A Decent Morse Practice Oscillator

About nine months ago, when I was embarking on my “learn Morse” plan I did quite a bit of digging, trying to find a decent quality Morse Practice Oscillator to aid in the learning. Admittedly my Yaesu FT857D has the ability to practice Morse utilising the keyer circuit and is pretty good at what it does. That said I wanted something portable so I could take the learning process wherever I wanted. There are an awful lot of circuits out there which do the job. At the end of the day all you want is something which beeps when you close the Morse key, but I wanted a degree of refinement which was fulfilled in the guise of the Morse Express T-Tone Code Practice Oscillator from Milestone Technologies.

Like most of my projects, we never got to the finish line in that I built the circuit and have been merrily using the naked PCB with a load of wires sprawling everywhere. That’s until FPARC have decided that October’s meeting will be an introduction to Morse, with a concerted effort to support those trying to learn. Better stick this thing in a box and make it road trip proof!

Now, this is hardly blog worthy, but like most achievements, the devil is in the detail. I needed to make a speaker grill so the audio tone could escape the enclosure. Not owning a CNC milling machine, a considerable amount of time was spent with a 2mm drill bit fashioning this by hand.

I’m really happy with the final result, to the point I may well go the extra mile and print some custom case decals as I did with my 1 Watter.

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If nothing else it’s another “almost completed project” ticked off my list!

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

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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.

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

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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.

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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.

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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.

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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!

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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.

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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!

Resources

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

Portable Operations #4 – Pre Field Weekend Preparation

OK! Since the last field weekend I’ve managed to achieve the square root of nothing with regards to overcoming the few encountered hiccups and with the Bank Holiday Weekend and next Field Weekend fast approaching, the weather starting to score a cool 100% on the naff weather-o-meter; it was time to do something about it all.

The biggest problem was to be waterproof. As fun as it would be to get a “you can’t bend it 2 man tent” to use as my base of operations, it would be considered far more sociable to join the party in the club marquee so I invested a whole £4-50 in 10 meters of RG58U and set about building myself a feeder extension cable. With that easily squared away the next issue was to make that all so vulnerable metal of the plug to plug mating weatherproof.

Now this little trick, I can claim no credit for whatsoever. That goes to Mike Parkin G0JMI of Alton Antenna Arrays. Costing a whole £2-40 from Screwfix and providing enough hardware to waterproof countless future cables, you’ve got to admire the simplicity of this.

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By creating a rubber bung using self-amalgamating tape above one PL259 plug a 25mm plastic conduit coupler is secured to the antenna feeder. A section of 25mm conduit is then cut and slid over the feeder extension. Plug your two PL259’s together using a back to back connector and slide the conduit into the coupler et voila, one weatherproof union! Just to stop any build up of water that drips down the antenna cable from working its way into the rubber bung I sealed the top end with a coating of epoxy resin. You’ve got to agree, simple is always best!

 

Portable Operations #3 – Field Weekend

At 0530 hr this morning, when the birds were giving their vocal chords a stretch it wasn’t looking too bad out there.

Strangely, in the time it took me to move from the horizontal to the vertical a few hours later it was very much a case that the days proceedings were going to be sponsored by our old friends precipitation and cloud. Having just spent the last couple of weeks having to deal with the stress and strains of weather like this –

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I was hoping for something a bit better than this –

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When it comes to the Great British weather, there’s nothing “Great” about it whatsoever. I’m assuming that it’s Brexited on a permanent basis along with our EU membership!!

Anyway, not to be defeatist I removed all my essentials like sunscreen, sunglasses and cap from my gear bag and replaced them with wet weather kit. We didn’t come all this way to quit so quickly! Somewhat annoyingly I’d been looking at offers on 2 man pop up tents online yesterday thinking “Nah, don’t need one, won’t need one, I’ll get one another day, it can wait, this weekend’s gonna be great”. Hmm, how wrong can you be?

So, with the rain clouds looming I set about deploying all my toys. Like everything first time out there was a bit of trial and error to get things just how they needed to be, but we got there.

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My 728HFA sat perfectly aloft the trigpoint mount and with 100ft of paracord attached to the dogbone insulator, I ran it back to a tent peg pushed into the ground further along the battlements of the fort, which gave a 25-33 degree declination over the run.

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The first snag arose when my feeder which was 8m in length and great for use in the garden or when you’re sat at the base of your mast, was just a bit too short to get me into the environmental safety of the club marquee. This was overcome by a bit of lateral thinking and a rummage around the boot of the car revealed the beach shelter which I set up literally at the marquee door, much to the amusement of the rest of the club. The colour scheme didn’t help matters greatly. I need something more manly and tactical!

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And there we have it, M0XXF/P up and running. The next goof was realising I’d managed to unpack my ground sheet from the car while packing, so I spent the rest of the day in the prone position on top of an old Gortex soft shell jacket which had been in the car boot.

All I can say is what a great day. It just goes to show what 100m of elevation away from the electrical noise of the urban environment can do for antenna reception! I’ve never seen so many signals and with a marked increase in reception clarity.

At home my 728HFA runs east – west hidden beneath the facia board of the house and has to contend with the proximity of a brick building and the electrical pollution of the urban environment. Today it’s orientated north – south, so in effect side on to Europe with absolutely nothing of note near it. As such I was seeing PSK31 signals from countries and areas I’ve never seen before, Indonesia being one of note. All my QSO’s during the day were made on 20W, simply because my T1 ATU isn’t happy above that level and I couldn’t be bothered to keep adjusting the power settings within the rig. That said, I had packed my LDG YT-100, so could have upped my power if I’d wanted. I managed to bag a suitable number of QSO’s to make the day worthwhile, which was the primary objective.

Eventually the sun came out to brighten up the day which was a bonus, that was promptly countered by an invasion of flying ants, motivated to take a flying lesson, by the spontaneous return of summer. Note to self, a blue and yellow beach shelter obviously looks like food to the critters and I think most of them decided to drop in to see what was going on. I’ve been picking the damn things out my kit bag for the past 2 days!

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So come BBQ time and the end of the day, what had we learnt?

  1. Operating portable is great fun
  2. Get a longer feeder for my antenna
  3. A blue and yellow beach shelter really isn’t manly!
  4. I should have bought that pop up tent!

 

 

Portable Operations #2 – Field Weekend T-1 and counting

OK, we are now officially 15 hours away from FPARC’s July Field Weekend and the excitement is bubbling!

Not wishing to look a prize buffoon by rocking up with lots of stuff and finding it doesn’t work, I thought it prudent to actually see if my portable concept worked in the relative safety of the back garden. So, duly equipped with a pair of shorts and Oakley Half Jackets I gingerly transferred my rig to the patio table and started working out what I was going to take with me.
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After considerable wrestling with the drivers for my rig-cat cable, reminiscent of my post Rig Cat Problems #3 and forgetting how to use my Elecraft T1 ATU, we finally got there! The next trick was to get this stuff packed down into a portable package.

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Now this is a bit of a cheat as originally I was going to build a manpack based around M0PZT’s Porta-Frame which is a very cool idea.

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The however comes in that when I priced up all the copper fittings, tubing, brazing torch, solder and flux I’d need to build one, it came in at about £4 cheaper than the FT-817/857 backpack I found on eBay. Don’t get me wrong I was all geared up to build one but here’s the thing. Expensive electrical items, by their very nature don’t take too kindly to moisture and being the UK, we have plenty of that. Just ask your 52″ LCD TV how it feels about standing out in the Great British weather for half an hour and I think you’ll get the idea. The backpack is fold and go, so when the heavens open, we’ve got some immediate protection. Also, the fact it has a ground sheet layer built into it means you can unfold and work without having to worry overly about the dampness of the ground. Everything folds down very cleverly and buckles tight. The storage pockets for cables and bits are a bonus and the rucksack straps make it instantly portable.

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As this my first road trip, like any adventure, it’s worth overpacking! With a few elements of redundancy along for the ride my entire portable setup, minus my field mast, is packed in three small bags – an Aldi bag for life, a Bomber Barrel grip (best damn grip in the world!) and my FT-817/857 backpack.

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All I need now is my BBQ contribution and we’re there!

 

Portable Operations #1 – Field mast

The objective for 2016 is to get out of the shack and into the wild with a radio. This has been on the agenda since day one, but like every idea there are teething problems, interuptions and cost implications!

That said we took one step closer today when I finalised my antenna mounting platform for use at field day events. This is a two pronged attack, giving me a mast I can mount an HF antenna on along with my BBHN node, which will give me Mesh access for WX, Cluster reporting and logging. While I mention WX have a look at this – blitzortung.org. It’s always useful to know how far away the serious trouble is!

So, on a bright and cheery Sunday morning I took a little trip to Fort Purbrook to see if my latest creation actually worked as it was based on a sketch and dimensions I was gifted and unfortunately I wasn’t able to actually get a hands on, prebuild examination of the trig point to get things straight in my head before I started hacking up my very limited supply of free plywood. Added to that, I have the woodworking finesse of dry rot, so the margin for error was slimmer than the shrinking exchange rate value of the pound!

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In the words of Shrek, “That’ll do Donkey, that’ll do!”

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When it drys out from the soaking with drizzle this morning I’ll give it a quick once over with yacht varnish to stop mould and the like setting in while in storage. The whole kit breaks down very nicely to a light weight bundle for transporting.

101 uses for a DVB-T dongle

I only got into Amatuer Radio proper in 2014 as a byproduct of something else I was playing with at the time. Some kit I was looking to buy carried the caveat of “may require an Amatuer Radio licence to operate on certain frequencies” and not wishing to end up on the wrong end of some draconian individual I decided to sort the licence side out first before shelling out my hard earned on my new toys. Somewhat naively I assumed obtaining a licence to operate radio equipment was similar to obtaining a licence to fish in common waterways. You know? Rock up at the local council office, flash your cash and walk away with a small square of paper saying you’re hot to trot. How wrong can you be?

Two years on and I’m slightly more educated and definitely finding radio more rewarding than previous ventures. Now when I landed in the world of the Foundation Licence learning it all seemed a bit abstract. I’m very much a learner by application rather than just being able to read and comprehend, so I wanted/needed a very cheap setup to play with to cement the theory. I wasn’t planning on being in radio land for very long (originally) so the cheapest way to do this seemed more appealing than ever.

I had a dabble with WebSDR to start with, especially Hack Green. Lets face it anything that says it’s based at the site of a previous secret nuclear bunker is going to draw the crowds! From there I fell for the idea of software defined radio and started reading, stumbling across RTL-SDR. What a resource that site is! Now I loved the idea of actually having a tangible SDR radio for the princely sum of 10 quid and invested.

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Meet my first radio! So after working out how to use it and listening to the limited range of content, mostly commercial wideband FM broadcast stations I needed something slightly more challenging to have a play with.

RTL-SDR offers a whole host of projects for the humble DVB-T stick and the whole idea of ADS-B radar fired my imagination. Living on the south coast with a host of commercial and private airfields in the county, plus a multitude of shipping traffic bobbing past in the Solent, this whole thing definitely had legs.

Next thing you know I was making antennas for the sole purpose of receiving aircraft ADS-B beacon transmissions.

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This is my massively successful quarter wave ground plane antenna built using the guide at ATOUK’s site. A copy is attached here for easy reference

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Bearing in mind I didn’t have a Scooby what I was doing I was gob smacked by the increase in reception of my little receiver when compared to the supplied stock antenna. I was on a mission from then on! I took myself off to Nevada and bought myself some lengths of coax and spent some time fashioning various collinear coax and wire antennas and testing them using various software tools to plot their reception characteristics. Nothing I made beat the tiny quarter wave ground plane, it reigns supreme to this day in the ADS-B stakes! Unfortunately I don’t have any of my original work to share with you as I dumped it when I upgraded my PC, but it was good fun.

From there I added a Raspberry Pi to the equation to make a dedicated ADS-B server

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followed by an ADS-B SAW filter to improve reception. I scoured eBay for the EPCOS 1090 MHz SMD device and fashioned myself a PCB.

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Again, the improvement in reception was dramatic.

Next came the addition of a LN4ALL low noise amplifier

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And all this to watch aircraft on a PC screen in a manner similar to an air traffic controller!

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It’s a project I really need to resurrect when I get 5 minutes.

Since then my trusty RTL-SDR dongle has found itself playing a key role in a few side projects alongside other SDR and conventional radios. It’s a piece of kit everyone should own in my opinion!

So how about turning your phone into an SDR radio? SDRTouch for Android does just that. There are apps such as glSDR which give you WebSDR, but if you’re not on WiFi or 4G it’s a bit limited. SDRTouch takes your phone and allows you to plug your RTL-SDR dongle into it and gives you your own portable SDR receiver for the cost of 99p for the OTG cable from eBay.

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And proof that it’s not just a fancy screen saver –

SDRTouch RTL-SDR test