2018 ~ The Year of SSB Transceivers
Starting off on the Proper Course.
If one were to be driving from St Louis (Middle America) to New York (East Coast) you would not want to stock your favorite VW Micro bus with maps that only take you from St Louis to Los Angeles. Sure the road signage today is pretty decent but once you get off the well traveled road, a map is just the ticket.
There is a point to this (what seems obvious) in that when you start out on an electronics journey you need the right kind of "maps" which in this case means reference materials, tools, test equipment and a supply of parts. Yes it also helps if you have the knack. An inquiring mind is also on the list. For some this is a hill too far and thus they resort to complaining abut everything except that they did not properly prepare for the journey.
Today (as opposed to when I started my journey) there is a myriad of information and information sources available to us that is until Ajit Pai starts charging us to download from the internet. When I started we had the ARRL Handbook and a few monthly publications like QST and CQ. Typically those publications were at the local library and that was free. I can remember hand copying circuits from the latest QST as these were for reference and not for check out.
So what I am saying, with a bit of arrogance, I know how to build stuff because I did indeed collect reference materials, I did study how to use simulation programs and I did research how to effectively stock a junk box and over time acquired proper test equipment. I also have the knack and an inquiring mind.
I did not do this over night but it is a learning journey. There is a very sound reason to play Mr. Miyagi (like in the Karate Kid movie) and program an Arduino to on command "LED ON" LED OFF". But what may seem like a stupid exercise teaches you how to organize information and to use the hardware. True it was a steep step to learn how to control a Si5351 to provide LO and BFO frequencies -- but now I know how to do it. I even taught myself how to integrate a keypad to make band selections on a multi-band transceiver. But that did not happen in the space of an hour.
So stop complaining and "map out" your course. It also helps to start small (LED ON, LED OFF). Newcomers to homebrewing are successful because they did the research and learned the theory as a first step before even thinking about turning on a soldering iron.
March 5th, 1942 - March 5th, 2018
Happy Birthday US Navy SeaBees!
Some 76 years ago on this day, the US Navy officially formed the US Naval Construction Battalions commonly taking their name SeaBees from the initials "CB". Their accomplishments are legendary spanning the building of advanced air bases in the Pacific Islands of WWII to current day bases in places like Afghanistan and Iraq. Always known for their motto "Can Do" we proudly salute the men and women of the US Naval Construction Forces --SeaBees!
It is with pride that I served in MCB 10 (Mobile Construction Battalion 10) as well as the 30th and 31st Naval Construction Regiments. Go SeaBees!
Any SeaBees out there in radio land -- drop me a note at email@example.com?
Get off the couch and start a project!
Projects can vary in size and scope. But foremost a project should have some goals and a fundamental underlying principle is the learning journey. The sojourn may be to learn new software or working with new technology components. Or perhaps it may be the testing of a new concept. The following bit of information has many of these elements. But this is not a project for a beginner as it would require knowledge, experience, tools, test equipment and a large stock of parts. The only reason it is even being showcased -- to show the possibilities. For some you may just not connect with this discussion, so just stay on the couch!
I would like to start by sharing an update on the 40 Meter Driver stage which is now become a part of a new transceiver for 2018. Mind you my garage lab/shack is still cold but this effort started before we had the cold spell.
Let me highlight the basics of this transceiver. There are no schematics and for the most part this exercise was a proof of concept.
- Starting with the three German Crystal Filter board available from eBay (Israeli supplier) I built an IF strip that uses the 9 MHz Upper and Lower Sideband filters. These filters are diode steered based on USB/LSB selection via a simple toggle switch. Ahead and following the filters are the Plessey designed 2N3904/2N3906 bilateral amp stages. Ahead and following the IF amplifiers are ADE-1 Double Balanced Mixers. Two DC signals are applied to this board with the first to accomplish USB/LSB selection and the second DC signal selects the direction of the signals (left to right or right to left).
- An Arduino Nano and Si5351 supply the LO and BFO signals which are fed to the ADE-1's. In this configuration there is no rerouting of LO and BFO signals as the 1st ADE-1 is both the receiver mixer and transmit mixer. In the case of the second ADE-1, it is the product detector on receive and balanced modulator on transmit.
- From the second ADE-1 a single shielded audio cable goes to a small module board that contains the microphone amp and the audio amp. The output of the microphone amp is paralleled with the input to the audio amp. Capacitors provide isolation and these two circuits are only powered on depending on whether it is receive (audio amp powered on) or transmit (microphone amp powered on). The Microphone amp is a single 2N3904 and the audio amp is a 2N3904 driving an LM380N. The circuit board that houses both circuits is less than 2 inches on a side!
- The previously described circuits (less the microphone amp & audio amp & Arduino) are on a PC Board that 4 X 6 inches. A second 4X6 board houses the 40M driver stage now embellished with 5 relays and the audio amp/microphone amp module. These two boards, stacked on top of each other are 80% of the transceiver. To these boards I hay wired in a small IRF510 amp board that was floating around one of the junk boxes and we now have a 5 watt 40M SSB transceiver.
- In one of the recent posts I proffered the possibility of relay switching elements of the driver stage so that it could be both used on transmit and received. That has been proven to work! So what we have now is a complete transceiver where the BFO is at a common frequency and the selection of USB or LSB is done by signal steering of the appropriate filter. This is the 2nd time I have done this and it follows what is done in commercial equipment as well as R L Drake in the TR -3 and TR-4 series of transceivers. Flip a switch and the TFT display tells you what sideband and the proper filter is switched into the circuit. Today's technology has really leveraged our ability to home construct rigs.
|40 Meter Driver Board before Modification|
To those who have suggested I write and share information in a convoluted fashion -- you'll just have to try and keep up.
There are no schematics and if you want other details send me an email to the QRZ.com address. This was a successful proof of concept and a learning journey. A lot of tribal knowledge was required to build this rig that simply can't be spewed out on a blog. I also have a very large junk box!