Custom Equipment offered by MP&A:


Retrofit Digital Display Unit for Harris SX-series AM Transmitters:


Workling display in transmitter

MP&A is finally shipping our retrofit color LCD display for Harris SX units.   We saw the clear need for these over the years, as the original alphanumeric displays, made by Texas Instruments, have proven to be terribly unreliable (most of them in transmitters are missing at least one segment, if not whole digits), were declared obsolete by TI many years ago, and have been essentially unobtainium for several years now.    

Display showing transmitter type confirmation screen


Even when the original display worked right, using it was cumbersome at best; the display showed only a 2-digit code for each channel/reading, and the user needed to have a chart of channel numbers to have any idea which reading was for what parameter, and another chart to see what the normal readings should be.  Out retrofit solves these problems, as the display lists the channel name in plain text, plus the normal reading, for any channel chosen.  Another chart was needed to decode overloads; our display lists the overloads in clear text, as well.  Our units have jumpers to select the type of transmitter (1, 2.5, or 5 kW), and will display proper normal values for the transmitter it's installed in. 


Retrofit display ready to drop and plug in 

Changing to the new display couldn't be simpler: Our display mounts onto the mounting studs of the old unit and plugs into the old one's ribbon cable.  You can either reuse the old keyboard, which will solder onto matching pins on the new one, or we can supply a new keyboard with the new display.

Units are in stock for immediate shipment.  Call or email us to secure your order.

Click here to see our marketing flier for the Harris SX Retrofit Display: New Life for the SX




Harris SX oscillator board

Replacement Oscillator Board for Harris SX-series AM transmitters:


MP&A now offers a drop-in replacement for the original crystal-controlled RF oscillator board used in all of the SX-series AM transmitters, including the SX-1/1A, the SX-2.5/2.5A, and the SX-5/5A.  Our board keeps the same basic design but uses modern integrated circuit types for the divide-by-two/four counter and the RF pre-driver/buffer amp.  We still use all through-hole components for ease of field repair.  There is only one custom-made part on the board (a small RF drive transformer, and we've got plenty of those!)--the rest of the parts are readily available from any of the major electronic parts houses.

Our price for these boards is $850, which is $350 less than the last price they were sold for when they were still available, several years ago.  Delivery date is two weeks ARO.  Call to place your order!



SC-1 AM/FM Site Controller:


 SC-1 Front Panel

MP&A is proud to offer our first custom-manufactured manufactured product, the SC-1 site controller.  Based on an industrial PLC with a touchscreen GUI, this unit is ruggedized for reliable service in the toughest environments, while providing complete control of the RF equipment system at any transmitter site. 






SC-1 dual power supplies


For an AM facility, the unit controls and monitors the operation of all RF contactors, and controls transmitter power levels and interlocks, to ensure that the right transmitter is always on-line at the right power level and into a correctly-configured antenna system. 

The SC-1 has dual redundant power supplies and extensive protection against surges and lightning.  An emergency control panel is also included should the PLC become unresponsive for any reason.  Each unit is custom-programmed to handle the unique configuration at your site.




SC-1 Screen Shot

  At an FM facility, the controller commands and monitors all motorized coax switches and controls the transmitters' interlocks to ensure that no coax switch is ever commanded to break the load's integrity while under power.  At either type of facility, dummy loads are fully interlocked and protected.

 An SC-1 can easily be retro-fitted into an existing facility in place of an older or ailing controller, or one with no controller at all, as well as being easily integrated into any new facility.

Call or email today to discuss your needs and how the SC-1 can be custom-configured and programmed to meet the needs of your next transmitter site construction project.



Retrofit Filter Capacitor PC boards for Nautel AMPFET-series high-power AM transmitters:


MP&A has developed several retrofit PC boards to allow modern (read: cheaper) snap-in large power supply filter capacitors in place of the conventional but very expensive computer-grade screw-terminal original power supply capacitors.  These new PC boards allow you to replace the old dying filter caps for less than half the cost of conventional parts, with no increase in labor time.  Total price depends on exact model number of transmitter to be retro-fitted; $80 per board.






Other custom solutions:


MP&A has developed a number of custom solutions to customers' unique problems through the years.  Please feel free to call and kick around your specific needs; we can almost certainly work up a suitable plan of action, using off-the-shelf or custom interface or retrofit gear.