JackAl Board Debut

Jack Purdum
 

All:

The FDIM conference was a good time and the trip to nearby Xenia for the Hamvention was also great. The rain didn't help, but it was better than last year, and I'm sure it will be even better next year.

Friday night was a sort of Show-and-Tell at FDIM and we used that opportunity to show our JackAl board in action. This photo shows a little more about what it is and does:

Inline image

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 customize 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 center frequency (e.g., 700Hz in the shot below), press the encoder, and then you see this:

Inline image

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 800x480 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.

Jack Purdum, W8TEE
Al Peter, AC8GY


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