Re: New program "Not a Trap"

From: Dirk Bruere at Neopax (dirk_at_neopax.com)
Date: 09/22/04 

Date: Wed, 22 Sep 2004 23:07:50 +0100

Reg Edwards wrote:

> Extract from program notes.
>
> Program Name: NOTATRAP.exe Author: R.J.Edwards G4FGQ
>
> A TWO-BAND ANTENNA WIRE LOADED WITH AN L & C PARALLEL-TUNED CIRCUIT
>
> The LC parallel-tuned circuit is constructed exactly like an antenna trap.
> It
> is located in the antenna wire and used as L or C loading at 2 other
> resonant
> frequencies. Parallel-tuned circuits have a reactive impedance on either
> side
> of resonance. On the low frequency side there is a +ve inductive reactance.
> On
> the high frequency side there is a -ve capacitative reactance.
>
> The purpose of the LC loading components is to detune the antenna wire from
> its natural 1/4-wave resonant frequency. When the loading circuit is
> behaving
> as an inductance the antenna resonant frequency is reduced. When the loading
> circuit is behaving as a capacitor the antenna resonant frequency is
> increased.
> The pair of resonant frequencies depend on the LC ratio, on wire length, and
> on the location of the LC loading circuit along the wire.
>
> For a given loading location along the wire and a given pair of resonant
> freq-
> encies this program calculates the L and C loading-component values. The
> pair
> of frequencies lie above and below the unloaded resonant frequency of the
> wire.
> The LC circuit behaves as an ordinary trap at its own resonant frequency
> which,
> by experiment, can sometimes be arranged to fall into a third amateur band.
> But
> to calculate such a fortunate coincidence is beyond my elderly patience.
>
> The program has a built in signal source which generates a wide-ranging
> testing frequency which can be used to 'measure' the input impedance of the
> antenna versus frequency, checking resonant frequencies and other antenna
> characteristics.
>
> Download program NOTATRAP from website below and run immediately.
> ----
> ...........................................................
> Regards from Reg, G4FGQ
> For Free Radio Design Software go to
> http://www.btinternet.com/~g4fgq.regp
> ...........................................................

Go for it suckers! 

-- 
Dirk
The Consensus:-
The political party for the new millenium
http://www.theconsensus.org

Relevant Pages

  • New program "Not a Trap"
    ... A TWO-BAND ANTENNA WIRE LOADED WITH AN L & C PARALLEL-TUNED CIRCUIT ... The LC parallel-tuned circuit is constructed exactly like an antenna trap. ... as an inductance the antenna resonant frequency is reduced. ...
    (sci.electronics.design)
  • Re: Antenna physical size
    ... When the air breaks down around an antenna it is because the antenna ... to sharp points when using wire or a whip with a pointed tip. ... a series circuit is replaced by a tank circuit it clearly shows that ... dinky radiator" picnic is not the radiator and it's abilities to be ...
    (rec.radio.amateur.antenna)
  • Re: Rx antenna questions
    ... the antenna (fixed to the receiver). ... Is there a way to put a disconnect in the antenna wire near the receiver? ... length that was suited to the circuit and reasonable for the model - a 1/4 ...
    (rec.models.rc.water)
  • Re: Rx antenna questions
    ... but I don't know what to do about the antenna (fixed to the receiver). ... What about using one wire of a JR type connector? ... length that was suited to the circuit and reasonable for the model - a 1/4 ...
    (rec.models.rc.water)
  • Building a Multi-Element 1/4 Wave Length Shortwave Listening (SWL) Antenna
    ... The Shortwave Listeners (SWL) AM/FM Antennas Groups ... Cable for a Shortwave Antenna -and- Want the greater ... Insulated Hoop-Up Wire or Antenna Wire from RadioShack; ... This Pipe should be about XX Inches Long. ...
    (rec.radio.shortwave)