Linear Technology LINEARCOM3000 Operation Manual page 17

In most cases the cable signal delays can be calculated manually using in addition the delay
switch calculation tool.
How to calculate the delay switch positions manually for systems with one, two or more
transmitters will be described in the next sections. Refer to the delay switch calculation tool
for information how to do to get a computed value for the delay switch position.
There are no cable signal delays in systems with only one transmitter and radiators directly
connected to the transmitter with cables of identical length. The delay switches on all
radiators are to be set to zero. Subsequently check whether to compensate for radiation
signal delay. If the cable lengths differ from radiator to radiator, the delay switch parameter
can be calculated with the formula. Take signal delay rate as 5.6 ns/m as example :
• X : Delay compensation parameter, displayed on LCD
• LMAX : Maximum cable length in the considered chain
• L : Cable length between transmitter and radiator
Use the following procedure to determine the delay switch position based on cable lengths :
1. Measure the cable length L between the transmitter and every single radiator;
2. Determine the maximum cable length LMAX. For each radiator calculate the cable length
difference value LMAX-L;
3. To obtain the cable signal delays for each radiator, multiply the cable length difference of
each radiator with the cable signal delay per meter;
4. Divide the calculated signal delay difference by 25. The rounded off figure is the signal
delay switch position for the radiator;
5. If applicable, add delay switch positions for radiators under a balcony;
6. Set the delay switches to the calculated switch positions.
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X = [ ( LMAX – L ) x 5.6 ] / 25