M0UAW's Blog

I bought a very cheap Yaesu VX1-R dual band handy last year, it's a cute little thing that covers 2 and 70 but unfortunately it came without the battery. No problem, if it works I'll just buy a replacement, simple. But WOW, the FNB-52 battery is *expensive*, more than three times what I paid for the radio and I could not find one in stock anywhere (I have since found them)... I did find out that the battery pack is a standard 14650 Li-Ion cell in a molded plastic case (presumably including a battery management circuit) and a quick search of everyone's favourite tat bazaar eBay found a pack of two for a not expensive £9 so I ordered some and waited. When they arrived I gave them a few hours on charge and then tried one in the handy, it worked but of course it rattles about and runs the risk of being damaged or, worse, exploding if charged incorrectly as the cell isn't 'protected'. Now I do have a charger but it meant I'd have to remove th...

A quick update, I needed a heatsink so I found one from an old PC which is more than adequate, weighing in at almost 650 grammes I reckon it should be able to handle the heat. Problem though, it's not flat. Which makes it kind of difficult to mount the board. Now, I could use some standoffs, PCB pillars cut to length but I'm a little light on machine tools to make an accurate job of it and it'd annoy me that it was 'wobbly'. As it happens, I recently bought myself a new toy. A Flashforge 3D printer so this seemed an ideal opportunity to learn to use a CAD program and find out how dimensionally accurate the printer is. It turns out, it's pretty good. And the PLA takes a thread really nicely. So, my Mini PA board now has mounts, I just need to drill and tap some holes in the heatsink.

I mentioned Si5351 chips in the last post, this QCX arrived in a bit of a state, there'd been an issue with the 5V rail which had fried a few chips, the owner had removed the 74ACT00 already (and there was some minor track damage as a result) but wasn't confident he could deal with the Si5351 chip so he was about to scrap the radio. Which seems a bit of a shame for a chip that costs less than £1 but I understand, the chip is tiny and fiddly to rework, it's not a part I'd recommend working with if you've little or no SMD rework experience. I contacted him off list and offered to help, the radio arrived in due course and this is an intermediate progress pic, the Si5351 chip, IC1, removed, prior to flux cleanup. I had to take out C2, R4 and R4 as well as the crystal to be able to get to the tiny MSOP-10 chip, the SOIC-16 FST3253 chip is huge in comparison. After replacement (and removal of the FST3253, it's cheap enough that it's silly not to repla...

I've bought a few bits from Hans Summers via his QRP Labs site , low pass filters, an Si5351 synthesizer kit, they've been really nice quality and work as advertised, I highly recommend Hans' kits, they're well thought out, good quality and great fun, Hans is also very helpful and active on the QRPLabs mailing list with tips, suggestions and advice on how to sort out problems people may encounter. But, the mailing list, there are posts on there from people who have had accidents with their QCX or other kits and need repairs that they just don't feel confident or able to do, SMD rework of the FST3253 chip or the more difficult Si5351 chip (which is tiny) seem to be the main stumbling block for most so I've offered assistance to a few people and have built up a small stock of spare parts for the QCX. I usually offer free labour repair for things that interest me because it allows me to get my hands on equipment I wouldn't or can't buy for myself for va...

We've all seen switching FETs used as PA devices in HF radios, I've experimented with them a few times, lashing up circuits using IRF520s and, my favourite, the FQP13N10, they can produce some useful power for such a cheap device and if you drive them hard, they give some serious power, at 24 volts, with a shade over 3 watts drive I've measured 45 watts output at 30MHz from a single device into a dummy load (you really don't want to put one on the air like that though, the output was horrible) When you drive them hard, they're fragile, gouts of smoke, chunks of epoxy encapsulation flying across the room and dead fuses are easy to obtain so, I gave up, 'proper' RF devices aren't that much more expensive and are designed for use in radios. So, why am I talking about them again? Well, I bought myself one of the Chinese eBay specials, a Mini PA 70W HF amplifier that uses a pair of IRF520* devices to produce a reputed 70 Watts output. (I've no idea ...

First thing I should say, this is my 'design' and I offer no guarantee that it will work for you, be careful if you build one, do your own testing to be certain it's not going to blow up your laptop and or radio, cause a rift in space time and the instant destruction of the entire universe as we know it. OK, guff out of the way, the Opto Isolated CI-V Interface I mentioned earlier, And the schematic! It's rough, hand drawn and there have been a couple of changes to component values, mainly because I found a document that suggests the CI-V interface port on the radio shouldn't have to sink more than 2.5mA, so one resistor has been changed (the 680R on pin 2 of the right hand side opto is now 2K) and another removed completely (the pull up on pin 5 of the left hand side opto) to comply with that. If I short the CI-V line with my ammeter, I get this: 1.6 milliamps, I'm comfortable with that. Currently (yeah yeah) it works reliably as a serial loop...

The parts used so far and the prices: CM108 USB Sound card,       £2.32 CH340G USB-Serial Bridge  £0.74 1:1 Audio transformers, 2 of  £0.29 each. PC817 Optocoupler                £0.02 Yes, 2 whole pennies each, this part controls TX. 3.5mm Jack Plug                    £0.49 For the CI-V port on the radio USB Hub                                £2.30 Not as expensive as I thought it was 13 Pin DIN Plug                     £3.79 The most expensive bit, the Icom Accessory socket plug. Proto board                             £0.30 Absolute bargain, great quality and through hole plated too. Cables were from the junk box and the resistor (there is one)...

I'm sat here with a pile of bits and a spaghetti mess of wires which is the partially developed radio interface. This mess, above, is a working USB-CI-V, PTT and sound card interface. Which connects to: The audio isolator and PTT Isolator board All connected to this, my IC-718. So the big question, does it work? I'd say that's a yes. Heard 5051 kilometres away ! Colour me impressed but that's with 5 Watts into a random length of wire, roughly 15 metres in length and tuned by the AT-130.

Amateur radio, a hobby for experimentation, investigation and learning. Me?  I'm poor so I build or buy things that have function, they're usually not that pretty but they get the job done. I've got a nice, simple, HF radio, the Icom 718, it's not got a lot of bells and whistles and a lot of 'serious' operators will (and have) sneer at it, preferring something with more buttons, knobs and switches than a NASA control room and enough processing power to find the meaning of life (42) but my little Icom is capable of 100 Watts across all the HF bands, works as a general coverage receiver  and was cheap enough for me to buy. I like it. I wanted to try digital modes, WSPR, FT8 etc. and to do that I need a computer interface. I went looking to buy one. Ouch. They're ridiculously expensive for what I thought must only be a few bubble gum components. I started researching to see why, what the secret sauce was that meant they were uncomfortable for my...

Flushed with success and a shiny new Foundation M6 callsign we immediately began the Intermediate course, more practical work, a Chinese Pixie Kit bought, built and tested, sending Morse across a desk to another candidate is surprisingly good fun, possibly more fun than running lots of power into a well installed antenna system! Suffice it to say, the course went well and I took the Intermediate test, along with another two candidates, on Sunday, 12th November 2017 Again preliminary indication was for a pass and sure enough, the pass letter came along in the post ten days later on the 22nd November so I logged into the OFCOM portal again and let it choose a callsign for me, this time 2E0EOA (a mouthful on 'phone, even worse in Morse, ..---  .  -----  .  ---  .-)  Lesson learned, the next callsign will get some thought put into it.  By this time confidence had set in and I began studying for the full licence, again with the RSGB book, Ad...

Really? You're still reading? Wow, thank you, we're almost up to date and at the bit where the exams started. So, David, G0VIE, replied, patiently answered some questions about the course and suggested I come along to meet him at the club where we could discuss the course and exam a little more. David was most helpful and agreed to train me on Sundays, once a fortnight to fit in with my childcare needs, the course, if you've ever considered getting licensed, do it, it's fun and at foundation level, it's a good grounding in the basics of operating, some electronics and electrical theory and a little practical.  Morse appreciation with Jill was also plenty of fun, it sounds a little daunting and, honestly, I was nervous, I have never been able to get Morse into my head so while there's no Morse requirement any more, the 'appreciation' part of the course felt like a hurdle (I'm determined to learn and become proficient, it feels like a r...

So, what's all this got to do with M0UAW and why is an M0 'newly licensed? We're getting there, I promise... I'd been mulling the idea of becoming a licensed amateur for years, ever since the (pre legalisation) heyday of CB, a few of my friends were/are G7s and I could whistle a pitch perfect 1750Hz, into the legal days then on and off for the next three decades. Finally, in 2016, I visited the Telford rally (did I mention I liked and had been attending rallies for years?) at Ingenuity and got chatting to the young bloke on the RSGB stand (I was already a GQRP member) who kindly sold me a copy of the Foundation Now book. The book, well I read it, then put it away, almost convinced I was missing something, it was too easy! A few months passed by and then I found the book again, read it and decided, no, it really wasn't more complex than that so I started to try and find a club who would allow me to take the exam. Herein we discover one of the reasons wh...

Still here?  Good. Read on. Latterly (OK, 17 years ago) I moved away from repair for money but still like to tinker for fun, I take on repairs of radio gear, for preference things that other people have declared unrepairable, it's brought me all kinds of radios, some CB sets, some Ham sets and a few PMR or commercial devices.  I worked out the EPROM in some wonderful Key Communications 50 Watt radios that had been customised for data use and figured out how to get them on 2M where they performed beautifully with minimal adjustment. The EPROM in the Storno CQM6334 and CQM 6114 radios similarly fell to my interests and sat squarely in the 4M and 2M bands but I never really did much after I'd worked them out, it was the fun of the hack that got me, the undocumented and unknown interested me. All of this, I did for my own interest and I didn't bother to publish any of it, the journey was the fun for me, the end result was boring, I realise now that ther...

Hi, welcome, how on earth did you find me? I suppose I should introduce myself, I'm Clint, I live in the North West of England, IO83tj and I'm a newly licensed radio amateur (Yeah, that's right, newly licensed and  an M0 not an M6 or a 2E. Read on)... I have been tinkering with radio and electronics since I was a small boy, I can blame my interest on my Grandfather, Harry, who was one of those people who knew about everything, was continually curious and passed on that spark to me.  So, one of my first electronics projects at around the age of 11 was a digital die, based on the venerable 555 timer and a 4017 CMOS decade counter.  I saved for a few weeks and bought all the parts from the local electronics shop (there was a choice of three in my home town, amazing!) yet, for all my reading and 'knowledge' I hadn't realised I needed to break the tracks on the Vero board so of course, it didn't work.  But, I had built it, and I was proud, eve...