DDUtil FlexWire Adapter

Today with the help of two heavy lifters (Eric Wachsmann & Bob Tracy) the ADC (Analog to Digital Converter) was tested successfully using CAT commands to read external negative voltage representing the ALC (Automatic Level Control) volts from an amplifier.

This represents a big step in the development cycle as the amplifier ALC voltage is variable from 0 to -12vdc depending on the amp. This voltage has to be inverted and scaled down to a range of 0 to +2.5vdc which is the measuring range of the ADC being used.

Eric created new routines in the bowels of PSDR to implement the functions needed to access the FlexWire interface and Bob created the necessary CAT commands to make the functions usable by us mere mortals. My hat is off to you both.

With this milestone achieved the next step will be to finish coding DDUtil to use the data. This logic will evolve as the usefulness of the data is realized by experimenting with how well I can control the PSDR power level from the amplifier ALC feedback. This is very TBD (to be determined) and if proven to be unusable the ALC portion of the adapter will be scrapped.

One of my fears is that RFI will be a unsolvable problem with a line running directly to the amp. I have attempted to harden the adapter against ESD and RF by shielding and bypassing techniques but how effective it is remains to be seen.

more later...

General Info

This adapter is intended to allow users of the Flex-5000/3000/1500 radios the ability to attach BCD controlled devices to the FlexWire port on the back of their radios. This device can be used to control many types of equipment based on the radio frequency or band selected, including but not limited to:

Band switching of uWave transverters and associated apparatus
Band switching of Coax switches
Linear Amplifier band switching requiring BCD input
Antenna stack management (manual)
Antenna array steering (manual)

Features

Two 8-bit output ports (TTL*) controlled by two DDUtil matrices wired to the VHF+ buttons in the PowerSDR console allows a total of 16 bits of control for each of the VHF+ bands. Data signals may be inverted for use with Phil Theis's Universal Controller Board (UCB) or other device requiring inverted signals.
One 8-bit output port (TTL*) wired to the HF BCD function in DDUtil's device tab. This allows great flexibility in selecting multiple antennas per band based on frequency or controlling other frequency following equipment. Data signals may be inverted.
One 8-bit output port (TTL*) manually controlled by DDUtil's macro function. Uses for this port could be managing an antenna stack or steering an array of verticals or any other need for manual switching not tied to radio band/frequency.
Auto-on port for amps equipped for +12vdc auto-on voltage sensing (Quadra, Prometheus, ?).
ALC input from an amplifier. This port is under development and may or may not be included in the final design depending on the usefulness of the feature.
Power Input is available from the FlexWire connector (13.8vdc) or from a secondary power connector on the card (+7 - 15vdc).
Signal Output is available from two (2) DB25F connectors. DB25 #1 contains the VHF+ signals for ports A & B. DB25 #2 contains signals for the HF BCD port and the Macro BCD port. These plugs plug into the headers on the PCB via ribbon connectors.
Auxiliary Power 12vdc (pass thru), 5vdc (reg) and 3.3vdc (reg) are available in one of the DB25F port connectors if needed. Maximum total current draw from these sources and from the signal lines is 500ma and is fused internally.

*TTL voltage level is considered to be 5vdc @ <= 10ma source current or 0vdc @ <= 20ma sink current.

Control

Control of the adapter is provided by DDUtil, a secondary software program written by me and available here. DDUtil interfaces to PowerSDR via CAT commands and allows multiple Radio Control Programs (RCPs) and various equipment to be connected to the radio at one time.
Note: This adapter will not work without an auxiliary software program to control it.
PSDR WILL NOT support this device by itself.

Construction

SMD (surface mount device) components are used primarily for the active and passive components with SOIC and 0805 sizes used.

Current Development Status

First prototype cards (5) have been received from the board house. Proto #1 has been assembled and initial tests on the BCD ports were successful.
ADC tests are underway using the low-level facility in PowerSDR. Waiting for CAT command creation before additional testing can begin in DDUtil.
Prototype enclosure design is complete and fabrication is in process.