Antenna Factors

Purpose
This training modules steps you through Antennas and how to deal with them, including:-
Important Points
Updating Antenna Factors

Creating Antenna Factors

Antenna Factor Selection
            
Antenna Factors: Important points
Number of points
Dependent how you configure Vasona, the antenna factors used may be limited to the number of points which the analyser can accept, ie for the HP8546A this is 80points.

Frequency Order + Zero
Points need to be entered in frequency order, a sort facility is available, or click on the Frequency Label.  In addition, files should not contain a 0 in the frequency column, the Log of 0 is not a valid number.

Overall Correction Factor
Vasona uses the frequency points in this file as a reference.  For example it will ONLY add associated cable losses, pre-amplifier gains at the frequencies contained in this reference file.  You should look at your factors carefully to ensure that all variations have been covered.

Antenna Calibration
The antenna factors used during assessment must be those supplied by a calibration laboratory.  There are many ways to calibrate antennas, we recommend using free space factors. Please note antenna factors are dependent upon the following:-

1. Antenna height
2. Polarisation
3. Measurement distance
4. Particular in vertical polarization, which way up the antenna is !

                        .......   plus the obvious type, manufacturer and geometry. 

Further advice should be sort from calibration laboratories which have experience with antennas, for example NPL in the UK, and Liberty Labs in the US.
           
Update Antenna Factors
No Function Form Description
1. Select Menu + View Antennas Main Menu  
Select of the Details Options Click on the View Details button.

Select the Antenna TAB. You will then see a selection of antennas.

Various Antennas

 

2. Select  Antenna Main Menu
DataSET
 
Select Edit Mode

From these antennas, move your mouse over the one you want to edit, right-mouse button click, select "Edit File".

The DataSET manipulation window should now be displayed.

Note: you can see from these options that you can perform other functions:-

1. View the relevant file.
2. Edit, change and update the contents.
3. Open a completely new file.
4. Rename the existing file.
5. Delete the file altogether.
6. Look at various properties of the file.

3. Save file
DataSET
DataSET

 

Save DataSET From within DataSET do the following:-

1. From the menu bar select File.
2. Select option "Save".

 

        
Creating Antenna Factors
No Function Form Description
1. Select Menu +
View Antennas
Main Menu  
Select of the Details Options Click on the View Details button.

Select the Antenna TAB. You will then see a selection of antennas.

Various Antennas

 

2. Open  DataSET Menu Main Menu
DataSET
 
Select Edit Mode

Right mouse button click within the ICON display section. Then select "Open New File".

The DataSET manipulation window should now be displayed.

3. Select File Type DataSET  

Selection of DataSET Type

Update the file type with Bilog Antenna factor.

Bilog antenna ICON Note that the Bilog Icon will appear ! 

 

4. Update DataSET DataSET  
Title of DataSET ! Enter the title of the Antenna, for example "Bilog".
Set level to "n/a".
Set Distance to "0

These are only required for Specification limits.
Level of DataSET
Amplitude Units Set 'Amplitude Units' to dB. 

 

4. Update Values in
DataSET
DataSET  
Selection of freq Click in the frequency box, where the value .000 appears.

Enter the relevant Value
Level of DataSET Type in 30, hit arrow key right  '>' , then enter the relevant amplitude/level.
Data Entry Press arrow key right '>' twice, then add a further frequency.

Continue with this process till you have added all you points.

 

5. Plot from within DataSET

Upon completion of the DataSET input it may be useful to plot the points to view if you have made any mistakes.  To do this perform the following:-

1. Select Tools from the menu bar.
2. Select Plot.
3. Select Log.

A plot will now appear, see the following example.

Plot of a typical bilog antenna factor.

 

5. Save file
DataSET
DataSET

 

Save DataSET From within DataSET do the following:-

1. From the menu bar select File.
2. Select option "Save".

 

          
Selecting Your New Antenna Factors
No Function Form Description

Open Vasona, and do NOT run a template, you can not select a new antenna factor once a test has begun.

1. Select Antenna in your template Main Menu Open Vasona and select your Radiated Emission Template.
Select of the Details Options Click on the View Details button.

Select the Antenna TAB. You will then see a selection of antennas.

Various Antennas

 

2. Drag Antenna. Main Menu  
Drag + Drop selection of an Antenna Left mouse button click on the antenna icon and drag it to the Antenna symbol. or space.

The next time you run this template this antenna factor will be used.


If there is a Antenna symbol there, this will be updated once you have dropped your new antenna in !.

 

3. Verification of which antenna is loaded. Main Menu  
Icon Properties of a transducer in a template. Move your mouse over the Antenna icon within the "Template Diagram" and your antenna should be displayed in the Menu details.
View File Options from the Template Main Menu To view the contents of the antenna factor, do the following:-

1. Move mouse over the antenna symbol.
2. Right Mouse button Click.
3. Select "View File"
4. The DataSET window should appear

You can now look at the actual values.

 

The other details....
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