A brief post to show you the CC1 prototype, now inside of its aluminum enclosure. This is the actual enclosure that will be used for production, but I will have the end caps custom cut and silkscreened, so you won't have to do it yourself. Pardon my questionable metalworking skills, and please note the the production tuning knob will be different (a bit smaller so as to not interfere with the LEDs). At least this will give you some idea of what the final product will look like. The dimensions of the enclosure is 70 x 100 x 29 mm (or 2.75 x 3.93 x 1.14 inches). The first photo shows a size comparison with a standard deck of cards. The weight is 190 grams (6.7 oz).
After the latest circuit tweaks, everything is looking very good with this beta test. I will have more news for the beta testers in the near future. Exciting!
Two days ago, I received my pack of 10 CC1 prototype PCBs from Seeed Studio. The excitement was too much, so I immediately started building the first CC1 prototype as soon as my wife got home from work. Not surprisingly, I didn't go to bed until I completed the build, sometime around 3 AM. I knew it was futile to even try to sleep, as I'd just lie in bed wondering if I had messed something up with the circuit. The radio seemed to pass all of the basic checks early that morning, but had a few oddities that needed to be worked out.
Yesterday, I was able to tweak some component values and got almost everything in line with my Manhattan-built prototype. I could hear a good rush of band noise as the antenna was connected, signals were coming in, and there was a stable 3 W CW output from the transmitter. Everything was looking great, but by the time the radio was ready to go QRV, 40 meters was closed and I was dead tired anyway.
Tonight, I tried to make a first QSO with AA7EE, but 40 meters had already gone long by the time I was able to make it to the radio at 6 PM, and Oakland was well out of the skip zone. There were a lot of signals from Rockies and east on the band, so I cruised a bit looking for a CQ. No luck finding anybody CQing, so I found a clear spot just above the QRP watering hole and called CQ with the CC1 keyer memory. Right off the bat, I got a call from WA0JLY! We gave each other 559 reports, but he actually came up to 579 by the end of the QSO. It was a very short QSO, as just as we exchanged reports, I was called away to help with our 10 month old son Eli. So I apologize Denny for the cutting the QSO short and for my shaky fist! Earlier today, I made some special QSL cards to commemorate the occasion and WA0JLY will get the first one. I do plan on getting more on-air time with the CC1 over the next few months, something that I've set aside far too much while I've been doing design.
So the initial verdict for this CC1 beta test is looking good. I will be getting in touch with the original beta testers soon and soon after that will contact those who requested to be in on the next beta (if you are one of those people and you don't hear from me soon, feel free to contact me). As I've been saying recently, I'm cautiously optimistic about this board spin. I hope that I will be able to deliver a good product to my beta testers that has all of the original bugs eliminated.
I've had a lot of people ask for details about the CC1 and I forgot that it has been a while since I've last reviewed the details about the rig on the blog. So here's a quick list of specs. Please keep in mind that this is strictly preliminary and subject to change for the release version.
Monoband CW QRP transceiver kit
DDS VFO (AD9834), full band coverage
Mostly SMT construction (0805 resistor/capacitors)
Initial available bands: 40, 30, 20, 15 (probably will add 80 and 17 if there is demand)
ATmega328P microcontroller with built-in keyer and straight key mode, audio frequency annunciation, RIT/XIT, voltage supply readout, breakout headers to UART, I2C, ADC, GPS port for WSPR transmission (and hopefully APRS over PSK63)
TX output power: 3 W
RX current: ~40 mA
TX current (13.7 VDC, 3 W): ~370 mA
MDS: -125 dBm
IF rejection: 86 dB
Image rejection: 95 dB
Two-tone, 3rd order IMD dynamic range: 75 dB
PCB dimensions: 70 x 99 mm
Custom matching aluminum enclosure measuring 70 x 100 x 25 mm will be included
Yes, a belated Happy New Year greetings! It's hard to believe that 2013 is already well under way. I figured it was about time to give you a quick update on what's going on in the shack right now.
First up is the discrete component grabber receiver for 14.141 MHz that I prototyped to be paired with the OpenBeaconMini project. The receiver itself consists of a roughly 2 kHz wide crystal filter on the front end, feeding into a single-balanced diode ring mixer, which drives an AF amp using 2N4401 and 2N4403 transistors. Because I'm not able to put up a proper outdoor antenna for the grabber right now, I decided to put the VE7BPO cascode active antenna on it instead. It seems to work well, but I don't know for sure because there are basically no signals on this part of the band. I intended to use my Raspberry Pi with the receiver as a grabber, but I had no luck getting either LOPORA or QRSSVD to work properly and reliably. It may just be asking too much of the poor beast. So I'm going to try to appropriate another PC in order to get the grabber receiver QRV so that on-air testing of OpenBeaconMini can begin in earnest.
Next, I wanted to give you a very brief overview of my most recent purchase for the lab: a Rigol DS1022U arbitrary waveform generator. As far as I can tell, this appears to be pretty much the same as the DS1022A model that is sold in the US. But being a typical ham, I wanted to save a few dollars, so I purchased it off of eBay from seller who says he is an authorized Rigol dealer.
The DG1022[U|A] has two channels that can output a sine wave up to 25 MHz in 1 mHz (as in millihertz) steps. It can also provide square, ramp, pulse, noise, and arbitrary waveforms at lesser frequencies. It can modulate the waveform in a variety of ways, including AM, FM, PM, PWM, and FSK. It can, of course, also do sweeps of various parameters. The output amplitude into 50 Ω ranges from 10 Vpp on Channel 1 or 3 Vpp on Channel 2 down to 2 mVpp on both channels (or -50 dBm). The shielding on this AWG seems to be excellent. Using my HP 355C/355D attenuator combo, I can get a signal down to about -140 dBm (disclaimer: not a scientific measurement, made using my ear as a detector and listening on my IC-718). The dual outputs makes it very useful for a variety of two-tone receiver measurements, one of the big reasons driving my purchase. The Channel 2 output also doubles as a 200 MHz frequency counter input. Paired with the USB connectivity of the device (it seems to enumerate as a usbtmc device), that will be extremely handy for measuring oscillator drift. The DG1022 can also link the two channels together and give them a specific phase difference, as you can see below. This will make it very handy as a I/Q LO when I want to experiment with phasing and SDR rigs.
So far, I've been very pleased with my purchase. I don't feel like I've had it or used it long enough to give you a full review, but I thought that this preview would at least be a bit helpful for those thinking about using it. One of my goals for the new year is to do a much better job of characterizing everything that I build. Since I intend to start selling transceivers in the near future, it's doubly-important that I can make accurate measurements of my products so that I can properly state their specifications. To this end, I've decided to sell off a bunch of my unused or replaceable test equipment (please take a look at the for sale posting) in order to finance the new, calibrated test gear. Next up on my purchase list is a Rigol DSA815TG spectrum analyzer (just reviewed favorably in the February 2013 QST), but that's going to require the sale of everything on that page!
Finally, I've got the CC1 prototype PCBs on their way from Seeed Studio right now. It looks like they just cleared customs in the US, so hopefully they will be in my hands in the next few days. With any luck, I'll have the first one built by the weekend and will be well on the way to a new beta test. I'll put up a quick post to show off the PCBs, and when the first prototype unit is completed. Stay tuned!