Zero Forward Power on SSPA

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kenshin03 Senior Member ★★★ Offline Posts: 61	Jul 16^th, 2011 at 1:19am Sir do you have any idea why we are having a zero output power on our AWMT SSPA C100-CSE even it was on the transmit mode? thanks, ken u.
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Eric Johnston

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Reply #1 - Jul 16^th, 2011 at 7:08am

Some ideas...

No or negligible input signal power. Use enough input power to give say 10W out and no more.
Muted due to command state.
Muted due to internal error. (e.g. voltages or temperature out of limits, excess input power)
Muted due to excess reflected power due to output not terminated correctly.

Output power measuring device not connected to the device under test.(check waveguide switch states)
Output power measuring device faulty. (check with output of known good amplifier)

Best regards, Eric.

« Last Edit: Jul 16^th, 2011 at 8:11am by Eric Johnston »

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kenshin03 Senior Member ★★★ Offline Posts: 61	Reply #2 - Jul 17^th, 2011 at 1:01am Sir this time I have already output power but very low even I set my SSPA on its maximum gain only 35 dBm forward power. But please note that we are able to have a forward power because I increase the TX LVL on my modulator from -20 dBm to -12dBm (modulator TX LVl is from -20 to 0 dBm). Thanks, Ken U.
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Eric Johnston

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Reply #3 - Jul 17^th, 2011 at 7:54am

Maybe there is 13 dB attenuation in the cable to the SSPA ? �

What frequency is the output of your modulator ? What type cable ? �How long is it ?

If the gain of the SSPA is 60 dB then +50 dBm output (100W) will need an input (at the input socket of the SSPA) of -10 dBm.

Do any alarms show on the SSPA monitor and control interface ?

Do you have the operating manual for your SSPA ?

Be careful, you need a finned heatsink dummy load rated at 100W on the output of the SSPA. 100W is dangerous.

+30 dBm = 0 dBW = 1W
+35 dBm = +5 dBW = 3W
+40 dBm = +10 dBW = 10W
+49 dBm = +19 dBW = 79W (-1dB recommended operating max for single carrier)
+50 dBm = +20 dBW = 100W

Best regards, Eric.

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kenshin03 Senior Member ★★★ Offline Posts: 61	Reply #4 - Jul 18^th, 2011 at 7:29am Sir we use 70.25 MHz and the cable is Belden 1523A Coax 30ft to 40 ft long. No alarms has been shown on the sspa and yes we have a manual. We check the IF output from the modulator using shorter cable and the installed cable (the one connected to the SSPA) using a spectrum and we have the same signal level. thanks, Ken U
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