Options and Setup
 

Click on the option menu to open the dialog box, where you can specify MMANA-GAL environment options including resonance, coil, matching circuit, and stub.

Resonance

You can calculate L and C from the frequency and reactance, and vice versa.

 

Coil

  You can calculate the diameter and the number of turns of the air coil from L, and vice versa.  This could be useful for making an air coil by yourself.  Bear in mind, however, that this calculation is not so accurate, and therefore please put up with some level of error.

LC match

  The simplest LC matching circuit.  It should be useful for the design of matching circuit for a whip or vertical antenna.  Significantly small value of the reactance is supposed to be equivalent with the short state.  Significantly large value of the reactance is supposed to be equivalent with the open (isolated) state. You can conjecture the LC combination for the automatic tuner (ATU) using this tool. It should be noted that the loss R is not taken into consideration.  Generally speaking, the lager the L or C, the larger the loss.  In addition to that, L should have much larger loss than C.  As a result, it is a good idea to keep the L value as small as possible.

Line match 1

  This tool is used for the calculation of impedance, Q-match section, and serial matching section using a distributed-constant circuit (e.g., a ladder feeder and a coaxial cable). The impedance calculation is done by obtaining the impedance of the output end of the feeder with respect to the impedance of the input end.  To make use of this process, the antenna impedance can be measured by using a coaxial cable in arbitrary length and a noise bridge.  SWR becomes smaller if the transmission line has a loss, which you can find in a handbook.
 The Q-match section uses a cable and the series match section uses two cables connected in series.  Push the TUNE button to calculate the section length that gives the minimum SWR with respect to the input end (Ri).  For the Q-match section, put the same value to the Ri and feeder impedance.  MMANA-GAL assumes a no loss line.  The impedances at the center and input end of the line are displayed in the impedance boxes at the top of the window. The line length (L) is noted in the electric length.  You have to consider the velocity factor of the feeder for the physical length.

Line match 2

  Stub match, that is, trap match is calculated.  ZL is the load (antenna) impedance, Zo is the feeder impedancd of L1 and L2, and Zi is the feeder impedance.  SWR is calculated on a basis of the feeder impedance.  The velocity factor and the frequency affect the lengths of L1 and L2.
Push TUNE button to calculate the L1 and L2 that give the minimum SWR.  MMANA-GAL offers two solutions at maximum, but it sometimes cannot find one.

L1

Distance from the load to the stub

ZS 

Impedance at the stub (in case of no stub)

XS

 Stub reactance

L2s

Stub length (short stub)

L2o

Stub length (open stub)

Zi 

Impedance at the source (SWR impedance)

      
The short stub is frequently used, but the open stub is used in case it is shorter. You could use a lumped-constant load in the stub.  Insert XS as an inductance (coil) or a capacitance (capacitor).

Stub

X, L, and C of the ladder or coaxial feeder used for the stub. For reference, the X of open and short stubs are calculated by:

Short stub

X = Zo • tan( 2 • p • l / l )

Open stub

X = -Zo • cot( 2 • p • l / l )

It is said that the home made ladder feeder has the following impedance:   Zo = 276 • log10(2D/d)   (D: Line space,  d: Wire diameter, velocity factor = 1).


Setup

   [Rear range of the F/B ratio]
   This specifies the range of rear angle used for the F/B ratio calculation. When you want to see the lobe in plus minus 60 degrees from the right behind, put 120.  You can put any value between 0 and 359, and there fore you could take the side lobes into consideration of the F/B ratio by putting, say 270.
   From a vertical viewpoint, MMANA-GAL searches the lobes on the place that includes the peak point of the front beam.  If you put a value other than zero, MMANA-GAL searches the lobes from zero degrees to the specified angle at the right behind.  You can put any value between 0 and 179, so you could see the high-angle front lobes as the F/B ratio.

   [Standard Z for SWR calculation]
   The impedance for the SWR calculation.  The default is 50 Ohm.  Using this, you can see the SWR with a matching circuit.  In this case, however, the matching circuit has a very broad characteristic in terms of frequency, and therefore the SWR is different from the actual value.  You may not worry about the lag because each amateur band is narrow.
   Push the Hairpin match button and input the target Z value to calculate jX of the hairpin match.  If you want to use a capacitive match, input a plus jX.  In either case, the target Z must be greater than the reference R.

   [Current display - Specify direction]
   Display the current direction in the antenna view window.  It will not always give the correct direction.  It depends on the antenna configuration.

   [Last files (menu)]
   The number of file names shown in the File drop down menu.  When the MMANA-GAL only box is uncheck, *.mab and *.mao files are also displayed.

   [Maximum pulse number]
   Maximum pulse number that MMANA-GAL can use.  The default use autodetect memory of the your PC.  For reference, here are the sizes of the memory that stores the impedance matrix.