Left Coast Political Scene

This is real homebrew radio, and no kits involved here. You have to know stuff to pull this off! A huge tip of the cap to JF3HZB for a piece of superb engineering. This circular analog dial display has been around since 2019 (maybe earlier), but I am just getting to it! This somewhat adds a bit of soothing ointment to the sting of the MHST. This has got to be as Slick as Grace Slick! Sure, dresses up a homebrew radio. The display is an ILI9341.  In the software nulled out is the "LSB" which I changed and luckily it was written for 40M. I also limited the LO range, so it only tunes from 6.995 to 7.305 MHz, as this prevents out of band operation. I added my call sign to the front panel display.  Caveat Emptor -- not for 1st time Arduino users! Search for the software as it is on a Github and ESP Version 2.05 for the Board Manager Check You Tube for JF3HZB and other implementations of the dial. Them that know can make it go. A rookie mistake is to say, "I made no mistakes!...

Time to yell Uncle! The MHST has been relegated to the Shelf of Shame. After two months of toil, consternation, abject failure and losing some hair I am throwing in the towel. I must apologize as this could have been a pretty nifty project, but I have exhausted my tribal knowledge base and am just plain stumped as to what to try next. Maybe at some future time I will trip over some unrelated project that suddenly like a missive from the Oracle at Delphi reveals the root cause. It is likely some simple thing -- I just don't see it. Yesterday I fiddled and fooled with signal levels out of the I and Q channels as well as the quadrature LO level. This was to assure that each ADE-1 was not being overdriven which could result in spurs. All that did was reduce the amplitude of the spur (and the desired signal) but the spur always slightly stronger than the desired signal. Thusly the MHST joins a host of other failed projects with a prominent place on the Shelf of Shame. It was a hairbrain...

I covered this before but JIC (just in case). Inputting signals to your DSO and invoking X versus Y functionality you can derive a relationship between signals such as Phase difference. A 90-degree phase difference is critical in the SDR world.  The 1st line and middle set of three figures is where two signal inputs are shown for a square wave. The last figure in this middle set is for a 90-degree phase shift, our tilted square shown yesterday. The last figure in the first set of three is the circle which as we saw yesterday from the I and Q output of the sound card was not a perfect circle indicating not 90 degrees. These graphs have a technical name called Lissajous Figures (some suggest pronounced Leesa Juice) and are old school and approaching over 200 years old (circa 1815).   For those who served in the US Navy and had to do navigation, Nathan Bowditch is a name that invented those figures for navigation. I had to take a course in Navigation while a Midshipmen. I wa...

No cigars or celebrations just yet! But some data points to ponder. One input from a blog reader was that the LO quadrature signals were not quadrature, or 90 degrees out of phase.  Using the XY function on my Siglent scope if you have two sine waves exactly 90 degrees out of phase the resulting plot is a perfect circle. But the output from a Si5351 is more like a square wave and two square waves 90 degrees out of phase produce a tilted square. This is the XY Plot of CLK0 vs CLK2. The Tilted Square is indicative of a 90 Degree shift between CLK0 and CLK2. So, check that off the list. Another reader input was that the quadrature signals coming from the Sound Card on transmit was an issue. Below is a photo of the I and Q outputs from the Sound Card on transmit. There is slight difference in amplitude which I think can be corrected in the Pulse Sound App. But what I see is about a 90-degree shift and very good-looking waveforms. Amplitudes are Different but Correctable Pulse Audio Pan...

You smell a burnt resistor, you see a discolored resistor and you see no voltage on the other side of the resistor. You conclude it is a defective (smoked) resistor. But that is just one part of the issue and next question follows the "WHY" is it toast. Our burnt resistor is an easy problem to define as we have sensory tests to tell us exactly its condition: smelly, discolored and open. The Transmit issue with the MHST is similar but different in that it appears only on transmit, can be heard 300 miles away and is consistently linked to the actual desired transmit signal.  I think back to the early 1960's SBE-33 SSB Transceiver that had a receive "birdie" just above the high end of the 40M Band. The SBE Engineers never did fix it but instead highlighted its usefulness in determining the dial calibration. Quote: "If you hear this signal at the specified location, then your dial calibration was right on." We can't use that logic or excuse with the MH...

The Noodling Process is a deliberative approach to solve a problem involving a fault tree analysis. The old Italian Mechanic is merely describing a symptom when he says: "She don'ta work". That gives no clue to a solution or where to start. Thus job #1 is to describe the problem. But accurately formulating a problem statement is a result of gathering data and analyzing that data t0 arrive at something more substantive than the observation of our old Italian Mechanic. Our somewhat real-world crass analogy: It took some time to figure out that Mary Jo, our 300-pound close friend, had to have two Bob's Big Boy hamburgers first, before she could be enticed into the back seat of a 57VW Beetle.  Try to image 450 pounds of raging teenage hormones in the back seat of this 57VW. Scary? To formulate a real problem statement requires assembling known facts. * The mainboard with the ADE-1's is a known design and works with QUISK. Other rigs using this same board design + QUIS...