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“I have mentioned to Bill and Oliver that I would like to see a small PCB hold the 4 connectors (mic, PTT, headphones, and key) just because the current direct wiring makes the front look like a rat's nest. It's purely aesthetics for me and something most people will never see. “ I’ve been working on this for a while but have tied it to an overall audio system. Here’s what I have on the list (Comments welcome): For AUDIO OUTPUT: Stereo output for RX1 and RX2. Separate Line output with variable gain (TDA1308, TDA7050, TDA7313) Separate Headphone output variable gain/ headphone amp (LM4811, TPA6120, TDA7050, TDA7313). Speaker output with on-off and variable gain. 3+W amp for speaker output (TDA2030, LM4950). For AUDIO OUTPUT: 2x MIC input (front and back panel (TDA7309) Line Input (TDA7309) Connection boards: FRONT and BACK: Front: i. AUDIO: Mic, PTT in, Phones, ii. Key? iii. On/off Back: i. AUDIO: Mic, Line in, Line out, speaker (internal). ii. Key iii. PTT IN iv. KEY OUT (from LPF) v. ACC Connector (BAND0-BAND3 from LPF Inverted). vi. USB2 vii. RS232 This is all sitting in a box here waiting to proto it up and try. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email: bill@...

Like Oliver on the Software side, I have graciously been handed the hardware side of the T41 development moving forward. (Just my take with this next statement) The software side is easier to experiment with… basically because its easier to “roll it back” if the experiment fails. To that end it requires more discussion and engineering calculation on the hardware side to make measurable steps forward. I do have a stable of engineers that work for me… but they are not here to work on the T41 project (unless they do it off-hours). To that end, I will start permanent “hashtag” sub-groups in the AmateurRadioBuilders when there is a growing interest in any aspect of the T41 hardware to address and discuss. There will be some changes to the building process tools I want to announce today. I will begin to stock solder masks shortly… something I have not done in the past. I originally considered stocking solder masks and “renting them out” for reuse. But after understanding that the SHIPPING for return would cost about the same as purchasing a mask outright… I will simply sell them outright. Then you can share them on a local/ club level. I’ve shipped about 50 of the display driver hardware devices. I have about 150 more in stock and then I will restock. Eventually, this hardware can be moved to the main board if there is an update. Remember, there is a difference between the T41 hardware and my K9HZ, and the K9HZ/KI3P hardware projects that we may or may not allow group think due to the fact that there may be external requirements that you are not aware of (e.g. the 100W PA module, the VHF/UHF Module, ETC.). Here are a few hardware things I am thinking about for the existing T41 boards. If we update the main board to a 12.7 at some point, I think we should consider placing the hardware from the audio hat directly on the main board. I would also put the SPI display driver on the board… a pair of ultra-low noise references for the A/D and D/A as needed, and possibly update the linear regulators with ultra noise LT3045 (etc.) devices. Maybe splitting the A/Ds and D/As to a separate card… off the Main board may facilitate more experimentation at that level too… making it easier to change. All of these are small changes… but if you are an experimenter, it might be up your alley. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email: bill@...

Hey for those that want boards, I’ll be in town for about 5 days so now it the time to order… ALSO I’d like to get a couple of these display driver boards into peoples hands (yes, build and free) to see if they work. Everyone of my 4 radios is in a different state and I don’t really have the freeze-up issue… but I do want to fix it permanently. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email: bill@...

Hey 'yall, I'm still working off a 2' wip in the basement, so not the best environment. Lots of noise on 20M but still picking up 4's and 5's !!! Anyhow, I may misunderstand what the book (3rd ed) is saying but when I adjust the noise floor, the spectrum goes UP and the waterfall colors get more out of wack (my opinion). I mod'ed the code to allow the Noise Floor to go negative and it does what I was hoping/expecting/understanding. Is there something here I don't understand? Do I misunderstand what the book is saying? I'm running the latest 66.9, v12. I'm still working my noise problems. Thanks Mark KU3O

Just wanted to let everyone know that Amazon is NOT shipping the latest 3rd Edition of the book, at I didn't receive one. Maybe they are trying to get rid on the 'old' Third Edition copies first? Duane - K5CA

I am running the latest SW ver66.9, downloaded today. I am use the analog SWR circuits. I have good FWD-V (~1.5V) and REV-V (0.005) into the dummy load and REV-V varies as load resistance varies. In the Cal screen, Power and SWR measure "inf" and "nan". Nothing changes them. And, where should the pots, RV19 and RV27, be set? Thanks for the help. dave, n3ds

I am getting about 50mv noise out of the 20W amp in SSB with PTT engaged; no mic plugged in. I'm running version 66.9 and am all calibrated. Additionally, when PTT is engaged there is a burst of signal (about500mv) that exponentially decays in 5ms. The audio sounds pretty rough on my other radio, but wonder if that is because of such close proximity. Amplitude is affected by MIC GAIN. Any thoughts? dave, n3ds

Love this new format! Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton - J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com email: bill@...

I have Dr. Bills PA and a similar (same finals) from 60dbm shop. Both on 13V same 0dB sweep from SA. I attached the 60dBm Schematic for reference. Here is Dr. Bills with 0dB in His with -10dB in, 60dbm shop amp 0dBin

The subject of problems with the SPI interface between the T4.x & RA8875 displays comes up quite often on the Teensy forum. I would like to point out that the SPI interface is not anything that PJRC has much control over (it's baked into the processor that NXP created). I'm not defending PJRC, just suggesting that any angst should almost certainly be directed to NXP rather than PJRC. I personally am using an RA8875 display from buydisplay.com in my TeensyMIDIPolySynth (TMPS) project, & my experience with incorporating this display included some significant challenges. I initially wire-wrapped a prototype of my TMPS & everything worked like a champ. When I took the design to PCB, I transitioned through multiple (very expensive, with the PCB being 5.5" x 8.5" !!) versions of the PCB (with additional decoupling caps, with additional ground plane, with no ground plane, with two ground planes sandwiching everything else & a very large number of thru-vias stitching them closely together, with shorter SPI signal traces, with orthagonal SPI signal traces, etc.). I was very frustrated until I found a few posts on the Teensy forum suggesting placing small value resistors (50-100ohm) inline with some of the SPI signals. So, I cut traces on one of my non-working PCBs & patched in some resistors. Doing so actually resolved my specific display problems. I determined (thru experimentation & by observing the signals on my o-scope) that 100ohm resistors resulted in the cleanest SPI signals for my particular setup, so that's what the final PCB version for my TMPS successfully includes. I am using the SPI interface connected to the RA8875 display at native speeds, with no software slowdown. I have not had any RA8875 display problems of any kind since. To me, this is very counter-intuitive: how could a very sloppy wire-wrapped board work just fine, but a very clean looking PCB not allow the display to work ?? Signal ringing & signal cross-talk were the major contributors to my display failures. I know that there's some controversy with this "solution" of using inline small value resistors, but, for reference, here's a very recent Teensy forum post that visually shows the difference in the quality of the SPI signals before & after the use of inline small value resistors: https://forum.pjrc.com/index.php?threads/ra8875-teensy-4-1-again.76621/post-356579 For comparison, I'd be interested in testing one of my non-working TMPS PCBs with the K9HZ buffer chip, if that's still an available option. Mark J Culross KD5RXT P.S. As a side note (since the subject of using serial interconnects between processors has also recently been discussed), my TMPS makes use of two Teensy boards: T4.1 runs the display & manages traditional 5-pin DIN serial MIDI, USBmidi, & USBhostMIDI, while a T4.0 manages all of the audio thru a Teensy Audio Adapter. The two Teensy boards communicate over a shared 500Kbps serial port (settings flow T4.1-to-T4.0, audio/performance status flows T4.0-to-T4.1, & debug info flows both ways). The device is a 3-voice, multi-waveform, multi-modulator (selectable FM & PM), 12-poly synth, with filtering & envelope control of all generators, where all of the controls are digitally displayed as buttons & sliders on the RA8875 display, switching between & among multiple menu screens, & everything can be adjusted in real time with no degradation of the resulting sound while it is being generated, & no induced delays in the MIDI response. I am continually impressed with what a beast the T4.x actually is. MJC

I’m back for a while and working on kits again. I put a very high priority on the new Display Driver board that fixes the T41 display freeze issue and allows a nice long cable to the display. I offer a 3.3V ONLY kit and a 3.3V and 5V kit (until I run out of 3.3V kits… then I will only stock the combo 3.3V and 5V kit). I’m still writing the assembly manual for the display kits but it should be done by this afternoon. I will order the last few parts for them today… I should have them by Tuesday and will begin shipping them then. Also new to the list is the 20W Dummy Load/ 40 db attenuator tap for the calibration steps. I’ve attached the full list so you can look it over if you need something. Those boards and Kits with $0.00 are not in stock. Remember, don’t send me money, I’ll invoice you… and make SURE you include your address. All prices below are without shipping, taxes, and Paypal fee. I will be at FDIM Thursday night… and have a booth at Hamvention (Booth 4111 in Building 4) where we will have a special guest… Al Peter to show off the T41 and answer any questions. I will be selling boards and kits both places and you won’t have to pay shipping on them if you carry them away. Respond via my private email bill@... as to not clog the space here with our transactions. Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email: bill@...