Relook 400S Spectrum Analyzer Version 2

My first Relook400S project                                                                      Charles Putney     Dublin, Ireland

Spectrum Analyzer 2

Changes from Version 1:

Layout and readability improved

Tuner and DiSEqC selection

Adjustable Gain setting

Autogain setting mode

Help page scrolling

Spectrum Analyzer Ver 1

Spectrum Analyzer Ver 3

Spectrum Analyzer Ver 4

Spectrum Analyzer 5

Spectrum Analyzer 6

Spectrum Analyzer 7

Spectrum Analyzer 8

My Dish 

Spectrum Analyzer Version 2< xml="true" ns="urn:schemas-microsoft-com:office:office" prefix="o" namespace="">

The graph displays the signal level for the frequency range chosen.  The centre of the spectrum scan is the cursor frequency at the start of the scan.  The cursor frequency can be adjusted up and down by using the left and right arrow keys.  The frequency scan starts at the centre frequency and sweeps up and down

to the graph edges.  When the cursor frequency is changed, the centre frequency and the centre of the scan remains unless the cursor is moved beyond the graph.  At this point, a new scan is started with the centre frequency as the cursor frequency.  The frequency step size can be adjusted from 20kHz to 10000 kHz

using the up and down arrow keys.  These function like a zoom for the frequency display.   Either the vertical or horizontal spectrum can be displayed using the red and green buttons.  In the scanning mode, the OK key will replot the spectrum with the cursor frequency as the centre.    The positioner is not moved initially at the start of the plugin and the DiSEqC switch is left as it was before the plugin started.  The user position is taken from the database and must be correct for accurate positioner movement using the USALS setup menu.



OK Key: This clears the spectrum window and starts a new spectrum plot with the centre of the plot set to the cursor frequency displayed in the upper right of the screen.  The display starts at the centre frequency and moves upward and downward in frequency plotting the high and low frequencies alternately.  The current step size is used to determine the frequencies that are plotted.  The

LNB is adjusted for the frequency being sampled.  To prevent un-necessary LNB setting, the algorithm is:

       if ((freq > LNB_LOW_FREQ+INPUT_HIGH_FREQ) &&   

(LNB_freq == LNB_LOW_FREQ))

       then switch the LNB to high freq

       if ((freq < LNB_HIGH_FREQ+INPUT_LOW_FREQ) && (LNB_freq == LNB_HIGH_FREQ)) then switch the LNB to low freq

This allows the minimum of LNB switching when operating near the midpoint.


Left / Right Arrow Key: These adjust the cursor frequency.  The frequency range is from 10700 MHz to 12750 MHz. If the cursor frequency is adjusted beyond the current window of the graph, the spectrum display is restarted with the cursor frequency at the centre of the display.


Up / Down Arrow Key: These change the step size of the spectrum display.  The step size can be adjusted from 20 KHz to 10000 KHz.  The default value when the plugin is started is 1000 KHz.  Adjusting the cursor frequency by a large amount is easier if you first change the step size to 10000 kHz, then move the cursor frequency, and adjust the step size back to a more reasonable value like 1000



Red Key: Clears the spectrum window and plots the Vertical spectrum using the current step size and the cursor frequency as the centre frequency.


Green Key: Clears the spectrum window and plots the Horizontal spectrum using the current step size and the cursor frequency as the centre frequency.


i Key: This checks the cursor frequency and tries to identify the symbol rate and FEC, by trying a number of typical symbol rates.  EXIT or MENU will escape from this checking.  This checking stops the frequency display until completed or EXIT/MENU is pressed.


Check Key: This allows entry of a custom symbol rate in the range 1000 to 50000.  When the OK key is pressed, if the symbol rate is within these limits, the tuner will attempt lock and if successful, will display this symbol rate and the FEC found.


Yellow Key: Changes the Tuner and DiSEqC selection by toggling through 8 settings.


Blue Key: Shows a help screen.  In the help screen, the Up/Down Keys are used to scroll.  Menu or Exit will return to the spectrum display.


Page Up / Page Down Keys: These move the positioner.  At the start of the plugin, the positioner is not changed.  Single presses of the Page Up or page Down keys increment the positioner angle by 0.1 degree, and continuous press increment or decrement by 1.0 degree.  The user location is shown on the screen and is taken from the database.  The database is updated by the USALS setting

menu as in the DGS firmware.


Volume Up / Volume Down Keys: This changes the DC bias level for the spectrum display. 


EPG/RCL Keys: These change the spectrum display gain manually.  At the plugin start, the gain is 1.0 Adjustment is within the range 0.3 to 4.0


0 Key: This toggles the AutoGain mode.  One full sweep is needed for autogain.  After a full sweep, the gain and DC bias are set to give a reasonable presentation.  Autogain is switched off by the 0 key, and also if gain or DC Bias are adjusted manually.


EXIT/MENU Keys: If currently displaying the spectrum, this ends the plugin.  If in the Help screen or checking the symbol rate, this escapes and restarts the spectrum display.


Compiled Plugin:



30/11/2006 Charles Putney