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 Amateur Radio Frequency Measurements:

 

 0-30MHZ RF Power Measurement:
 
 
Old Projects:
  PIC 16F876A LCD Power Meter: FD-PM2 
PIC 16F88 LCD VHF SWR Meter: FD-SWM-VHF
PIC 16F877A LCD 100W HF SWR Meter: FD-SWM-HF
HF 100W LCD PIC16F877A SWR Meter:
 

Previous project is here.........

New Dual channel SWR Meter RS232 Project is here....

New USB SWR Meter Project is here.......


FD-SWM-CPU

FD-SWM-HF-BRIDGE

 

Please consider New Design: Dual Channel LCD SWR Meter

 

Measuring SWR at HF from 1MHZ to around 60MHZ  was always a concern to radio amateurs. Till today, thousands of radio amateur run their station without an SWR Meter, without knowing matching between their Tx and the Ant.

SWR Meters of Analog variety are planty, although, not very economical. LCD meters are more expensive, crossing a range of over $140.

LCD SWR Meter presented here meet many simple task using a PIC16F877A micro controller. The very basic purpose to make this project is to encourage radio amateurs to build their own SWR Meter at very low price.

 

Following task achieved thru this design:  

Simple single Micro Controller with built-in A/D converter (PIC16F877A)
 
Interchangeable, Individual Balanced RF Bridge for HF & VHF
 
CPU Unit has:
 
Back light control  
 
Stable Reference voltage.
 
D9 Connector for Bridge
 
SWR, FWD, POWER and Actual Power to antenna   calculations/Display.  
 
Bargraph mode for SWR & Forward Power  
 

 

Project Bases:

Project is developed on two double-sided PTH boards. The first one is CPU board where LCD, Regulator and Back Light Controllers are located. This board receives pure DC level from sensor board for calculation & display.

The second board is RF Sensor Bridge, where power from your transceiver comes in and goes out to antenna. It is a simple HF Toroidal Bridge design using BAT85 diodes.

Although SO239 types of connectors are used, there is no reason why you cannot use N type connectors. They will fit nicely on four mounting holes available for SO239 sockets.  

Kit is intended for experienced Radio Amateurs. Later, I will try to supply assembled units too.

Although, rated at 100W HF, this meter & bridge worked very well at a KW and above, on all bands. Readings were very accurate compared to commercial SWR Meter. 

However, it should be noted that, the Display Unit Firmware is limited to 100W maximum. Means, if you wish, you may set bridge presets to measure 1KW but meter will display 100W on LCD. 

This new, redesigned version of HF SWR Meter has two units: A CPU and a Bridge. CPU/LCD Unit is common for both HF & VHF bridges. Please visit SWR-VHF web page for details on VHF Bridge.

HF Bridge is supplied with SO239 Connectors as standard. You may order type N connectors at no extra cost if your transceiver uses type N connectors. 

 


Completed LCD RF Power Meter CPU Unit:

Click the image to enlarge


SWM HF Bridge: 

Click the image to enlarge

 


SWM HF CPU Without LCD

Click to enlarge

Schematics, Details & Parts List:
   
SWM-CPU Tech Info Doc. 0-500MHZ RF Sensor Document
    
SWM-CPU Schematic & Parts List 0-500MHZ RF Sensor Document
    
SWM-HF-Bridge Schematic & Parts List 0-500MHZ RF Sensor Document
     
SWM-CPU Schematic  JPG
     
SWM-HF-Bridge Schematic

Main Board 

JPG

HF Bridge Board

JPG

  
T1 & T2 Winding & Assembly Guideline

0-500MHZ RF Sensor Document

  
  
Project Datasheet 

Analog Device AD8307 Datasheet

PIC16F877A Firmware

Analog Device AD8307 Datasheet

 
 

Please consider New Design: Dual Channel LCD SWR Meter: SWM3

 

PCBs may be available from our school project website: Visit Foxdelta.net
  
 

 

 


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