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Two  programs are here available for free download Flux Density Calculator and Transmission Line Calculator

Flux Density Calculator V.1.0.3

This  program calculates the Flux Density of the Solar and Jovian bursts  as a function of the measured temperatures.

Many of us have a calibrated noise generator to estimate the temperature of the Jovian or Solar bursts and of the background sky, but if we compare the temperatures of the same burst recorded by different systems having different antenna gain or different bandwidth we will see different burst temperatures because the power, and the associated equivalent temperature collected by the antenna, will be different.    The temperatures are different but the flux density, that is, the power landing on a square meter per hertz of bandwidth will be the same.
This simple program calculates the flux density of the Solar and Jovian storms, as a function of the measured temperatures.

Here is a  description of this program:

The program will now show the Flux Density, in W/(m²Hz) and in jansky, of the burst and its level (dB) above the background. The Power and Voltage  (across 50 ohm) at the antenna feed point and at the receiver input are also shown. The Isotropic source spectral power and the Source to antenna path loss are shown.

If the user changes a parameter, for example the temperature of the burst or the antenna gain, then the output is automatically updated.

With this version it is now possible to save the results to a text file and to print the screen.

Download Flux Density V1.0.3 (

After having downloaded the file, unzip it and run the Setup.exe
If you have installed a previous version  you can just replace the old FluxDensity.exe with the new FluxDensity.exe


And here are some formulas:

The Antenna Capture Area  is : A = G * lambda² / 4pi   [m²]    where G is the antenna gain      G = 10^(dBi/10)

A calibrated noise source is needed to measure the temperature of the background sky (Tsky) and of the background sky plus the burst (Ttot) at the receiverís input. The temperature of the burst (T) is:

    T = Ttot-Tsky      [kelvin]

The power (Pr) of the burst at the receiver's input can then be calculated when the temperature T is known

    Pr = k*T*B           [W]                          where :    k=1.38*10^-23 [joules/kelvin]     T=Temperature [kelvin]     B=Bandwidth [Hz]

The cable, connectors, filter, power combiner and other devices connecting the antenna to the receiver introduce an attenuation. This means that the power (Pa) of the burst is higher at the antenna feedpoint.

    Pa = Pr * 10^(AttdB/10)                     where AttdB is the attenuation, in dB, introduced by the cable and its accessories.

The FLUX DENSITY of the burst is the power landing on Earth on a square meter and per hertz  [W/(m²Hz)]. The associated electromagnetic wave can be linearly, circularly or randomly polarized, its polarization can also vary over time.
It is assumed here that all the power landing on the antenna is collected, this regardless the polarization of the  wave. The Flux Density is therefore given by :

    S = Pa / A*B = k*T /A       [W/(m²Hz)]          where :    k=1.38*10^-23 [joules/kelvin]     T=Temperature [kelvin]     B=Bandwidth [Hz]   A=Antenna capture area [m²]

The unit of flux density is the jansky :     1 jansky = 10^-26 W/(m²Hz)

The BURST LEVEL above background is given by   10log(Ttot/Tsky)  where Ttot is the temperature of the burst  plus the background sky and Tsky is the temperature of the background sky only.

The  ISOTROPIC SOURCE SPECTRAL POWER  is the power emitted by the source on a 1 Hz bandwidth.

                   w = S*4pi*(AU*1.5*10^11)²    [W/Hz]

where AU is the distance Source-Earth in astronomical units, the astronomical unit is the mean distance  Sun-Earth  ( 1 AU = 1.5*10^11 meters). The mean distance Jupiter-Earth at opposition is 4.2 AU

SOURCE-TO-ANTENNA PATH LOSS:  by definition the Path Loss assumes that both transmitter and receiver  antennas are isotropic.

    Path-Loss = 22 + 20 log(D) - 20 log(lambda)  [dB]        Where D  is the distance in meters

Transmission Line Calculator V.1.0.1

This program has been developed as an aid when converting the length of a coax cable from electrical to physical length and vice-versa.
It can also be used to calculate what's the impedance of the load (antenna) when the impedance at its input is known.
Or the input impedance when the impedance of the load is known. Download Transmission Line Calculator V.1.0.1

After having downloaded the file, unzip it and run the Setup.exe

Some theory and formulas:

 An alternating voltage propagates in the cable at a speed that is lower than its  speed in  free space.  This because the presence of dielectric reduces the velocity
 so that   the wave travels more slowly in the cable. The wavelength in the cable is therefore shorter than in free space.
 The ratio between the velocity in cable and the velocity in free space is defined to be the Velocity Factor (Vf).    Vf = Vcable/Vfree-space
 It is  related to the  characteristics of the dielectric of the cable and is a number less  than one.:

      Vf = 0.80  polyethylene foam (whitish and porous)
      Vf = 0.66  solid polyethylene (bright and transparent)

 The wavelength in the cable is   LambdaCable = LambdaFreeSpace * Vf

 The length of a cable can be expressed in multiple (or fractions) of wavelengths or in  degrees.  360 degrees are equivalent to one wavelength,180 degrees to 1/2
 wavelength,  90 degrees to 1/4 wavelength.  The relationship between the number of wavelengths (N) and degrees is:   N = deg / 360

 The physical length (Lphysical) of the cable in meters will then be:  Lphysical = LambdaCable * N  The units of Lphysical will be the same as those used for
 As an example the "phasing cable" used for the RadioJove dual dipole antenna must  be O.375 wavelength (or 135 degrees) long, with Vf = 0.66 at a frequency
of 20.1 MHz it gives a cable length of 3.69 meters (12.115 feet)

 With : ZL = Load impedance      Zo = Cable impedance   Zin = Input impedance   deg = Length of the cable in degrees
 Zin  and ZL have both the resistance and reactance components in the form      Z = R + j X

 The impedance at the input of a cable when the impedance of the load is known is given by :

           Zin = Zo * (ZL cos(deg) + j Zo sin(deg) )/(Zo cos(deg)+ j ZL sin(deg) )

 Special cases for the input impedance are:
     Shorted line ( ZL=0 )       :   Zin= j Zo tan(deg)
                                                   odd multiples of 90°   --> Zin = j infinite
                                                   even multiples of 90°  --> Zin = 0

    Open line  ( ZL=infinite )  :   Zin= - J Zo cot(deg)
                                                   odd multiples of 90°   --> Zin = 0
                                                   even multiples of 90°  --> Zin = j infinite

 The impedance of the load when the input impedance is known  is given by
           ZL = Zo * ( - Zin cos(deg) + j Zo sin(deg) )/( - Zo cos(deg)+ j Zin sin(deg) )

NOTE: To simulate an infinite impedance enter a resistance or reactance value greater than 10 Mega ohm

Standing Wave Ratio (SWR) :
The Standing-Wave-Ratio (SWR) is defined as the ratio of the maximum voltage to the minimum voltage along the line.
 It is an indicator about the mismatch of the line. A mismatch occurs when the impedance of the load (ZL) is not equal to the characteristic impedance
of the line (Zo)
An SWR = 1 indicates that the load and the line are matched, so that there are no reflections.

 Defining a reflection coefficient :    gamma = ( ZL - Zo )/( ZL + Zo )         rho = absolute value of gamma,
 the Standing Wave Ratio is given by:        SWR = ( 1 + rho )/( 1 - rho )

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