How to best monitor SHF and UHF satellite communications for interference

[jschroeder13]

I'm need to develop a tool to monitor UHF Satellite Communication channels for interference.  While running this monitoring plan I'll need to view and measure other signals from SHF satellites.  Can your PXI 5660 do this?  If not, do you have another product that could do this.  What if I converted the SHF signals to L-Band, could it do the job then?

[Travis_W]

Hi,

The 5660 can downconvert a 20MHz band within the 2.7GHz range to IF and then digitize it.  Although SHF (3-30GHz) is out of this range, L-band (.39-1.55GHz) is well within this range.

It sounds like your application might be able to make use of 2 synchronized PXI-5660s.  With the PXI platform, this is very easy to accomplish.  What are the bandwidths of your SHF and UHF signals?

Have a great day!
Travis W

[jschroeder13]

The signal bandwidths vary from 5 Khz to 36 MHz.  Would the system be able to measure signals larger than 20 MHz?  You mentioned syncronizing two units to accomplish the task.  Would it require two separate receivers as well?  Can it perform a monitoring mission with one unit and detailed measurements of an interference signal with the other (hand-off)?  thanks for the info!

Jeff

[Travis_W]

Unfortunately, even 2 5660s together won't be able to measure the 36MHz signals.

The 5660s can only go to 20MHz bandwidth with each unit.  They can synchronize the 10 MHz reference clocks, but not the LOs because they are internal.  What this means is that the frequencies between the two units will be locked, but the phase will have an offset, and that offset can't be measured.  Therefore, the 5660 cannot acquire a 40 MHz bandwidth signal by stitching two 20MHz signals together while retaining phase information.

Have a great day!
Travis W

[jschroeder13]

If I use L-Band for my SHF signals and I don't measure anything about 20 MHz bandwidth, could I run a UHF multi-signal monitoring plan (continuously scanning through the channels of interest for EMI) on one unit and hand off any EMI to the second unit for detailed measurements and recording without affecting the monitoring plan of the first unit?  Second, while doing the monitoring plan with the first unit can I do measurements of my L-Band signlas with my second unit?  Thanks

Jeff S.

[Travis_W]

Jeff,

That sounds like it will work great.  The one consideration I can think of is for the second system.  You won't be able to measure the L-Band signal and do the EMI detailed measurements simultaneously if they are at different frequencies.  If the L-Band signals don't need to be monitored continously, however, that sounds like a great setup.

Let me know if you have any further questions.  Also, don't hesitate to call into NI Support if you need to ask more questions or place an order.  They are very helpful, and you can speak directly with an engineer with virtually no hastle.

Have a great day!
Travis W