Black Cat Systems
Follow our tweets!

Home
Purchase
News
Mac OS X Software
Mac OS 9 Software
Windows Software
Ham Radio iPhone/iPad
Linux Software
Documentation
Support/FAQ
Update Policy
Lost Reg Code?

Radiation Detectors
USB Icom CI-V Interface
MIL-STD-188 Interface

General Interest Programs

  Atomic Mac/PC
  Audiocorder
  Audio Toolbox
  Black Cat Timer
  Diet Sleuth
  iUnit
  Graffikon
  Graph Paper Maker
  Health Tracker
  Knitting Wizard
  Label Wizard
  Prog Audio Gen
  Sound Byte
  Synth 76477

Amateur Radio Programs
  Audiocorder
  Black Cat CW Keyer
  Cocoa 1090
  Cocoa RTL Server
  DGPS Decoding
  DX Toolbox
  Elmer
  eQSL Factory
  MatchMaker
  MININEC Pro
  Morse Mania
  MultiMode
  mySdrPlayback
  RF Toolbox
  SelCall
  Sonde

iPhone/iPad Apps
  ALE
  Atoms To Go
  dB Calc
  Clik Trak
  DGPS Decoder
  Drill Calc
  DX Toolbox
  Elmer Extra
  Elmer General
  Elmer Tech
  Feld Hellschreiber
  Field Strength Calc
  Function Generator Pad
  GMDSS
  Godafoss
  HF Weather Fax
  iAttenuate
  iFunctionGenerator
  iGeiger
  iSoundex
  iSoundByte
  iSweep
  iUnit
  Morse Mania
  ACARS Pad
  Morse Pad
  NAVTEX Pad
  Packet Pad
  PSK31 Pad
  SSTV Pad
  Photon Calc
  Rad Map Tracker
  RF Link Calc
  SelCall Tone Gen
  Sound Byte
  Sound Byte Control
  Spectrum Pad
  SWBC Schedules
  Synth 76477
  Synth Motion
  Transmission Line Calc
  Weather Calc
  Wire Calc

iPhone/iPad Bundles
  RF Calculator Apps
  Ham Radio Decoder Apps
  Audio Utility Apps
  Shortwave Weather Apps
  Ham Radio Exam Study Apps
  Shortwave Decoder Apps

Android Apps
  ACARS
  Audio Function Generator
  
DGPS Decoder
  HF Weather Fax
  NAVTEX
  Rad Map Tracker
  SelCall Tone Gen
  Sound Byte Control
  SWBC Schedules
  Wire Calc

About Black Cat Systems
Geiger Counter
Site Map
Our software for Mac OSX
Privacy Policy
Press/Media
HFunderground
Apple /// Emulator

Macintosh Links
Shortwave Radio
Pirate Radio
Spy Numbers Stations
Science and Electronics
Ham Radio Software
Geiger Counters


   


MatchMaker - RF Impedance Matching Tools

Make your radio fall in love with your antenna all over again


For this example, we will start with the following impedance data for the antenna:

Frequency   Resistance    Reactance
7.0 MHz     10.0          -60.0
7.2 MHz     16.5          -55.0
7.4 MHz     20.0          -50.0
We want to match all the points with an SWR of 2.0 or better.

First, let's start with a new window (ignore the impedance/SWR values from the cursor position):
Next, we need to enter in our impedance Data. Double click on Load Impedances:
We're presented with an empty list of frequency and impedance pairs. Click on Add Entry, and a new line will be added, with a frequency of 0:
Double click on the 0 to edit it. Change it to 7 for 7 MHz. Do the same for the resistance and reactance values to change them.

Repeat to add the impedances for 7.2 and 7.4 MHz:
Click OK.

Now we can see a plot of the impedance values. The SWR for each point is also calculated:
We want the impedance of the center frequency, 7.2 MHz, to be fairly close to 50 ohms, for a good match. A shunt inductor will move the point to 50 ohms (while a shunt capacitor would move it the opposite way).

Click Add, select a Shunt Inductor from the popup menu: We'll try an initial value of 2 uH, so enter in 2, click Apply. Click the new entry for Shunt Inductor 2 uH on the main window, to see the updated impedance in red:
The impedance is too high, closer to 100 ohms, so we need more inductance. Trying 3 uH, we get 44 ohms, closer, so now try 2.8, we get about 49 ohms, close enough:
next we need to move the cluster of points into the green SWR=2 circle in the center of the graph, using a series inductor. Click Add, and select Series Inductor We'll try 1 uH first, and find ou that it is not enough. trying 2 uH, we find that it is much closer, and 2.1 uH centers the impedances nicely:
Note that when we started, our SWR values ranged between about 5 and 12, now they are all under 2!


Email your comments and questions to info@blackcatsystems.com

Last modified January 28, 2010