Thursday, February 27, 2020

New Technology for 2020 ~ The Teensy 3.5 is back working (sort of)

The Aftermath of a Small Fire and Explosion!

 February 29, 2020 ~ Teensy 3.5 Update.

I have run a further test...

I am now convinced that the issue I am seeing with residue Sideband when going to USB lies with the Hilbert Transforms and the Audio Codec Board. Here was the test: I used the Teensy 3.5 to supply the LO signal to the RADIG V.3 but used an external sound card with my Linux Mint 64 computer running Quisk to see if the problem still existed. It did not. 

So the LO and RADIG Board are not the problem. One expert suggested there was an imbalance to the I and Q. If that were the case it would show up in Quisk. It did not and so I believe there is not an imbalance. I should note that is one of the reasons for the multiturn pots on the output of the 74AC74. I set those pots to less than 50 Ohms to ground before I even applied any signal to the ADE-1's. I also measured that the same LO signal level was present at the two ADE-1 LO Ports (Pin 6). So Imbalance was not an issue. 

Late Breaking News .. Problem may be solved!! 

I had nothing to do with the solution. I had some later code from Charlie (Nov 2019) and upon examination spotted he used 100 coefficients for the Hilbert transforms versus the 70 in the code I was using that dated back to two years ago. It was like turning on a light switch. I will make a video and share on this blog. Shift to USB and that is what you get! This is exciting!

Again all due credit to Charlie ZL2CTM.


Yesterday I uploaded a video of the latest Teensy 3.5  experimental SDR transceiver and that link is below. There have been some comments and rather than address the comments on the you tube page I will do it here.

The code I am using came from ZL2CTM and is perhaps behind in the improvements (read above it --not the latest) as it is likely over two years old.  Thus later code may actually have the issues I was seeing being resolved. (The later code does indeed.) Here are some key points:

  1. This is not a new issue as I saw the same thing with the RADIG #1 board over two years ago and that is what prompted me to switch over to using the Raspberry PI and ASUS Tinker Board
  2. The initial code used a LOW Pass Filter Hilbert Transform and previously I thought it should be a Band Pass Model. After sleeping on it that may be a fruitful experiment using the Iowa Hills Software to come up with a tighter (say 2.2 kHz) Band Pass model. The Quisk can go to 2.8 kHz but I always run it a 2.0 kHz.
  3. It was suggested that there may be an imbalance in the I and Q Detectors. I do not believe that is the case as this same RADIG Board is shown in a you tube video about two weeks ago with the ASUS Tinker Board and the external Si5351/Nano. If there was an imbalance it would have shown up on the Quisk Spectrum -- it is single signal reception so therefore the conclusion is that the RADIG Board is not the issue. 
  4. The RPi3 and the ASUS Tinker Board are full computers running quad cores at > 1.2 GHz so we must keep in mind that the Teensy 3.5 is a 120 MHz Microcontroller. I do not think we should set our expectations that they would perform exactly the same. The Teensy 3.5 is doing a creditable job; but may have some limitations in terms of horse power. The performance so far has to be in the class of amazing and has the possibility of further improvement. The Hilbert transforms look like the most likely area of improvement. (They are indeed as found out this afternoon.)  I do not think it is anything in the RADIG Hardware. Again Kudos to Charlie Morris ZL2CTM. 


 (We now have the right Teensy 3.5 loaded onto You Tube. Sorry for the confusion. Never name different videos by the same name. You will get wrapped up in your underwear. Neville sent me a question about the OLED and that is when I realized it was the wrong video with the right name.)

But first a PSA about the Coronavirus. There is no doubt it will hit here --- it is just a matter of time. 

So think hard about really taking that trip  you have booked to the Far East. Avoid crowds and have back up supplies like water, medications and surgical masks. Wash your hands often and no kissing of strangers. 

Now, some few Americans are very fortunate and perhaps have at their disposal "space suits' such as the one being modeled here. But few of us have the contacts to have such a suit.

The Coronavirus is so rampant that the emperor (with a very small e) has announced the designation of a Coronavirus Czar to oversee the response in the USA. In case you were not aware here is the person so designated.

Well I am not sure what you personally feel, but is this is the right "man" to lead this effort?


A special note here since I received some negative comments that I should not take credit as the originator of using the Teensy 3.5 as the heart of the SDR Transceiver. 

I do not believe that I have done that. True credit must go to Charlie Morris, ZL2CTM who shared his code and hardware information with me. 

However I did make some modifications to his original design to include the use of the ADE-1's and the addition of Modem Coupling Transformers to provide noise and ground isolation. Again, hats off to Charlie Morris ZL2CTM!

As I reported a couple of weeks ago the N6QW garage shack had a small explosion and fire a result of my misaligning the Teensy 3.5 in its socket which is actually affixed to the Codec board.

I had a spare Teensy 3.5; but I also suspected the Codec board possibly was damaged. So I changed out the Codec board and hooked up the RADIG V.3. I am now receiving signals albeit a few warts.

Teeny 3.5 & Codec Board

One item I have not resolved is that the opposite sideband can be faintly heard on receive. If you are listening to a very loud station on 7.195 MHz LSB and flip over to USB you can just faintly (and plainly) hear the same signal. While in USB, if you tune slightly lower in frequency you will hear the typical signal when the wrong sideband is being used. 

But at the dial location where you are copying the LSB signal but have USB selected, you can faintly hear the LSB signal. Why?

Now we talk about sideband suppression but I am not certain how much that is for this rig. In typical filter rigs it might be as much as 60 dB. 

In many SDR rigs/software there is a mechanism to reduce the effect of the opposite sideband. In Quisk you have capability to add a DC offset and reduce the amplitude -- for both transmit and receive. The Quisk functionality has a built in memory so it remembers that setting -- even when you change bands. I am unaware of the capability in the Teensy Code.

Now this might occur only on strong signals. My worry is if you are running 100 watts then the opposite sideband signal might be heard with measurable power, like perhaps as much as a 5 watt signal on the opposite sideband.

I just don't fully understand what I am hearing or if it is a real issue. More evaluation required. Many possibilities such as physical layout and signal bleed over or perhaps and imbalance of the signals being supplied to the ADE-1's. Other issues may be too wide of a digital filter. 

A lot more noodling is mandatory.


Pete N6QW

Friday, February 21, 2020

New Technology for 2020 ~ The Journey Continues

A 64 Bit Linux Mint Machine for $100.

February 25, 2020 ~ Washington, DC.

I was using WSPR this morning to do some testing and spotted a cluster of stations of where I thought our nation's capital was located (perhaps that is an ominous term and maybe should say is). Well Washington, DC to my surprise was not where I thought it was --it is more inland from the right coast than I imagined.

Then I discovered that you can zoom in using the WSPR map and many features suddenly came into view such as the National Mall and RFK stadium. But one really caught my eye. Boom we have an International Spy Museum. Wow; but it may not be long for existence as the emperor's (with a small e) vendetta with the "spooks" may be cause to close down such a facility.

Several years ago I saw the "traveling show" of this museum at the Regan Library. It was enlightening! 

One piece of spy stuff was really intriguing. Seems like one of our top diplomats in Europe ordered a pair of custom made Italian shoes. The delivery of the shoes seemed to take several weeks longer than expected. 

Upon arrival at the US Embassy the shoe box was opened and inspected -- I guess normal protocol. Something looked weird with the shoes as the soles seemed thicker than normal. Upon closer examination --the shoes had several micro-sized PC Boards embedded in the soles which were RF transmitters. It appears the Russians had the shoes diverted to Russia where the boards were installed in the shoes.

Now we have to wonder about the emperor's (with a small e) balls -- golf balls. Do they contain spy transmitters embedded in the balls?

You got to love all of this new technology --2020 is even better.

Pete N6QW

February 24, 2020 ~ More Fun!

This morning started before 0'dark 30 with Solder Smoke Podcast #218. Download this podcast from the blog site. Bill shared his experiences with the restoration of the S38-E receiver from hallicrafters. My view is ...

Great Fun. But today had a really nice QSO with a station near Sacramento, about 400 miles from me. The station there was trying to adjust his ICOM 7700 with a noise gate to eliminate any background noise.

I helped him make various adjustments by using the functionality built into the Quisk software. It has a voice recorder where I was able to record the various changes being made on the other end then with the over the air playback, he could hear the effects of the changes being made. All this with a less than $100 computer and some free software. I was running the Omnia (Peaberry V2) along with a 100 watt amp. 

He was most appreciative and I think all told with the computer, the amp and the Omnia. We are talking about $350. So You can have a competition grade station and it does not involve spending $10K.

Pete N6QW


February 22,2020 ~ 1st 60M Contact on the new Linux Mint 64 Bit Computer.

So it is one thing to listen to WSPR and make a few FT-8 contacts (which were done); but entirely something else to actually really talk to another ham in a real QSO. 

That happened last night on no less than 60M at a local time of 1715 (for those not used to military time that is 5:15 PM local). Two things were evident from that contact and those include that the Linux Mint 64 Bit Computer doing the heavy lifting  and  my Omnia SDR (Peaberry V2) on 60M. I was running 60 watts to my dipole. The Omnia is a four band QRP rig with 60 > 20 Meters and I was using an outboard amp to get me to 60 Watts. For an antenna I was using my 40M Dipole tuned up with my homebrew tuner.

But this was not just any contact --- it was a sort of DX contact with KE5ZR, Gene in Pampa, TX along with W6YLD, Bill, up in Santa Maria (about 90 miles from me). I think Gene said he had some sort of horizontal loop.

First some photos of my lash up...

Peaberry V2

Linux Mint 64 Bit with my webcam for Skyping

60M Channel 4


The "sleeper" here is that 60M was open and we were the only ones using Channel 4. The other fascinating point -- we were all running less than 100 watts of effective radiated power as required by the regulations.

The Radio Gods Have Spoken (TRGHS) as this was not my 1st contact with KE5ZR and I had a similar 40M contact with Gene using the RADIG V1 late last year and that was documented on a YouTube video which can be seen on the website.

Here we have another bit of new technology embedded into our ham rigs. Now that I have the Linux Mint 64 Bit working --- some new RADIG V3 hardware additions will be completed. So stay tuned to this channel!

Pete N6QW


The $75 Hewlett Packard machine from Amazon arrived and the day before that the 500 GB Western Digital refurbished SATA 3 arrived. The Hard Drive cost me $14 also on Amazon. So with taxes and shipping it cost me less than $100. The computer came with a keyboard and mouse.

My first act was to remove the 160GB SATA HD that came with the machine which was loaded with Windows 7 Professional. So that Drive may have other uses as a bonus. 

It is not difficult to load the Linux Mint onto the new machine. You need nothing more than a flash drive that has the Linux Mint 64 image stored on it. When the computer first boots up you hit F10 on the key board and that gives you access to the various boot methods. I selected the USB drive and Boom --20 minutes later I had Linux Mint 64 installed.

I was able to install the programs of most use to me like Qusik, Skype, WSJTX, LT Spice, the latest Arduino IDE -1.8.12. I even have the beta version of Teensyduino so I can load Teensy 4.0 using the Arduino IDE. This was all free and so my investment is relatively small.

The software installation is relatively easy using the built in tools. I have installed Cheese on this one too. Should confess one or two were a bit more difficult --- note I said relatively. So if you have a tax return coming to you -- this is a good place to spend $100.

Here is a shot of WSPR on 40 Meters earlier this morning.

Armed with this new Linux computer I hope to crank out a lot more stuff. Oh the latest LT Spice actually has new models added like the J310. So I will be using this Linux 64 Bit machine to do design work right at the workbench.

Pete N6QW

Friday, February 14, 2020

New Technology for 2020 ~ Linux Mint

Another OS to use with SDR Rigs.

Linux Mint

February 18,2020: 

Real Time Video Recording using the webcam and Linux Mint.

I have stated that 2020 will be the year of many technology implementations in our ham rigs. Already I can see where in just a month and a half into 2020, there are things far more important happening with our hobby than your emperor (with a very small e) and his latest antics.

Today I read something about some students in Norway (I think) who belonged to a school radio club. Seems like they were indeed fortunate to have for a club station a FLEX 6500 with the Maestro Console. 

Leave it to the youth -- they figured out how to hack the Windows embedded computer in the Maestro. Boom now they can do things with their station that even FLEX probably hadn't thought of doing. Then again that is how FLEX started.

Well today on a smaller scale (micro-scale is more like it) using my new Linux Mint Machine I was filming my attempts to make some FT-8 contacts all on the same machine. BTW the "Cheese Application" will work on a Raspberry Pi3.

sudo apt-get install cheese

It is a bit shaky as I held the webcam, while trying to operate the wireless keyboard. You get the idea...

BTW another FB feature of the Linux Mint is that it will examine your computer and give you a detailed report of everything connected and details about the machine and the peripherals. 

Two pieces of astonishing info came from that report. It told me that the battery in my Logitech wireless keyboard had 55% life remaining and that the temperature of my CPU was 4 Degrees C. (For those that just have to know that is 39.2F). It also explained why I was unsuccessful in getting the Linux version of Skype to launch. 

It seems that Skype in one of their latest revisions/updates no longer supports the Linux 32 Bit version. My Linux Mint computer (10 year old Intel 1.8 Ghz Atom machine repurposed) is a 32 Bit machine as identified in the Mint System Status. Mystery solved!

Keep on Tinkering...

Pete N6QW


February 16, 2020 More on Linux Mint:

A Video Microscope

So OK we now have shown that Linux Mint can do the SDR stuff and last night I worked out some kinks to using Arduino IDE 1.8.12 (I was the kink, not the Arduino software). So it is good in the hood. 

But I have always had in the back of my mind the idea of using a webcam as a Video Microscope. No, I didn't think of this; but can tell you first hand I saw this done back in the Mid-1970's. At that time I worked for Douglas Aircraft in Long Beach and we had a flight test facility in Yuma, AZ. 

Douglas built a private microwave link between Long Beach and Yuma. This enabled real time communications between the two sites. At night all of the flight test data was sent over the link for processing on the computers in Long Beach. There also were daily flight test debriefings over a then new technology called "video conferencing". It was leading edge stuff!

There happened to be a problem with the #2 engine which is located in the tail of the DC-10 and despite the video conference --the engineers in Long Beach did not grasp the problem that was being described by the engineers in Yuma. 

Then a voice at the back of the room said I have an idea -- let's get back together in 1 hour. During that hour the "wizards" in Yuma installed a camera on a lift platform located in the air about 40 feet and trained it on the problem area of the #2 engine. It took about 30 milli-microseconds for the engineers in Long Beach to see the issue. Overnight parts were built and flown down to Yuma and testing continued the very next day. This is the 1st time I saw a video microscope.

So why not now proceed with my own video microscope and found out that with an auxiliary program called Cheese you can plug in a webcam! Here is a test run --it was later uploaded direct from Linux Mint to you tube. I am impressed! I was using a Logitech C390 Camera.

At the terminal, type in:

sudo apt-get install cheese

When you know stuff you can do stuff! 

Pete, N6QW


February 15, 2020 Linux Mint Update:

[See last paragraph about the Arduino install on Linux.]

This morning I lit off the Peaberry V.2 that puts out 1 watt on 40M WSPR. The RECEIVED spots are shown above and this is a first for me to spot stations in Indonesia and the Philippines. I was spotted mostly stateside. The point here is that the Linux Mint is WORKING FB with Quisk and WSJTX. So if you happen to have an old computer lying around with say Windows XP or Windows 2000 or maybe even an old laptop with Vista -- convert that hummer to a Linux Mint machine.

BTW last night I watched a bit of Netflix as the special drivers are built into the Linux Mint. I needed to only connect to Netflix and provide my account info -- the rest was magic.

Today (when the garage gets above 39F) I want to install the Arduino IDE so I can use this machine for sketch development. We are only 46 days into 2020 and the good stuff just keeps moving forward. It got up to 60 and so Arduino IDE 1.8.12 has been installed. Very easy to do in Linux. See the following tutorial. Instead of the 1.8.2 the latest IDE is 1.8.12 and you will need to use those numbers.


Pete, N6QW

February 14, 2020

About two years ago I had a catastrophic event occur to my main computer which was running Windows 7. I replaced that with a new Windows 10 machine and attempted a repair on the old machine by installing a Windows 7 Disc purchased on eBay. 

I know better; but it was cheap and turned out to be counterfeit. So that rather small computer, an Atom running a dual core at 1.8 GHz, has been sitting idle for two years now.

As a result of the SolderSmoke Podcast I was contacted by KL7FLR who in passing mentioned the use of Linux Mint. Wow, have I been sleeping under a rock. 

The Linux Mint is not only free; but very feature rich. The install involved the use of a flash drive and a piece of software called Etcher. I simply downloaded the image of the Linux Mint on to one of the shop computers and then with the Etcher "Flashed" the USB Stick.

The next step involved setting the boot functionality for the Atom to boot off of the flash drive as the 1st boot. Insert the flash drive in the USB slot and turn on the computer and away it went.

After installing the basic Linux Mint OS I then installed Quisk and wsjtx. Wow --this is really nice and there is a 500 GB HD on this computer. KL7FLR provided me a link where I can do Arduino work on this computer --something for tomorrow.

 40 Meters with the Spectrum and the Waterfall.

WSJTX install was done with the package installer and we can see it perking along.

The SDR Board is a Peaberry V2 which has a built in sound card codec.

I have not fully explored the Linux Mint; but can see it also has office type software (Libre) and a whole host of software packages. Truly impressive and fairly straight forward to get up and running. Firefox is the main Internet browser. Oh it has Netflix software as well as YouTube built into the basic software.

So once again more technology at our finger tips.

I have it listening to WSPR right now as I type away. It is doing FB!

Stay tuned for more excitement from the left coast!

Pete N6QW

New Technology for 2020 --A Hands ON SDR Kit

A Hands On SDR Kit!

Hey guys I tripped over this SDR Kit and to me if you want to get your feet wet in SDR this may be your ticket to ride. BTW the cost of the shield (if I did the conversion correctly) is about $38 today not including any shipping or handling.

Watch the video but in a nutshell:

It is a kit that requires just a bit of minimum soldering on an Arduino Shield. Yes, it uses an Arduino Uno and it is a progressive kit that takes you from a basic receiver to a digital receiver that will copy FT-8 and WSPR. The final step adds the transmit capability.

It is not simply a boxed kit but is more of a tutorial course that starts with the fundamental's of SDR and progesses you through to a working transceiver. 

The Arduino Uno provides the frequency control for the on-board Si5351 located on the shield, thus it is a controller so you will need an external computer with SDR software. They have a link to the software that will drive this puppy. I suspect (although do not know specifically) that the board will work with Quisk. Quite possibly it will work with a Raspberry Pi 3 or 4.

Based on what I have posted I sense many blog readers are keenly interested in getting an SDR rig in their shacks. But the impedement with using any of my approaches is that 1) you have a lot of fabrication to be done that requires some special tools and 2) you got to know stuff. The Elektor Hands On Kit eliminates these two impediments.

This kit is worth a serious look.

Finally there are times when something catches your eye and you snicker and smile  bit. The emotion of this experience endures for several days as you ponder or reflect on the event. The following is a sign that graced the front of a local restaurant.

A very clever person thought of this paradigm and in itself gives pause to a snicker or two! However it has a sense of deep meaning about expectations and customer service.

Then I thought about such a sign appearing in the "Red Light" districts of your local town. Snicker about that for a day or two. 

Don't forget today is Valentine's Day so time to get a nice present for your favorite person (you) and the Elektor Hands-On SDR Kit is a perfect choice.

Pete N6QW

Friday, February 7, 2020

New Technology for 2020 -- A New SDR Transceiver

Out of Adversity Comes New Ideas!

Then it occurred to me … a different mousetrap.

February 13th, 2020 ~ Leading Edge SDR

This is a photo of a rig from the Radioberry SDR reflector where a ham is using his SDR to communicate with OSCAR - 100. Firstly the Radioberry board is quite advanced and it is a new favorite of the "extreme end" techie types of our hobby. 

Secondly many of the Radioberry boards are being run with a Raspberry Pi4 and here is another example of the rapid technology infusion into our rigs! Keep in mind it is only the second month and 45 days into  2020. 

My post of yesterday regarding conventional radios versus SDR seems to be in tune where the hobby and hardware are going. Today's board type SDR rigs are small, extremely powerful, feature rich and yet at a cost we can at least drool over. Just think an RPi4 with all of the bells and whistles is around the $60 to $70 range. The Radioberry board I think is around $300, so for less than $400 you can be talking to the satellites or having an on the air emperor (small e) "love fest" on 75M.

The Hermes Lite is another board similar to the Radioberry and can be run directly from Quisk. An added bonus of the Hermes Lite -- within Quisk is software to turn your Hermes Lite SDR into an advanced Vector Network Analyzer. Try that with your regen receiver...

So rather than resist SDR like many did in 1959 about transitioning to SSB, do the research and start small by learning about SDR and its benefits. Without hesitation I say that in time you will want to see the waterfall spectrum of signals and you will want to be able to invoke the digital filtering.

My good friend Bill, N2CQR in our latest podcast SS#217 spoke about a very capable hardware audio CW filter from the 4 States QRP Club which he will add to his uBitx V3. 

I am anxious to hear about his experience with this filter. That said, Quisk comes standard with CWL and CWU options as well as 5 digital filters ranging from 200 Hz to 1 kHz. Quisk is a free download and runs on a $35 Raspberry Pi3. The Quisk software will also run a host of SDR boards including homebrew rigs like my RADIG V1 and V3. 

Ad nauseum you can see more about this at

We live in the Golden Age of Homebrew Fabrication!

Pete N6QW


February 12, 2020 ~ SDR vs Conventional?

I can well remember the on the air discussions of transitioning from AM to SSB. The year was 1959 and there were many new SSB transceivers showing up on the scene including homebrew rigs. Some of those homebrew rigs mostly transmitters  graced the pages of the ARRL Handbook -- one even using a McCoy 9 MHz crystal filter. That was well before the ARRL became an advertising conglomerate dedicated to only selling ham gear.

The discussions were heated and there were complaints of the "Donald Duck" sounds coming out of the speakers on 75 and 40 Meters. The illuminati of  1959 saw it was only a matter of time before there would be a mass exodus to the then new form of SSB communication.

While to many homebrewers there is a sense of connection to the past by building a conventional analog transceiver complete with a homebrew filter, the SDR approach today in 2020 is the SSB of 1959.

I recently bought a Tech Special KWM-2 as a Christmas present to myself. It did not take much work to get it on the air. But there are things still needing attention. I am amazed at the frequency stability of the Collins PTO. That was something done right and endures to this day. My KWM-2 was built in 1962 (pull the crystals and look for the date code) and the S/N is in the 12XXX range --certainly before Nam. So something 60 years old still working is a very good sign.

But yesterday, after replacing a flaky 3.8 to 4 MHz heterodyne crystal I wished I was using my SDR RADIG V.1. Here is why -- two 6 Land hams were having a QSO on 75 Meters --it was around 5 PM. One ham was using a homebrew SSB transmitter (with LC Filter Components for his SSB Filter) and was built in 1947 and the other was using a FLEX 6XXX series. 

Well they were not on the same frequency --split by about a kHz -- My RADIG with the Quisk software has a built in RIT and I would have liked to look at the spectrum of the 1947 Transmitter. 

When they finished I called the guy with the 1947 Transceiver but he was operating with a separate Rx and Tx -- he seemed to have a problem "zeroing" us and he kept moving his transmitter VFO. I do not have the remote VFO for the KWM-2 and there is no "Record" capability as there is with my RADIG. So a bit frustrating and while operating the 1962 KWM-2 in 2020 is cool, I can see where in 2020 the SDR transceiver, especially a homebrew one, is the ticket.

Out here on the left coast, I also note that many hams operating the various 75M/40M nets and round tables simply shut off their receivers and use the web based SDR receivers in Utah and California. In fact many of these nets today, are only possible because stations while using perhaps conventional rigs for transmitting use the web SDR receivers for receiving. An often heard comment : "I can't hear you direct; but you are 5X9 on the Utah SDR receiver."

This does not look anything like a KWM-2 but sure outpaces it with capability.

There is also a significant cost differential for the capability -- about $11K (in todays dollars) for a KWM-2 versus about $300 for a RADIG complete.

My "new" KWM-2 acquired as a Tech Special seen above. So far have replaced three bad tubes, four electrolytic capacitors, one bad crystal and a severely out of tolerance 2 watt resistor. The value is supposed to be 820 Ohms -- it read once out of the circuit 2.7K Ohms. This resistor was in the screen circuit of the 6146's. There was a dramatic change in less bias voltage required once this resistor was replaced. In fact the Bias pot setting now is more in line with the other KWM-2 I have.


Pete N6QW


February 11, 2020 ~ RADIG V.3 Block Diagram

For those who like to follow the circuit block modules this is how it was done. 

Interesting note as many of these pieces are bought off the shelf and simply connected together. The Sound Card, Sound Dongle, HDMI Display and either the Raspberry Pi3 or the ASUS Tinker Board are off the shelf as is the Arduino Nano, Color  TFT and the Si5351. Other bits would include the keyboard/mouse and the headset microphone.

The "build hardware" is the bi-directional amp which can be just a simple pair of J310's that are relay steered as the Rx RF AMP or the Transmit Pre-Driver. The Driver stage is a 2N2219, and the IRF510 is the standard implementation. The USB to I2C is a build but you will need to contact Cecil Bayona to purchase the programmed microcontroller. You will also need to build the Band Pass Filters. 

The most critical build part is of course the RADIG board which has but a few components such as the 74AC74, the two ADE-1's which can be gotten as free samples. and the RF splitter (FT-37-43 core) and the two modem coupling transformers.

I am thinking of buying the 28.224 MHz Packaged Oscillator ($1.14) and testing that concept as that would reduce the hardware count (Nano, Color TFT and the Si5351) and gives you the digital operation on WSPR, JT-4 and FT-8 on 40Meters. Will keep you posted.

Pete N6QW


February 10, 2020...

Just finished testing 20M using the 20M BPF and resetting the LO so it would tune 20M ( about 56 MHz). I used the 20M FT-8 signals.

Spent a bit of time yesterday exploring some facets of the RADIG V.3 and will now share those with the blog readers.

  1.  My website dedicated to the use of SDR spends much time on the loading of Quisk onto a RPi3 and/or ASUS Tinker Board. There are now images available that make loading of the basic software much easier. I will need to update that website so that some of the drudgery is eliminated. There are also new versions of Quisk from N2ADR that will work with Python 2 (soon to reach EOL) and the new Python 3. Jim's new software likewise makes things much easier to implement Quisk.
  2. I mention many times in the videos and the blog about the setting of Quisk to a center frequency. A bit of explanation as it involves an initial data entry and not simply moving the cursor with the mouse. That said once the center frequency is set in Quisk you can freely tune frequencies either side of the CF simply by moving the mouse
  3. There is a Quisk functionality where you can manually enter a "specific frequency" in this case our center frequency. There is a block on the Quisk dashboard where this can be done and is shown in the photo below. Once entered that is the "center frequency" and appears in the very middle of the screen. From there you can tune 24 kHz either side. Noteworthy, the same center frequency must be set on the LO feeding the RADIG Board. These two must initially match! The Arduino / Si5351 is not tuned but Quisk is! While the UNO Color TFT display may show 7.200 MHz, the actual frequency being generated and fed to the 74AC74 is 4 x the display frequency! However with some high end sound cards that range can be extended to 48 kHz either side for a total of 96 kHz; but you also will need to make an entry on the Quisk configuration "Sound Tab" as the default is 48 kHz. I have such a card made by Creative Labs called the Xfinity V. The only negative is the weird connectors on Line Out (uses RCA) but 3.5 mm stereo on Line In and is an odd shape
  4. The RADIG V.3 has opened up possibilities for a "compact "digital only" SDR rig. I have a 5" inch HDMI screen and if you couple that with the fixed crystal oscillator to cover FT-8, JT-4 and WSPR with perhaps some CW thrown in for good measure this could be an ideal in the field digital radio.
  5. I have on order from China; ( I think any goods from there have to go through some quarantine process) but won't be here for several weeks, two DC to DC converters from Mean Well. With an input of anywhere from 9 to 18 Volts DC they output up to three amps at 5 VDC apiece. I also have some Micro USB power cables in transit to me. The plan is to cut off the standard USB side and fit the wire ends to the DC to DC converter to power the RPI3 or ASUS Tinker Board from 12 VDC. At  3 amps this will now even power a RPi4 but you will need a USB C to Micro USB adapter plug. The second DC to DC can supply power to the 5" or  7" HDMI or even charge a cell phone out in the field. 
  6. All this effort with the power supplies is to simplify powering any RADIG as right now there are several "Walwarts" plugged into a power strip and it is a mess of wires. Final configuration -- one simple connection to a bench 12 VDC Power Supply or to one of those Talent Cell Batteries (bigger amp version) as suggested by N2CQR.
Pete N6QW

February 9, 2020 

Much progress today as I better understood the concept of the "Center Frequency". The Uno and the Quisk must initially be manually set to the same frequency and once done you can "tune" the Quisk software 24 kHz in either direction from there/

A bit of FT-8 (once the setting of the center frequency for both at 7.070 and then the Quisk tuned to 7.074 USB).

An additional thought crossed my mind ... If you wanted to operate only FT-8 and WSPR exclusively with this rig then it might be possible to revert back to the early Soft Rock days. FT-8 is on 7.074 and WSPR on 7.038600, which means they are located 35 kHz apart. If you set the LO to 7.074 - 0.0175 the Center frequency of 7.0565 kHz will operate both digital modes along with JT-4. 

Now if you take 7.0565  X 4 = 28.226 Mhz, and use a fixed crystal oscillator operating at that frequency all you would need is the RADIG board (plus front end Rx RF amp and the Tx chain), the Raspberry Pi3, no sound card for audio; but a sound card for I and Q and the USB to I2C to toggle between transmit and receive. A small 7 inch HDMI display would make for a compact rig. CW operation might even be possible.

Bonus News: Digi-Key sells a 28.224 MHz Packaged Oscillator that when divided by 4 = 7.056 MHz that would give a spread from 7.032 to 7.080 MHz and the price  is $1.14. It is a SMD part but you can make it work. All you need to do is connect a source of 3.3 VDC plus ground and take an output and connect to the RADIG Board.

Digi-Key Part Number

This is exciting news!

I have also determined that with the USB to I2C control board installed, once you hit Spot or PTT, then +5 VDC appears on Pin #3 of the USB to I2C. So we now can have the RADIG go into transmit. [A programmed microcontroller that will work in this circuit was recently purchased from Cecil Bayona, K5NWA in Springdale, Arkansas.]

That said I was unable to communicate with the Si5351 directly -- Now I know it can't be done! A bit of further "internet snooping" and it appears the way the 570 and the 5351 develop the PLL multipliers they are incompatible insofar as just connecting some wires and hoping it will spit out RF regardless of which device is used. 

I do have a 2nd SDR Kits interface board (unbuilt) and that may be the shortest distance between two points. But this investigation shows that you could make the Arduino Uno and Si5351 drive the RADIG Board albeit a bit "klunky". 

I noted that on the posted you tube video of the first sharing of this project that there were 25 Thumbs Up and 0ne thumbs down --out of about 222 viewings. If you really didn't like it then tell me the "why" and perhaps I have overlooked something.

So for that one person, you must lack "Knack Skills" and are simply envious! Or perhaps are Republican, attend all emperor (with a small e) rallies and live in the Midwest.

Pete N6QW

February 8, 2020

Sometimes you get lucky and remember things from the past. Based on yesterday's discovery, I pondered how to turn on the PTT of the RADIG V.3 from the Quisk Software via USB. I even thought of the possibility of controlling the Si5351 from Quisk and eliminating the Arduino Uno and the Color TFT. One step at a time Grasshopper!

About 3:00 AM my brain awoke me and said check the box of old SDR parts from the Soft Rocks you built about 10 years ago. As the Soft Rock SDR radios were being developed there was a separate USB to I2C adapter kit being sold by Tony Parks. 

The schematic looked like this...

So there it was, a way to tap into the USB and trigger the PTT plus accept a pair of CW paddles. But also a couple of all important ports to control SDA and SCL originally on a Si570 but perhaps would work with the  Si5351. 

Now what is in the ATTiny 45 (or 85) is a code as stated set to control a Si570. I just don't know if that will work with the Si5351; but the firstly important piece is the PTT control. That I do know works as that is what is being done with original RADIG V.1.

There is a variant of this schematic as used on the Ensemble Soft Rock that has an Opto-isolator on the output and it looks like the schematic below. This seems like a good idea...

I did find that box this morning and this is what I found...

TRGHS --- here it is built for me (by me). I just need to match the wiring with the 1st schematic above and evaluate the Opto-isolator addition for the switching, checking initially the activation of the PTT. When you hit the Quisk Spot button do you in fact get an output on pin #3. That is the most critical piece to make this into a transceiver.

Later I can evaluate can I control the Si5351 with this same interface board. Baby Steps.

Stay Tuned for the excitement.

Pete N6QW

February 7, 2020...

So OK, I smoked a Teensy 3.5 (Not the 4.0) and I think the Codec board maybe gone too. These were used with the ZL2CTM SDR evaluation rig. I have another Codec board but need some 32 pin headers to mate the board with a second Teensy 3.5. So basically nothing will happen with this approach for a bit until new headers arrive in abut a week. But the new RADIG V.3 Board is working just fine.

Then today I thought about something from the past. Early Soft Rock users were kind of stuck with crystal control. You got one crystal and with the sound card you could cover about 48 kHz of the band. This was the V6.2 Crystal version. Having only a small slice of the band kind of sucked. Thence the V6.3 which used a Si570 under software control and you no longer were anchored to 48 kHz. Search for WB5RVZ to get the full dope on this history.

Thus my idea --suppose you used the Si5351 in place of a crystal and then use Quisk to tune the 48 kHz slice --all run with a Raspberry Pi or ASUS Tinker Board. 

Off to the races and --yes it works!

I also have been looking at how to use this RADIG on transmit. My original RADIG used a USB Synthesizer kit that is supplied from a company (SDR-Kits) in the UK. Basically the kit contains the ATTiny 45 microcontroller and the RF device is a Si570. That controller works flawlessly!

The programmed Microcontroller can be purchased from a ham here in US (Cecil Bayona). Thus you could actually partially build what is on the schematic so that you would have the PTT and CW paddle controls. But you still would need the Arduino for the Si5351.

I am not certain if the code set for the Si570 and Si5351 are the same; but a further experiment would be to substitute the Si5351 board in place of the Si570. If this works then a huge step up the ladder and you could eliminate the Uno or Nano and the display as everything would be under control of the Quisk software.

Stay tuned my hammie friends for more to come.

Pete N6QW

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