SSTRAN AMT3000 AM Transmitter

The SSTRAN AMT3000 transmitter.

One of the saddest things about my hobby of restoring vintage radios is the absolute lack of quality programming on the broadcast bands today. 

Not only is the golden age of radio long gone, today’s AM airwaves are chockful of hate filled right wing talk and syndicated FM commercial radio is mostly insipid crap music. A couple of summers ago, I built a 2 tube regen radio receiver kit with my 10-year-old niece, and while the build was quality time spent together, in the end she was left with a radio that is of no use to her.

But, while there may be very little worth listening to on the broadcast bands today, there is no shortage of excellent programming available as podcasts – good music, true crime, documentaries, comedy and even drama – free for the taking for enjoyment on your smart phone or other device.  This cornucopia of content can make ‘watching the radio’ wonderful again.

There are three easy ways to play modern podcasts and other recorded programs on a vintage radio. 

The first is to add an “AUX IN” to a vintage radio, like many new radios have.  The circuitry is simple and with a handful of parts, including a 1/8 stereo jack, you can easily play the output from your iPod, smart phone or CD player through the radio’s AF stage.

This “AUX IN” mod is popular with radio repair folk who restore vintage radios for resale.  Look at what is available for sale on http://www.radioattic.com and you’ll find many radios for sale with the mod.  If this interests you, check out the YouTubevideo by D-Lab Electronics here.

The second method is to add a Bluetooth receiver wired into the radio’s AF stage like the “AUX IN” jack mod above.  This mod is attractive as the listener can easily transmit podcasts and music from their smart phone to the vintage radio.

For me, the third method that I am profiling here, using a low power transmitter to ‘broadcast’ programs to my vintage radios is a bit more authentic as ‘real radio’ transmitting a modulated RF signal to the receiver where the ‘whole radio’ is being used from the RF to the IF to the AF.

So, a few years ago I decided to build the SSTRAN AMT3000 transmitter kit.  It is a popular solid state transmitter that costs about $100. As of this writing, it is not clear to me whether the kit is still available or not as the www.sstran.com website still has an announcement on the home page stating that as of November 12, 2017 they are not accepting any new orders. However the catalog page and shopping cart still appear functional. 

I had considered other options including a scratch build or this $40 tube based AM transmitter kit. The tube option had two solid arguments going for it – it was definitely cheaper and using a tube-based transmitter seemed a better match stylistically for most of my antique radios as they are tube based.

However, the AMT3000 won out as it had a few qualities that the tube kit did not offer.  These included separate up-front controls for gain, modulation and signal compression.  The AMT3000 is also easily tuned to different frequencies on the AM broadcast band by setting DIP switches. 

I had also read several online reviews and discovered that the kit had a very good reputation. The fit and finish were attractive too so the SSTRAN kit won out in the end.

I recall it took me two, maybe three evenings to construct the kit. The build was easy thanks to excellent documentation, good PCB layout and no toroids or coils to wind. There was a single surface mount IC, however, but it only has 14 leads and spacing was wide enough that I had no difficulty with my middle aged failing eyesight and shakier dexterity.

The completed circuit board.

In the top left view above you see there are two audio in jacks.  This is a mono transmitter, but you can feed a stereo signal through the two jacks which are combined to mono.  I use a stereo to RCA jack patch cable to connect the transmitter to my PC or CD player.

The transmitter comes with a wall wart step down transformer that puts out 11 VAC; the voltage regulator can be seen with the heatsink above. 

A PLL synthesizer references the 4 MHz crystal to precisely set the transmit frequency.  The DIP switches mentioned above to tune the transmitter is seen just below the heat sink on the voltage regulator. The manual includes a table showing the settings to tune across the AM broadcast band.

Notice the three RF chokes, which can be switched in or out of the circuit with jumpers to reduce hum caused by stray RF. Two chokes isolate the power input and the third isolates the audio input ground from the PCB ground. 

On the right side of the board you will see a four position DIP switch used to switch several inductors in and out of circuit to assist tuning the indoor long wire antenna supplied with the kit.  The instructions describe the construction of a base loaded vertical outdoor antenna that can be used to transmit up to a 2-mile radius which I have not built. When using the external antenna, these inductors are switched out.   

For my purposes, I have setup my home AM broadcast station on the operating desk of my ham radio stationon the second floor of my house.  As I amonly interested in transmitting a signal to radios within my house, I am usingthe provided long wire antenna which I have hanging out a second storywindow. 

My transmitter is tuned to 1,000 kHz which is a relatively dead spot on the AM dial in New Haven County, despite the number of signals coming from NYC to the southwest and Boston to the Northeast.  I get little interference day or night.

My transmitter is connected to a beater Dell laptop I bought refurbed from Walmart.com for a song.  I installed Ubuntu and use the Beatbox app to manage the queue of podcasts and MP3s.  I leave the station on 24/7 so now there is always something worth listening to on the radio.

I mentioned above that the AMT3000 has a compression control, which is a real nice touch.  Turning down the compression increases the hi fidelity of the signal, music actually sounds better to my ears than what is typically heard from commercial AM stations.

My home AM radio station – the SSTRAN AMT3000 transmitter sits atop my EICO 723 Novice transmitter on the AB1DQ operating bench. Programming is queued via the Beatbox app on my Ubuntu Dell laptop.

If you are looking for an AM transmitter to bring life back to your vintage radios, you won’t do any better than the SSTRAN AMT3000.  It is a real solid performer and simple enough build for anyone with moderate soldering skills.  I have gotten many years of satisfaction from mine.  Every December I use it to transmit holiday music to vintage radios placed throughout our house during our annual Christmas party – it’s a fine way to showcase the radios I have lovingly restored.

SSTRAN AMT3000 SPECS:

  • FCC Part 15 Compliant
  • Emission type: A3 Amplitude Modulation.
  • Modulation Type: Series Modulation.
  • Modulation Capability: 100%
  • Carrier Shift: less than 0.5%
  • Broadcast Frequency Range: 530 kHz to 1705 kHzin 10 kHz increments
    (a 9kHz increment version is also available for non-US radios)
  • Frequency Response: 10Hz to 20kHz
  • Audio Input Level: 200mV for 100% modulation
  • Audio Input Impedance: 4 ohms to 50K ohms
  • Distortion: 0.5%
  • Final DC Input Power: 100 milliwatts (full legallimit per FCC Part 15)
  • Duty Cycle: 100%
  • AC Ripple (Hum): Less than 0.3%.
  • Frequency Stability: 0.003%
  • Antenna Matching System: Pi-Network

Mr. Carlson’s Lab High Voltage Capacitor Discharge Tool

My favorite scratch build of 2018 was the capacitor discharge tool designed by and published by Mr. (Paul) Carlson on his Patreon website, Mr. Carlson’s Lab

Mr. Carlson’s Lab is the best YouTube/Patreon channel I have found dedicated to electronics repair, restoration, building and most importantly, theory.  His lab is simply amazing, his expertise is second-to-none, and his willingness to share what he knows is beyond generous. 

Paul’s presentation style is easy to follow and well-paced, making the material easy to absorb and his attention to detail borders on obsessive. He not only guides the viewer through construction step-by-step, he takes the time to explain the theory behind each circuit and occasionally challenges the viewer to solve problems along the way.

There is simply no better place to gain a quality electronics education at any cost.  Many of the Mr. Carlson’s Lab videos are available for free on YouTube, but for those like me, wanting to learn and know more, Mr. Carlson offers an in-depth electronics course via Patreon.  The capacitor discharge tool I built was presented on the Patreon site in a pair of videos.

In the first video, Mr. Carlson introduces the concept and specs and provided the list of components needed for the build, He challenged his viewers to attempt to design the circuit themselves and the best viewer circuits were showcased in the second video where he revealed his design for the project followed by step by step build instructions.

The circuit is composed of four 1k 50 w resistors wired in series to provide a load to drain charged capacitors. There are two LEDs wired in parallel with dropping resistors and a 5.6 v 5 w Zener diode to control current direction. Depending on polarity, one if the two LEDs will light when the probes are connected to the cap and will dim out as the cap is discharged. The other set of probe leads us into a standard voltmeter to show the cap charge. This way I can be sure when the cap is safely discharged. 

My completed capacitor discharge unit internals.
My finished project.

My finished and tested project is shown above. By connecting the output probes to my Ohm meter and getting a 4K ohm reading, I confirmed the load resistors were properly wired in series. For the next test, I shorted the input probes and watched the ohmmeter drop to zero, confirming that the probes were correctly wired and were not open. Lastly, switching the VOM to the DC voltage scale and applying the same input leads across a 9v battery I could read the 9v on the meter and observe one of the LEDs lighting up. Then reversing polarity of the probes on the battery the other LED lit confirming proper wiring of the circuit. 

Do you subscribe to Mr. Carlson’s Lab? Have you built any of his original projects? Can you recommend any other YouTube channels for learning electronics? Please add your comments below or drop me a line at ab1dq@protonmail.com.

My previous capacitor discharge tool…
not nearly as precise and a bit more exciting to use.

©2019 James M. Surprenant

Punch Bareknuckle Rothschild

Sunday, December 30, 2018 and I am at the Owl Shop in New Haven, watching the final Pats game of the regular season.  Brady & company are hosting the NY Jets and playing for a first round bye in the playoffs.

Today’s cigar is the Punch Bareknuckle Rothschild.  It’s a short 4.5” 50 ring gauge stick with a dark, oily and somewhat toothy sun grown Ecuadorian Habano wrapper. The cigar features a distinctive foot band.  Construction is nice and firm from foot to its neat double-cap.  Inside the Bareknuckle contains Honduran and Nicaraguan long fillers, laced with flavorful ligeros. 

Today’s Bareknuckle smoke is my second.  I purchased a pack of five from cigar.com for $24.00 which makes this a darn good value at $4.80.

Other online reviews of the Bareknuckle that I consulted note that this full-flavor offering from Punch is a welcome return to the label’s previous reputation as most of their offerings have become far milder in recent years.  For what it’s worth, I typically favor a milder cigar, however will enjoy medium to full body sticks from time to time.

I cut today’s cigar with a straight cutter; typically, I prefer a punch or a notch cutter. The cold-draw is very flavorful, and I pick up strong notes of cocoa, fruit and earthiness.

The first third.

Appropriately enough, the Bareknuckle starts off with a flavorful “punch” from the very first draw.  The initial flavor is a strong woodiness that initially tastes oaky to my palette but quickly develops into a nice cedar.  Also notable at the start is a good amount of pepper.  The draw is just about perfect, and the burn is good, although a bit uneven.

Ash is a nice salt & pepper but broke off just over the half inch mark.

Flavor remains cedar, pepper with a slight hint of vanilla at the end of the first third.

At the end of the first quarter, the Pats are up 7-3 over the Jets.

The second third

Draw remains very good and the burn has even upped on its own without touching up.

The vanilla notes are getting stronger, with the nice cedar and spice still predominant.  By the midpoint the vanilla starts taking the lead.  It’s distinctly vanilla, not the creaminess experienced in most cigars – it’s very nice.

At the mid-point the draw suddenly became much looser and the cigar needed re-lighting.  This also happened with the first Punch Bareknuckle I smoked a few weeks ago.

At the mid-point the draw suddenly became much looser and the cigar needed re-lighting.  This also happened with the first Punch Bareknuckle I smoked a few weeks ago.

The last third

The last third starts off with the cedar giving way to the vanilla notes accented by pepper.  Throughout the entire cigar, these three flavors – cedar, pepper and vanilla – were balanced nicely.  At the very end, the cigar needed touching up again.  Despite the good and even burn, the cigar wanted to go out again.

Overall impressions

As I stated above, I generally prefer milder cigars, but the Punch Bareknuckle is a wonderful medium- to full- bodied choice.  I enjoyed my first Bareknuckle with a double-shot of Jack Daniels on the rocks, and today’s stick was enjoyed with a pot of Lapsong Souchong, my go-to non-alcoholic beverage choice to enjoy with a fine cigar as the tea’s smoky flavor pairs well with most sticks.

Total smoking time was about an hour and fifteen minutes.  I rate the Punch Bareknuckle Rothschild a solid 9 out of 10, and will definitely be keeping some in my humidor for when I am craving a cigar with more intense flavor. 

© 2018 James M. Surprenant

The Altair-Duino

The most exciting and satisfying kit I built in 2018 was the Altair-Duino, an Arduino based emulator of the Altair 8800, the legendary microcomputer designed in 1974 by MITS (Micro Instrumentation and Telemetry  Systems) and featured on the cover of the January 1975 issue of Popular Electronics.

Although I was only 9 years old when that issue of PE was published, I remember reading and making photocopies of the article at my local library a few years later. 

At such a tender age, I didn’t have any of the resources needed to build my own Altair.  It would have taken me two and a half years to have saved up the $439 cost of the kit at my $2/week allowance, and while I had access to my grandfather’s radio and TV work bench, his parts bins contained hundreds of vacuum tubes but hardly any transistors and no computer chips.

So imagine my excitement when I discovered this year that a modern day emulator was available in kit form.  The Altair-Duino kit is offered by KB0WWP, Chris Davies and based on the Altair 8800 emulator project published on hackster.io by David Hansel.  The Altair-Duino kit comes complete with a high quality etched PCB, bamboo case, replica face plate, and all components and hardware. 

What’s even better is the price – online inflation calculators suggest that the original Altair kit’s $439 price tag would be equivalent to $2,057 in 2018 dollars, but the complete Altair-Duino kit is only $149…  WOW!

It is worth mentioning that another modern day Altair emulator option for retro computing fans is Mike Douglas’ Altair 8800 Clone (www.altairclone.com) which is available built for $621 at the time of this writing.

The Build

Building the Altair-Duino was straightforward and simple for my kit building skills, which I would rate as proficient.  Using the very good documentation found online on the http://www.adwaterandstir.com site I built the complete kit in about 5 hours’ time over two days.

Assembling the kit involves soldering 72 resistors, 36 transistors, 36 LEDs, and 25 toggle switches on the top side of the PCB.  The bottom of the board holds the Arduino Due and a Bluetooth board, the SD card, and a few discreet components to regulate the power supply.

The fit and finish of the kit is exceptionally well done. The beautiful face plate serves as a handy template for properly aligning both the LEDs and the toggle switches when attaching them to the PCB, and the shallow wooden cabinet is pre-drilled for the rear connections panel and has a cut out slot on the backside so the builder can easily access the SD card which comes pre-loaded with the Altair software.

Operations

The Adwater & Stir website has an excellent operations page that includes a link to the original Altair 8800 operations manual which can be used with the Altair-Duino as it is 100% compatible with the original Altair 8800.  The operations page also provides easy to follow step-by-step directions that I found easy to follow and useful for instant gratification.

I connected my Altair-Duino to my PC via the USB cable and Windows 10 recognizes the device on COM 4.  The Altair-Duino can also be connected via a serial cable or Bluetooth.  

Using the recommended terminal program PuTTY, I have had fun experimenting with a couple of the various pre-loaded versions of BASIC: Bill Gates’ 4k Altair BASIC and MITS 16K ROM BASIC, have puttered around with SuperCALC and have enjoyed a nostalgic trip through the Underground Empire of ZORK.

There is much more that can be done with the Altair-Duino and I look forward to experimenting further. 

Have you built an Altair-Duino or do you have the Mike Douglas Altair 8800 clone?  Did you have an original Altair back in the day?  I’d love to hear from you – please comment or drop me a line at ab1dq@protonmail.com.

© 2018 James M. Surprenant


Something new from AB1DQ

Hello and welcome to the new AB1DQ blog, I hope you find this site informative, inspiring and fun.

My name is James M. Surprenant and AB1DQ is my amateur radio call sign. I hold an Amateur Extra Class license and earned my first ticket as KB1IAR in 2002.

Although I came to ham radio later in life, I have always been fascinated with radio and electronics ever since I was a child ‘wasting time’ at my grandfather’s workbench.

My intent for this new blog is that it should be a place for me to share ideas of personal interest and projects that are currently on my workbench.

This is a personal site and like most persons, I’m not one dimensional. I have many personal interests including, but not limited to, photography, spirituality, cigars, whisky, baseball, poetry and music. Thus not all of the content here will be related to electronics and radio. I ask that all visitors here consume the content I share with an open mind, take what they need and leave the rest.

So, thank you VERY much for visiting – please drop me at ab1dq@protonmail.com and let me know what you think.

This “Cheshire Cat” is my ham radio logo and appears on my QSL card.
It was created by professional cartoonist and fellow ham radio operator N2EST, Jim Massara. Lear more about Jim and his work at http://www.hamtoons.net.

73 de AB1DQ
James
Cheshire, CT

Altar Q Cigar by Oscar Valladares

I smoked my first Altar Q cigar by Oscar Valladares a couple of weeks ago at a whisky tasting at the Owl Shop in New Haven, Connecticut.  It was my first cigar from Oscar Valladares, although I have been meaning to try their Leaf for some time.  The Altar Q impressed me with a lot of flavor that evening and I noted that it paired particularly well with the Laphroaig Lore Scotch whisky that was being poured.

It is noontime New Year’s Eve 2018 and I stopped in at the Owl again today to try another Altar Q. after running some year-end errands.

The cigar comes boxed in a wooden box of 16 with the cigars separated by paper. The cigars do not have a cellophane wrapper but instead have a beautiful wide 3.5” paper foot band honoring Mayan tobacco.  Currently Neptune Cigar offers the box of 16 for $168 which makes the cost of an individual stick $10.50 – a bit pricey for me, but really worth it.

Oscar Valladares Tobacco, is located in Danli, Honduras. It started operating on 2012, the Factory was founded by Oscar Valladares, Hector Valladares and Bayron Duarte, with experience in the tobacco industry; Oscar worked for more than 9 years with Rocky Patel and Bayron worked for more than 20 years for General Cigars and Oliva.

The Altar Q is a 52 ring gauge 6” cigar and features a Ecuadorian Sumatra wrapper, a Honduran Copan region binder and Honduran long fillers.  The appearance is oily and smooth, seamless with very few visible veins.  The cigar has a triple-cap and a pigtail.  Construction is fairly firm, and just a bit squishy.

I cut the cigar with my notch cutter and found the pre-light draw to be flavorful – very spicy, leathery, earth and classic tobacco flavored.

First third

Upon lighting, the Altar Q starts off with a big bite of spicy pepper – wow.  Also notable from the get go are subtle citrus, slight honey notes and some nuttiness.  The draw is very good and the burn is decent, a little uneven and required some slight touching up.  The cigar produces good smoke and produces a nice solid salt and pepper ash.

Second third

The strong pepper flavor is yielding a bit to a nice nutty and citrus flavor at the start of the second third.  The draw and burn both continue to be very good.  Just beyond the mid-point the flavor is becoming nuttier and the creaminess begins, however, the cigar needed re-lighting at this point, just as my first Altar Q needed a couple of weeks ago.

Final third

The last third begins with more creaminess, some nuttiness and the ever-present pepper.  The burn remained good and even and the draw was perfect.  As I smoked my way through the last third, the flavor became more and more creamy – a very tasty and satisfying smoke.

Overall

I consider the Altar Q an instant classic and a new favorite.   It pairs exceptionally well with a smoky peaty scotch such as Laphroaig Lore or a hot pot of Lapsong Souchong tea. I would rate it a 9 out of 10 and I look forward to picking up a full box before too long.

© 2019 James M. Surprenant