how to get rid of spikes from generator?

[Jennifer]

We are runing our side scan sonar in a boat where the power supply is provided by a Honda 60Hz AC generator. Our sonar is working on the frequency around 300KHz. The problem is that once the generator is runing, the collected signals from our sonar are corrupted by lots of spikes (in the time domain). We analyzed the spikes and found that it has the pattern of 60Hz and harmonics of 60Hz. We suspect those spikes are from the generator that is not brushless, but we don't know how to get rid of them. Does anyone come across this kind of problem in a real side-scan sonar application or know how to solve this kind of problem?

[schmidt karl]

Re: how to get rid of spikes from generator?

the spots come from the Honda generator. use a separate battery to operate your side scan and enlange the distance from honda to your system and/or work with special power supply cables.

[Derek A]

Re: how to get rid of spikes from generator?

I know this problem well. AC power absolutely runs havoc on sonar systems of all types. I assume you are running a 12VDC system so you do not rely on the generator to power your side scan. A pure sine-wave inverter is the best bet if you are using AC powered devices.

Your best bet would be to keep the system as far away from the generator as possible. Grounding the unit may help a little, but never enough to get rid of lines.

I have installed some sonars in boats where we had to put dampeners on the sonar and generators to try and get rid of as much noise as possible becuase once they turn on, your screen turns red. Sometimes you get lucky and sometimes you do not. After working on an AC powered side scan, I have come to the conclusion that it is not feasible and have just switched over to a 12VDC power supply and have had no problems since.

Good luck and hang in there, some boats just will not be suitable for sonar systems.

[Alec Collyer]

Re: how to get rid of spikes from generator?

A cheap 1st try is to get a computer AC filter unit from your local computer shop. Best wishes and happy hunting for 2005 ! Alec.

[Richard]

Re: how to get rid of spikes from generator?

Which SideScan unit are you using and what is the cross track resolution? Do you have a screen shot of the output? Are the "spikes" cross track or along track?

[Rob]

Re: how to get rid of spikes from generator?

Richard,

What kind of side scan are you using?

It sounds like you need to ground your generator to the water or ground plate.

If that doesn't work you should try running through an isolation transformer.

Regards,

Rob