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NEC4WIN95
 
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NEC4WIN/VM
Advanced virtual memory version
for
Windows 95, 98, NT, 2000 and XP

NEC4WIN95VM is the Virtual Memory version of NEC4WIN95. The user interface is the same as in NEC4WIN95 with many additional features:

  • Virtual Memory allows a number of wires and segments limited only by physical memory and free space on disk
  • 3D interactive display of Near Field data.
  • Smith Chart impedance output on Frequency Range.
  • Loop Correction for more accurate simulation of loops and Quads (also in NEC4WIN95).
  • ICEPAC File 13 generated by NEC4WIN95VM can be used with powerful ICEPAC (IONCAP or VOACAP) Propagation Analysis software.

More on Advanced features 

What is Virtual Memory?

Virtual memory is a mechanism by which the hard disk is used as a transparent external memory system. When real RAM is not sufficient, blocks of memory are swapped to the disk to create more space in physical RAM.

NEC4WIN95VM resolution time for a specific model is not growing in direct proportion to the number of segments, but as a power 3 of that number.

For an N segments model, computation time is on the order of N^3 (N power 3). This means that

  • If Project 1 with N segments takes 1 minute to compute impedance
  • Project 2 with 2N (twice) will take (2*N)^2 or 4 minutes
  • Project 3 with 3N segments will take 3^3 or ... 27 minutes.
  • Who needs NEC4WIN95VM?

    Anybody who simulates large models with more than 50 wires and/or 250 segments which are the limitations imposed by Mininec on NEC4WIN95.

    50+ wire models are easy to reach with multi-element beams using tapered tubes, loops and quads, multi antennas systems, helicoidal antennas etc...

    How many wires or segments can I use with NEC4WIN95VM?

    This depends on how much physical RAM you have and if you have enough free space on disk to swap that memory out. The main matrix used by the program must fit in physical memory and can't be split. Look at the projects below and you will see can you can indeed have huge projects. But don't forget that these projects take hours if not days to simulate.

    NEC4WIN95VM Limitations

    The engine is still based on Mininec and it has the same limitations as the non VM version.  Close parallel wires, horizontal wires too close to the ground, sharp corners may be a problem to simulate. Log Periodics and Transmission Lines can't be simulated accurately with it. Antenna impedance is always calculated based on Perfect Ground.

    NEC4WIN95VM Projects Gallery

    NEC4WIN95VM is currently used by a number of professionals and amateurs working on large antenna systems. Take a look at the monster project at the bottom of the page. This monster is a system  from Broadcast Partners in The Netherlands (www.CBT.nl) and is used to transmit FM on the tallest antenna in Europe (bigger than Eiffel tower). This will give you an idea of NEC4WIN95VM capacity to handle large projects. 

     

    VHF beam array

    Loop for 232Mhz with grid reflector by  Guenter Koellner, DL4MEA
    Loop for 232Mhz with grid reflector by Guenter Koellner, DL4MEA

    QFH by G0HPO
    QFH by G0HPO

    and this monster ...

    monster.jpg (22627 bytes)

    Limitations

    Some MININEC3 limitations still apply. Close parallel wires and wires close to the ground do not simulate well. Sharp corners need segment tapering except in looped antennas. Impedance calculation assumes a perfect ground.

    Limitation

    Standard version

    Virtual Memory version

    MAXIMUM NUMBER OF PULSES
    MAXIMUM NUMBER OF SEGMENTS
    MAXIMUM NUMBER OF WIRES
    MAXIMUM NUMBER OF SEGMENTS PER WIRE
    MAXIMUM NUMBER OF SOURCES
    MAXIMUM NUMBER OF LOADS
    MAXIMUM WIRE LENGTH IN ANY UNIT

    250
    250
    50
    50
    10
    20
    10000

    *
    *
    *
    50
    100
    100
    10000

    *  Limited only by maximum physical memory and hard disk space to swap all memory to disk.


    Download Evaluation


    Sorry! NEC4WIN/VM is not available as an evaluation. 

     

    Order info!

    NEC4WIN/VM is $50 for Electronic Download

    When you order by Credit Card you can download an Electronic copy as soon as we are notified of your order.

    Credit cards orders via Internet!
    (click on the cards)

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