Here’s a quote from Wes describing the equipment that he was using on his end:
I hope that my signal was OK when we worked. I was in the midst of wrapping up a frequency synthesizer project and had it running on the rig for the first time. When I heard you on 20, I could not resist calling. You were the first contact using that source. But I then discovered that the PLL was oscillating. It was a low level oscillation and didn’t present an obvious problem with regard to what I heard on the air. But it was there. I have since then changed the phase/frequency detector circuitry and have eliminated the oscillation. I am not thrilled with the 74HC4046. I get much more repeatable performance from a dual D FF with a NAND gate.
I feel pretty guilty that I’ve let the blog content slide in 2011. As you can imagine, between having a near-toddler cruising around the house, doing a major redesign of a QRP transceiver, and trying to bootstrap a new small business, free time is at a premium (and my wife and kid owns what little there is). The least that I can do is give you a quick glimpse into the progress with the radio.
If you don’t follow me on Twitter, you probably don’t know any of the details of my progress with the CC-Series radio. After advancing the design of the radio to a point where I thought it was production-ready (two PCB turns, lots of design review and tweaking), I ended up failing pretty miserably in the end. The problem was with a subtle, but noticeable pull on the free-running VFO on transmit (which was not present on the prototype). I spent close to 2 months attempting to troubleshoot that one little problem, but sadly it ended up defeating me. Perhaps “defeat” isn’t the correct word. There was a part of me that wanted to keep stubbornly trying until I tackled the problem (ask poor Jennifer about my stubbornness). But I had to look at the issue realistically, from a business point-of-view. I had no idea if it would take me a few more days or many more months to solve my problem. So in the interest of trying to save my fledgling company, which hasn’t even made it out of the nest, I made the difficult decision to temporarily abandon the CC-Series development.
Instead, I decided that I would take on a similar project: revamping my minimalist entry in the 2010 FDIM Challenge (the 72 part rig). It started as just a few upgrades, but quickly spun into a new project of its own. When the VXO scheme that I wanted to try didn’t work out as I had hoped, I decided that I would bite the bullet and add a DDS to the project. I planned on reworking the CC-Series with a DDS anyway, so this would be a good way to learn how one works. In order to make the rig worthy to be sold to other people, I kept incorporating changes and features from the CC-Series. I also leveraged my firmware from the CC-Series, which made it easy to get up to speed with the new radio fairly quickly. By now, the rig resembles what I intended the CC-Series to be in the first place.
A few nights ago, I made my first QSO with the rig with W7GVE in AZ. We had a nice little chat and he let me know that I had a little bit of chirp on my signal. Right after I signed off with Ed, I got a really pleasant surprise. Who else but the great father of us QRP homebrewers, W7ZOI! He dropped in to give me a quick “hi” when he heard me on the QRP watering hole of 14.060 MHz. According to my (admittedly incomplete) log on my PC, this was my first QSO with Wes. It was a great thrill, but unfortunately I missed about 25% of his transmissions because I was too nervous to copy CW well. I fully admit that my CW is still lousy, and my comprehension drops off the cliff when the other guy is going greater than about 15 WPM and I’m jittery.
I made some tweaks to the transmitter (and torched some finals in a spectacular, fireworks fashion), then managed to make a sked with one of my partners in crime, AA7EE. It was a rough QSO, especially for me, but we exchanged signal reports so it counted (20 meters at 2200 local on a short path between us is not conducive to communication). Better yet, Dave reported that the signal was rock-solid and chirp-free.
So where do we stand now? I want to do a little more on-the-air testing, then I’m going to start laying out the PCB. The last time I ordered prototype PCBs from my vendor, they were very high-quality, but the turn around time was less than desirable (nearly 3 weeks). This time, I’m going to see if I can lay out the board with minimum vias (probably not going to happen). If I can do that, I might be able to make my own board with the toner transfer method. If not, then I’m going to look into a vendor that can give me boards with more alacrity, at least for the prototypes.
It’s been frustrating, but it’s also forced me to refine all of the circuits in my radio in order to make them as bulletproof as possible. As long as I can get this puppy to market, then it will have been worth the heartache.
Last night, I had another QSO with AA7EE so that he could record my transmissions and send me back the recording for evaluation. We had talked about meeting sometime after dinner, but set no specific time. Right around 1900 local, I fired up the rig on 14.060 MHz and was just getting ready to send a tweet to Dave to see if he was around. Within about 30 seconds of turning on the rig, I heard someone calling CQ on the watering hole frequency. Sure enough, it was AA7EE. I established contact and we had a quick little chat. Thanks to Dave’s generosity, I’ve posted his recording of the QSO below. The QSB was bad on my end, but as you can hear from the recording it wasn’t very bad on his end. Even though the signal was weak, the note from the rig sounds clean, stable, and chirp-free. Be sure to stick around to the end of the recording for a few moments of commentary from Dave himself.
Things have been a bit quiet on the blog front as I work to get the CC-40 beta up and running. Last month, I had an initial set of beta PCBs manufactured, but I made a really big mistake. Somehow I bungled the footprint of the ATmega168 microcontroller, and it ended up much smaller than it should have been. I managed to wire the microcontroller to the PCB using 30 AWG Kynar, but another problem manifested itself. The wires acted like an antenna and radiated the 16 MHz clock all over the board, causing a high pitched whine in the audio. I continued to build the board, and for the most part, the rest of it worked as expected, but I couldn’t release a board with such an obvious fault to the beta testers. It was probably a good thing that I was forced to spin the board again, as I found some other subtle problems that needed to be corrected. The new PCB design was submitted to the PCB vendor early this morning, and with any luck the new board will be here in about two weeks.
The current beta test unit is still usable, especially if I hook it up to my external AF amp, which cuts off high frequencies pretty well. Early this morning, I shot a video comparing CC-40 to my SW-40. I’m listening to JA1NUT and manually switching between the CC-40 and the SW-40. It’s not a great indicator of the performance, but at least it will give you a little taste of the character of the radio.
While I wait for the new beta PCBs to get here, I’ve still got plenty of work to do in preparing documentation, setting up my shipping station, and getting my web shopping cart configured. We’re also going through the fun of Noah teething, so sleep is at a bit of a premium for us at the moment. With any luck, the next update will be some happy news about how the new beta PCBs work great!
I’m pleased to announce that I’ve filed the appropriate paperwork, and that my new open source amateur radio company is born! The logo links to the new domain, but there’s nothing on the web yet.
I’ve also given “Project X” a proper name. It’s now going to be known as the CC-series of transceivers (with the current 40 meter beta units being CC-40 models). The beta PCBs are in the process of being manufactured, and are due to get here by the end of January. Once the boards come in and I can build a working beta unit, the real beta test will be on; with any luck by early February. It’s not quite as fast as I had hoped for, but you can’t rush certain things.
In the meantime, I’ll be working on getting the online store functional and navigating the maze of bureaucracy to make sure that I don’t run afoul of some obscure regulations and get shot down before I even take off. The blog updates will pick up again once the beta testing gets going.
Over the last few days, Jennifer has been off work, so I’ve been able to spend more time in the shack working on Project X. I only recently made my first QSO with the prototype rig (I think propagation was unfavorable for me when I was trying late in the evenings), so I’ve been leaving the radio hooked up to my bench AF amp and monitoring 7030 kHz during the day.
Late this afternoon, I heard a very strong station calling CQ just a bit up from 7030. I bumped the VFO up a bit and found that it was KE7GKM calling at a nice, comfortable speed for me (my CW is rusty after quite a few months off the air). While I called him back, the thought occurred to me that the call sounded familiar, but I couldn’t remember how. After getting the QSO basics out of the way, I remembered why. Bob said that he was using a VRX-1 and homebrew QRP transmitter combo! Then it hit me that Bob had just e-mailed me about a week ago to ask me a few questions regarding the VRX-1.
I don’t get on the air as much as I should (seems like I’m melting solder way more than pounding brass), but when I get a chance, it means so much to me to have a contact with someone who has built one of my radio designs. It’s even more special when I get that make that QSO with a homebrewed radio on my own end as well. If I remember correctly, this is only the second time that I’ve done such a thing.
Bob told me that he is trying to get to 100 QSOs with his VRX-1/HB TX combo, and that I was QSO #80 (if I remember correctly, my notes aren’t great). I wish Bob all the best of luck in his endeavor. It certainly looks like he doesn’t have much more to do in order to meet his goal.
It’s hard to beat an experience like this in capturing the essence of amateur radio for me. It is my hope that more amateurs will homebrew their own gear so that they can get that same thrill.
I decided to make my initial Project X prototype PCBs at home using the old tried-and-true method of toner transfer (via Pulsar Professional paper and foil). Since I’m a novice at PCB layout, I didn’t feel comfortable paying the money for a few proto PCBs from a board house, then finding out that I did something wrong and flushing that money down the drain. Instead of buying Pulsar’s starter kit, I just purchased a pack of the transfer paper and a roll of the green foil. I also got the required GBC laminator from Amazon instead of paying significantly more for it from Pulsar.
Last night, it was time to give the process a whirl, so I decided to make a PCB of the G3UUR crystal checker circuit that was printed in the Fall 2010 QRP Quarterly (an excellent article, by the way). The instructions seemed clear enough, but I had about five failures before I finally figured out how to make the process work correctly. I was just about ready to chuck the whole thing in the trash bin, but I managed to keep my wits and persevere through it. For those who might be new to the process, let me help you to avoid some of the problems that I had:
Give yourself at least 0.5 inches of copper clad clearance on each margin of the final board edge in order to give the laminator good purchase on the board and transfer paper. Putting the toner traces too close to the edge will result in those edges failing to adhere to the board. There’s just not enough heat and pressure to do the job properly at the edge.
When passing the copper clad plus transfer paper through the GBC laminator, I found that it worked better with four passes. Pass the board once, turn it 90°, pass it again, etc., until all four edges have been the leading edge through the laminator.
I didn’t see this mentioned in the instructions, but after you apply the foil on top of the toner traces, you must let everything cool down to room temperature before attempting to peel the foil off the board. Failing to do so will rip most of your toner off of the board!
Once I got the bugs worked out, I was quite happy with the end result. I also decided to try out a new etching method. Instead of using ferric chloride, I used the hydrogen peroxide/hydrochloric acid recipe that I’ve seen touted on the Internet. Let me just say that it worked out beautifully and is waaaaay cheaper than buying ferric chloride. It only took about 3 minutes to etch my small board in a Ziploc baggie. No need to mess with expensive equipment or chemicals!
The etched board turned out very well. There are a few places with very close traces, as you can see in the photo above. These etched out perfectly, no problems at all. You might notice some bad copper on the bounding rectangle on my board, but that was because of the close clearance between that trace and the board edges. I know how to avoid that in the future.
Tonight, I got the board all soldered together and it worked perfectly on first power-up! That’s always an extremely satisfying feeling. Now that I’ve got a handle on the process, I feel comfortable using it on the Project X prototype. Stay tuned for more progress on the new radio!
Here’s a video that I made this afternoon of the Project X receiver listening to 40 CW during Sweepstakes. Once I’ve got the microcontroller code up and running, hopefully I can get you a video of a complete QSO. Enjoy!
It’s kinda big with thru-hole components, but the current plan is to use SMT in production. Does that sound like a good idea, or does the mere mention of surface mount turn you off?
Due to “popular demand”, I’ve decided to release a bit of information on this rig. This isn’t a guarantee of final specifications, but the end product should be pretty close to this.
The rig above is a 40 meter CW superhet. Cascode JFET circuitry is used extensively throughout the radio. I’m aiming for this to be a trail-friendly radio. I don’t have any hard specs yet, but here are some general observations:
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
Hopefully that will whet your appetite a bit. Let me know in the comments any features that you would find useful that would be appropriate for a radio of this class.