Standard Horizon GX1600 noisy with Fridge Compressor On

[Sid at SailAway]

Not sure how long the problem has existed. A bridge tender let me know the vhf transmission sounded like an engine running in the background. Sure enough, with a Sea Tow test, when the compressor comes on the noise starts. I isolated everything else including the fan to the compressor. Definitely the compressor. Question is, how do I remedy this? The interference is bad enough to make the transmission difficult to understand. Thanks!

[Typhoon]

Not an unusual problem . What is causing the noise is the signal processing that the controller goes through to convert your dc source to 3 phase to control the windings inside the compressor to turn the crankshaft which in turn moves the piston up and down creating the compression you need to have the refrigeration system work .
What kind of a compressor is it ?

Regards John Tully

[Typhoon]

If it is a Danfoss compressor , you can get an aluminium cover that controls the RF interference . Looks like this




Regards John Tully

[Sid at SailAway]

It is a BD35 compressor. Where did you find the shield?

[Typhoon]

Originally Posted by Sid at SailAway

It is a BD35 compressor. Where did you find the shield?

I actually bought these controllers with the optional RF interference shield already on them .

Not sure if they sell it by them selfs . Im sure if you can't find one you could make one yourself out of a bit of thin aluminum sheet and a pair of sheet metal snips.

If you would like me to send you a few more photos of the shield I can , it just slips over the controller .


Regards John Tully

[leftbrainstuff]

You could also treat the rf noise into the radio. Isolation of power, ferrites, rerouting antenna. Trial and error.

Having terminal blocks at strategic locations can also help to break rf paths. More by accident than by design.

We have the same controllers. Don't experience any rf issues with them. We have ssb, han, multuple vhfs, etc.

[Jim Cate]

Originally Posted by ColdEh Marine

I actually bought these controllers with the optional RF interference shield already on them .

Not sure if they sell it by them selfs . Im sure if you can't find one you could make one yourself out of a bit of thin aluminum sheet and a pair of sheet metal snips.

If you would like me to send you a few more photos of the shield I can , it just slips over the controller .


Regards John Tully

does this shield reduce HF noise broadcasting as well as VHF?

IF so, they ought to be standard equipment! Those damn things are very noisy and intrusive, and the noise seems to carry surprising distances. I've had many a ham radio contact terminated by a neighbor's fridge turning on, despite their being anchored a hundred meters away.

JIm

[Sid at SailAway]

Originally Posted by ColdEh Marine

If it is a Danfoss compressor , you can get an aluminium cover that controls the RF interference . Looks like this


Attachment 139522

Regards John Tully

Are the cooling fins still exposed with the cover in place?

[robertsquire]

or you could just go out and buy an inline suppresor

[Xthewater]

Shielded and the shield grounded, should solve the issue.

[Typhoon]

Originally Posted by Sid at SailAway

Are the cooling fins still exposed with the cover in place?

Yes the fins are still exposed.

Regards John Tully

[Typhoon]

Originally Posted by Jim Cate

does this shield reduce HF noise broadcasting as well as VHF?

IF so, they ought to be standard equipment! Those damn things are very noisy and intrusive, and the noise seems to carry surprising distances. I've had many a ham radio contact terminated by a neighbor's fridge turning on, despite their being anchored a hundred meters away.

JIm

Yes they should be standard equipment , but you have to order them with the shield.

Funny some people don't have any RF interference and some do ? Must be where the system is placed and how it is grounded .

Regards John Tully

[varkpilot]

Originally Posted by leftbrainstuff

You could also treat the rf noise into the radio. Isolation of power, ferrites, rerouting antenna. Trial and error.

Having terminal blocks at strategic locations can also help to break rf paths. More by accident than by design.

We have the same controllers. Don't experience any rf issues with them. We have ssb, han, multuple vhfs, etc.

If you don't have the interference, I'd wager you also have very good grounding throughout your systems. I talk about airplanes a lot in my few piddly answers, and that's because boats and planes have a lot of things in common. Radio Frequency Interference, or Electro-Magnetic Interference being one of those similarities. I earned a master's degree in Electrical Engineering (electronics) many years ago and applied it to Air Force planes. One of the first things we learned was that all the (many) systems on those planes suffered EMI unless all the systems were thoroughly grounded. The grounds had to be checked for corrosion build-up as time went on. The corrosion acts as an insulator and you begin to pick up the EMI until the grounds are cleaned and reset in whichever unit was either transmitting or receiving the EMI. ALL of the coax going from any unit to an antenna MUST have the shielded portion of that cable WELL grounded, preferably to your engine for a solid ground reference point that actually then becomes a true earth ground. Electrical devices you would not expect to broadcast noise should also have their cases grounded. The metal case doesn't stop RFI. But if that metal case is grounded, the RF is channeled harmlessly to ground. Such is our modern world of toys.

[cal20dennis]

Check your radio antenna cable...a surplus of cable coiled near a power line or GPS antenna cable will pickup RF.

[Sid at SailAway]

Originally Posted by robertsquire

or you could just go out and buy an inline suppresor

Originally Posted by Xthewater

Shielded and the shield grounded, should solve the issue.

Update..The local Radio Shack here in Key Largo only carried the ferrite cores. I tried one on the positive lead going to the radio and no joy. Tried one on the antenna coax leading into the radio and no joy. Then tried one on the positive lead going to the compressor and no dice. Does the size of the ferrite matter? Am I putting them in the right place?

Shielded and the shield grounded, not sure what this means. Can you expound on it?