FT-817 QuickTune  

Table of contents

Purpose

The FT-817 QuickTune is a handy little utility for producing a carrier to tune an automatic tuner without the need to navigate through the FT-817 Menus. It is based on a PIC Microcontroller (either 12Cxx series or 16x84x series). There are no SMD parts but even so the PCB size is realy small so it could be easily attached to the FT-817.

DISCLAIMER:
THIS CONTENT IS PROVIDED TO INTERESTED PEOPLE "AS IS" FOR NON COMERCIAL
PURPOSE ONLY. UNDER  NO CIRCUMSTANCES I AM RESPONSIBLE  FOR ANY DAMAGES 
TO  YOUR RADIO, PC OR OTHER  EQUIPMENT. THIS  DEVICE  WAS TESTED  UNDER 
DIFFERENT  CONDITIONS   AND  UNTIL  NOW  IT  WORKS   WITHOUT  PROBLEMS.

Schematics

QuickTune consists of a 12C5xx PIC using the internal 4 MHz oscilliator, a push button switch which starts the tuning process, a LED as activity/error indicator and serial RS232 in- and outputs to the FT-817.

QuickTune can be powered in 2 ways:

  1. Direct powered and
  2. On Demand powered.

When direct powerd, QuickTune always draws little power from the FT-817 (even if it is turned off). In this case there is no need for C2 and you can jumper SW1b with a piece of wire.

Demand powered means that QuickTune is only powered during the tuning process. This is accomplished by SW1b and C2. When SW1a and SW1b are pressed the same time C2 is first loaded and then the PIC starts operating. Because of SW1a which is also pressed it starts the tuning process immediately. When SW1a and SW1b are released the process ends and also the power to QuickTune is cut. In oder to set back the FT-817 to the state as it was before pressing SW1 it is now powered from C2. The power from C2 should be enough for the PIC to do this and then shut itself off.

The software within the PIC handles the communication to the FT-817 via the RS232 level converters T1 and T2 using CAT commands at a speed of 9600 baud. When you press SW1 the PIC first tries to accuire the current mode of the FT-817. If this fails (eg. no connection, wrong baud rate etc.) then LED D1 starts blinking and QuickTune again tries to figure out the current mode as long as it succeeds or SW1 is released. If the mode could be read it is saved in the PIC. Next the mode of the FT-817 is set to CW. You could use other modes for tuning. This must be configured within the assembler source. Then the FT-817 is locked and PTT is set to ON. As long as you press SW1 PTT stays on and a carrier for the tuner is generated. After releasing SW1 PTT is set to off, the FT-817 is unlocked and the saved mode is restored so that the FT-817 is in the same state as before pressing SW1.

By using a PIC of the 12C5xx series you must also pay attention to the oscilliator callibration value which could be different for every PIC. It is placed during production into the last memorylocation. By using it you can fine tune the internal 4 MHz R/C oscilliator. This is important because the 9600 baud RS232 communication routines need accurate timing. For more informations on this see the Microchip PIC12Cxx release notes.

You can also use a PIC of the 84 series (16C84, F84, F84A). Just set the type within MPLAB and the source should compile for a 84 without problems. By using the 84 there will also some space for additional functionality like a direct frequency input using a number keypad. I may add this later.

FT-817 QuickTune schematic
Image 1: FT-817 QuickTune Schematic

The PCB

The PCB
Image 2: The PCB

  Component positions
Image 3: Component positions

You can download a PDF File with the schematic and the PCB here.
If you dont have the Adobe Acrobat Reader installed on your machine you can find it here

Pictures of the finished QuickTune

Here you can see how the module looks during different stages of the building process and how it looks when it's finished. A picture says more than thousand words.

The etched PCB
Image 3: The etched PCB

  Finished PCB
Image 4: The finished PCB with all components

Prototyping the QuickTune
Image 5: Prototyping the QuickTune ....

Notes & Comments

in the Press

This paper can also be found in the german HAM Radio Magazine
"Funkamateur" at www.funkamateur.de, Issue 11 / 2003, Page 1135,
Title: "QuickTune für den FT-817"

Credits

If you have any comments or sugestions just drop me a line.

73, OE1RIB