[SBE] NEC/4 Modeling

[Paul Christensen]

Cris,

Good info.  I've also noticed a high degree of computed Z variability under both NEC-2 and NEC-4.  It seems the computed Z for free space designs (e.g., Yagi) model much more accurately than ground-dependent radiators.   

Paul



====================================
Paul Christensen, CPBE CBNT 8-VSB AMD
LAW OFFICE of P. B. CHRISTENSEN, P.A.
3749 Southern Hills,  Jacksonville, Florida 32225
Office: (904) 379-7802    Facsimile: (904) 212-0050
pchristensen at ieee.org





  ----- Original Message ----- 
  From: Cris Alexander 
  To: 'sbe member discussion mail list' 
  Sent: Thursday, May 17, 2012 5:48 PM
  Subject: Re: [SBE] NEC/4 Modeling


  Okay, Paul. I understand.

   

  I've done a ton of modeling over the years and in my experience, the far field E-field differences between a modeled radial system and a perfect ground plane are hardly worth all the trouble to model it all. We're talking fractions of a dB at 1 km, and the base Z predictions are certainly in the ballpark if not the infield. That being said, impedance prediction is probably the weakest function of NEC/MN.

   

  I can heartily endorse J.L.'s book and in fact the equations therein were the basis for my own MN program (ACSModel).

   

  ______________________________

  W.C. Alexander, CPBE, AMD, DRB

  Crawford Broadcasting Company

  Denver, CO

  (303) 433-0104 Tel.

  (303) 433-0905 Fax.

   

  From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Paul Christensen
  Sent: Thursday, May 17, 2012 2:30 PM
  To: sbe member discussion mail list
  Subject: Re: [SBE] NEC/4 Modeling

   

  Hi Cris,

   

  I'm trying to get accurate base Z results as well as surface wave field strength predictions.  Within 4Nec2 is a fast radial wizard, but it does not allow for changing ground placement, albeit the effect may be small.   In any case, creating a buried system is easy enough through the geometry builder utility.  The examples would be used to ensure that I've done the job correctly.  

   

  I've had this discussion with Arie Voors, 4Nec2's developer, as well as Jerry Burke at LLNL.  The consensus is to create a modeled radial system for best results.   Ben Dawson suggested J.L. Smith's examples, so I can start there.

   

  Regards,

  Paul



  ===================================
  Paul Christensen, Esq.
  LAW OFFICE of PAUL B. CHRISTENSEN, P.A.
  3749 Southern Hills
  Jacksonville, Florida 32225
  Office: (904) 379-7802
  Facsimile: (904) 212-0050
  Skype ID:  pc-immigration-lawyer
  attorney at immigration-lawyer-us.com
  http://www.immigration-lawyer-us.com
  Admitted to the Florida Bar #507334

  This message and any attachments to it is intended solely for the
  addressee(s) and may contain CONFIDENTIAL material. In no event will this
  correspondence create an attorney-client agreement without an express,
  written agreement between parties.  If you received this message in error,
  please delete this message from your system and notify us immediately by
  replying to attorney at immigration-lawyer-us.com or by calling us at
  904-379-7802.  Any interception, review, retransmission, dissemination, or
  other use thereof, or taking of action upon this information by persons or
  entities other than the intended recipient(s) is strictly prohibited.

    ----- Original Message ----- 

    From: Cris Alexander 

    To: 'sbe member discussion mail list' 

    Sent: Thursday, May 17, 2012 4:12 PM

    Subject: Re: [SBE] NEC/4 Modeling

     

    Is this for AM broadcast? If so, set the environment for ground plane and forget about trying to model a buried ground medium.

     

    ______________________________

    W.C. Alexander, CPBE, AMD, DRB

    Crawford Broadcasting Company

    Denver, CO

    (303) 433-0104 Tel.

    (303) 433-0905 Fax.

     

    From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Paul Christensen
    Sent: Thursday, May 17, 2012 1:39 PM
    To: sbe member discussion mail list
    Subject: [SBE] NEC/4 Modeling

     

    Looking to validate the buried radial parameters of a .NEC input file for a non-phased, single monopole radiator.  I've been using the geometry builder utility within 4Nec2 software, but I want to confirm radial depth results as well as source/load parameters.  If anyone has an input file to share, it would be very much appreciated.  I have J.L. Smith's book on order and will use his examples as well.  Thanks!

     

    Regards,

     

    Paul

     

     

    ====================================
    Paul Christensen, CPBE  CBNT  8-VSB  AMD
    LAW OFFICE of P. B. CHRISTENSEN, P.A.
    3749 Southern Hills,  Jacksonville, Florida 32225
    Office: (904) 379-7802    Facsimile: (904) 212-0050
    pchristensen at ieee.org

     


----------------------------------------------------------------------------

    _______________________________________________
    The SBE Roundtable, SBE at sbe.org
    To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

    http://seven.pairlist.net/mailman/listinfo/sbe



------------------------------------------------------------------------------


  _______________________________________________
  The SBE Roundtable, SBE at sbe.org
  To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

  http://seven.pairlist.net/mailman/listinfo/sbe
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://seven.pairlist.net/pipermail/sbe/attachments/20120517/9924402f/attachment.html>