(Again a bi-weekly program ... mostly)
April 22, 2014
Network Analyzer Terminal (NAT)
A handheld graphic display terminal for controlling the Simple Scalar Network Analyzer ... and more!
Test instruments, radios and bench accessories for the electronics experimenter these days are increasingly using the PC to augment the instrument’s control, data processing and display capabilities. Whether for remote operation, remote display or post processing, the PC offers much computational power via the serial port connection to the instrument. However this extension of the instrument’s capabilities comes at a price, considering the size of the PC, the complexity of making the serial connections work, and the updating and configuration of the PC application being used for the enhanced capabilities.
Enter the Network Analyzer Terminal … N2APB and AD7JT designed the NAT to serve as a convenient, small, inexpensive and dedicated “terminal and controller” for instruments offering serial port expansion capabilities. The cost of bright, multi-color, and moderate-resolution VGA displays has come down in recent years to enable a small form-factor device such as the NAT to be developed. Further, the display’s touch-sensitive surface will allow the developer to use “soft keys”, thus eliminating the need for mechanical pushbuttons and other controls.
Lastly, adding a jack to accept low-cost, industry standard, mini keyboards allows the terminal to be “bidirectional” for the operator to conveniently enter textual information, numeric calibration data or whatever specific input the instrument requires.
The small size of the NAT pc board (approx 3” x 4” x ¾”) enables users to add it to the front panel of the enclosure that houses the instrument itself (e.g., the PHSNA Simple Scalar Network Analyzer), or even into a small, dedicated enclosure for use as a handheld accessory that is tethered to the target instrument via the serial cable.
The NAT platform incorporates the use of an SD Card to provide massive spooling of the instrument’s incoming data stream, thus enabling at-speed operation of the instrument, long multi-point scanning capability, and convenient/extensible data storage. The user can also use the SD Card for transfer of instrument data to other platforms. Further, the SD Card offers a convenient way to upgrade the NAT firmware in the field … just load the latest NAT firmware release or an entirely different application onto the card and then command the NAT to reflash itself using that file!
While initially designed as an optional accessory for the PHSNA instrument (discussed in the last episode of CWTD), other applications of the Network Analyzer Terminal are planned for follow-on releases, including use as serial port terminals for the Micro908 Antenna Analyst and for the SDR Cube Transceiver, as well as CAT terminals for popular rigs from Yaesu, Icom, Kenwood and Elecraft. And with plug-in options, the NAT can easily become an attractive standalone VFO, power meter and display/control head for other commonly used equipment in Amateur Radio.
With the Network Analyzer Terminal, the capabilities of many bench instruments and accessories are instantaneously expanded, and many interesting new applications are made possible!”
73, George N2APB & Joe N2CX
CWTD Episode #67: Network Analyzer Terminal
... A handheld graphic display terminal for controlling the Simple Scalar Network Analyzer ... and more!
NAT co-designer and guest host with us for this episode: Dave Collins, AD7JT
The "frame" below is the separate web page we created for the NAT ...
SSNA Yahoo Group (open membership – support documents will be posted here) ... http://groups.yahoo.com/group/PHSNA
Arduino UNO® Support: http://arduino.cc/en/Main/ArduinoBoardUno
AD-9850 Modules (a selection of overseas eBay sources):
W7ZOI RF Power Meter (QST June 2001, available in print archive for ARRL members) ... http://w7zoi.net/Power%20meter%20updates.pdf
Analog Devices AD-9850 DDS datasheet: ... http://www.analog.com/static/imported-files/data_sheets/AD9850.pdf
Analog Devices AD-8307 RF Power Detector Datasheet ... http://www.analog.com/static/imported-files/data_sheets/AD8307.pdf
Graphical Analysis for Windows – scientific graphing application ... http://www.vernier.com/products/software/ga/