Do you recognise this 'electronic' VHF interference?

[MattS]

The last few times I've been out sailing, I've struggled with VHF interference on a couple of channels. This weekend it was on Ch08, which I wanted to use to call into the local harbour master.

I thought I might have an issue with my masthead aerial, until I realised I was getting the same interference on my handheld too. As you can see in the video, I have the squelch right up - way past where I'd normally expect to set it, and I still couldn't seem to get rid of the interference. In the end I just had to switch it off.

Does anyone recognise the slight more 'electronic' sound of this interference? It doesn't sound like your usual interference at low levels of squelch which is easily recognisable. This seems to have an electronic 'tone' to it.

I'm trying to work out whether this is something local to my boat, or whether there was something in the area creating that noise on the channel (obviously I couldn't move away from the boat to test that!)

VHF Interference - Queenborough Harbour

 

[Plum]

The last few times I've been out sailing, I've struggled with VHF interference on a couple of channels. This weekend it was on Ch08, which I wanted to use to call into the local harbour master.

I thought I might have an issue with my masthead aerial, until I realised I was getting the same interference on my handheld too. As you can see in the video, I have the squelch right up - way past where I'd normally expect to set it, and I still couldn't seem to get rid of the interference. In the end I just had to switch it off.

Does anyone recognise the slight more 'electronic' sound of this interference? It doesn't sound like your usual interference at low levels of squelch which is easily recognisable. This seems to have an electronic 'tone' to it.

I'm trying to work out whether this is something local to my boat, or whether there was something in the area creating that noise on the channel (obviously I couldn't move away from the boat to test that!)

VHF Interference - Queenborough Harbour

On two occasions I have had VHF interference, each time it was on different channels and different conditions but both times it was a 12v usb phone charger!

Www.solocoastalsailing.co.uk

 

[mucklestone]

Not got much experience with VHF but with high end car audio it tends to cheap chargers, dash cams, devices like that etc. Basically cheap electronics that cause more interference than they should.

Perhaps next time could you turn off all electrical devices including portable ones like mobile phones tablets (only if safe to do so) and then turn them on one by one until you find the cause???

 

[MattS]

Interesting - if you've seen interference from that sort of thing before I will definitely need to do a process of elimination. I have all kinds of things plugged in charging!

Must be giving out quite a hum to upset the VHF handheld out in the cockpit too!

 

[[70521]]

Might be worth adding a 'choke' to the supply to the USB. Your VHF should have one fitted that came with the unit.

 

[MattS]

Might be worth adding a 'choke' to the supply to the USB. Your VHF should have one fitted that came with the unit.

Forgive me, but what is a choke?

 

[TSailors]

Forgive me, but what is a choke?

a ring that's made of iron dust.. it goes around the power wires.. you've probably seen it in lots of adaptors and stuff. my laptop has one around its power cord.. you can get them from any electronics store -- or steal one from an adaptor you are not using

 

[MattS]

a ring that's made of iron dust.. it goes around the power wires.. you've probably seen it in lots of adaptors and stuff. my laptop has one around its power cord.. you can get them from any electronics store -- or steal one from an adaptor you are not using

Ah yes - I know what you mean, thanks. You can imagine what I got when I googled "cable choke" ?

 

[[70521]]

Forgive me, but what is a choke?

See hyperlink. I suspected that the question might be asked. ?

 

[MattS]

See hyperlink. I suspected that the question might be asked. ?

Oops, I didn't even notice that was hyperlinked sorry!

 

[Spirit (of Glenans)]

Forgive me, but what is a choke?

I have seen the term "ferrite" used for this type of item on this forum.

 

[Davy_S]

I have seen the term "ferrite" used for this type of item on this forum.

Yes, i used ferrite rings to stop a paper echosounder interfering with differential GPS, it could also be heard on the radio as a tick tick tick, it worked.

 

[Daverw]

Not sure how this would help the hand held though, air born interference most likely from led or switch mod units that are poorly designed.

 

[jwfrary]

Led lights are known to cause EMF that interferes with vhf

 

[AntarcticPilot]

Led lights are known to cause EMF that interferes with vhf

Not all LED lights do, only some. Given the intermittent nature of the noise, a constant source such as a poorly designed LED is unlikely.

The noise sounds like two components - constant white noise with an intermittent tone superimposed. When I listened to it, I couldn't think of any boating equipment that would match those characteristics. Perhaps a noisy motor in an autopilot?

 

[oldgit]

from memory...
ferrite rings will only help suppress interference being transmitted down wiring
It will not help with much else.

Power down stuff in sequence .
Just about everthing capable of radiating RF including invertors, voltage droppers. etc.
Cheap cigar socket plugs are notorious emitters of interference.

 

[jdc]

Port operation channels are notorious for 'open mic' conditions where the squelch is always lifted. In some places ch 9 always has white noise plus some odd burbles and tones. So try to make 100% sure that it's your boat and not local conditions which are causing the problem before fiddling around with ferrites.

 

[MattS]

Not all LED lights do, only some. Given the intermittent nature of the noise, a constant source such as a poorly designed LED is unlikely.

The noise sounds like two components - constant white noise with an intermittent tone superimposed. When I listened to it, I couldn't think of any boating equipment that would match those characteristics. Perhaps a noisy motor in an autopilot?

Can rule that one out! I only have a tiller pilot - and it wasn't activated at this point (was hand steering).

 

[MattS]

I think the only feasible next step is wait for it to happen again, and then shut everything off to see if it kills it. If it disappears, I'll know that I need to find the offending bit of equipment!

 

[AntarcticPilot]

Can rule that one out! I only have a tiller pilot - and it wasn't activated at this point (was hand steering).

I include tiller pilot in autopilots - they have motors too! But if it wasn't on, that eliminates that one. But the intermittent nature of part of the noise does seem to me to eliminate many possible sources, and suggests that soemthing in the instrument setup is a possible source.