Thursday 14 March 2024

HAND-HELD PC

GPD WIN MAX

Three years ago (doesn't time fly?) I bought a used notebook to take with me out in the field and it's served me well, but it's not the fastest thing in the world and it's not the smallest or toughest, so I gifted it to my mother-in-law and it suits her low demands perfectly.

So I wanted to replace it with something very small, light and pretty tough. I didn't need blisteringly fast performance, but I certainly wanted something with an above average GPU, fast ram and an SSD. I own a very fast Gaming Laptop, but it's just way too big to be lugging around with a radio.

I looked all over and was pretty shocked at the prices of things, so I turned to the second hand market. It was there that I came across something for sale right here in my hometown. It's something I'd heard about before when I was searching for my gaming laptop, but it didn't appeal due to its small screen.

The PC I'm referring to is the tiny hand-held GPD WIN MAX. Looking at the specs and the construction, it seemed like it might be the perfect device for my needs, so I started to find out more about it on the internet and I read a whole bunch of very complimentary reviews.


It's approximately an 8"x6" clamshell design with nice rounded corners and it's about an inch high. Under the lid is an 8" Touch-Screen - perfect!  I can't tell you how many times I find myself prodding dumb-screens with my finger, lol. The screen also benefits from the use of Gorilla Glass which is pretty darned scratch-resistant.

Despite the small dimensions, the GPD WIN MAX features a full QWERTY keyboard including F1-F12 function keys and number keys.  Above the keyboard is a Touch-Pad which supports multi-finger gestures and clicking.

In the upper corners are a number of gaming pad controls, plus two very high quality James Alps analogue sticks which are robust and work incredibly well. For gamers, there's the familiar L1/2 and R1/2 buttons on the outside edges. 

Under the covers lives an Intel i5 cpu and Intel Iris Plus 940 graphics processor, which makes this a great little performer! In fact, it's primary role is gaming - including the ability to emulate other platforms such as Xbox and PlayStation. Not something I'll be doing, but I'll certainly benefit from the added ooomph!

This is backed up with 16Gb of DDR4 ram running at 3733MHz and an M.2 PCIe 512Gb SSD.  If 512Gb storage isn't enough ๐Ÿ˜‚ you can also take advantage of the built-in SDCARD slot which is A2 compatible - mine had a 256Gb Sandisk A2 Extreme Pro already fitted. Of course it's also extremely easy to add an external drive in the form of a plug-in USB SSD (if you work with large video files, etc).

Connectivity is great - there's Wi-Fi 6 built in and Bluetooth 5, along with an Ethernet RJ-45 socket for direct connection. The good news is that that the PC recognises my AirPod Pros and that includes full and proper use of the Airpod's microphone!

Other connectors include a full-size HDMI, two USB-A, one USB-C and one ThunderBolt 3. The USB-C port acts as the charging port and the Win Max comes with a 65W charger.

One of the very best connectors is the Thunderbolt 3. With this, it is easy to expand your machine and make it even faster and more convenient by adding a Thunderbolt Docking Station.

This allows you to have a single cable from your PC to the dock and have all the other connections provided at the hub, including ultra-fast transfer speeds, multiple external monitors and more. This is fantastic if your GPD WIN MAX is your only machine and you use it as your home-base computer as well as your portable.

Anyway, for me it's just a compact PC to take out in the field. On it I will have all my radio-related software and little else. It comes in a faux leather pouch and will easily drop into my RuckShack.

Battery-Life is claimed to be over 10 hours, but we all know that's a load of nonsense. For that to work, you'd have to switch on every single power-saving function and avoid running anything which caused the cpu to speed up. In real-life terms it seems to be around 6 hours, which is plenty for a day out playing radio.

I managed to get a free upgrade to Windows 11 and everything is running fine. All my regular Ham Software is installed and I'm extremely happy with this tiny marvel.

Connecting to the FlexRadio 6300 remotely was no problem and running two panadapters was effortless - no glitches or stuttering at all. It was all very fluid and enjoyable.

Up to now I've not hit any problems with anything, so it's all good. I'm not sure if the top bank of gaming controls can be configured for other uses - it would be handy if they could! 

So in summary, I reckon this will be a pretty darned handy device for SOTA/POTA work. It's very light and compact and yet powerful and fully featured. On the secondhand market you can buy them for around £350, which is a bit of a bargain.




73, Tom, M7MCQ



Sunday 10 March 2024

RADIO-KITS EXPLORER (PART-2)

 PART 2 - TESTING! 

Having previously posted about building the Radio-Kits Explorer, now is the time to switch it on and see if the magic smoke is released.

I had followed the instructions and run all the tests listed in the instruction guide. Thankfully, everything seemed fine and to spec, so I finished off the last bits of construction and got it ready for full operation. For the first switch-on I used a 12V 600mA psu and plugged it in. The radio lit up and made radio-like noises. No smoke!! ๐Ÿ‘

I connected an EFHW and checked the receive capability of the Explorer and I'm happy to report that everything is working really well! Thankfully, there was a contest running , so there were lots of SSB signals to listen to from all over the world. The narrow CW filter worked well too down at the bottom of the band. So far, so good! ๐Ÿ‘๐Ÿ‘๐Ÿ‘

Then I plugged the Explorer into a computer and Windows saw the device and assigned it a COM port ๐Ÿ‘

The PA BIAS adjustment was odd. It is set by default to 100, which is too low. When you select the option, the radio goes into TX (no RF) and the red LED lights up. The current draw went from 154mA (RX) to 285mA and adjusting the BIAS made no difference - it's supposed to increase the current draw and you keep rotating the dial until you've added about 40mA to the initial reading you got. 

Odder still, every time I return to the BIAS menu option, the figure has defaulted back to 100. I assumed it would maintain the adjusted level, but it doesn't. Apparently, this is normal but I’d personally prefer it to remember the figure. The reason Steve forces it to default to 100 is in case an owner changes the PA transistor. If I had to change the transistor, I’d probably do a full reset anyway.

The end result is that the radio isn’t transmitting. I tested it in CW mode on a straight key and every time I keyed-up, I saw a current draw around 280-290mA and the Power Out reading on the radio's screen was 0W. ๐Ÿ˜จ 

I wrote to Radio-Kits and Steve said he'd put together a list of things to check. 

 5TH MARCH 

Steve emailed back promptly and gave me some things to check...


With a 13.8V input and the receiver set to measure bias current (SYS MENU - TX BIAS - 100 - red led on), Point-1 should be around 13.8V and Point-2 should be 0V. They were both fine๐Ÿ‘

Next up was a resistance measurement between Point-1 and Ground (with the power supply disconnected). It should be 890 Ohms - it was ๐Ÿ‘

Next was the bias voltage. This involved setting the bias figure to 300 and measuring the voltage at Point-3. It should be 2.1V and it was. Voltage at Point-4 should be 1.5V and it was. ๐Ÿ‘

Next, Steve wanted to know the voltage at Point-5 (the PA transistor Gate) with the bias setting at 300. It should be 2V and it was. ๐Ÿ‘

He also wanted to know the current being drawn by the radio if the bias setting was increased to 400. The current didn't alter at all with the increase from 300 to 400. In fact, the current stayed the same even if I increased the bias setting to 1000 ๐Ÿ˜ฎ

If you're an outright beginner and you're not exactly sure how to use your multi-meter to measure current, see the diagram above. Be sure (in this instance) to pick the mA port on the meter. 

By this time, it was getting late into the evening, so we called it a day. Steve signed off with a note about the PA transistor, saying to check the voltage reading on the metal tab which backs onto the case and he also mentioned the connections on the T2 windings. I'll leave it for tomorrow.

 

 6TH MARCH 

I checked the voltage on the transistor’s metal tab and it read 13.8V which was correct. At this point, I took note of Steve’s suspicion that the output transformer (T2) wires might not be making contact.

Checking the wires with a continuity tester, everything seemed fine, but I decided to reflow the solder joints anyway and boom - it worked! Thanks for your guidance Steve!!

FULL 5W OUTPUT
With the radio showing a solid 5W into a dummy load, I rebuilt the radio and started to run some on-air CW tests. I connected an EFHW and used my Elecraft T1 tuner to get a good match. During the tuning process, I saw the output power vary between 1.5W and 6W. This prompted me to ask Steve if the Explorer had any built-in SWR protection and the answer was no.

He followed it up with a reassurance that it won’t fail as long as it doesn’t get too hot. The Elecraft T1 usually finds a match very quickly, so I’m not too worried about that, but obviously, you need to be cautious when using data modes such as FT8.

Once I’d got the radio matched to the antenna, I started to put out some CW TEST messages and within a minute or two of sending, spots appeared on the Reverse Beacon Network as far away as 1,100 miles away into Eastern Europe. Conditions were very poor tonight, so I was quite happy to see those. 

Later, I tried again and managed to make 3 contacts in the USA, over 3,500 miles away! I’ll try again at the weekend from a better location.  I also need to find a suitable microphone to run some SSB. 


While I've been fiddling around with the Explorer (especially during the testing phase) I thought that the radio would benefit from a Power Switch - so I fitted one!

I'd noticed that the PCB had two contacts marked power-switch and I asked Steve how these could be used. He explained that one simply needed to cut the track in-between the contacts and then route a switch to it. The problem, he said, was which switch to use and where to put it.

Well I looked around and bought some single-pole, single-throw, latching, push-button switches on Amazon and when they arrived, I discovered that they were much too long and would touch the PCB, so I simply fitted one of the fixing nuts above the fascia plate and one below. I then splayed the legs out and hey-presto, it fitted perfectly! If I can find a lower profile switch later, I'll swap it out.

I opted for a white colour to match the writing on the radio fascia. I think it adds a real convenience to the radio and saves you from repeatedly plugging/unplugging the power plug.

Modified with Power-Switch

I also made some other tiny mods which obviously make no difference to performance - it's purely cosmetic - but it personalises the kit you've just toiled over. Apart from the heatsink and the power switch, I also swapped out the case screws for some stainless-steel low profile cap-heads from ACCU. And finally, I fitted a black aluminium knurled finish tuning knob.

Oh, just for convenience, I also fitted a kick-back stand to angle the radio up toward me. These are actually sold as Laptop Stands and I've used them lots of times on portable radios. 


 

I do plan to make one more mod and that relates to the Mic Bias option. Inside the case there's a link which you fit a small jumper to if you want to introduce a 5V bias to the microphone for electret mics. I think I'll fit a small slider switch to the side of the radio to bypass the need to open and shut the case if you want to switch mics.

At the time of writing, the manual didn't include any diagrams showing the connector configurations, so I've knocked together a sketch below...

More testing... 

Obviously, I'm a Foundation License holder with no fancy test-equipment and even less expertise. All I can do is look at the Explorer from a practical end-user point of view and maybe compare it to a couple of other similarly priced radios.

To give a radio the best chance of working to it's maximum ability, I always test radios from a quiet location, where the noise floor is low and the take-off is good. I have a holiday home on the edge of the Forest of Bowland, so no better place to play radio! 

I decided to head up to a slightly elevated location called Bodie Hill above the Port of Lancaster. This place overlooks Morecambe Bay, out toward the Irish Sea and beyond. It's a great take-off point and it's also a beautiful place to work from. It's weird how you can see ships floating above the houses at Sunderland Point. One of my favourite places to operate from, not least of all because there's loos and cafe's not too far away ๐Ÿ˜‚


Because I'm working a single band, I setup with a 20/40 Linked Dipole from SotaBeams - it can always be relied upon for great results as long as you've got the space to erect it. If I didn't have the space required, I'd use my Super Antenna MP1 Vertical on a tripod.


The first thing that I normally notice when I switch on a radio here, is the stony silence, but the Explorer has around S3 noise with no antenna connected. When I was at home, I'd blamed the local QRM, but no, it was the same here too. Now bear in mind that it may be due to my build-skills and not the radio. Or it might just be the way the S-Meter is setup ๐Ÿคท‍♂️.

As I tuned around, the incoming signals negated the need for a super low noise floor anyway - almost everyone was S5 to S9+ anyway and boy, did the signals flow in - it was a busy day on 20M.

I tuned to the CW portion of the band and put out some CQ TEST messages to see how far my signal was being spotted on RBN. I spent a few minutes doing this, changing the frequency each time. I'll download the report later.

To use SSB I plugged in a TNT microphone that I'd hurriedly made up to suit the jack-plug configuration of the Explorer - I was using a non-electret mic on this occasion. I found someone calling CQ and went back to him, unsure if the mic was actually working. He came back to me immediately, confirming that I'd got the wiring right, lol.

He gave me a 59 from Bykovo, Russia, which I think was more of a bouquet of flowers than a true report, but I took it anyway. He certainly wasn't struggling to hear me.

Next up was a contact in Lithuania, followed by two Germans, an Italian and an American guy in Austin, Texas! I got great signal reports from everyone, apart from the Texan, who gave me a 4/0. Despite this, I was talking with him longer than any of the others, so he had no problem copying me. He was very impressed with the fact that I was using a kit-radio and asked for the manufacturer's website.

After a few more SSB contacts, the rain started to pour and made a cold day, colder! I was happy that I’d tested the radio sufficiently enough to draw conclusions on its performance, so I packed up and headed back to the caravan.

Back home, I was interested in trying out different mics and I tried to alter the mic-gain, but Steve informed me that it's not variable - it's fixed by R29 at 100k. So I will have to spend time playing around with other mics which means cutting connectors off and fitting new ones ๐Ÿ˜จ 


CONCLUSION 

Let me preface this by saying that I really enjoyed building this kit and I am really pleased with the finished product, including the form factor and that blue case. It is not a compact radio like a (tr)uSDX or a QMX and doesn’t try to be. In fact, its size makes it A) unique in the marketplace and B) easier to build. In contrast, QRP-Labs seem to have gone to great lengths to keep the QMX as small as their QDX by using a 6-layer pcb and construction methods which can make the build quite a challenge (although their instructions are second to none).

The Explorer construction/user guide is perfectly adequate for seasoned kit builders, but I’d say it’s a bit lacking from a novice’s point of view. Having said that, the designer acknowledged this and is about to make some alterations.

The radio does not have a bootloader, so there’ll be no firmware upgrades available through the USB port - something we’ve all become familiar with in recent years, to the point that we now expect it.

Ergonomically, I’d say the radio is lacking. There’s only one controller and that makes some tasks a bit laborious. I was quite shocked to find that you cannot change the Tuning Step unless you use CAT Control ๐Ÿ˜ฎ, although the Explorer does feature Progressive Tuning, where the tuning rate increases the faster you spin the dial. I’m not sure how much would be involved in a redesign  to include a second encoder or additional function buttons, but I’m sure it would make a huge difference to the enjoyment of the radio.

Performance-wise I found the receiver to be quite sensitive and selective when fed with a good antenna in good conditions. It was definitely better than the (tr)uSDX but not massively so. 

In terms of value for money, I guess the Explorer doesn't do well compared to the competition. For less money, you can buy kits which provide you with five times as many bands to play with, more modes, lower power consumption, better ergonomics, a built-in microphone, ptt/morse key, morse decoder, memories, swr bridge, colour screen, firmware upgrades and more!

It sounds like I’m not very happy with my purchase, but the fact is, I’m glad I bought the Explorer and for me, it’s a keeper. As I said previously, I love building these kits and Radio-Kits.co.uk have made something that is just that bit different.  If they bring out a V2 with a richer feature list and better ergonomics, I’d buy that too!

But I’m not normal ๐Ÿ˜‚ Most people buying a kit-radio would be doing so to save money and they’d be keen to get the best feature-set for the least money. This is where the (tr)uSDX really makes sense. So too does the QMX, even though it currently doesn’t include SSB (although future firmware upgrades will add it). If your main modus-operandi is CW, then the QMX would easily win out here, thanks to its click-reducing envelope shaping.

Anyway, I’ll be keeping my eye on the Radio-Kits website and look forward to any new additions to their range.

If you have any comments, please leave a note below and try to include your callsign.


73, Tom, M7MCQ.


UPDATE 14 MARCH 2024

I have been testing microphones and experienced a rather big issue. For some strange reason, my transmissions sounded DREADFUL!!! I had the power output on the Explorer extremely low and was listening in on my RGO ONE. Every time I keyed up and spoke, the audio was shockingly bad.

I couldn't understand what was going on, because I was calling CQ all last weekend and had been getting great reports!

I approached Steve and explained what was happening - he was baffled like me. He asked if there was power out when I spoke into the mic and I told him, yes. He said he'd give it some thought and get back to me.

I returned to the radio and transmitted some more, but this time I turned the VFO dial on the RGO ONE - boom - it was then that I discovered the Explorer's VFO Calibration was out by 70Hz ๐Ÿ˜ถ

Lesson learned - RTFM! Well in all fairness, I didn't really think I'd need to calibrate the VFO after reading this part of the manual...

VFO Calibration Frequency calibration will already be close due to use of a TCXO but may be improved if required.

I should, of course, have checked though. All my fault.

73, Tom, M7MCQ


Tuesday 5 March 2024

RADIO-KITS EXPLORER (PART-1)

PART 1 - THE BUILD

I just love building kits, despite me having zero electronics knowledge. I'm not sure why these kits attract me so strongly - perhaps it's the creative side of me that longs to 'make something'. Maybe it's my inquisitive nature which always wants to peek and poke around to see how things work. Whatever it is, I am always excited when a new kit drops through my letterbox.

Radio-Kits is based here in the UK, operated by Steve Drury (G6ALU). He’s offered a few kits over the years, but this 5W CW/SSB Transceiver is his latest.  The design is actually the progression of an older radio called the MKARS80 which sold in limited numbers for a period of about 15 years before becoming obsolete due to the unavailability of components. This new version is vastly improved and can now be offered as a 20, 40 or 80M transceiver. 

There's very little information about the Radio-Kits Explorer on the internet at the time of writing (March 2024) which is surprising - nothing on YouTube even! I found a post on the SOTA Reflector by M1BUU who had just completed the build and he was very happy with it, which is encouraging. I also found a post on the AE5X blog and he's about to start the build in April.

Initially, I thought the blue case might not be as visually pleasing as the professional steel/aluminium cases supplied by other manufacturers, but now I’ve seen it in the flesh, I really like it! You can of course choose to source your own case - how easy that would be is another question.

Size wise, the Explorer is bigger than I thought - it measures approximately 6" x 4" with a decent 2-line LCD screen just under 3" wide. There’s only a single control on the front panel which, from an ergonomics point of view, is less than ideal. It has a decent built-in speaker.

The kit cost me £115 plus postage. I guess the closest radio to this that I already own is the (tr)uSDX which is also available in kit form (£70) and is also a 5W CW/SSB Transceiver, but the big difference between them is that the (tr)uSDX is a 5-band radio while the Explorer is only single band. The 'orange wonder' also has quite a few extra useful features which are lacking on the Explorer.

Maybe the Explorer's receiver is a far better performer than the (tr)uSDX - I don't know yet, but we'll soon find out I guess.

The kit itself arrives in lots of sealed bags, separating components and keeping things organised. There are probably over 800 solder-joints to be made in this full kit, so that's a lot of soldering!! Thankfully, there is no SMD work.



Broadly speaking, the construction manual looks well written and includes great diagrams and photographs. Because it's a mono-band radio, there are only three circular toroids to wind, but there are five inductors/transformers - T4 and T5 being trifilar.  Looking at that part of the manual, I'd have to say that the winding instructions would be challenging for an outright beginner. Then again, some might say that a beginner should not attempt something as complex as this kit. 

I'll try to include clearer explanations of the winding process to make it more understandable for any newbies reading this. Note that the 80M kit requires twice as many windings on T37-6 than the 20M kit, so it’s that much more difficult.

Just like I did with the QDX KIT and the QCX KIT (amongst others) I will post on here throughout the build process, showing warts and all. If I mess something up, I will declare it and I will tell you how I got around it (or how it all ended right there). If it ends up in smoke, then so what? There'll be no tears. This isn't a $2 Billion space shuttle! 

This post is PART ONE which will show the build. PART TWO will be a separate post covering the testing and performance of the kit (as built by a clueless beginner ๐Ÿ˜‚ )

 First job was to print off the manual and in particular the PCB LAYOUT page, so that each component can be marked off as it's soldered to the board. This is a really handy thing to do and it slows you down, which is always a good thing!!

The first components to be installed are the ones from the bag marked "20M" and these include 1 resistor, 4 inductors, 11 capacitors and 8 crystals. None of these are polarised, so you can insert them any way around. My own pedantic nature forces me to insert the components in a particular way - eg all resistors are placed on the board in a manner that makes it easy to read their values - with the tolerance bands all to the right (or at the bottom if placed vertically). Having said that, I noticed later that I'd not fitted the yellow toroids all the same way ๐Ÿ˜ก I might desolder and turn it around๐Ÿ˜‚

It very quickly becomes apparent that it can TAKE AGES to find things on the PCB because of how densely populated it is. Eg, I was searching for R93 for what seemed like forever. It wasn’t in an unusual place - I just couldn’t seem to see it! To help others quickly locate component locations, I’ve created some images (below) which will hopefully prove to be useful by showing you exactly where each component is located on the board to save you hunting around each time. I've grouped components together relevant to how they appear in the construction manual.












Before beginning, you'll benefit from laying out your components, identifying them and marking them up so they're easy to find and there's no chance of you picking up the wrong value....

I strongly advise that you buy a PCB HOLDER like the one below to make life easier for yourself. Good lighting and a magnifier really helps too. And don't go cheap on the soldering iron - you'll need a good quality iron for this kit - one which can maintain 350+ degrees with a nice, fine chisel-tip. All these resistors are the miniature-type and much smaller than you may be used to.

Populating the board with all the resistors, capacitors and diodes is long and laborious, so it's important not to rush through - it'll just end up in tears further down the line. Checking for correct component value, correct placement and good solder joints every single time is crucial - the key to success.

Just a word of warning about the diodes - make sure you get the orientation right because one bank of diodes is oriented the same way, while other banks alternate. It's easy to get it wrong if you're not focusing.


I used to insert a few components and then turn over the PCB and do the soldering, but it's not the best way for a beginner. Far better to insert a single component and then solder it and snip off the legs. It will take longer, but it's your best guarantee of getting it all right. Trust me!

It took me a good few hours, but eventually, the bulk of the components were in place and I was ready for the winding of the toroids, transformers and inductors.



There are five tiny binocular cores and a single larger one. Start with the smaller ones. T4 and T5 are both Trifilar wound which means that instead of feeding a single wire through, you feed three wires through that have been twisted together - don't worry - it's easy!

You  need to cut three lengths of different colour 34SWG wire (that's the thinnest) about 10-12" long. Put them together and twist one end tightly and solder the tip so they stay in place and are easy to thread through the core.  

Then twist the three wires all along their length - I put one end into a small drill chuck and held the other end while it turned. Don't over do it and make sure there are no kinks.

You're now ready to wind the cores.  T4 and T5 need 4 TURNS each and below are diagrams to explain what actually constitutes a turn....




Every time a wire goes through the core and back out, it is 1 turn. Just bear in mind that even though you are feeding through three wires at once, it still only counts as one turn each time you go through...
So feed the twisted wires through the core until you have completed 4 turns, leaving approx 40mm tails at the end. Then untwist the tails so you're back to three wires each side.

Then scrape off the enamel coating using a sharp scalpel knife, before tinning the area that will be soldered. Don't scrape off the enamel too close to the ferrite!


Once you've completed that task, get your multi-meter, and make sure that you have continuity between the wires on both sides...


There should be continuity A-A, B-B and C-C, but obviously nowhere else (check)!

Now you're ready to install T4 & T5, so cut two small pieces of double-sided sticky foam pads and attach to the pcb. Feed the six wires into the relevant holes on the pcb and when you're happy with the position, lay down the ferrite onto the sticky pad.

Affix two pads
 
Feed wires thru and pull gently from other side

T4 & T5 completed!


Next up are T1 and T3. These are easy to do - they have 4 Turns of 34SWG wire each side!  So, using two lengths of wire, each about 8" long, complete 4 Turns from one side of the binocular core and then turn it around and do another 4 Turns, leaving 40mm tails both sides.

Below is an image of this type of winding showing just one turn (you need to do 4)
Like you did previously, scrape off the enamel from the ends of the tails and tin them before fitting them to the pcb and soldering them. No need for sticky pads this time.

Next up is the L2, which is the last of the tiny binoculars and this time it stands upright on the pcb. It is wound with just 2-Turns of the 27SWG wire and is super simple to fit.

And now for the big one! The T2 is easier to handle because it's bigger but it uses thicker wire. You wind this one just like you wound T1 and T3. Cut two 10" lengths of the thickest wire (24SWG) and do 4 Turns from each side

Then add a single turn of the medium sized wire (27SWG) wire through one end. It should look like this...



When ready, carefully scrape off the enamel and tin the wires before soldering.



Now it's time to explain how you wind the circular inductors (toroids) - there are three of them and they're easy to do on the 20M version (less so on the 80M version).

If you've never wound a toroid, don't worry - there's no black magic involved. All you need to do is count the turns carefully and space them apart equally after you've completed it.

A turn is when the wire goes through the centre of the toroid, so count out loud each time you feed the wire through the hole and be mindful of the fact that the wire needs to be nice and taught - not loose and baggy - don't over stress it though.


When you think you've done the right number of turns, do a careful count - taking a photo of it on your phone can help, since you can zoom in easily.

Here's a photo of the inductors on my Explorer....

L1 and L5 need 15 turns, while L3 needs 16 turns


The rest of the build is pretty straightforward and the supplied build manual explains it all perfectly. Just watch out though for those parts which need soldering on the underside of the pcb!! 

I should point out that I didn't use the supplied heatsink - I just didn't like the look of it, so I used one that I had in the shack…


Here's some photos of the finished product, prior to testing...






So there you have it!! The next post will be all about testing the build and (assuming everything is fine) looking at the performance of the radio. Click here to read it.

Thanks for reading the post and I hope that someone benefits from it.

73, Tom, M7MCQ.