Showing posts from September, 2020

New Technology for 2020 ~ You almost can't keep up and here is #48 with #49 and #50 not far behind.

#48 is Finished --- #49 in Work. October 3, 2020 ~  uSDX NOW Working! This morning I touched up the solder joints on the encoder and the switches. Boom now working on receive! BUT THIS IS WHERE I WAS LATE YESTERDAY. Still food for thought about the encoder, switches and display... I received the missing parts installed same including the new firmware and #49 is best described as a crystal set with only 5 feet of wire attached! I have three ATMEGA 328 microcontrollers that have the very latest firmware installed and the condition is exactly the same with any of the controllers in the radio. I do get some of the functionality so I know the code has been loaded on the 328's. My belief is that there is a hardware issue other than the 328 quite possibly in the encoder and the push button switches. Here is the issue --the radio does not respond to the command inputs. This is a menu operated radio and it is difficult to get the radio to respond to command inputs. There have been some guid

New Technology for 2020 ~ A Return To Crystal Sets...

 Crystal Sets, Is That What You Said? In the 1950's living outside of Pittsburgh I was fortunate to have some very high powered AM radio stations close by namely KDKA. This early pioneering radio station had a 50KW transmitter and was "Clear Channel". Bottom line a simple crystal set with a modest antenna could hear KDKA. I had a crystal set and an exposed bed spring antenna provided many hours of enjoyment. No Crystal set was complete without a pair of Brush headphones. I am a side sleeper and to this day one of my ears (the one one the side facing down)  is slightly bent from an earphone constantly pressing on that  ear. It was an an amazing time for me as I did not have a kit crystal set but one that I actually homebrewed myself. So it is today that there are many new radios, totally driven by technology, that are like those crystal sets of old.  Sparse on hardware but driven by software. There is a "hot on fire" new SDR radio that is enjoying viral trending

New Technology for 2020 ~ Moving beyond the MC1496 Direct Conversion Receiver

  The MC1496 SSB Transceiver ~ #47 9/21/2020 Added Schematics and Layouts I had 40673's! This shows J310's as a substitute It all started with SolderSmoke Podcast #224 and the comment from N2CQR about a transceiver project from Paul, VK3HN. It seems Paul found an assembly at a Radio Rally (hamfest) that was a project in SSDRA pp203-205. This assembly was an IF amp stage (2 X 40673 and Crystal Filter) and a Transmit mixer Stage comprised of the Motorola MC1496 DBM. VK3HN took that assembly and added bits and pieces to create a Four Band Transceiver he called The Prowler. I was intrigued by that project and started small with a Direct Conversion Receiver using the MC1496. My effort called The Cat-Around (like a left coast Prowler) was but a stepping stone to a full transceiver using the MC1496 in four key locations: The Receiver Mixer The Balanced Modulator The Transmit Mixer The Product Detector The Balanced Modulator and Product Detector circuits were a direct lift form the Mot

New Technology for 2020 ~ A FREE TKT ( Tribal Knowledge Tip)

  How to Handle More Than One Band! [ Arduino Code Snippet ADDED to this post ] So you have just homebrewed a new QRP transceiver and it doesn't matter if it is SSB or CW and as a bonus have included two bands. Now the problem how to switch all the needed circuits so that with a simple DPDT Toggle switch -- the magic happens! But let us back up in the sewer so we get the full aroma. Switching bands entails several actions including switching the LO range (I am presuming a digital LO) as well as the Band Pass and Low Pass Filters. One half of our DPDT can be dedicated to the Arduino Input for band change while the other half of the switch can "Power On" sets of relays to select the one of two bands. Above is a two band LPF with the yellow core being the 20 Meter Section and the red core the 40 Meter Section. The two black relays are SPDT. and the Yellow relay is a DPDT. By my wiring convention I made it so the NC contacts on the DPST are connected to the 40M Section and th