Dave Richards AA7EE

October 18, 2011

A Trilogy With T32C – Thanks To The CC-20

Filed under: Amateur Radio,Ham Radio,QRP,Uncategorized — AA7EE @ 4:42 pm
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In the last post I reported that I had made contact with the T32C team on 40M with 4W from my Norcal 2N2/40, and also with 4W on 80M from my Tut80.  The goal was to make a contact with them on every band I have capability for here, which meant just one more band – 20M with the first beta version of Jason NT7s’ CC-20.  Last night I achieved that goal, and was surprised at how easy the mechanics of it was with this monoband QRP rig. What made it easy was Jason’s recent addition of XIT to the firmware. If you push and hold the tuning encoder in for half a second, on releasing it, you hear a morse code “R” in the headphones and the front panel LED lights, indicating that you are in RIT mode.  Holding it in for another half second gives you an “X” in the headphones, and the LED flashes, indicating that you are in XIT mode, giving you independent control over your transmit frequency.

Here’s where it gets neat. While in RIT or XIT mode, if you briefly depress and release the tuning button, you can listen on either your transmit or receive frequency, which is very useful for finding out where stations are calling during a split-frequency operation in XIT mode. Press the tuning knob once, and you hear an “R”, meaning that you’re listening on the receive frequency. Push it again and you hear a T, which means that you are now listening on the transmit frequency.  Also, while in RIT or XIT mode, pushing the FREQ/OK button (one of two front-panel pushbuttons) will trigger a readout of the frequency difference between your receive and transmit frequency in morse code. When operating normally, this button triggers a direct readout of the operating frequency. If you look at this new picture of my first beta version, you’ll see one addition; the front panel LED to indicate RIT/XIT mode. You’ll also notice that I forgot to install the screws on the side of the case for the photo. The screws have been off recently, as there have been several firmware updates while Jason fine-tunes the firmware:

It has been fun watching the CC-20 slowly take shape and for a compact and trail-friendly radio, I do believe this is about as full-featured as they come. This is not a final spec – that will have to come from Jason, but here’s a rough list:

*Rx current consumption ~ 40mA

*Tx output power 2W

*Full band coverage (14 – 14.35MHz) from a rock-solid DDS VFO with fast (100Hz) and slow (20Hz) tuning steps

*Readout of operating frequency in Morse code, also readout of difference between receive and transmit frequencies in RIT and XIT modes

*Readout of battery voltage in Morse code

*Built-in keyer with two programmable memories (I think this will be increased to 4 memories for the final production version)

*This kit will make extensive use of SMT devices.  Models available for 40, 30, 20 and 15.  Not sure if Jason’s planning an 80m version

* The board will come with the micro-controller installed and pre-loaded with the firmware, though the source code will be freely available for those who want to write and share their own code.

 

If I had a multi-band HF rig, I’d be gunning for a clean sweep with T32C on all HF bands on CW. The one band on which I’d really like to make contact with them on though is 160M. It would be a real challenge from this QTH.

As well as our current beta-testers Mikey WB8ICN, Paul K3PG, and Brian N1FIY, we will be welcoming John AE5X and two more beta testers for the second round of testing before the CC-series becomes available as a kit. Fun times!

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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

OMG

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 🙂

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