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I'm writing a report to see if it's feasible to power a secondary surveillance radar with wind energy. I'm having trouble with sizing the turbine but I can't seem to find an energy demand for a SSR anywhere. any help is appreciated.

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    $\begingroup$ What kind of SSR do you need to power? What range, what update rate /revolutions per minute. Mode A/C or Mode S. How many aircraft in range? $\endgroup$ – DeltaLima Nov 14 '17 at 22:37
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    $\begingroup$ This one with a range of 300 km has a peak power of 2 kW. That likely means you need 3 or 4 kW to feed it. Technical characteristics. You surely need to have displays, processing power and a backup power source. $\endgroup$ – mins Nov 14 '17 at 22:58
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    $\begingroup$ @mins, that figure is probably excluding the motor for turning the antenna assembly. But in total 4 kW should be about right. $\endgroup$ – DeltaLima Nov 14 '17 at 23:24
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    $\begingroup$ @mins I am not sure whether it is the peak transmission power or it is the average power consumption during peak capacity operation of the whole radar chain, including scheduler, interrogator, receiver, extractor and output generator. The beam itself may have a high peak power, but the duty cycle is quite low because most of the time the receiver is connected to the antenna. When the radar is transmitting, it will draw power from its capacitors, those are recharged while the radar is listening to the reply. $\endgroup$ – DeltaLima Nov 14 '17 at 23:54
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What you propose is possible. TCAS is essentially a secondary surveillance radar, and is a piece of avionics which doesn't break the bank power wise. In a moderate traffic environment, I have seen 3 to 5 amps at 24VDC. I am sure it is higher in a dense environment. The interrogation power requirement doesn't go up but processing the returns may take more power.

5 amps at 24VDC is a modest power requirement for a mid-sized wind energy system, therefore at first blush, what you propose is quite possible.

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    $\begingroup$ Uh... a typical SSR has quite different requirements from TCAS. Yes, they use similar concepts, even the same frequencies and data formats but the range and azimuth requirements are in an entirely different league $\endgroup$ – DeltaLima Nov 14 '17 at 22:35
  • $\begingroup$ TCAS range is 4.5 NM/14 NM, in relative silence of air, not compatible with ATC use. $\endgroup$ – mins Nov 14 '17 at 22:41
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    $\begingroup$ I was hoping to get the energy demand in kWh. $\endgroup$ – darragh mcsweeney Nov 14 '17 at 22:51
  • $\begingroup$ @darragh That's nonsensical, like asking how fast a car is, measured in feet. Besides, P=U*I, so that's 120W for TCAS (although I also doubt whether that is a realistic number for a ground station). $\endgroup$ – Sanchises Nov 14 '17 at 22:55
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    $\begingroup$ @darraghmcsweeney If you can't effortlessly convert among SI units like W and kW and figure out how kWH relates to kW ... don't quit your day job :) You can get kWH from kW if you know how many hours (H) you plan to run this thing. $\endgroup$ – Harper Nov 15 '17 at 5:28

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