What is the effect of electromagnetic field of a generator on SATCOM equipments?

Question

We are installing a 1000KVA diesel gen set near our satalite communication receiver . Whether the satalite communication system shall have any effect from the electromagnatic fields generated from the generator.

Answer 1

Based on just what you describe, I cannot forsee any difficulties with your satellite reception. Just make sure the generator is installed properly and grounded properly.

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Answer 2

That is a pretty hefty gen set! If the satcom gear is installed correctly there should be no effect. Usually, the receive side of the satcom gear (the most sensitive) is down converted at the antenna for transport over coax to the actual receiver and all this is done at hundreds of Megahertz and has to be well shielded from stray radiation. Even harmonics of the spectrum emitted from the gen set will only reach kilohertz so any picked up by the receiver should be in the noise.

Having said that, it is more likely that those harmonics will get in to the receiver over the power line. If the internal power supply is well designed they should stop there.

In general, it is a good idea to keep radio reception gear and high power gear separate. If you can't do that consider shielding the generator if it is not already encased and by all means be sure it is well grounded.

Answer 3

While I have no experience with how noisy a diesel gen is, if it's really bad and generates big transients or spikes, I'd personally disagree with the previous answers. My experience has been that any large low-frequency spikes seem to ALWAYS find their way into microwave equipment through ground loops, onto the outside of coaxial cable shielding, and then through the resistance of the ground connections at the coax connectors or through the resistance of the shield wire itself. As a result, if the low freq. spikes are large enough, it's incredibly difficult to completely exclude them from the DC-coupled lines such as BUC's or LNB's that require power to be provided on the center conductor of the IF coax line. Furthermore, the rejection of this DC noise is never perfect within the equipment, and once it's inside the box it always shows up to some degree on the spectrum analyser.
So, you may be more lucky than me and have no problems or you may need to take some special steps to isolate the noise, which may work if you're lucky. If you're particularly unlucky, as has occasionally been my experience, you can do every type of shielding you can think of and still see the spurs, and in the end have to relocate your equipment.