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

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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!

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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.

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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.

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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.

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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!

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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?

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QSB-01 (qrp-tech synchronous buildathon) #3 – receiver build updated @ 26/04/16

Rather than loads of posts, this blog is going to be my notebook for the QSB-01 in a rolling style. Also, rather than bore you to death with a blow by blow account it is simply going to be the necessary photo or answers requested by Yoda (Chuck Adams K7QO) at the conclusion of each phase of the build, along with a few others where relevant.

For it to all make sense have the necessary QSB-01 web pages one and two to hand.

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Phase 9 – LPF Section

Commenced 12/04/16  Completed 26/04/16

It’s taken two weeks to insert 5 components! That’s what happens when servers go wrong!

Phase 9 assembly work

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Phase 9 testing

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Video file – Phase 9 testing of completed receiver section

https://www.dropbox.com/s/zrnvkta3eyp0bip/20160426_162406.mp4?dl=0

Unfortunately, on the day the band was closed with absolutely no QSO’s to test the receiver against which is a real shame.

Phase 9 completed

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Phase 8 – TR/BPF Section

Commenced 12/04/16  Completed 12/04/16

Phase 8 assembly work

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Phase 8 testing

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Phase 8 completed

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Phase 7 – Advanced Testing Addendum

The display unit as it stands is pretty good but would be vastly improved by calibrating it, as the supplier comments that it shows 100Hz error when checked against a 10MHz reference standard. There is a trimpot on the board which allows calibration but I don’t own a DDS Frequency Standard. Remember the old “How to Build an Atomic Clock” post? Yep, that rubidium standard would really come in handy now!

Now without anything like that readily available, in a flash of inspiration/desperation I remembered my Elecraft XG2 Receiver Test Oscillator that I had paid a stupid amount of money for (129€’s to be precise!) when I was setting up my SoftRock Ensemble.

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So at 4.3€ or £3.34 per component it seemed silly not to see if it would do the trick as it provides 50uV and 1uV signals for 80m, 40m and 20m.

In short, it didn’t, which is a pain, but thankfully I’ve found someone with a 10Mhz frequency generator who will be able to loan me 5 minutes of their time at some point to calibrate things.

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Phase 7 – Impedance Matching Transformer T4 and Band Pass Filter

Commenced 06/04/16  Completed 06/04/16

Phase 7 assembly work

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T4 torroid transformer 4T:28T


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Phase 7 Testing

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Audio file – power up, no wire, 15cm wire @ L3, 15cm wire @ L3 adjustment showing two peak positions

https://www.dropbox.com/s/lqyt3czbj8ffg9x/Phase%207%20testing.m4a?dl=0

Phase 7 Advanced Testing

This required a separate build of a digital display unit. I went for the one plugged by Chuck at http://www.qrpguys.com/

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Having set my mind on a final enclosure and so forth building the display threw a spanner in the works as it’s a really cool addition. As such I built it so it could be enclosure mounted (trimmer pot and push button mounted on the rear rather than front for easy access once mounted).

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Once built the display is attached to the header at J7. I added a tuning pot at J1 to allow testing

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My camera struggles under all the lighting on my bench to show the display with the clarity it provides in reality

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Video file – Phase 7 advanced testing with the display attached to the VXO

https://www.dropbox.com/s/qad5p4q5fz23zu9/20160407_190949.mp4?dl=0

Now the astute amongst you would have noticed that the display is saying 8.0628MHz. For 20M you’d be expecting something around 14MHz, which you get from mixing the VFO frequency with the IF (intermediate frequency) of the receiver. The display is taking its single input from the VFO, which is variable. The clever bit comes in that the display can be set to add or subtract the IF. In short you plumb the display to the IF at pin 7 of U5, power it up, hit the button on the unit and it saves it to memory. Now, when it is reattached to J1 it takes the value from memory and adds it to the input value giving you your desired frequency. It really is that simple!

Phase 7 Completed

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Phase 6 – Variable Crystal Oscillator (VXO) Section Testing

Commenced 06/04/16  Completed 06/04/16

J1 Voltage = 9.94V

Audio file – 15cm wire placed at pins 1 and 2 of U4

https://www.dropbox.com/s/iger33dzx3jgvrs/Phase%206%20testing.m4a?dl=0

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Phase 5 – Variable Crystal Oscillator (VXO) Section

Commenced 05/04/16  Completed 06/04/16

Phase 5 assembly work

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Phase 5 Completed

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Phase 4 – IF Crystal Filter

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

Phase 4 assembly work

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Phase 4 Testing

15cm wire placed at pins 1 and 2 of U4

https://www.dropbox.com/s/0qdegbd5tezkn53/Phase%204%20test.m4a?dl=0

Phase 4 Completed

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Phase 3 – Audio Detector Mixer (BFO) Installation

Commenced 27/03/16  Completed 29/03/16

Phase 3 assembly work

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Crystal testing

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Not all crystals are equal! Two showed fluctuation between 5.9993-5.9994MHz with some stability after running and warming up(?)

Winding T5 binocular toroid

Hardly blog worthy other than the instructions at Kitsandparts.com aren’t very clear and never having wound one of these before it was worth noting for future reference.

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In one hole and out the other constitutes ONE turn. As such if TWO turns are completed there will be TWO “wraps” of wire visible at one end of the toroid and ONE at the opposite end

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Resource

http://www.calmont.com/pdf/calmont-eng-wire-gauge.pdf

The magnet wire in the kit isn’t marked and is supplied all in one bag! Now bearing in mind the difference between some of the gauges is fractions of millimeters a fair amount of time was spent checking and double checking with a set of digital calipers and then clearly labelling each to prevent any cock up!

Phase 3 Testing

On power up hiss heard BUT no difference in noise heard when 15cm wire touched on upper pad C32!

Phase 3 Advanced Testing

When a crystal oscillator with a 6MHz crystal is placed next to the 1Watter at this point in the build a distinct oscillating tone is heard.

The lack of any tone change being heard at basic testing was nagging so I sought advice from Chuck on this one.

His advice was to place the crystal oscillator away from the radio and then place the 15cm wire on the non grounded pad of C32.

With the oscillator 10″ from the board, with no wire nothing can be heard. With the wire touched against the pad the oscillator can be heard as clearly as when they are next to each other. Chuck’s advice, if you can hear that all is good! The suggestion is there’s insufficient electrical noise within the house to up the background noise, hence the lack of response at basic testing.

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Phase 3 complete

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Phase 2 – Commenced 27/03/16  Completed 27/03/16

Phase 2 Part 1 assembly work

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Phase 2 Part 1 assembly completed

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Reverse side of PCB

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Highlighted section of schematic reflects completed build on PCB

Phase 2 Part 1 Testing – A/C hum test at C37 & C38

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https://www.dropbox.com/s/omeo118p3vv7cgf/C37-C38%20AC%20hum.m4a?dl=0

Phase 2 Part 2 assembly work

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Phase 2 Part 2 Testing – A/C hum test at U5 pins 4 & 5

https://www.dropbox.com/s/w1sx0pslzv8qh4q/U5%20pin%204%20%26%205%20AC%20hum.m4a?dl=0

Phase 2 Part 2 Complete

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Phase 1 – Commenced 27/03/16  Completed 27/03/16

Homework Completed 

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Ordered & Delivered 1Watter 20m kit – S/N 60720160319_103320

Phase 1 Assembly work

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Phase 1 assembly completed – Jumper power connection to PCB & completed power supply section

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Reverse side of PCB showing solder connections and stand off spacer

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Highlighted section of schematic reflects completed build on PCB

Phase 1 Testing

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Voltage test at C7 top pad – 12.65V, battery voltage – 12.72V

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Reversed polarity voltage test

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Further voltage checks at U6-6

Battery = 12.72V, Voltage at C7 = 12.65V, Voltage at U6-6 = 12.66V

Enclosure considerations 

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1/ BUD Industries aluminium enclosure available from Mouser – commercial option

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2/ QRPbuilders double sided PCB enclosure for 1 Watter – homebrew

 

QSB-01 (qrp-tech synchronous buildathon) #1

Despite the fact my Rockmite ][ is sat patiently waiting for me to build it, once again I’ve been suckered in by yet another potential awesome build project!

While treading water the other day I notice a post on the QRP-Tech Yahoo Group, where Chuck Adams was promoting a buildathon utilising the kitasandparts.com 1 Watter kit which made interesting reading.

I’d seen one of these before for sale on eBay as a completed build and was gob smacked at the amount of interest it attracted and its final sale price, twice the kit form price and a bit more.

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 Admittedly it was a very professional looking job but was the 15m model and being a US purchase would attract a disproportionate shipping cost coupled with yet another contribution to the coffers of Royal Mail and Border Force in Customs duty and handling charges.

I discounted the idea and it wasn’t until Chuck’s post I started reading and realised that one of these would be an interesting project as there are a smattering of SMD devices and a structured build which uses completed sections of the circuit to “self test the next/previously completed stage.
Going for the 20m model as per Chuck’s group project would give me another transceiver over and above my little family of 40m QRP flavoured devices.

The support from W8DIZ (the supplier) and Chuck’s buildathon, previously published guides and YouTube video tutorial series makes this a perfect guided build for anyone new to construction. It’s almost like a distance learning course which gives you something very worthwhile to use at the end!

The icing on the cake was the prospect of building a PCB enclosure to house the finished item.

I absolutely adore Dave Richards AA7EE’s WBR regen receiver build where he enclosed the receiver in a copper clad PCB enclosure.

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 The finished item is a work of art and utilises Manhattan style construction using Rex Harper’s (he of Rockmite ][ QRPme fame) MePADs and MeSQUAREs, a technique I don’t really get and would make a complete hash of if attempted.

Fortunately when it comes to giving a 1 Watter a box to be proud of Ken, WA4MNT, hosts a repository of resources at qrpbuilder.com which teach you how to build PCB enclosures convincingly, including a bespoke build for a 1 Watter.

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 With this potential support network readily available and the need to have at least a few projects available to see me through 2016, it seemed silly not to “Add to Basket”.

This one will be a slow build and I’m keeping it for the warmer months when I can get some late night work in, in a garage which is erring on the too warm rather than sub zero temperature scale!

Website resources

Building an enclosure from PCB material
http://www.qrpbuilder.com/downloads/pcb_chassis_a.pdf
http://www.qrpbuilder.com/downloads/1_watter_092815.pdf

Kitsandparts.com build guide and order page
http://kitsandparts.com/1watter-V3.php
http://www.kitsandparts.com/store2.php

Chuck Adams (K7QO) QRP-Tech Synchronous Build
http://www.k7qo.net/qsb-01.html
http://www.k7qo.net/qsb-02.html

https://www.youtube.com/watch?v=W0CH9Rhcm0A

http://www.k7qo.net/onewatter.html

http://www.k7qo.net/1w-108.pdf

Not a Chinese QRP Transceiver #1 – Rockmite ][ 40m

You could say that my QRP transceiver kit addiction is getting slightly out of control but where’s the fun in life if you can’t build things that put a smile on your face?

This whole flirtation with the Chinese kit market has caused me to do some delving into the history of the original kits that they look to emulate or some would say “rip off”.

As I’ve alluded to before the Ham fraternity in America is huge and a lot of the QRP kits or ideas originate from that side of the globe. My plan post Pixie/Frog was to have a look at a thing called a Super Rockmite, which again hails from the Asian markets and can be readily found on eBay and the likes. It is an evolution of the other kits and adds a computer interface to allow the transceiver to be hooked to a PC and to generate CW directly from software. Sound familiar?

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Well one thing that this has taught me is that despite liking the idea of a PC doing the hard work, it’s very much a case of missing out if you’re not pressing the key or the paddle yourself and with that in mind I’m having a serious go at learning code using the Koch method using IZ2UUF’s Morse Koch CW app for Android. I’m not saying it’s easy and to become proficient will take a lot of time and effort but then reward isn’t without endeavour!

Now with that very much at the front of my mind when I started reading the forums about the shoddy standard of both Super Rockmite kits and fully assembled purchases, poor audio quality and inability to find English version software it was very much a case of “Do I really want to waste my time on this one?” Short answer, no!

Then a bit more delving into the term Rockmite revealed the history of Dave Benson’s, K1SWL, nifty RockMite QRP transceiver kits, Small Wonder Labs and the NorCal QRP club. What a shame Small Wonder Labs are no more! Until I found out that QRPme have taken on the mantle of supplying an updated version of the kit which is a true testament to the original device. Even better Kanga Products in the UK are the authorised distributors avoiding the pain of being mugged by Border Force and Royal Mail for import duty charges!

It was an absolute no brainer and after a brief email exchange with Rex Harper at QRPme and Dennis Anderson at Kanga I secured a bespoke RockMite ][ enclosure (unfortunately you can’t get the Heathkit green one anymore)

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along with a RockMite][ in the 40m flavour

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The kit landed today (12/02/16) and I genuinely can’t wait to build this thing!

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The enclosure landed on a month later and is a work of art and nicer than anything I could make myself

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Unlike the Asian kit’s this thing is a work of perfection on all levels, with everything included and loads of support and documentation available online to assist in the build and getting it up and running. I won’t be rushing this that’s for sure as it’d be great to have this working perfectly from the outset and running as my outdoor rig for the summer in conjunction with something like an Emtech-ZM-2 ATU and a Palm Radio Mini Paddle.

That’s more money and several months away so lets finish the projects sat on the desk first!

Chinese QRP Transceivers #1

I’ve been sat twiddling my thumbs waiting for my Pixie transceiver kit to arrive so that I could crack on with my computer CW project, which has allowed me to hit the forums and have a general scout around as to how best to utilise it or even pimp these things for other applications.

By absolute coincidence the guys at FPARC posted an idea on the club forum yesterday suggesting that the Pixie kit would be an ideal club project for those new to construction or looking to complete Intermediate Licence builds. There was also the suggestion of a workshop tent at the forthcoming field days and then the idea of a Pixie net and test transmissions across the parade ground at the fort. Brilliant!

Like everything once a pool of like minds get together the ideas start flowing including the brilliant suggestion of using a piece of free DSP filtering software on a Netbook to give a much clearer reception of a single signal as the front end on a Pixie is “as wide as a barn door”. Again an excellent idea.

One suggestion I stumbled on in kb2hsh’s blogspot was the idea of using a K1EL K16 keyer kit between the Pixie and the Morse key to allow a paddle or Capacitive Touch Key to be used with it as, in its native form the Pixie will only work with a straight key.

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Ironically this diminutive device replicates nearly all the features of the Winkeyer which I commented on in my first post about computer generated CW.

Although I’m not planning to use it for all of the features at the outset it’s useful to have around as a potential “evolving” project. Again its another waiting game while the USPS delivers!

Now as much as I’d love to splash the cash and by a really nice Morse key to join my growing pile of kit, I am actually starting to get the hang of my touch key and the action is making sense. Ironically the CW Geeks Guide to choosing a Morse key makes comment about how it takes real practice to make dits and dahs that are the same length over and over and reports of arm ache after about 30-40 mins use with a straight key. Added to that I built my Capacitive Touch Key and it’s a waste not to use it.

There are loads of good sites out there discussing everything to do with Pixie Transcievers, and a select few are here for reference

http://www.eham.net/reviews/detail/12382

http://la3za.blogspot.co.uk/2011/05/pixie2-ultralow-minimalist-transceiver.html

I also stumbled across literature relating to one of the iconic homebrew QRP transceivers, the Forty-Niner

Forty-9er-3W-CW-transceiver-kit-newspaper-reported-electromechanical-machine-shortwave-radio-7-023MHz

Once again there are a host of Chinese clones available as above but at the minute I’ll stick to my Pixie and Frog builds as, at the end of the day they all do pretty much the same thing.

The Foxx range of kits are still popular and companies such as Kanga still supply them.