Screwdriver Antenna Controller

Started by kg4pid September 9, 2010
Since I know that there are a few ham radio operators here I thought that I would ask if anyone has used a pic to communicate with an Icom radio using the CI-V port (an open collector TTL level bi-directional serial data port). I am thinking of trying to build a screwdriver antenna controller and would get band and frequency data among other things thru the CI-V port. There are controllers available but I think they are way over priced so I would like to build my own. Could use PWM to drive the motor, count the turns as it is moving, read SWR from the radio, etc. Any hams see a problem or have done something similar?

Max

A good place to start would be my PIC-based SWR/wattmeter design. Go to http://www.jasonhsu.com/swrwatt.html for more. My design consists of a directional coupler circuit designed for 1.8-30 MHz and 200mW-200W, an active rectifier (rectifying diodes plus a log amp to compensate for the diode drop loss) and a PIC16F872 microcontroller to process the outputs of the active rectifier and light up output LEDs.

A Screwdriver Antenna Controller would use a microcontroller with an output port dedicated to controlling the motor. You'll probably also need a buffer between the microcontroller and the antenna. One possible solution for buffering the microcontroller output is an H-driver like the TI SN754410NE used in the Seattle Robotic Society Workshop Robot.

P.S. I am looking for a position as an embedded/firmware electrical engineer in the Twin Cities. Please email me at e...@jasonhsu.com if you or anyone you know is hiring. In addition to my PIC-based SWR/wattmeter project, check out my work on the Atmel-based SRS Workshop Robot at http://www.jasonhsu.com/ee-robot.html .

I was going to keep it simple and just read the SWR out of my IC-7000 although an external SWR meter would allow it to work with other radios but add alot of cost. I have already been looking at motor drivers with current sensing and current limiting. I think when I get started I'll first create a simple turns counter with memory. Once I get that working I'll add reading the SWR and "tweeking" the tuning by moving the antenna and watching for a dip in the SWR. I will be 4-6 weeks before I really get started on this as I have other projects to get finished.

Max

--- In p..., "Embedded Engineer" wrote:
>
> A good place to start would be my PIC-based SWR/wattmeter design. Go to http://www.jasonhsu.com/swrwatt.html for more. My design consists of a directional coupler circuit designed for 1.8-30 MHz and 200mW-200W, an active rectifier (rectifying diodes plus a log amp to compensate for the diode drop loss) and a PIC16F872 microcontroller to process the outputs of the active rectifier and light up output LEDs.
>
> A Screwdriver Antenna Controller would use a microcontroller with an output port dedicated to controlling the motor. You'll probably also need a buffer between the microcontroller and the antenna. One possible solution for buffering the microcontroller output is an H-driver like the TI SN754410NE used in the Seattle Robotic Society Workshop Robot.
>
> P.S. I am looking for a position as an embedded/firmware electrical engineer in the Twin Cities. Please email me at embedded_engineer@... if you or anyone you know is hiring. In addition to my PIC-based SWR/wattmeter project, check out my work on the Atmel-based SRS Workshop Robot at http://www.jasonhsu.com/ee-robot.html .
>