a bonus for those without those resources to hand.

Phase 11 completed


I’ve corrected the display unit now by adding the IF frequency to the display’s memory function. Now it adds 6MHz to its received input giving a more accurate and usable reading


Phase 10 – Keyer & Keying Circuit

Commenced 26/04/16  Completed 27/04/16

Phase 10 assembly work


Phase 10 testing


Video file – Keyer Circuit test



Phase 10 completed




1Watter YouTube video resources

The following videos were produced by Chuck Adams K7QO and although they don’t follow the step by step guide as per his website they are a very useful resource especially phase 9 (final alignment and testing) and phase 10 (introduction to the 1Watter keyer)

Phase 1

Phase 2

Phase 3

Phase 4

Phase 5

Phase 6

Phase 7

Phase 8

Phase 9 – Testing and alignment of completed 1Watter

Phase 10 – 1Watter keyer

Aluminium enclosure construction