Pay More and Get Less. Flash the Cash!

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...

The issue of the extraneous signal coming from the MHST has reached the point where it is time for a break from this project. NOODLING will afford me the time to think more about the causal factors. It just does not make sense and obviously I must be missing something. I broke out another HB SDR which has an almost identical main board but does not have the extraneous signal issues. But this board uses the Softrock package in QUISK and not the VWS. I also hooked it up to a 0.11KW amp, the AN 762 from CCI. In the afternoon it was like shooting fish in the barrel and great signal reports. 5W HB 20M SDR Transceiver HB 20M SDR with an external AN762 Amp I might even resort to cutting a new mainboard on the CNC and using all new parts -- it is a drastic move, but nothing so far has fixed the issue. RIP Pope Francis and we are saddened at your passing. The current Washington crowd must be sad too --- out of the news cycle for at least a week. But then again, a simple solution:  Manufactu...

Religious beliefs aside it is a great day for Chocolate lovers and a great time for being with family. I have many fond memories of my four kids especially ones associated with holidays.  My eldest son now 56 when at about age 7 one Easter Sunday came screaming into the house and I was trying hard to decipher the problem. It seems like he ate too many jellybeans at one time and his teeth were stuck together. My mind quickly turned to the soldering iron or a very large screwdriver. But then reason took over and the most important thing was to have him calm down. In time the salvia melted the jellybeans, and he was good to go. The things as parents we see, makes you go bald. I was sent the above video by my #3 son, and it is worth watching at least two times. As I watched the video, my thoughts turned to 50% of our population who are cheering the actions of those in control. All that whacking is hiding the actual processes of cleanup. With certainty they have no clue of those process...

But 1st, the MHST had its first 40M QSO yesterday with a check in to the Jefferson Noontime Net. The temptation was too great and that weird in band signal is not totally gone -- but the MHST does work and now a real incentive to get it working 100%. But the real news of the day which I proudly present forthwith is the "Mouse Tuning Knob". I have wanted this capability for a long time on my SDR Rigs and arising from the depths of the Silicon Forest is the Mouse Tuning Knob. This is a real boon for those of us with Fat Fingers and whose eye hand coordination may be on a downhill slide. Some detractors of SDR complain about the lack of knobs, especially a Tuning Knob. Complain no more!  This is so cool and a real aid to those of us with FFS. The Mouse Tuning Knob is revealed. I am just an Alpha Tester and had no involvement in its development, but this is one sweet tool. Sign up for Todd's newsletter at his website. https://www.mostlydiyrf.com as the product release will b...

If one constantly repeats the same test repeatedly without changing a thing, then why would you expect a different result each time you run the test? I have another homebrew SDR transceiver that closely resembles the MSHT. It too uses QUISK and an identical mainboard. The same Driver, and Final and a steerable single BJT amp. The single difference is this one uses the SDR LLC interface while the MHST uses the Pi Pico. The actual QUISK rig selection for the Pi Pico is the VWS Package and for this one it uses the Soft Rock USB.  The Pi Pico uses the Si5351 and the SDR LLC the Si570. The Pi Pico turns out a quadrature LO at frequency directly and the SDR LLC is at 4X and run through a 74C74 D Flip Flop which results in a 1X Quadrature signal stream. SDR Using the SDR LLC Controller and Soft Rock Package   Yesterday was spent comparing the two rigs, The SDR LLC does not have that nasty signal that exits with the Pi Pico. The SDR LLC produces a single transmitted output at the corr...

I wish I could report I made two hundred 40M contacts on the MHST including DX to Western Samoa, but alas that is not the case. The issue is the transmitted signal and not receive.  While I can abate the spurs and image signals using the QUISK tool, one additional frequency is getting transmitted. It is stronger than the operating frequency, of the opposite sideband and is not touched by the QUISK controls. I can even see it on the Half Moon Bay SDR site which is 300 miles from here.  Thus, the transmitter remains a problem for me.  I need to do a bit of research and see if any other homebrewers have seen this effect.  Them that know can make it go. 73's Pete N6QW

If you are just now wading through the shoe box of receipts to prepare your 2024 Income tax, this might be a tough day. Elon has you in his sights for waste fraud and abuse. Certainly, no pressure on you. I once was audited in the 1970's and spent a whole day with an IRS agent who you could tell had one goal -- find a problem and make her day. That year I must have fit the profile of those they wanted to investigate. At the end of the day, she said I didn't like the way you handled some expenses associated with a piece of rental property I owned.  After pounding away on her calculator, she said you owe $100 in back taxes. I sat there astonished! I had to take a day off of work and certainly the 8 hours she spent trying to nail me was more costly than $100 she was about to recover. Then in a piece of coordination I have never seen before, 3 days later I got a Bill from the State of California for $21 in back taxes. Here is an example of what she went after. I claimed $56 in tele...

A bit of progress yesterday as we found a wrong connection on the Receiver path which was a result of when I added the IRF510, the right wire was in the wrong pace. With that fixed we will look to see if we can make some on the air contacts. The Pout as I predicted is 4 watts.  IRF510 Final Amp/LPF IRF510 & 2N2219A Driver Steered Amp, 2N2219A & IRF510/LPF We are getting closer to our goal of a minimalist SDR transceiver run off of a Raspberry Pi5 SBC. As can be seen in the photo above -- not a lot of components. If this could be done all in SMD then a very small footprint. But even with Manhattan style not that big. Them that know can make it go.  If you have a tax refund coming, it will probably have to be reviewed by Teflon Elon before they cut you a check.  More on proving who you are. The Voter ID project will most likely require a separate Voter ID Card if you don't have a Passport or Real ID. So, you best get some certified copies of your birth certificate a...

 So, you got caught up thinking hey I could build a SSB Jr. Well, pilgrim think twice as the trick pony is the phase shift network. Back in the day you could just buy one from Barker and Williamson the Model 350 known as the type 2Q4. They can be found on eBay but hold on to your butt -- this one cost $100. You would be better served by researching the work of Rick Campbell, KK7B who designed the R2 and T2 which are phasing type receiver and transmitter boards. Campbell used operational amplifiers coupled with precision capacitors and resistors in his design. Components to build a complete rig based on his design can be had for the cost of the 2Q4. When it rains it pours. I did build the IRF510 RF Linear amp and as I predicted about 4 watts to a dummy load. That said there is now some sort of anomaly on the receive side -- a perfect definition of SNAFU. Well, it does keep me out of the bars and/or getting into all sorts of trouble. I am attending a Grief Group and the group leader ...

History is a marvelous teacher which a large segment of our society recently ignored, and we have the chaos we have today. As my mom used to say: "a leopard doesn't change his spots".  So, it is with ham radio as historical events serve us well as we try to troubleshoot our rigs. Early SSB transmitters did not use crystal filters and our amazing SDR rigs today are direct descendants of those efforts using phasing techniques. The W2EWL converted ARC-5 SSB mobile rig and the SSB Jr. from the GE Ham News are the history. The SSB Jr. used three tubes less the RF drive coming from either a Crystal Oscillator or VFO. Before you hit the send button yes, the "IMP" from Joe, W4IMP   was also a three-tube circuit and later converted to solid state. Basically 1/2 of a 12AU7 is a Microphone amp which passes audio through an RC Phase Shift Network to create an I and Q signal streams and then amplified by two sections of the 12AT7. The 2nd half of the 12AU7 (the other half of...

Power Output from an IRF510 Final Amplifier Stage is like predicted gas milage of your conventional car or for those of you who still own a Tesla -- the range of travel on a single charge. (There is still time to dump your M3.) But 1st a short observation from the parking lot of my local Albertson's. I drive a 20-year-old car whose EOL may be rapidly approaching. While my XYL was with us, a huge part of my savings and income went to her care. I did not mind that in the least. Simply stated: It was a part of the original deal. Thus, I tuned out any thoughts of new cars and the new-fangled features. Back to the parking lot. Opposite to me as I pulled into the parking slot was a rather large Tesla, black in color and had fully tinted windows. This car arrived at about the same time mine did. Then as if by magic the rear door opened upwards like a gull wing. It was like a symphony of motion.  The driver alighted first, a small, attractive, well-dressed Asian woman who quickly moved to ...

  Them That Know Can Make It Go! MHST 2N2219A Driver! Our next phase will be the Final Amp using the IRF510. I expect about 3 or so watts on 40M. 73's Pete N6QW

Just as many homebrewers rely on Bitx circuits for use in their rigs, I like to use and reuse stuff I have designed. The MHST Driver stage is straight out of the P3ST Project. A quick hookup to the steerable amp produced 12 Volts PTP. A power calculation results in 12^2 = 144 and that value times 2.5 = 360 milliwatts. So, OK if you can only think the old way. The 12 Volts must be divided by 2 for the Peak Value or 6. That must be multiplied by .707 to yield 4.242 Volts RMS. Next, you square that and divide by 50 (Ohms) to yield 0.35989128 watts. Or 359.89128 milliwatts. Duh, you really want to do all that or just square the PTP and multiply by 2.5. Compact Driver Stage for the MHST MHST Driver Stage Schematic Tomorrow I will post a video of the output with the Driver stage. You ask about the Real ID adventure with the California DMV -- A TOTAL BUST! Despite having an appointment, I waited in the cattle line for 1 hour just to get inside the door and then another half hour  to ...

After much gnashing, wailing and grinding of teeth, the main board of the MHST is sufficiently along to proceed with the remaining boards for the 40M MHST. With about 3.6 milliwatts coming out of the mainboard steerable amp (1.2 Volts PTP) we need several boards to boost that output to > 300 Milliwatts to drive the IRF510. Below is a short video of how the output looks on 40M from the mainboard. I have built several homebrew SDR transceivers over the last 5 years, but the challenges of this particular rig have really been a learning experience for me. Hopefully others will build along and gain that same experience.  Before getting too excited bear in mind this is a minimalist SDR and translating this design to higher bands will entail additional amplification stages. It is not a matter of simply changing out the BPF and LPF and you get several watts on 10M. The higher bands will need more intermediate stages of amplification. Them that know can make it go. Wish me luck today wit...

After waiting nearly, a month for an appointment, last Friday was the date to visit the US Passport Office in Los Olivos California. In my earlier quest to find a place to apply for a new passport this was the closest place I could find that had actual appointments open on a schedule. Prior to the visit, I had prepared all of the paperwork and had all of the required documents including the confirmation appointment document and two checks. The next question was: Where in the hell is Los Olivos? Google Maps said 85 miles away. I started my journey at 6AM as there is always highway construction and I was totally unfamiliar with the area. Santa Barbara is but 42 miles north of me using the Highway 101 Freeway. After passing through Santa Barbara, you take exit 101B on to Highway 154 and 43 miles later you are in Los Olivos. Near Santa Barbara there was road construction and slow traffic. Lest we also forget morning rush hour. It was like a trip to wonderland once on the Hwy 154. It was ve...