Possible vhf Interference from PV/MPPT?

[rajjes]

Hi,

I have recently upgraded from an 80W solar panel to 2X100W with a 20A MPPT controller (china made). I'm happy with the installation and I can now finally use the fridge etc at anchor while still seeing the batteries being charged!

However, i have noticed that since the upgrade the fixed vhf is not picking up some traffic which is picked up clearly by the handheld. (both VHF's are recent models). While i can still hear some communications clearly, there are occasions when a reply is heard clearly on the hand held but nothing at all on the main unit. I have checked the squelch control and the aerial connections and all seems fine.

Another thing is that while the NASA depth log used to show the occasional 'out' it is not almost constantly 'out' with the occasional reading shown when the engine is at higher revs. I check ed the oil for the transducer and the wiring and again all seems fine.

Could these symptoms have anything to do with the PV upgrade or is it just a coincidence?

I will try disconnecting the mppt and see how it goes but thought I'd ask for some feedback from here first?

Regards,

Duncan

 

[ex-Gladys]

I think you may have given us a clue, in that you can now run your fridge in circs which you were unable to... Try turning off the fridge which is far more likely to be producing EM type interference

 

[Billjratt]

Wander around with a portable radio to find sources of interference. possibly need some ferrites.

 

[William_H]

The MPPT controller is actually a power converter converting DC from the panels to AC then DC in a switch mode type power supply to transform 20v to 14v
Switching at 100s of kilohertz. So yes a likely source of interference. However as said so is fridge.
If the squelch is adjustable on the VHF set it to just cutting out hiss with solar and fridge off. Then turn each on and note if hiss appears as interference.
Easist way to turn off solar is to cover the panels or disconnect panel input to controller.
If MPPT or indeed fridge is causing interference then you need filters. As said a ferrite is a piece of black ceramic like material which is good at conducting magnetic fields. It comes in various shapes. A toroid will allow you to wind your supply wire through it for several turns. This produces an inductance which forms a blockage for the high frequency AC. Capacitors either side of this inductance to negative will tend to bypass the AC component.
The ferrite can be found in computer components. ie on the cable iside a keyboard printer or inside a computer power supply or here are some in an electronics shop. http://www.altronics.com.au/search/all/?sr=Ferrite
The capacitors should be rated at 20 volts or more and .1 microfarrad ceramic although almost any small value will do. Good for fridge or MPPT controller output good luck olewill

 

[rajjes]

Many thanks for your help. Will try out recommendations and see how it goes...and apologies for not replying earlier but just back from a long weekend on the boat.