What are you thinking — I am not trying to break any world record? My XYL asked me that question today — why are you building another rig? Followed up by a snide comment that I had so many rigs now why do I need another one. Well the answer plain and simple because I can!
For the longest time in the late 60’s early 70’s my success rate with homebrew SSB transceivers was miserable. At that time I lacked the more sophisticated test gear and let’s face it some of the technology wasn’t that great. Crappy Analog VFO’s were high on the list of impediments! I also had to work and to give a fair share of my time to the family — it is that balance thing.
But today that is all changed –better test gear, better technology like Digital VFO’s and a bit more time. The latest project is to demonstrate that some of the components out of boat anchors can indeed be reworked to provide a very modern, very capable rig.
Version 2 — What is it? V2.0 is the Simpleceiver Plus SSB Transceiver Architecture with the following changes:
A GRQP Club 9.0 MHz Crystal Filter is used in place of the homebrew 12.096 Four Pole Filter. This gives the advantage of acquiring the matching crystals for the BFO and with a 5 MHz Analog VFO you can have a two band rig (20 meters or 80 Meters). The only change required is the appropriate matching Band Pass and Low Pass Filters. A couple of relays and a toggle switch will put you on either band. So a big plus here. Or you can leave it on 40 Meters.
Compacting the rig in physical size. I have used two 4 X 6 inch PC Board and fit all of the circuitry on these two boards which will then be stacked upon each other.
In 2011 I fulfilled a dream of building a shirt pocket sized QRP SSB transceiver. Well actually I built two of them and the second was a diminutive 2″ X 4″ X 2″. Both used through hole components –so no cheating with SMD. In each case the IF was 4.0152 MHz and employed a crystal switched VXO that essentially gave about 100 kHz on 20M SSB. But it was a VXO and there was not full band coverage. But nevertheless a small miracle (or so I thought) that they both worked! You can see the two versions blow.
But with new technology now available to us my next goal is to fit the larger rig with the Si5351 and an OLED display. Today I made that happen!
If you buy an amateur transceiver cheap enough to make a reasonable grab bag gift or stocking stuffer, you get what you pay for. And if this extensive analysis of cheap radios is any indication, you get a little more than you pay for in the spurious emissions department.
Amateur radio in the United States is regulated by the FCC’s Part 97 rules with special attention given to transmitter technical specifications in Subpart D. Spurious emissions need to be well below the mean power of the fundamental frequency of the transmitter, and [Megas3300] suspected that the readily available Baofeng UV-5RA dual-band transceiver was a little off spec. He put the $20 radio through a battery of tests using equipment that easily cost two orders of magnitude more than the test subject. Power output was verified with a wattmeter, proper attenuators were selected, and the output signal scanned with a spectrum analyzer. Careful measurements showed that some or all of the Baofeng’s harmonics were well above the FCC limits. [Megas3300] tested a few other radios that turned out to be mostly compliant, but however it all turned out, the test procedure is well documented and informative, and well worth a look.
The intended market for these radios is more the unlicensed crowd than the compliant ham, so it’s not surprising that they’d be out of spec. A ham might want to bring these rigs back into compliance with a low pass filter, for which purpose the RF Biscuit might prove useful.
There was a time when the idea of building your own single-sideband transceiver was too daunting for all but the most hardcore of amateur radio constructors. After all the process of creating SSB is complex enough in itself without adding the extra complexity of a receiver and the associated switching circuitry.
In 2003 an Indian radio amateur, [Ashhar Farhan], [VU2ESE] changed all that. His BitX SSB transceiver used a bidirectional amplifier design and readily available components such that it could be built by almost anyone using dead bug construction techniques for an extremely reasonable price.
Over the years since [Ashhar] first published his circuit, his design has been taken and enhanced, been presented in kit form, and extended to other bands by multiple other radio amateurs. Until now though it seems as though he himself has taken very little advantage of his work.
It is therefore with great interest that we note a new 40-meter BitX transceiver on the market from a company founded by the man himself. The transceiver itself is an Indian-assembled PCB with an updated circuit using a 12 MHz IF, varicap tuning, and large surface-mount components for easy modification. Just as with the original circuit, there is a full technical run-down of its operation should you wish to build one yourself. For a rather impressive $45 though you might wish to put down the soldering iron, it looks very much worth the wait for international postage.
We don’t often feature commercial product launches here on Hackaday, though we are besieged by people trying to persuade us to do so. So why this one? When the creator of a design that has been as significant as the BitX has been to its community of builders releases a new version it is newsworthy in itself, and if they are commercializing their work then they deserve that reward.
Today we complete most of the mechanical work and the only item remaining is the RC Filter to turn the Square Waves into Sine Waves for the tune signal. We have had it on the air in the current box as you always worry that even though it worked on the bench there is always a danger it won’t work in the box.
This rig has a lot of soul as some of the boards were used in the 30M CW transceiver and then moved over to the LBS on the bread board and now this radio. The main tuning knob was purchased in St Louis some 20 years ago and now is now controlling the encoder.
Just in case you are wondering this is not a BITX design but does use bilateral amplifiers originally designed by Plessey. The driver stage is from EMRFD and the intermediate bi-directional amp is my own design as is the 40M Band Pass Filter and the microphone amp. The Low Pass Filter is from W3NQN.