Dave Richards AA7EE

January 12, 2015

A Crowdfunded Si5351 Breakout Board From Jason NT7S

Followers of Jason NT7S’ blog “Ripples In The Ether” will know that he has been experimenting with the Si5351 chip.  This little $1.50 (or cheaper) device is a PLL clock generator which provides 3 independently programmable outputs from 8KHz to 160MHz. While it’s phase noise is not quite as good as the Si570 (the chip used as the frequency-determining element in the Elecraft KX3), it’s a whole lot cheaper, and indications are that it’s performance will be easily good enough  for many rigs. There was some talk over on the Minima mailing list about using it in a version of Farhan’s new open-source transceiver project, The Minima.  At less than $1.50 for the device, you can imagine how useful this could be as the frequency determining element in a whole new generation of QRP rigs.

Jason talks about it at length on his blog at http://nt7s.com/

Enter the Etherkit Si5351 breakout board –

An earlier version of the Etherkit Si5351 breakout board. The crowd-funded version will omit the broadband output transformers T1, T2 and T3 in order to keep costs down. (Photo courtesy of NT7S)


To make experimenting with this chip even more tempting, Jason is crowd-funding a run of these Etherkit Si5351 breakout boards. More details here. As this blog-post goes to press, the Indiegogo campaign, which was launched earlier today (Sunday) has already reached it’s minimum goal for funding. It runs until Feb 10th. Show your support for Etherkit!

Join Jason’s Indiegogo campaign here!

March 21, 2013

The Etherkit CC1 1st Beta – A Trail-Friendly QRP CW Transceiver

About a year and a half ago, I posted that I had completed the first beta version of the Etherkit CC-Series QRP CW Transceiver.  It was a neat little rig, with low RX power consumption (of the order of 50mA – a bit less, I think), full DDS VFO coverage of any one HF band, a built-in keyer with memories, RIT and XIT, as well as firmware that could be updated at will with a simple AVR ISP programmer (you can get them for around $20). It also used a lot of SMT devices, and was my first serious project using these tiny parts (the KD1JV Digital Dial was the first).

My CC-20 beta worked, and I made quite a few QSO’s with it, including some DX. It wasn’t perfect though. The DDS VFO had some in-band spurs, the TX/RX switching produced a thumping sound, the input and output of the crystal filter weren’t as isolated as they should have been, you could hear some low-level processor noise on the receiver audio,  and the sidetone sounded a little rough too.  Although that sounds like a long list of woes, I think that anyone who designs circuits is used to tackling these kinds of issues one by one, until the dragon is slain. We (by which I mean Jason NT7S, the man behind Etherkit) did manage to improve the isolation of the crystal filter by a fairly good amount during this beta build.

Then he came out with the OpenBeacon kit and the EtherProg.  I knew he hadn’t forgotten about the CC-series, but I’m thinking he wanted to get a few other kits up and running before coming back to tackle it again, which he duly did.

The rig has been renamed the CC1 and although it retains the same basic architecture, there are a number of changes and upgrades to the design. It is still a monoband QRP CW HF transceiver (available in your choice of band) with an output of 2 – 3W (depending on the power supply), and it still has a DDS VFO (tuned with a real knob!) that covers the entire band, as well as RIT and XIT (useful for working split), freq readout in morse code and a built-in keyer with memories. The firmware is still also upgradeable via an AVR ISP programmer.  Although at this stage in the development it has not yet been implemented in the firmware, Jason thinks it should be possible to include APRS functionality and WSPR too. That’s quite a lot for a rig that is not much bigger than a pack of playing cards.

The beta kit arrived in a Priority Mail flat-rate box (what a neat sight on top of my mailbox!)  The enclosure is to the left, in the middle was the bag of parts for the EtherProg (a separate Etherkit product which can be used to update the CC1 firmware). The big bag on the right is the bag of parts for the CC1 –

The CC1 parts bag opened up to reveal the inner packaging.  The bag containing the bigger parts has been opened and those parts dumped into a mint tin.  The EtherProg, as I mentioned, is a separate Etherkit product and is available now, but I’ve included it in this photo. You can see the board slid partially into the enclosure –

A view of the underside of the board. Our beta kits had the microcontroller pre-installed. Currently, this was the only way Jason could supply it to us flashed with the firmware, but regular production kits will not have this IC pre-installed (it will have the firmware already flashed though) –

In true Etherkit spirit (the phrase “Open Source Amateur Radio” is on their home page), the beta testing forums are open for anyone to view here, and the forum for the CC1 beta is here. Only beta testers can post in these forums, but anyone can post in the product support forums which are here (you have to register first.)  The CC1 beta forums include schematics and an assembly guide which, although not final of course, will be of interest to anyone who might have an interest in the kit when it becomes available.

A couple of days of soldering, and the receiver section (which is about 85% of the circuit) was finished. Alignment consists of peaking 2 trimmer caps in the bandpass filter, and adjusting the BFO so that the wanted signal is in the center of the passband.  The passband for my filter is not flat – there is a definite peak in the response,  so I adjusted the BFO to place the wanted signal at the peak of the filter curve.  I already had a noise source that I had built to adjust the filters for my K2, and Spectrogram on my computer (for the same purpose) so I used these to adjust the BFO frequency.  Both the noise source and the use of Spectrogram are detailed here. With the receiver aligned, I have now spent every evening since just listening to it. I keep looking at it and thinking, “That little thing is a radio?”

Here’s the CC1 board with the receiver section completed –

You can see the GPS connector at the left-hand side of the board (the rear) immediately under the green key jack –

The onboard connectors are really great. They save a whole lot of hassle with wiring, and make it a lot easier to run the rig on the bench before putting it in an enclosure. In the following picture of the underside of the board, you can see U4, the 50Mhz master oscillator and to the right of it, U5, the DDS VFO chip. On the right-hand side of the board in the center, is U1, the NE5532 AF amplifier (I just saw a cat hair lying on top of U1 – those things get everywhere).  You can also see the space for U2, the transmit buffer –

At first, I thought the receiver wasn’t functioning correctly, because on attaching an antenna, I heard only a very faint increase in background noise. I tweeted to Jason and informed him as such, as well as posting to the other beta testers in the forum.  My theory was that the AF amp had low gain.  As it turned out, it was a combination of the bandpass filter being way off it’s peak, and the initial BFO freq placing the signal fairly well outside the passband of the crystal filter. Had I thought to peak the trimmers before jumping to conclusions, I would have realized that all was well.

The receiver was sounding good. The DDS spurs that were present in my CC-20 beta are no longer an issue.  The crystal filter has better isolation – there is still some room for improvement, and that will be improved further before it comes to market – in fact, Jason just suggested a circuit change in this direction that beta testers are implementing as we speak. The TX/RX switching is very smooth and the sidetone sounds nice. There is a sharp leading edge on the sidetone waveform which gives a clicking sound, but that will just require some simple shaping, which, once again will be taken care of in the production model. EDIT – another blog, and also a discussion in a Yahoo groupo, seem to have misread my last statement as meaning that there are key-clicks on the transmitted signal.  This is NOT the case. The transmitted signal sounds nice. I was referring to the sidetone only, which is a simple thing to take care of.  I emphasize also that this is a beta,  and we will most likely be taking this little rig through another beta before it goes into production. The other issue, the processor noise that was present in the audio, is vastly reduced and by the time you read this, will most likely be cured altogether, as Jason just re-wrote the firmware, which I am waiting to apply to my beta.  Things are looking very good for this little rig.

A couple more views of the board at this stage, before we move on –

Having confirmed that the receiver is working,  the final push was on to build the transmitter and complete the rig.  It didn’t take long – just the installation of 12 parts and 2 more toroids to wind.

Here’s the completed board, before installation in the enclosure –

The world of SMT seemed like a closeted world of intrigue and mystery before I built my first project using them.  I had read web sites detailing the use of solder paste and hair dryers, or toaster ovens for soldering these tiny little parts.  It was a while before I realized that you can actually solder them the good old-fashioned way – with a soldering iron and a roll of solder.  I pick up resistors and caps and place them close to their final resting place on the board with a fine pair of needle-nosed pliers. Then, with a small jeweler’s screwdriver, I gently nudge them into their exact position on the pads. While carefully holding the part down with the tip of the screwdriver, I tack-solder one end in place. Then I solder the other end, and go back to the first end to properly solder it.  I use a 1/32″ chisel tip and 63/37 .02″ solder with a mildly active rosin core.  0.015″ solder would be even better, as it’s easy to apply too much solder (which is where a good-quality de-soldering braid, such as Soder-Wick, proves invaluable.)

IC’s with fine lead pitch are a little trickier. The NE5532 AF amp was relatively easy, as the leads are far enough apart to solder them individually. Needless to say, a very clean and well-tinned tip is vital. I wipe my tip on a damp rag and tin it before every joint – unless I’m soldering a number of joints in quick succession one after the other, such as with IC’s.  The AD9834 DDS chip has leads that are too closely-spaced to solder them individually. The technique that I learned from Jason involves soldering all the leads on one side with a big wodge of solder, paying no attention to whether the leads are bridged together with solder.  Afterwards, you clean up the solder bridges with de-soldering braid and a larger iron tip. A larger tip is useful here because you can wick up the excess solder more swiftly in order to avoid destroying the chip. Jason posted a good description of how to do this in the assembly guide.  Search for U5 on that page and you’ll find the description, along with a picture.  Flux is said to be very helpful here.  I managed it with no extra flux (other than that in the solder) , but plan on getting some for future use.

The CC1 is billed as a trail-friendly rig, and the kit will come complete with a pre-drilled enclosure with silk-screened front and back panels.  The enclosure we received with our beta kits is the exact same enclosure that will go out with the kits, with the exception that ours weren’t drilled or printed.  So the following pictures represent roughly what the final CC1 will look like, without the silk-screened panels. There might be a slight adjustment in the spacing of the controls before the final production model too.

Firstly, this one’s for size comparison with my CC-20 beta –

The board slides into rails in the side of the extruded aluminum case and is held in place by the nut on the BNC connector at the back.  Here’s a couple of front views without the front panel –

Man, is this thing a beaut or what?

I’m very fond of this little rig. I’ve only made 1 QSO with it so far (with Jason NT7S) but have spent every evening listening to it. It’s great to have the earbuds in, listening to 40M on this diminutive little transceiver while working.

I’m hoping to get some audio up at some point, but it may take a while. If you’re wondering when you can get one of these, well, it’s still in development but at this point I think it’s safe to say that it will be coming out. I do know that Jason NT7S is a perfectionist and won’t release it until he feels it’s truly worthy, and all issues have been thoroughly worked out. The design is already very close to where it should be and there’s a great momentum behind it, but we still have a 2nd beta to go through  Stay tuned and we’ll keep you posted.

May 28, 2012

The Etherkit OpenBeacon – A Very Versatile Programmable MEPT

etherkit’s OpenBeacon is the first kit to be offered by proprietor Jason NT7S and I think it’s a good one for him to open up with.  Sure, it’s not the first QRSS transmitter kit on the market but unless I’m missing something (and I don’t believe that I am) it is the most versatile one offered to date. Here is a list of all the modes that it can transmit:

  • Dual Frequency CW with 3, 6, 10 or 120 second dits (3 second DFCW is the most commonly used QRSS mode on the HF amateur bands and is the default mode programmed into OpenBeacon)
  • QRSS CW with 3, 6, 10 or 120 second dits
  • Regular CW (you choose the speed)
  • Sequential Multi-Tone Hellschreiber
  • WSPR – billed as an experimental mode, but I’ve used it with success
  • Glyphcode – a mode that uses Hellschreiber to generate dots and dashes
  • A special calibration mode that is useful for setting the center-frequency and bandwidth of your transmitted signal

There are no jumpers for mode-switching. It’s all done with the software client that is available for Windows, Linux and Mac OS X. This software control opens the door for anyone who wishes to come up with their own code to control OpenBeacon (and hopefully share it with other users in the etherkit OpenBeacon forum.)

First things first. Here’s what you get:

In this shot, I took the rather good-looking PCB out of it’s wrapping so you can see it a bit better:

Construction is straightforward. If you’re new to kit assembly and the art of soldering, it may take a little longer to figure out. The usual guidelines apply – identify all the parts, and don’t solder anything into the board until you’re sure that it’s the right part, and you’re soldering it in with the correct orientation. There are useful checks included at several points during the build and after the first stage has been completed, you get to connect the board to a USB cable and see your computer recognize the OpenBeacon. If you’re running Windows, you’ll need to install a driver before this can be accomplished, but it’s reassuring to have the project recognized by your computer at such an early stage of construction.

Here’s the finished board:

And another view of the completed board:

Apologies – I forgot to include a rule in the pictures to give you an idea of the size of the board, so for the record, it measures 70mm x 90mm.

One thing I really like about OpenBeacon is the on-board connectors. Once you’ve finished assembling it, you can plug in a USB cable and an antenna, program it with your call-sign and you’re on the air. If you want to run higher RF output power than the approximately 40mW max you get from USB power, then you can plug in DC power to the on-board DC power connector and get about 300mW from a 13.8V supply. These kinds of QRSS transmitters are often not installed in conventional enclosures anyway, so it’s really good to be able to begin experimenting with OpenBeacon straight off the bat.

This is a bit gratuitous, but here’s a really close-up view of part of the board:

If you don’t already have a QRSS viewer, Argo is the easiest to set up and get going with.  OpenBeacon is already set to transmit in QRSS3 as the default mode, but you will need to program it with your callsign by downloading the client for your particular operating system and following the directions on the etherkit site. If you have problems with any of this, Jason NT7S, or one of the etherkit forum members should be able to help you out.

Of course, the first thing you want to do with a transmitter like this is to see what your QRSS signal looks like on your own viewer:

The very next thing was to see what my callsign looked like in Multi-Tone Sequential Hellschreiber:

You’ll notice that the vertical scale on my Argo screen captures is calibrated with the frequency.  To achieve this, you’ll need to accurately calibrate your receiver so that you can set it to 10139 KHz. In my case, I know that after it has been running for a while, my K2 receives at about 10Hz lower than the dial frequency, so to receive on 10139 KHz I set my K2 to 10139.01. The next step is to enter an offset of 10139000 in the calibration menu and you’re all set. The QRSS band normally runs from 10140 to 10140.1, so a carrier in the center of the QRSS band will produce a tone of 1050 Hz in the speaker of your receiver.

One thing that’s very important to remember if you run into any difficulties during assembly –

Incidentally, before anyone suggests that I was illegally radiating a sginal without proper identification, the above screen capture was taken as a result of outputting 5mW from the OpenBeacon into a 50 ohm dummy load – not too much radiating was taking place.

I did run OpenBeacon for one night in QRSS3 mode but wasn’t able to find my signal on any grabbers.  It was only one night and I was, after all, running just 5mW RF output (sucker for punishment here). I’ll be trying it again soon, but at the time I was keen to forge ahead and try the WSPR experimental mode.  I did briefly have a go at figuring out Glyphcode but either the instructions in the Client Software Useage Guide on the etherkit site weren’t clear, or I was being a bit thick.  It could well have been the latter. I’ve no doubt that Glyphcode isn’t hard to program but at the time, was more immediately interested in playing around with WSPR on OpenBeacon, so I hoofed it on forward to that section of the online guide.

To transmit a WSPR signal with OpenBeacon, you first have to load the buffer with the appropriate code. I downloaded wsprcode.exe and placed it in the root directory of my PC.  This is a description of what I did on my PC running Windows. Your mileage will vary if you are running any other OS. In DOS at the command prompt I typed wsprcode “AA7EE CM87 7”  You’ll need to do the same with your callsign, 4-digit locator and power level (in dBM). wsprcode will output the data symbols, sync symbols and channel symbols for your particular data – all you need is the last set of characters – the channel symbols.  Cut and paste this data into a simple text editor (I used notepad on my PC) and edit it to erase all spaces between characters as well as any carriage returns so that all you are left with are 162 characters in a continuous string with no spaces (or anything else) between them.

The next step is to program the buffer of your OpenBeacon with the WSPR code. Using the OpenBeacon client software, the command for this is openbeacon wsprbuffer “flangesprocket” where flangesprocket represents the string of 162 channel symbol characters.

All that remains is to place OpenBeacon in wspr mode, adjust the transmission bandwidth to 10Hz, and the frequency to put you in the wspr band, and manually trigger OpenBeacon (either with S1 or through the client software) at the beginning of an even-numbered minute. OpenBeacon will transmit your wspr signal for the required 1 min 50 seconds.

Here are the unique spots representing 2 evenings of operation:

Date Call Frequency SNR Drift Grid dBm W
by loc km mi
 2012-05-28 02:36  AA7EE  10.140138  -17  0  CM87ut  +7  0.005  K7LG  DM04se  530  329
 2012-05-28 02:20  AA7EE  10.140102  -23  0  CM87ut  +7  0.005  VE6PDQ/1  DO33fl  1867  1160
 2012-05-27 05:24  AA7EE  10.140108  -22  -1  CM87ut  +7  0.005  K7MSC  CN76wv  1021  634
 2012-05-26 07:20  AA7EE  10.140125  -19  0  CM87ut  +17  0.050  W7WKR  CN98pi  1179  733
 2012-05-26 07:10  AA7EE  10.140144  -16  0  CM87ut  +17  0.050  W5OLF  DM78hb  1482  921
 2012-05-26 06:20  AA7EE  10.140138  -22  0  CM87ut  +17  0.050  K7UEB  DN06tb  973  605
 2012-05-26 05:34  AA7EE  10.140129  -26  0  CM87ut  +17  0.050  VE6PDQ  DO34ir  2000  1243
 2012-05-26 04:36  AA7EE  10.140108  -8  0  CM87ut  +17  0.050  KC6KGE  DM05gd  390  242
 2012-05-26 00:08  AA7EE  10.140114  -16  0  CM87ut  +17  0.050  N6RY  DM13id  688  428

Not a lot of unique spots, but I was only running 5mW.  The first spots were reported as being 50mW, but this was my mistake – I was actually running just 5mW and corrected the wspr code as soon as I discovered my error. I decided to stick with an output power of +7dBM as that is the power I feed my diode ring mixers, and it just slightly blows me away that my signals were decoded by VE6PDQ over 1200 miles from me with the same power that my local oscillators put out. Quite amazing. I have no doubt that I’ll achieve even better DX if I keep at it.  As I have developed an affinity for level 7 diode ring mixers, running a power output of +7dBM from the OpenBeacon seems very fitting.

Now, as etherkit is an open source amateur radio company, I’m hoping that someone will write a routine to automatically trigger OpenBeacon when in WSPR mode. It definitely seems to work quite well in that mode.

This is where I stand with my OpenBeacon so far, and I think it’s the most versatile MEPT available in kit form. It boasts many different modes and speeds (as well as WSPR) and to change between them you don’t have to fuss around with wire jumpers. It’s all done in software, like many other things in OpenBeacon. This ability to control it in software, along with the wide variety of modes, and the open-source nature of etherkit make it, in my opinion, the ideal MEPT for a lot of users.

September 24, 2011

The CC-20 First Beta Version

Phew.  I’ve finally finished the first CC-20 beta and fitted it into a case.  I can now sit back, look at it and listen to it! In this post a few weeks ago, I showed the unpopulated board with the connectors lying on a sheet of the red PCB material I was planning to use to fabricate an enclosure. By the way, the 6 pin connector you can see at the bottom of the board in the center in the photo in that post is one thing that makes this rig different from many others. It is marked ICSP, which stands for “In-Circuit Serial Programming”.  Etherkit bills itself as an open-source amateur radio company and the hope is that code-minded amateurs will write their own code for this rig if they feel they can add features, or improve on the code that the micro-controller in the kit will come programmed with. If you don’t write code, by the time the kit is available to the general public, the stock code will be solid, so no need to worry if, like me, you’re the type of person who needs others to write your programs for you. I did build a USBtinyISP so that I could flash the firmware on my beta though – the beta kit was shipped to the testers with a version of firmware that is not the final version.

Before we go any further, just in case you’re wondering what the CC-20 is, it’s the first transceiver in what will be known as the CC-series, designed by Jason NT7S.  These are a series of monoband trail-friendly QRP CW transceivers with a DDS VFO, superhet receiver with 3 pole crystal filter, and TX that puts out about 2W.  The kit makes copious use of SMT devices. If you’re good at soldering, have reasonable eyesight and a steady hand, you should be able to assemble this kit, but I wouldn’t recommend attempting it if you have never soldered SMT parts before – it would be best to get your practice on a smaller and easier kit (I built 2 KD1JV Digital Dials, which also uses SMT devices, but is a much simpler project, taking less time to complete).

In that previous post, you saw what the board looked like. Here’s what it looks like when fully populated with connectors and controls wired in. Bear in mind that the final board will be a little (though probably not much) different. This board has some blue wire jumpers that will not be present on the final board:

Of course, the first thing to do after completing the board was hook it up to a paddle, earbuds and antenna, and see if it would work.  The first QSO was with W7VXS in the Salmon Run.  I then rattled off 8 more Salmon Run QSO’s – looks like this little rig works! I also had a regular QSO with K1CTR in Denver, CO.

At some point afterwards (I think it was during an extended key-down period while tuning the TX) the finals overheated and fried. The production version will have a redesigned driver and finals and will most likely have an automatic dotting mode programmed into the firmware to prevent overheating of the BS170 final transistors.  For this version of the rig however, to help guard against this happening again, I epoxied a small chunk of aluminum to the new finals to act as a heat-sink.

Here’s the enclosure I fabricated from PCB material. The great thing about making enclosures this way is that you can make it to whatever size you need.  Finding ready-made enclosures to specific sizes can be a lengthy task that doesn’t always end in success but this way,  I got a case for the CC-20 sized exactly how I wanted it – a nice low-profile enclosure just a little over 1″ high:

The next image is of the CC-20 in it’s enclosure. You can’t see them, but I fitted 4 rubber feet to the bottom of the case. You can see where I accidentally drilled a hole in the side of the chassis, redrilled it in the correct place, and filled in the mistake hole with JB Weld. I did make a number of mistakes on this case from which I will learn if I make any more. I say “if” because making these PCB enclosures is quite time consuming and I’m feeling the strong urge to use ready-made enclosures for future projects:

On the front panel, from left to right, is the headphone jack,  the AF gain control, the CMD button, the FREQ/OK button, and the tuning encoder.  The tuning control tunes in either 100Hz or 20Hz steps, switchable by pressing the tuning knob. The CMD and FREQ/OK buttons are used to access much of the functionality of the rig,  functions which include:

– changing keyer speed

-selecting straight key or paddle

-recording to and playing back the keyer memories

-reading out supply voltage (in Morse code)

-reading out SWR (to be implemented later)

-reading out operating frequency to the nearest 100Hz

-reading out keyer speed

A lot of functionality is controlled from quite a minimal front panel:

What a cracking little radio:

Oh yes. One thing I almost forgot to mention is that after fitting the new finals, I called CQ on 14061 and was replied to by Steve the Goathiker WG0AT. Now that’s a good omen!

Mikey WB8ICN, Paul K3PG and Brian N1FIY are getting close to finishing their CC-20 betas, and I’m looking forward to comparing results. Mikey has already finished the receiver part of his, and our results are similar.  There are a few issues with the first beta that Jason will be working on to fine-tune. This, of course, is the whole purpose of beta-testing.  I was also thrilled to hear that John AE5X will be joining us for the second round of beta testing. I think we will also have one or two more beta testers joining us for the second round, but I’m not sure who they are.

In the meantime, I now have 20M capability and this little radio is fun to operate. Thanks Jason!

August 29, 2011

A Very Early Look At The CC-20 Beta

A few days ago, a small flat-rate Priority Mail box showed up at my doorstep. It was pretty unassuming but it held great promise, as inside was the beta kit for the Etherkit CC-20 transceiver.  Jason has been working on this transceiver kit for quite a while now, and he’s overcome many challenges but finally, his version has a sensitive and stable receiver (superhet with crystal filter) with a DDS VFO that is rock-solid and free of spurs.  You can follow the fun of the beta-build over at the Etherkit forums.

The day after receiving my beta kit, I set about building it with gusto, but didn’t get very far.  Etherkit is billed as “open source amateur radio” so in the spirit of being open, I guess I should ‘fess up and tell you what I did.

Firstly, let me mention that the boards as received are not the final production boards. There will need to be some modifications made to the traces on the board, so Jason modded our boards for us by cutting some traces and soldering in some wiring so that we could use the PCB’s we had at this stage of the game. He also soldered in the DDS and micro-controller IC’s, as well as the 2 regulator IC’s, and checked that they were working before shipping them to us. All I had to do for the very first stage of building was to solder in a diode, an electrolytic capacitor and the power jack, and then check for 3.3V and 5V at the output of the regulators. Simple eh?

You’d think that a diode for reverse voltage protection would be a safeguard against bozos like me, but as well as connecting the power with the wrong polarity, I also soldered the reverse-voltage protection diode in the wrong way.

It just beggars belief. It really does.  Even I am asking myself why I did that.  The moment I connected the power to the board and saw sparks fly out of both voltage regulators I knew it was all over – at least for the time being.

When I build circuits myself from scratch I get things pretty much right because I am checking the circuit as I go. When I build kits, I don’t have to concentrate quite as hard because the instructions tell me what to do.  The problem is that as a beta tester, I should have reminded myself that although this will be a kit in the near future,  right now it is a beta, and I am expected to proceed carefully, checking myself as I go. Somehow, I convinced myself that I had wired things the correct way and didn’t bother to check the circuit board traces in order to make sure, leading to *poof*!

Rest assured that by the time the CC-20 is a finalized product, Jason will have ensured that the only way you could make a simple mistake like this is if for some odd reason, you really want to.

While waiting for extra parts to arrive, I started putting some thought into what to use for an enclosure. I have some 4″ x 6″ sheets of single-sided PCB material, some in blue and some in red, that I think that would look really nifty, so I laid out the board with the connectors in roughly the positions I envisage they will be. Bear in mind that in the final version, the colored side of the board will be facing outwards with the copper-clad side on the inside:

The red PCB material you see is 4″ x 6″, which should allow for a nice easy fit.  I’m thinking that the case need only be about 1″ high. I’d like to take advantage of the fact that the micro-controller outputs the operating frequency in morse code, allowing for a compact installation without a frequency display. Because the majority of the time I’ll be using it at home, I’ll fit an RCA jack on the back panel with an output to drive an outboard digital dial (probably the N3ZI Digital Dial), so when portable, can take a nice compact transceiver with me.

On the front panel, from left to right, is the AF gain control, the headphone jack, the command button, the frequency button (commands the micro-controller to output the operating frequency in morse code),  and the encoder to control the tuning of the DDS VFO. The back panel has the paddle jack, the antenna jack and the DC power jack. There will also be an RCA jack for an output to a digital dial.

I may even start building the enclosure this week while waiting for parts (possibly a new board) to arrive.

This is going to be one really neat little transceiver.

UPDATE:  The replacement voltage regulators arrived from Jason this morning and I was happy to discover that my misadventures with reverse polarity hadn’t fried the DDS and AVR IC’s.  The build continues!

August 23, 2011


There have been very few times in my life when I have uttered the words “Oh my god”.  I don’t really like that particular exclamation; it’s certainly not my style. For the only the second time I can remember, I just uttered those words twice in a row when this appeared in my inbox just now:

I’m not even going to try and explain how exciting the above is to me.  Don’t worry – I’ll have plenty of words at some point in the future. By the way, although the above mentions the CC-40, I’m pretty sure the beta kit I’ll be receiving will be for the CC-20.

OK, calm yourself Dave. Try to act normal, and suppress the urge to run around in the street and yell gibberish, interspersed with maniacally happy laughter. That kind of behavior is NOT NORMAL.

I also just received notification that my WM-2 QRP Wattmeter kit just shipped today from Oak Hills Research so once again, things will be busy at the AA7EE ranch very soon 🙂

January 25, 2011

Beta Testing A New CW Transceiver

I’ve been passing on news in this blog about Jason NT7S’ upcoming QRP transceiver kit, which he initially referred to as “Project X” before revealing the name of the series of transceivers as the CC series, and the first model for 40M, the CC-40. He also told us that his new open-source amateur radio company will be called etherkit.

I was thrilled to find out that I’ll be beta-testing the CC-40 which is great news.  I finally have a 40M antenna that seems to perform quite well – an inverted vee dipole with the center at 47 feet. I’ve never beta-tested a product before, and the idea of doing so is quite novel to me.  I’m not a circuit design person, but am quite proficient at building circuits and kits to other people’s instructions.  This makes me,  I think, closely fit the profile of the kind of people who build kits, and therefore, good material for a beta tester.  That’s my tin pot theory anyway!

I do like to take my own pictures of the projects embarked on here at AA7EE to break up the monotony of all-text blog posts, so as long as it’s OK with Jason, I’ll be posting pictures of the pre-production versions of the CC-40 and letting you know how construction, as well as operation, goes. When at the workbench I’ll have a radio tuned to 7030 and will be eager to try the CC-40 out on the same, or similar, frequency.

One recent update of Jason’s did make me happy, and that is that he has decided to include a sinewave sidetone. This does increase the current consumption of the circuit, but in my opinion,  should make for a much better operating experience.

I’m not quite sure when beta testing will begin, but it looks like it will be a matter of weeks.  As always, ground zero for updates on the CC-40 and CC series of transceivers will be at the upcoming etherkit site and on Jason NT7S’ blog.

January 21, 2011

Etherkit – A New Kit Company

If you follow Jason NT7S’ blog, you’ll be well aware that he has been developing a QRP CW transceiver with low receive current drain that looks like it would make a good trail-friendly radio. He has just publicly announced that his open-source amateur radio company will be called etherkit:

Sorry for lifting your logo Jason.  I know that strictly speaking it’s a breach of copyright, but I’ve linked it to your new site, so hopefully it qualifies as “fair use”!

The first kit offered will be the CC-40, and lifted from this blog post on Jason’s site, here are initial specs.  They may have changed somewhat since he posted these, but it gives you an idea of what will be on offer:

  • RX current draw is now around 30 mA, but I’d like to squeeze it down further if I can
  • TX is Class E, so TX current draw should be pretty good as well
  • Nominal TX output power is 2 W
  • MDS should be around -130 dBm (500 Hz BW)
  • VFO tuning range approximately 40-50 kHz
  • VFO stability is very good (~2 MHz VFO frequency)
  • ATmega88 microcontroller for built-in keyer, mute, frequency counter, battery status, etc.
  • Other planned bands are 80 m, 30 m, and 20 m. Would like to tweak design for upper bands as well for a future date

You can glean some more info from the various posts on Jason’s blog here.

I think the part that interests me is the low current draw on receive.  I already have visions of running my own 40m station with a CC-40 powered entirely by a small solar panel.

Fingers crossed that the beta testing goes well and we’ll be able to buy the CC-40 soon!


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