Photos of LBS Completed DC Receiver Projects
Dean AC9JQ sent along these photos of his completed LBS DC receiver as described in Part I. As we encourage all builders "this is a platform for experimentation". Dean has already added Band Pass Filters for 20 Meters and has chosen to use IC op amps for the the Audio and Microphone Amp stages. Our goal for the LBS was to use discrete components to make it easier to find parts and to keep it simple. Feel free to use what you like. But there is a caveat here -- if a builder uses something other than what is in the article and there are any issues, we simply do not have the time or resources to "chase down" what may be wrong. But that is also an opportunity for learning.
I am happy to report that Dean AC9JQ has completed the SSB Receiver portion of the transceiver and here is a video
Mikele 9A3XZ, sent along this photo of his build of the LBS and we wish to thank him for sharing his work. See and listen to the LBS from 9A3XZ
Jim, N0TKN sent us a photo of initial work he is doing with a "group build" of the LBS project. Here we see the use of the Nokia 5110 type display and it indeed looks great. Thanks Jim for sharing with us.
From Greg in Australia (Soon to be licensed and where he used the LBS Project to build his 1st receiver and as an aid in preparing for his radio license examination.)
Please find attached a photo of my receiver in its current state. Actually its a bit of a mockup as I'm about to tune the bandpass filter, so I'll be feeding the filter from the si5351 and logging the output levels with the arduino, but anyway.
From the bottom left going clockwise Its the Arduino Uno, then the rotary encoder (from an old car radio) and the si5351. Above that is my IO expander board, which isn't actually required for the project, then the DBM, bandpass filter and RF amplifier boards. The audio amp board is down at the bottom, along with the speaker I salvaged from a small bluetooth speaker. the small pot to the left is the gain control for that. I'll change the signal lines to coax as soon as I pick some up. Not shown is the LCD display, as I havn't hooked that up yet. That is one of today's projects.
I made PCBs for all the boards. The audio amp board was made using the toner transfer method, but I had problems getting a good transfer on the other boards due to the large ground plane area I had. I ended up using my CNC mill to route the boards, which turned out to be the easiest method for PCB manufacture. However, I'm certain it would have been much faster to use the Manhattan method with the pads. Making the bare PCBs took about 30 minutes for each one.
I also went with SMD components for the RF amplifier board and the IO expander. Soldering them by hand isn't hard, but I'd recommend making a jig that allows you to hold the components in place while you solder them. I use a bolt with the end ground down to a point. The bolt goes through a nut that is glued to a couple of right angle brackets that sit above the board. just turn it down gently onto the component and your hands are free to solder.
As I mentioned earlier it works!. My first ever reception of an amateur radio signal was with this setup just yesterday. For anybody not sure if they can do this - just try it. Winding the toroids is very easy, so don't stress about them like I did. Use the pad construction method and you'll be up and operating in no time.
73's Greg (Way Down Under)
Jim KG5DZC sent us some progress photos of his LBS Part I. Jim followed the recommended approach of using graph paper to layout the circuit and then made a grid on the Copper Board and only used the number of MePads to complete the build. Very nice build of the Audio Amp Stage and the Double Balanced Mixer,