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

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