Thursday, March 26, 2020

New Technology for 2020 ~ The AD9833 RF Generator Board

A New Toy on the N6QW Workbench!

3/29/2020 ~ Your uBitx may contain a critical part of the next generation of Covid 19 Ventilators.

3/30/2020 -- Double Balanced Mixers!

I am happy to report that Mouser now carries the ADE-1 Double Balanced Mixers and are available in single lot quantities for about $6 and some change. Nice! 

Just checking I went to the SolderSmoke Blog and searched in the Amazon block and typed in Double Balanced Mixers and this is what showed up ($1000)


It is a mixer; but probably won't work too well in my design. Guess it is important to be specific.

Pete N6QW






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[I have a sudden interest in 3D Printers. Looking for recommendations firstly, on a good software package as that is probably more important than the machine itself and likely dictate what I buy. Given a robust software, secondly is a specific machine recommendation in the $300 to $400 range. My interest is in making knobs --big knobs.]



It seems like the University of Florida has been working on a ventilator design that uses plastic pipe and sprinkler valves. Such an approach would enable building such devices simply by making a trip to Home Depot. 

But then there is the issue of how to control the system. Boom hams to the rescue! According to what I just read on the Bitx20.io reflector several hams have prototyped a control system to work with the plastic pipe / sprinkler valve ventilator. A posting on the reflector states today that  the involved hams will mate the Arduino / 2N3055 transistor control system with plastic pipe and sprinkler valves to breadboard a working model. How cool is that?

So while you are twiddling the knob on your uBitx that Arduino inside may be the heart of an international open sourced homebrew ventilator. That old adage is once again proven: Necessity is the mother of invention!

Just watch --- the emperor (with the nano particle sized e) will claim he invented it!


3/28/2020 ~ A new way forward!






We are now at 103K known Coronavirus cases in the USA and this is driving many changes in the way we do things that likely will be permanent!

Yesterday I made an inquiry of one of my XYL's Doctor's as she has an appointment coming up on April 7th. The office staff gave me instructions to download Zoom and that the appointment would be kept using the Zoom application. 

Payment for services will be by credit card and we already had setup prescription refills via the Dr. sending an email to our pharmacy. In the past seeing this Dr. was a bear! Her office had limited parking spaces and it was located 10 miles away. Man I foresee all future appointments being done this way. 

Ditto for her primary care doctor who will visit with you via a telemedicine application to determine what further action would be required. I happen to have a higher quality BP machine and a pulse oximeter so the Dr. can get some vital signs right over the internet.

Got an email from our dentist who is suspending his practice for a month -- not sure how you get your teeth cleaned via the internet; but someone surely is working on an application.

I discovered you can order "the college student staple food", Top Ramen via Amazon. The price is cheaper too. Funny story --on Monday I am getting a combined package from Amazon consisting of two items: A set of replacement probes for my Rigol DSO and a case of Beef Flavored Top Ramen. 

This Monday I will be all set --new DSO probes and Top Ramen! Just other day I received some high quality buttermilk biscuit mix from Amazon. 

It is likely in the future I will be doing more food ordering from Whole Foods and PillPak for the meds. What can I say other than Bezos is a genius: Stuff, Food and Medications all quickly delivered to my door. 

You have got to love technology! The stay at home order will change the paradigm! It saves gas too and is good for the planet. I am running some calculations on the gas savings versus the added delivery costs. That will be interesting.

Remember: #TOT, your life depends on it! Listen to the real leaders like Dr. Fauci and Gov. Cuomo!

3/27/2020 ~ Loaded the Code!




I just copied the code from the earlier link into a blank sketch and then of course you have to null out lines, add libraries, do the usual fiddling  and ultimately you should get a display that looks like this. You will note it says AD9850 because the author took that code from a prior project and repurposed it. [Thanks again DuWayne!]



For my use I will have to do some major surgery on this code; but this is a starting place. I want to limit the frequency range to 5 to 5.5 MHz and I don't like what was used for pin assignments --- but you can make it play as is.



I had an Uno R3 with an attached display and that is what I used. But in keeping with a small size you would want the Nano. We are moving forward...



Just  finished listening to the daily briefing from NY Governor Andrew Cuomo. Now there is a straight talking "leader" and such a vast difference from the emperor (with a microscopic e) who essentially is misleading all of us.

You can listen to and believe the emperor;  but you do so at your own risk! Just look at the numbers of cases: that data is truth! We are past 100K cases --when do you stop listening to the emperor?

Why did he wait until now to invoke the war production mandate. Weeks ago he could have ordered GM to make ventilators. This is the problem of a lack of competence to lead!



It must be that the Trump properties are losing money and that is the rationale for opening the country by Easter.




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But 1st, I see where the USA leads the world in the number of Covid-19 cases, at greater than 80K of our population. We now have surpassed the 1000 mark in number of deaths!

We must look to the emperor (with a microscopic e) as a potential reason as to why so many cases. From the outset he was in denial, calling it a Democratic hoax designed to make him look bad. 

It is well known that he was briefed on the impact of this scourge over two months ago. But instead of taking action, he frittered away precious time. The emperor chose to ignore the experts and to trust his gut. Well it seems his gut was wrong.


Anyone who listens to him or believes what he is saying --we'll check back with you in about two weeks to see if you are still alive! Good Luck!

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http://www.vwlowen.co.uk/arduino/AD9833-waveform-generator/AD9833-waveform-generator.htm

Today my AD9833 RF Generator board arrived. I kid you not it is the size of a postage stamp. When the envelope arrived I thought at first that it was an empty envelope.

The link above has the key to unlocking its secrets! The plan is to fabricate a generator in the range of 5 to 5.5 MHz as this is a common VFO frequency for many of the OLDE Boat Anchors. I have a Ten Tec Omni C that has a drifty VFO and is a candidate for this jewel. Heathkit, Drake, Galaxy and National all used a VFO in the 5 MHz range.

I am working on the AD9833 as I await the PSN's to arrive from the UK or maybe Turkey.

See the link at the top, thanks to our good friend DuWayne , down in Riverdale, GA, we now have the "how to".

It is time to TOT!

73's
Pete N6QW

Saturday, March 21, 2020

New Technology for 2020 ~ Lets Build a Phasing SSB Transceiver

LBAPT ~ Let's Build a Phasing Transceiver!

3/24/2020 ~ A bit of new hardware!


After a Skype session with ZL2CTM and also in an attempt to produce a quadrature output Si5351 --- I finally bumbled and stumbled through  many failures and now have something working (with a lot of help from around the world).


The idea of a quadrature output Si5351 has been around for some time, only I was not too successful in implementing the actual hardware -- until now. It gets harder as you get older! 

In my conversation with ZL2CTM he mentioned the idea of using a separate Arduino/Si5351 to generate the Quadrature outputs to free up the workload on the Teensy 4.0 which is running at 600 MHz and is fast. This then opens up the possibility of two displays. One could do an amazing spectrum waterfall piece and another would do just the frequency and other housekeeping tasks like Step Tuning Function, Sideband Select, etc.

One critical piece is the library that you use for the Si5351. Frankly this has me confused as I have four different versions of the Si5351 library and one caused you to have a 180 Degree shift an another a 45 Degree shift. I simply do not know why. But I guess the third time got me there.


This is all preliminary but having the separate Arduino /Si5351 Quadrature output is a piece needed for our Phasing Transceiver project. 

By the Way check out the LTC5599 IC from Analog Devices. It is a 30MHz to > 1Ghz SDR transmitter on a chip and can be had for about $11. One ham shared with me he has this working on 17M. 

Ahhh the new technology in 2020 is amazing!

If you are interested in hearing straight talk about the Covid-19 tune into one of the briefings by Governor Andrew Cuomo from New York. Listening to the emperor (with a small e) is a waste of time and riddled with misinformation (MOM).

I personally believe that blindly following the emperor (with a small e) puts you at a grave risk! You only need to observe the daily exponential growth in cases to see that opening the country by Easter is unthinkable.

Its like saying use a 47 Ohms resistor --it is ok just use a 1/4 watt. But the load requires a 100 watt. True same value wrong watt rating! Listen to Dr. Fauci and Governor Cumo. They know best!

Is the drive to open by Easter purely a personal desire -- surely the Trump properties are tanking right now? Some sobering food for thought. 

73's
Pete N6QW


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Fellow Hams --we are on our own! The lack of leadership at the top has put us all at risk. There is a huge difference in "playing a president" and being one. A real leader would have taken immediate and decisive action -- he took a golfing trip! 

It is really easy to spot the true "leaders" in the fight against CV-19: Cuomo, Newsome, Inslee.

Just observe --- the $2 Trillion Stimulus package will benefit the rich, the emperor's friends, and the large corporations. BUT those who need it the most will only get the crumbs. Who are the Republicans kidding?

I have coined two new Acronym's MOM and #LTCTOT. A clue: MOM is not about your mum. It is Master Of Misinformation --wonder who that is?  



CV-19 Blues Crush






Caveat Emptor ~ I may  really be in the weeds this go around. But, Hey, 20%  of the USA population are home bound so maybe we can collectively do it together.







Firstly I bought two of the QRP Labs Phase Shift Networks which are in route to me. I did a bit of further examination and there are two mods that will be required. (This is not a kit project!). The first issue is to decode how to connect to the inputs which I will need to pursue further study. But there are two other identified "hurdles".

The first hurdle aside from interconnection is that the PSN has a narrow band width of perhaps about 1500 Hz which will really piss off the 40 Meter FLEX Radio guys. But this 1st go around is proof of concept and then I will need to see how to make that wider.

The 2nd hurdle is that the PSN is not bidirectional -- it was made to chunk in a receiver. Use in a transmitter requires some significant modifications. So there is some electronics on the board that SUM the I and Q channels to produce an audio output for the receive mode. That part of the circuitry will have to be bypassed so it can feed the I and Q Channels on the RADIG Board. Now on the front end of the PSN we will have to build an interface that takes the single ended output of the 2N3904  Microphone amp and splits it into two signals to feed the input side of the PSN. My first thought would be to use something like a modem coupling transformer to create a balanced input. There likely will be development needed here.

So before you buy a set, you might want to see how I fare. But this is the fun and it is a time killer. I think that in about a week the total US will be in lockdown. 

I have tried to contact Hans Summers about these two issues and have not heard back --so I might try a different email.

So those of you who thought this was a hoax --we are here because the emperor (with a miniscule e) is in denial. The last thing anyone should do is believe him or any of his claims. #LTCTOT! In essence we are on our own and the emperor (with a microscopic e)  has written us off! So let us observe the safe practices and LBAPT!

73's
Pete N6QW

Tuesday, March 17, 2020

New Technology for 2020 ~ A simple way to build a Phasing SSB Transmitter

PWKSCDS -- I just realized I made a very bad assumption. It came to me in a dream!



3-20-2020 ~ The emperor's buddies strike again!

[But 1st. Some people are saying that 3 Republican Senators got advanced notice of the CV-19 impact and sold huge chunks of stock BEFORE the market crash. Sounds like the swamp got a bit deeper. I sure would have liked to have been privy to that info so I could have sold  my few shares of stock and not taken a hit. Shame on them!]


[3/19/2020, 6:43 PM PST. California has essentially been shut down with most businesses to close by midnight. You are permitted limited travel (like taking a walk) and you can buy groceries; but that is about it. Aren't you glad that you now have a project to work on while you are holed up?]


A Phasing Rig must have struck a couple of nice chords. Today I got two  inputs from "down under". One VK ham (Thanks Greg!) has provided me a source for homebrewing your own audio phase shift network which is found at this link.  http://www.antennoloog.nl/polyphase-networks/  and the spreadsheet for the calculations at this location 

This work was done by PIM PA2PIM

The second input (Thanks Stephen!) made me aware that in the G-QRP Club SPRAT #120 someone did the heavy lifting and translated the 'toob" SSB jr. to an all Solid State version. Now that would be nice. That source also referred me to a project by   Fred Johnson ZL2AMJ called "The Tucker Tin #2". 

Lea Earnshaw, ZL1AAX, (founder of Southcom Intl and Kachina Radio) published a nice book called The Transistor Radio Handbook and in there is a very excellent simple Solid State Phasing Transmitter. So it can be done with little hardware!



March 19th, 2020 ~ More CVHI Projects.

Here is the bad assumption that I made: That hardware building skills still abound. Wrong! The hardware building skill level today, in our hobby, has been outstripped by those with software skills. Hardly anyone scratch builds stuff today and an even very smaller percentage builds "toob" gear

It would be a simple matter for me to go to my stock of aluminum chassis boxes, dig out the Greenlee Chassis punches, drill a few holes with my floor mounted drill press and I would have the chassis for the SSB Jr (below) . The total elapsed time --about 1 hour. Not many hams have those skills nor the tools to use a chassis punch today.

I also have several power supplies that would power a tube transmitter. Scratch that idea --no one would build it and most hams only have $1.95 Walwarts. Too hard!

Don't Give Up Just Yet!



But let us not give up on the quest to build a phasing SSB transmitter and ultimately a phasing transceiver. The "hard nut to crack" was the Audio Phase Shift Network. But then I discovered today that you can buy one from a very reputable supplier. Boom! Hans Summers and his QRP Labs sells the Polyphase Network  for an amazing price of $11. It is intended to be added to a receiver block so may require some modifications; but PWKSCDS.

So gang what if we undertake using two of the PSN Networks in a transceiver and brew our own phasing rig using these networks? We could actually take the SSB Jr schematic building blocks to create comparable solid state building blocks and at this stage I envision a low part count rig. I would start with the transmitter first as we could use the Web SDR receivers for the other end.

After I finished the block diagram it hit me -- quite possibly only a single PSN may be required and only the Mic Amp and Audio Amp are switched at a common port. That would make for a huge simplification. Sideband reversal would be done as normal by switching the outputs out of the PSN to get either USB or LSB. 

My intent would be to design the rig as we go along and some modules exist already. I have circuits for an excellent simple 2N3904 microphone amplifier as well as the Bi-Directional RF Amp stage (2N2219), plus RF Driver Stage (2N2219A) and IRF510 Final. 

Using the already proven RADIG Board would mean even less development required. We is on a roll!


The Audio Phase Shift Networks would be purchased. The Tough Nut is no longer as the RADIG takes care of the RF Phase Shift and the Balanced Modulators

Enter the Si5351 where one clock would supply the RF for a basic transmitter and a second clock could provide frequencies to heterodyne that signal to other bands. Sounds like I am designing the rig as I type. (I am!)

This may all be a bust; but a solid state rig with one of the critical components purchased at a reasonable price may result in more hams having an interest to build one while in CVHI. 

This might even encourage some hams who read this blog with circuit board experience to design boards that could be commercially manufactured. This is an option  for those hams who always start by saying where can I buy the PC Board?

Yes this could be done with Tayloe Detectors/Mixers; but what fun is that. We are starting on a journey to build a modern day 1950's Transmitter/Transceiver.

73's
Pete N6QW



CVHI = Corona Virus Home Isolation


A Little Laughter is Good Medicine!


The GE SSB Jr. 3 Tube Transmitter


I suggest you visit the N4TRB Wesbsite where you can download the complete Article from the GE Ham News #205. Below is the Schematic for the SSB Jr.

I will see if I can find some substitutes for the audio transformers. Now think beyond what is possible and use the Web SDR receivers as a simple station. You can be heard on 40 Meters with just 5 watts. 

This is a great CVHI project and the parts are common (once I find you the transformer substitutes) Ebay and Antique Electronic Supply has everything else you need!

CRHI = Corona Virus Home Isolation.


We could start a whole new revolution of home brew Phasing Transmitters. We also need to think about a NET frequency so we can have our own exclusive net. I believe 7.285 MHz is the recognized 40m QRP Frequency -- so either find some crystals OR look to the AD9833 Oscillator Board as a source for VFO control. The AD9833 Board and Arduino Nano can be had for less than $10 and are available on Amazon. Couple that with a cheap LCD and we are uptown.

For those inclined to really tinker -- this could be transported to a solid state version. But having a tube rig would be a blast.

Let the parts hunt begin.

Pete N6QW

Wednesday, March 11, 2020

New Technology for 202 ~ The Iowa Hills Software --- Hilbert Transforms

March 16, 2020 ~ Time Killer


Go to soldersmoke.blogspot.com and tune into Podcast SS #219. This is good for 1.5 hours and may help pass some of the time you now have as the USA closes down for business. 

I am having a difficult time reconciling what I am seeing on the ground and what we hear from the emperor (with an extremely small e). This is going to get worse! Note: "He is responsible and it happened on his watch!"

There was a line at the grocery store this morning at 5:30 AM and the store didn't open
until 6 AM. Friends that is 0'Dark 30!

How are your stocks doing today? Are the Russian hackers at work trying to penetrate our national health agencies? The emperor (with a very small e) probably will most likely claim it is the deep state who did this. At around 1PM eastern the DOW was down about 2000 points. So emperor (with a very small e) how is your metric doing????

This actually may be a really good time/place to pick up women. But it probably is money is the big draw moreso than the ability to cook!

Pete N6QW

March 15, 2020 ~ This Sucks!

Today in California they closed the bars, night clubs, wineries, and brew houses. That means no more watching girls pole dancing. 

Most of the public and parochial schools in the major metro areas (SF, LA, SD) are closed. I expect the senior centers will be shut down on Monday.

Gatherings are limited to no more than 50 people. We are also told that if you are a senior citizen you must self isolate yourself by not going out in public.

Today our local grocery store (Albertson's) which is one of their flagship stores was out of the following:


  • No Paper Towels or Toilet Paper
  • No Clorox Wipes or Clorox Spray
  • No Bread
  • No Butter
  • No Pasta or Macaroni
  • The Soup stock was down by 75%
  • Canned vegetables were down
  • But Plenty of Beer & Wine but given todays proclamation that too will be gone
  • Water was in short supply.

The good news story is that I have a shack full of waiting projects, lots of parts and plenty of solder.

73's
Pete N6QW


Today's Question:

Is the stable genius tanking our country? How did your 401K do today? Some people are saying his shortcomings are showing! Where is the leadership we so desperately need? Tomorrow will be another "bumpy ride" as more cases surface.


The Iowa Hills Software:  Hilbert Transforms

So what I am about to share with you comes from someone who knows very little about the Iowa Hills  Software. Yes, it is a case of the blind leading the blind.


For those of you deeply into mathematics, or a high level software architect, the subject of Digital Signal Processing and Hilbert Transforms is much like Massimo Banzai starting by saying "The Arduino is a simple tool to make things happen". Mr Banzai of course is the face of all things Arduino just so you know. Bob if you are reading this, then time to engage "the snooze control".

The Hilbert Transform dates back to 1905 so it was not invented in Silicon Valley and I encourage you to do the Wikipedia thing and look up Hilbert Transforms. It made my head hurt...

The Hilbert transform is important in signal processing, where it derives the analytic representation of a real-valued signal u(t). Specifically, the Hilbert transform of u is its harmonic conjugate v, a function of the real variable t such that the complex-valued function u + iv admits an extension to the complex upper half-plane satisfying the Cauchy–Riemann equations. The Hilbert transform was first introduced by David Hilbert in this setting, to solve a special case of the Riemann–Hilbert problem for analytic functions.

So the bottom line is that someone who wanted to do digital signal processing reached back in time and had a Eureka Moment -- use Hilbert Transforms. 

The Iowa Hills Software essentially takes all of what you see in the Wikipedia page and compresses it into a Simulator where you simply move some cursors around a graph to form the type of filter you want. 

Since we are using the I and Q approach (90 Degrees out of phase) which is processed at audio frequencies, then we must do the phase added option where we run the simulation twice. One is at + 45 Degrees Phase Added and the other at - 45 Degrees Phase Added. The span between the two is of course 90 Degrees.

But wait -- long ago and for those of you who once owned a Central Electronics 10A (with a BC458 VFO) or perhaps like N2CQR who has a pristine hallicrafters HT-37 (in addition to his restored S-38E) this idea of I and Q was done with hardware --HDR as Bill says. 

Essentially resistor and capacitor networks provided the 90 Degree shift in the audio signals. This was (and is) problematic as the hardware networks drifted over time and required a lot of constant fiddling. 

Anthony Vitale, W2EWL, came up with a SSB transmitter all fitted inside and using much of the original Military ARC-5 transmitter components to produce a compact Phasing SSB transmitter, Now that was advanced technology for the late 1950's (March 1956 QST). Many units built from his design found their way into Mobile SSB transmitters.

But now with the advent of creating phase shift networks digitally, the problem of drift and changing component values is simply GONE! 

The Iowa Hills Software now lets you create the digital filters and provide the all important 90 Degree Phase Shifted Values so that you can create nearly perfect I and Q Data Streams. Couple that with powerful microcontrollers like the Teensy 3.5, 3.6 and 4.0 with the integral CODEC board you now have a very capable SDR transceiver in a very small platform. 

Let us not breeze by that too quickly -- the same hardware used in my front end is bilateral -- so one set of hardware does all. My ADE-1's are used on both transmit and receive. 

Another simplification which I have as yet to implement (it is me having some cockpit problems making that happen) is to generate the quadrature RF signals directly from the Si5351 at the operating frequency. 

This is impactful in that you could make the Si5351 into a Two Meter SDR transceiver. Right now my Si5351 outputs at 4X and that is frequency divided by the 74AC74. This has two limitations where the 160 MHz end of the Si5351 would limit the upper operating frequency to 40 MHz and the 74AC74 drops off the radar at 95 MHz. 

Zl2CTM has provided me some code to directly generate the two out of phase RF signals. But I keep getting error messages about my variant of the Si5351 that is stashed in my library directory. Just need to fix that and test drive the higher limit frequencies possible by eliminating the 74AC74 and the 4X frequency multiplication. 

So ok what about those of you who are ardent CW operators and want a CW filter. Below is a plot of a potential CW Filter where I chose the Center Frequency of the filter to be 500 Hz and the 3 dB Band Width to be 500 Hz. 

At 60 dB down the BW is 1 kHz. If I remember this correctly the shape factor is the ratio of these two and so we have a 2:1 Shape Factor. For the purist that probably is too large and some would like to see perhaps a 1.6 to 1 shape factor. That might be possible --I just didn't fiddle with the numbers -- hey this took me all of 5 minutes. 

Note worthy along the left hand top edge are some blocks to check. The last one is Coefficients. Checking that block will produce 115 coefficients that appear along the right hand side of the plot. The normal default when you select Phase Added under the Pass Band Tab is +45 Degrees. Run the coefficients at this setting and then under the File Tab -- save the coefficients with the added title  +45. Now look at the Help Tab and just below that and to the right is the Phase Add block. Use the down arrow to make that value - 45 and rerun the Coefficients and save that with the added title -45.

These values with a bit of added information are embedded into the Arduino Sketch and instant filter 




Next week I hope to test drive this filter in a Teensy 3.5. Hopefully I will also make a video so you can listen to the filter on the air. But a real test is to find a CW contest weekend and see how well it holds up. In my mind the chosen 500 Hz BW is a compromise between having a narrow CW filter, yet not so narrow as to present some issues like ringing or significantly reduced audio volume because of a very narrow BW.

Keep in mind this is very new to me and I may have some incorrect assumptions … the long journey starts with the 1st step. The on the air test is the key. I haven't figured out how to make this transmit CW --just another day at the home office.

The value of having two Teensy 3.5's is that I can use one as a test bed and the other as "standard" when I want to operate the rig. I only need to exercise care that I plug Teensy 3.5 Pin #1 into Socket Pin #1

Ok Bob, snooze over!

73's
Pete N6QW


Wednesday, March 4, 2020

New Technology for 2020 ~ The ZL2CTM Teensy 3.5 SDR Rig

ZL2CTM Teensy 3.5 SDR Rig - More!


The Teensy 3.5 and RADIG V.3 Are Alive!!!!!



 RADIG V.3 & Web SDR


3/10/2020 ~ St. Paddy's Day --a  Week Away!

So OK  a small drift into the Pasta Pete mode then back to SDR.

My XYL is part Irish (and no part Italian --if she were part Italian we'd probably would have killed each other by now) and loves her traditional Corned Beef and Cabbage St Paddy's Day dinner. 

There is a trick to cooking this meal entirely in one large pot. You must have the small white Potatoes, Cabbage Wedges, Carrots and of course the Slab of Corned Beef. Did anyone mention garlic? One year this celebration involved my cooking for 12 guests. 

For that dinner I bought a 12 pound slab of Corned Beef from Katz's Delicatessen in New York and had it air shipped to Seattle. That cost me about the price of a Ubitx V.6 with all of the bells and whistles. But hey, it was for the wifey. After dinner I looked for left overs -- there were none. It was that good.

There was a Romance Comedy movie about 25 years ago "When Harry Met Sally". Part of that movie was filmed in Katz's Deli. I have also eaten at the Deli and it is indeed superb. So if you are looking for some authentic Corned Beef --they have a website and with plastic in hand you can have "real" Corned Beef at your St Paddy's Day Dinner! There is time to order one; but the window is rapidly closing.

Funny story with that Corned Beef and New York. When the box arrived --sure enough it was one huge slab. Not wanting to screw this up, I called the Deli and asked to speak to someone about how to cook this jewel. One of the staff shared that indeed it was a good idea to cut the slab in half so it all gets cooked properly. 

The day following the dinner I called Katz's Deli and asked to speak to the manager. This grumpy, grizzly guy gets on the phone and in typical NY fashion starts off by saying "What do you want to complain about?" 

I quickly said No, I want to thank you and your staff. They were so helpful and the Corned Beef was totally consumed and nothing left -- 12 people ate 12 Pounds of Corned Beef. It was excellent! He then says --Nobody Calls to Thank Us --and hung up. Well that's NY. 

Back to SDR. ZL2CTM's winning design continues to garner excellent signal reports. So visit Charlie's you tube channel and learn how to build this amazing radio. No computer needed and if you feel the need to see your waterfall --tune in one of the web based SDR receivers. I did that just to look at the sideband suppression on the opposite side band. 

I have made about three dozen contacts so far and it has performed well. I am indeed impressed! 

Some of my future posts will be about how I stumbled through the Iowa Hills Software and the results of the filter changes. ( A note to Bob, you will probably want to tune out this part.)  

I want to test filters of various band widths such a 6 kHz (AM Receive), 2.8 kHz, 2.0 kHz and maybe even 600 Hz. Just thinking ahead -- a selector switch with four positions, and a two digit decode so  two Teensy pins could result in 4 band widths. Now how cool is that? 

Oh something else ZL2CTM shared with me during our Skype event. He asked if I had looked at the AD9833 DDS board. I said no. This is a really small DDS board and is only good to 12 MHz but just think for a minute -- those radios which use a 5 MHz VFO or PTO. 

In fact a couple of my Ten Tec Radios including a Ten Tec Omni C that has a drifty PTO. This TT radio brings the PTO signals out to a jumper on the back panel so you can fit a Remote VFO to this radio. Wow you wouldn't even have to mess with the radio. Pull the jumper plug and fit the AD9833 output into the Omni C. Charlie buys these for about $1.50 for the complete board. Amazon has them for around $4.

In doing a bit of research on the AD9833 --one homebrewer directly soldered the AD9833 to the back side of an Arduino Nano as the pins needed for the AD9833 all aligned that way. Man that was really small. He added an OLED display and in the palm of your hand a complete Frequency Generator good to 12 MHz and it would even work with your Bitx40.

2020 and yet more technology for us!

Remember scrub your hand just like a Democrat that shook hands with the emperor (with a very small e) as one precautionary preventive move in the stemming of the spread of COVID-19.

73's
Pete N6QW



3/9/2020 ~ A Conversation with ZL2CTM

There is nothing like a bit of face to face time to clear the cloud of smoke surrounding what you are doing. Regrettably some of the smoke was from my burning parts.

Yesterday I got an email from Charlie, ZL2CTM suggesting we Skype. You have got to love this advanced technology as we were able to do just that. 

Firstly, I discovered that I had been "dabbling" with the wrong version of the Iowa Hills Software. There are several different forms (all good when used properly). Seems like I have been using the general purpose set of filter design hardware and what you really want is the Hilbert Transform (HT) Variant. 

The HT math operators have been around for a long time; but have become a staple for digital signal processing. Since we are not using DDC but the I and Q method then the In Phase (I) and the Out of Phase Quadrature (Q) signals coming from the two ADE-1 Direct Conversion receivers are separated by 90 degrees. The mathematical processing ongoing in the Teensy 3.5 recognizes and processes these 90 Degree out of phase signals using the Hilbert Transforms.

But to do this you must have the HT processing be designated in the sketch. Thus the Iowa Hills Software  generates these two sets of math operators one of which is at 45 Degrees phase added and the second is -45 Degrees phase added. Thus with the + 45 Degrees  and - 45 Degrees the span is 90 Degrees. 

This realization, a result of my conversation with ZL2CTM led me to the Hilbert Transform Software within the Iowa Hills Suite and we now have a filter that looks like what is shown below. In a contra approach to the many Commercial Box operators, I have set the bandwidth to around 2.4 kHz whereas the FLEX guys seem to like 2.8 to 3 kHz so their signals have "presence" and are not yellowie!

Now I need to collect the two sets of coefficients and embed them into a Teensy 3.5 sketch. For this 1st test run I will be using 100 coefficients and if my "dabbling" works, then I will test drive more coefficients. 

In theory more coefficients add more points to the curve and this provides a better  defined filter. The question remains. How many is enough before you reach the law of diminishing returns.

A big Thank You to ZL2CTM for suggesting we Skype -- Otherwise I would have been in the weeds for a very long time.


Stay tuned for the excitement. 


Coronavirus Tip: It is important to wash your hands in a manner just as if you were a Democrat and were forced to shake hands with the emperor (with a very small e). Special note:  it is more than just a quick rinse, it is a thorough Scrubbing!

As an aid Sing Along like Ensign Nellie Forebush in the movie South Pacific "I'm going to wash that man right out of my hands". Several chorus loops through that song is about the right length of scrubbing!

73's
Pete N6QW




3/8/2020 ~ The 2N3866 Bi-Directional Amp!




PWKSCDS

***************
3/6/2020 ~ 1St Contact with W7LTG, Francesca at 1314 PST on 7.204 MHz -- My report: 5X9 + with good audio ~ Running  100 Watts. I may try to work the contest this weekend. You just got to love this technology.

2nd contact with WV6PBJ, Dave at 1400 PST. We are on a roll.

Worked some of the DX Contest including a XE2, 4A7S, TI7W, KH6, TO3 (Guadeloupe), PJ4G and JA3YBK . We are indeed on a roll. I was running 600 Watts --this contest is not for the QRP kids!

I will be further testing the opposite sideband suppression. But significantly the RADIG V3 Main Board and my bi-directional 2N3866 RF Amp board are doing very well.  



BTW the RF Amp stages following the Band Pass Filter on the RADIG Board are a 2N3866 steerable amp and following that is a 2N3866 Driver Stage and the Final is the IRF510. This lash up produces in excess of 5 watts. The amplifier following the RADIG is the CCI AN762. The antenna is my inverted V with a 35 foot apex.



Ugly and Al Fresco but works!!!!!

This morning I spent some time with the Iowa Hill Software and defined a 7 Pole Chebyshev 
Band Pass Filter comprised of 127 Coefficients. This filter is only 2.4 kHz wide and looks like this. It looks like a Brick Wall.

In "diddling" with the software my first run was to set the 3 dB point on the low end to about 250 Hz and on the high end to about 2650 which effectively make the 3 dB bandwidth 2.4 kHz. At 60 dB down we are around 3.5 kHz (thus my brick wall comment). But until I actually load it into the software and test it I won't know the "real world" performance. 

This was essentially my 1st run at seriously using the Iowa Hills Software so I really may be off in the weeds. I am just at the learning stage and the seasoned pro's are likely having a good laugh. 


I have the coefficients but I think in the ZL2CTM software you have to have two sets of filter coefficients so that the other is 90 Degrees from each other. Need to study that but from what I inspected in ZL2CTM's code that appears to be the case.

I dumped the 127 coefficients into an Excel Spreadsheet but have not figured out how to make a second column where the first series of points is simply inverted. I have been doing it by hand --it may take a while to cut and paste all 127 values. But that is only half the task, as you must precede every one of the values with an identifier in the Arduino code. So that is 254 entries. It may take a day or two for me to get it all done and test drive it.

Here are the 127 coefficients:

-0.00145151
-4.65E-04
4.33E-04
0.001329462
0.002258667
0.002865166
0.00259709
0.001081036
-0.001858205
-0.006391743
-0.012684756
-0.020735604
-0.030317289
-0.041010182
-0.052191803
-0.06303164
-0.072575248
-0.079856866
-0.083980378
-0.084209883
-0.080081336
-0.071477129
-0.058650131
-0.042229236
-0.023195131
-0.002799094
0.017553243
0.036424438
0.052479742
0.064627489
0.072130783
0.074675596
0.072402618
0.065894145
0.05610445
0.044249241
0.03167521
0.019715506
0.009544312
0.002057282
-0.002208487
-0.003115033
-9.18E-04
0.003787228
0.010160715
0.017227087
0.024000243
0.029603667
0.03336817
0.034896403
0.03409305
0.031156935
0.026534562
0.020846461
0.014799533
0.009093628
0.004333681
9.62E-04
-7.85E-04
-8.87E-04
4.67E-04
0.002926969
0.006032333
0.009282744
0.012202263
0.014399063
0.01560802
0.015713103
0.01475021
0.012890381
0.010405788
0.007625942
0.004891207
0.002508133
7.12E-04
-3.56E-04
-6.59E-04
-2.61E-04
6.90E-04
0.001993799
0.003420847
0.004750315
0.005795487
0.00642559
0.006577244
0.006255898
0.005528736
0.004510053
0.003341293
0.002169768
0.001129063
3.23E-04
-1.86E-04
-3.80E-04
-2.83E-04
4.70E-05
5.26E-04
0.001063346
0.001569604
0.001971346
0.002217828
0.0022856
0.002178341
0.001923024
0.001563585
0.001152894
7.44E-04
3.84E-04
1.06E-04
-7.14E-05
-1.46E-04
-1.30E-04
-4.55E-05
7.85E-05
2.13E-04
3.31E-04
4.15E-04
4.55E-04
4.48E-04
4.02E-04
3.29E-04
2.43E-04
1.59E-04
8.75E-05
3.65E-05
7.56E-06

-2.37E-06

My eyes hurt...




73's
Pete N6QW



In unrelated news.. Mick is gone and are what people saying true that Mikey may be replaced by Nikki?
The emperor must be pissed.. Coronavirus has shown up in Florida and New Jersey and that is sure to impact his golf game! 
********************************
3/5/2020 ~ SEABEE Birthday -- 78 years ago the SEABEE's were formed ( 5 March 1942). So to all SEABEE's world wide, present and former --Happy Birthday -- Can Do!

WG5EEK posted a nice video on you tube about SDR Dongles -- again something that just showed up on my phone. 

There is some really sophisticated software floating around and one lets you have what is in essence a "super scanner" all for $20. 

There is another piece of software called SDR# that had a very nice spectrum and waterfall. 

So like "quickly" rather than slowly but surely, -- SDR is finding its way into our hobby. Most of the software is Windows based but some is also dual Windows and Linux (like Quisk). I am finding a whole new world with software that is Linux based.


3/4/2020

[New additional video of the transmit waveform just posted.]

My initial posting of this morning described some issues I was having in making the transition from receive to transmit and back to receive. 

That configuration used a DPST relay which switched 12 Volts between receive and transmit. On receive the switched +12 VDC was only switched to the audio amp stage. On Transmit at least 4 relays were involved to add voltage to the transmit circuits and to steer signals through the bi-directional amplifier stage.

There was a considerable amount of back EMF and despite having some snubber diodes -- even the Si5351 jumped 100 Hz in the transition. NOT GOOD MY FRIEND!

The remedy was to permanently connect the 12 VDC to the audio amp stage as the muting in the software takes care of that issue. 

For the transmit side -- an old trick. The switched voltage is run through an LM317 Voltage Regulator. On the input side is a 100 NF cap and on the output side is a 1 Ufd electrolytic. From the V Output to V Adjust is a 220 Ohm Resistor. To that junction is connected 1820 Ohms to Ground comprised of a 1K and 820 Ohm in series. The LM317 Calculator says with these constants you should get around 11.5 VDC. 




Now the problem is gone and the supply to the Teensy stages is clean. No longer does the Si5351 jump in frequency as you transition. 

This is a video using my new 12 MegaPixel Camera acquired from Amazon for less than $10. There is no audio and I am using the Linux Mint shop computer with the program Cheese. 

The transmit signal is raw coming out of the bidirectional amp stage (single 2N3866). With a bit of additional filtering we should be good to go.

Don't you just love this technology -- another event in 2020. 












I am having some issues making this radio transceieve. This same Teensy 3.5 board was used previously and worked FB.

It will work receiving and like wise transmitting but upon return to receive it is like the transmitter is transmitting into the receiver. Not good.

I may have corrupted the code as there are provisions in the code to efficiently handle this transition. Another possibility is some of the relays may be hanging up. More investigation needed.

The receiver is picking up some DX --must be a contest coming up this weekend.



Just when you thought you escaped commentary on the Coronavirus, a friend sent me this calling it "The Redneck  Coronavirus Cure"








Spray in mouth liberally and often.




Might  not help, but at least you won't care!


73's
Pete N6QW


New Technology for 2020 ~ Improvise, Adapt and Overcome

What to do during the Pandemic? This is a chance to get back on the air or to take up an interest in homebrewing your own rig. You can bui...