JackAl is here!

Jack W8TEE and Al AC8GY have  released details of the JackAl board following FDIM (preceding Dayton Hamvention).

Friday night is a sort of Show-and-Tell at FDIM and they used that opportunity to show their JackAl board in action. The photo above shows a little more about what it is and does.

At the show, Al hooked up a noise generator to the µBITX to show how the filters work. (There are 4 preset filters for CW and 4 for SSB.) In addition, you can customise one CW and SSB filter to the bandwidth you desire. You might be able to see that the skirts are pretty steep for the filters on the scope in the background. The setting of the CW custom skirts are set differently, in that you pick a centre frequency (e.g., 700Hz in the shot below), press the encoder, and then you see this:

In this case, turning the encoder CCW increases the bandspread (i.e., the 440 red number above, although it looks orange in the photo) by simultaneously moving the skirts (480Hz and 920Hz) further apart. If you turn the encoder CW, you narrow the bandspread. Most CW users will probably center the bandpass on their favorite sidetone frequency, which centers the bandpass on that frequency.

The demo used a 5″ display, although a 7″ display is also available. The third knob on the front is for a second encoder that we use for everything from setting the CW keyer speed to adjusting the filter skirts. You can see some of the plots on the panel at the rear of the picture above for some of the board’s features (e.g., filter responses, compression, etc.) Those will be included in the documentation when the (downloadable) manual is finished.

The JackAl board has the following features:

  • 5″ or 7” touch screen 800×480 TFT color display
  • Dual VFO’s
  • RIT
  • S meter
  • RTC
  • CW keyer, 5 to 50wpm (we could go up to 100wpm, but…really?)
  • Up to 50 CW preset messages, selectable at runtime…perfect for contest messages
  • Touch screen function and control selection (e.g., band changes, RIT, mode, VFO, VFO increment, LSB/USB, etc.)
  • Automatic LSB/USB selection based on frequency (overrideable)
  • One touch frequency increment changes (1Hz to 1MHz in multiples of 10…the white underscore in the frequency window)
  • Dual encoders (frequency, features)
  • EEPROM storage of user preferences (one-click reset to “factory” defaults)
  • Uses Teensy 3.6 processor (1Mb flash @180MHz) and companion audio board
  • Support for 3 external CW push button switches (NO) for sending stored CW messages (e.g., contesting)
  • Hardware AGC using IF take-off
  • Audio AGC with adjustable threshold
  • Mic compressor with adjustable threshold
  • 8 band audio equalizer
  • Receive audio filter: 48dB/octave (8 pole equivalent DSP filters)
  • 4 CW presets (150, 300, 400, 600, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter
  • 4 SSB presets (1500, 1800, 2200, 3000, [or none] Hz 3dB bandwidth) + 1 user-defined knee frequencies (at runtime!) filter’
  • Variable Notch filter, encoder adjustable, use specified Q
  • 7 watt power amplifier

The board will be distributed with all (surface mounted) parts in place. The user must supply the Teensy 3.6 ($30), its supporting audio board ($15), and the 5″ ($34) or 7″ ($44) touch screen displaying (using the RA8875 controller chip, BuyDisplay.com).

We expect the JackAl board to sell for $50.

We may need to adjust this price as we have only received “ballpark” cost estimates for the board since we only have the Gerber files for the Beta board.

Currently, we are using less than 20% of the available flash memory (out of 1Mb) and less than 15% of the SRAM (256K), so there is plenty of memory resources available for adding “stuff”. The board also brings out a number of I/O pins to help your experimentation. With the exception of removing one SMD resistor on the µBITX board and soldering two wires to those pads, all interconnections are via existing connectors.

Our best guess is that after finishing the modified Gerber files, production, Beta testing, and writing support manuals, it will be probably two months before we begin distribution. We will announce its availability here as soon as we can. BTW, if anyone knows a high-quality PCB manufacturer who also does pick-and-place at reasonable prices, we are getting quotes and would like to know about them.


Simulated S-Meter and SWR meter on small OLED display





Duwayne KV4QB has been playing with an Arduino Pro Mini and a small OLED display to use as a stand alone replacement for a analog meter.  The existing Raduino in the µBITx does not have sufficinet spare analog input pins to provide everything that Duwayne wanted to measure.

More information can be found on his blog at:

He is also working on a small board to provide forward and reflected power readings for SWR metering and power measurement.

This has created a bit of interest on the list, and represents an interesting idea that is potentially adaptable to other projects and use cases.


Poor man’s panadapter

Bruce KC1FSZ has been experimenting with a panadapter for his µBITx that is likely to be of interest to constructors, especially to anyone thinking about one of those fancy ICOM 7300s.

The goal was to build a crude panadapter into his BITX rig without resorting to external PCs, SDR dongles, etc.  He used a few cheats in his scratch-build BITX that may make this a bit more tricky on a stock unit.  However,  Bruce is sure that someone in the group can figure out how to expand this into the mainstream.

It’s a bit like a Sweeperino.  Bruce has built his firmware to quickly sweep the VFO across the band of interest (40m phone in Bruce’s case) and then to look at the AF spectrum at each point and display the result in a simplistic spectrum display. Obviously, this interrupts the receive for a brief instant when it is happening, but he has also set things up with an extra MOSFET so that the audio output can be suppressed during the sweep to hide the annoying sounds. This mod may already be in your rig if you’ve added an AGC.

The more sophisticated way to go is to do some DSP fiddling of the overlapping 3 kHz segments of the spectrum that are sampled during the sweep. At the moment Bruce sweeps in 500 Hz steps so there is overlap in the samples of the audio. This needs some more experimentation to get the optimal sweep speed, the cleanest way to stitch things together, averaging, etc. but even something basic is good enough to show the activity on the band.

Bruce also uses a cheap 128×64 OLED display, which makes these simple graphics possible.  Be aware that these displays can be noisy.

The picture at the top of this news items shows what the initial display looks like. The caret at the very bottom is pointing to where the VFO is currently set. You know it’s working because you can always see the signature 7199 BITX birdie!

Bruce has produced a video with the sweep slowed and the audio on so you can hear how it works.  It sounds like a strange SSTV mode, but it’s actually the entire 40m phone band being analyzed for activity.


Separating your display from the main board

Gordon W2TTT asked on the BITX20 Group list, “Does anyone have some links to the display/ Raduino extension cable parts?  I want to remote the display from the main board.”

If you want to separate your display from the main board, you should separate the display from the rest of the raduino and plug the “arduino nano” bit into the connector on the main board.  The reason for this is that you don’t want long leads spraying RF around from the oscillator outputs from the si5351a.  This is a sure recipe for birdies in your RX.

Use Dupont connectors (Male to Female) to do this.  Most will find either 10cm or 20cm connectors are suitable.

Jack W8TEE  comments “Jumper wires (aka Dupont wires) are great for breadboarding and experimenting, but my experience is that some of them don’t make a solid connection after recycling (connect/disconnect) a few times. We were getting a lot of noise on a TFT display line and finally tracked it to a faulty Dupont. The Chinese imports seem especially susceptible. If you experience noise or hashing on a display or in the audio, this would be one of the first places I’d look.”


Converting to an I2C display and other developments

Ian KD8CEC is busy opening up the possibilities for including different code sections in his new version 1.07 under development.  This will include the ability to readily shift to an I2C display in order to reclaim digital I/O ports needed for other features.

In the mean time, Bill K9HZ provides a succinct code listing required to get an I2C display to work

The following TWO things need to be done in Ian’s version 1.07 code (BETA):

1. Change Display models in “ubitx_20” :

From this:

#define UBITX_DISPLAY_LCD1602P      //LCD mounted on unmodified uBITX

//#define UBITX_DISPLAY_LCD1602I    //I2C type 16 x 02 LCD

//#define UBITX_DISPLAY_LCD2404P    //24 x 04 LCD

//#define UBITX_DISPLAY_LCD2404I    //I2C type 24 x 04 LCD

To this:

//#define UBITX_DISPLAY_LCD1602P    //LCD mounted on unmodified uBITX

#define UBITX_DISPLAY_LCD1602I        //I2C type 16 x 02 LCD

//#define UBITX_DISPLAY_LCD2404P    //24 x 04 LCD

//#define UBITX_DISPLAY_LCD2404I    //I2C type 24 x 04 LCD

2. Update Ian’s code to use the I2C libraries in “ubitx_lcd_1602i” :

From this:

#include <LiquidCrystal.h>

LiquidCrystal lcd(8,9,10,11,12,13);

To this:

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);  //


in the instance above the add-on board on the back of the display is set to address “3F”.  You can use the scanner to find the correct address.



16×2 Display Dimensions

Jim Reagan asks, “Can anyone give me the manufacturer of the LCD display?  Or the exact size?”

Jerry, KE7ER responding noting that “Adafruit says they nominally measure 24x69mm,  mine measures 24x71mm  https://www.adafruit.com/product/181″

“The 16×2 LCD (or 1602) is a generic display and there are clones of clones of clones for this display.  Who built it first has long since been lost to the mists of time, as has pretty much everything from the 1980’s.   But hobbyists have taken to it because it’s cheap, and speaks via 5v logic just like the equally ancient tech of their Arduino boards.  So they still get cranked out, by manufacturers too embarrassed to put a name on them.  The going price on eBay is down around $1.60.”

The LCD that comes with many uBitx is the  JHD 162:    https://www.sunrom.com/get/526000

The dimensions shown on page 16 are 24.1 x 72.2 mm.

Those pre-preparing a front panel while awaiting the arrival of their µBITx are advised to make a hole smaller than these dimensions, just in case the dimensions don’t match.   There is quite a bit of variation in 1602 display dimensions.


Mounting the display without screws showing on front panel

Mike WB8VGE claims, “mounting any LCD on a front panel is a pain”.  Probably most constructors would agree. Here’s how Mike does it without drilling holes in the corners to hold the display.

After you have painstakingly cut and filed the panel to allow the display to fit, fasten four .250 aluminum standoffs, one on each corner, and tighten with the correct screw. Use the shortest screw you have.
Check fitment and if necessary file away any panel material that might interfere with the display.
Using a sharpie pen, mark the corners. Don’t worry about being accurate, just a general location of each standoff will be enough.
Remove the display.
Use a bastard file and scratch around the area you just marked. The idea is to rough up the material.
Now, mix up a small batch of JB Weld.
Apply a generous amount to the bottom of each standoff, trying not to fill the hole up. (that’s why it’s best to use short screws so you don’t epoxy the screw in!)
Mount the display and with clamps, clamp the display onto the panel. I use small Irwin clamps and wood paint stirring sticks.
Wait 24 hours.
Whoa! You’ve mounted the display without trying to locate the mounting holes and without drilling holes!
Unless you go in there with a channel locks, you’re not going to be able to break the bond between the epoxy and the aluminum.

Tom  AB7WT has also tried this out.  He used shorter standoffs and put the JB weld on screws instead of longer standoffs. This way he could still unscrew the standoffs. It worked well and the screws were solid. The display and bezel look nice.