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Antenna matching network calculator?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by W0BTU, Apr 7, 2011.

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  1. W0BTU

    W0BTU Ham Member

    I'm playing around in EZNEC with some antenna designs to put up for the summer in place of my former 160 meter inverted-L. To that end, I'm looking for a web site or free software to calculate the proper matching network design (T-network, L-network, simple series L or C) and also calculate the values for that design, to match 75 ohm coax to numbers like "Impedance = 140.4 + J 629.8 ohms". I know how to re-invent the wheel, but I don't want to. :)

    I've searched, but came up with nothing.

    Any suggestions?
     
  2. WA7PRC

    WA7PRC Ham Member

  3. W0BTU

    W0BTU Ham Member

    Thanks, but every time I visit that site, it is unbelievably slow. Today is no exception, but at least it didn't time out continually.
    I did finally manage to fill out their contact form asking them about their speed problem.
     
  4. G3TXQ

    G3TXQ Ham Member

    Mike,

    The "classic" way would be to use a Smith Chart. There are electronic versions around for free download which make the matching task trivial, eg:

    http://www.fritz.dellsperger.net/

    Here's a Smith Chart matching solution to your example, using a simple L network at a frequency of 1.9MHz:

    [​IMG]

    73,
    Steve G3TXQ
     
  5. W0BTU

    W0BTU Ham Member

    Thanks! But I can't get the program to run, either under WINE or Windows XP running under VirtualBox. I'll try later on another PC running Windows 7.
     
  6. 4L4AGU

    4L4AGU Ham Member

    MMANA-GAL (Free antenna modeling software), has built-in calculator for LC match.

    Also, there's Java applet for T-Tuner calculations:

    http://dl2kq.de/mmana/4-10.htm
     
  7. G3TXQ

    G3TXQ Ham Member

    Mike,

    Try the earlier version 2.03 - it runs fine under XP.

    I downloaded his latest version and found I needed to install Microsoft .NET Framework 3.5 to get it to run.

    73,
    Steve G3TXQ
     
  8. G3TXQ

    G3TXQ Ham Member

    On that applet, how do you change the required matching impedance to 75 Ohms as the OP wanted?

    Steve G3TXQ
     
  9. 4L4AGU

    4L4AGU Ham Member

    Only by re-compiling the source code, and changing z0x = 50.0; to 75.....
     
  10. W5DXP

    W5DXP Ham Member

    I still use an old DOS program called MicroSmith, v2.01, written by Wes Hayward, w7Zoi, that will do the job. It will run under XP. Back in the 1990's, it was available from the ARRL. I don't know about present availability.
     
  11. K4VLF

    K4VLF XML Subscriber

    Last edited: Apr 7, 2011
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