The project aimed to build an HF Amplifier Controller that is needed in modern LDMOS Amplifier.
LDMOS Amplifier mostly need a TR Switch (Relay), bias voltage, SWR measurement and Power output measurement.
To accomplish the need, AVR ATMEGA328 is used. I am familiar with the uP, and it has the necessary subsystem needed with low cost.
The controller will have :
Circuit can be seen on the following diagram :
The PCB still under development. But this one is almost finished and ready to order :
I am surprised that PCBWay offer me a prototyping opportunity. Where PCBWay provide a free PCB for prototype project that you make. So, I order the PCB and after a few days, the PCB has arrived. PCB quality is very good. It was professional made PCB that will make the project easy and enjoyable to built.
Here is the video on unboxing. Too bad that my lightning setup was not sufficient. But I hope the picture of the PCB below tell how good is the PCB that I got for free.
Thank you PCBWay.
Update Feb 15-2023
I have been asked to repair 8x IRF260 HF Amplifier. So this project was delayed. Also, during the repair, I found it was important to have current limiter. So, another project was made : "Solid State Current Limiter". The link is in my blog with title "Solid State Current Limiter" here
Update Mar 2025
After so long no update, I am back.
There were many in-between projects that happened during the time. But, finally I have the controller implemented in my Low Band HF Amplifier. Not all features defined before are implemented here. Only essentials are implemented.
The board has mistakes (it happens!). PCF IO Expander can only sink current, and only source small amount of current. So, the LED indicator should be common Anode instead common Cathode configuration. Other modifications are :
I will put Amplifier project in other blog entry.
Here are some pictures of the finished amplifier:
The front panel is implemented like this
Controller mounted on the front panel from inside
Left is AUX 12V Switching power supply and the right board is VDD relay.
To accomplish the need, AVR ATMEGA328 is used. I am familiar with the uP, and it has the necessary subsystem needed with low cost.
The controller will have :
1. Band selector input from Operator 2. Band selector input from Transmitter (Band Data from Yaesu or ICOM) 3. TR Relay control 4. Delay needed for TR Relay 5. Bias switch 6. ALC voltage generator and switch 7. Power measurement from Forward & Reflected sensor 8. Power Display using LCD and Cross Needle
Circuit can be seen on the following diagram :
The PCB still under development. But this one is almost finished and ready to order :
I am surprised that PCBWay offer me a prototyping opportunity. Where PCBWay provide a free PCB for prototype project that you make. So, I order the PCB and after a few days, the PCB has arrived. PCB quality is very good. It was professional made PCB that will make the project easy and enjoyable to built.
Here is the video on unboxing. Too bad that my lightning setup was not sufficient. But I hope the picture of the PCB below tell how good is the PCB that I got for free.
Thank you PCBWay.
Update Feb 15-2023
I have been asked to repair 8x IRF260 HF Amplifier. So this project was delayed. Also, during the repair, I found it was important to have current limiter. So, another project was made : "Solid State Current Limiter". The link is in my blog with title "Solid State Current Limiter" here
Update Mar 2025
After so long no update, I am back.
There were many in-between projects that happened during the time. But, finally I have the controller implemented in my Low Band HF Amplifier. Not all features defined before are implemented here. Only essentials are implemented.
1. TR Relay control 2. Delay needed for TR Relay 3. Bias switch 4. Power measurement from Forward & Reflected sensor 5. Power Display using LCD and Cross Needle (LCD Only)
The board has mistakes (it happens!). PCF IO Expander can only sink current, and only source small amount of current. So, the LED indicator should be common Anode instead common Cathode configuration. Other modifications are :
1. Supported band is 40m, 80m and 160m 2. One ULN2003 output drive is used for VDD Relay switch. 3. One ULN2003 output drive is used for TR Relay switch. 4. PWM output is used for controlling FAN speed instead for CrossNeedle.
I will put Amplifier project in other blog entry.
Here are some pictures of the finished amplifier:
Comments
Any luck?
73 Mike
So far still good result. But slow due to other activity and constraint.
I will keep posting for further progress.
73