Radoi interference

Barry Montague · 02 May 2005, 13:35

Hi all
i have developed a problem with (yes i know) a silva s10
i am getting this with the engine running + when trimming
is it just the case of a supressor or will i need to look elsewhere
all ideas and help will be apreciated
Barry

Biggles · 02 May 2005, 19:37

Barry,

I've got exactly the same problem.

Its been recomended to me to fit a supressor on the Radio Power lead. I shal purchase one from Halfords tomorrow and fit it at the weekend.

Its also possible to fit the suprressors on the spark plug leads but some web sites say this can damage the engine. So i shan't be doing that.

Let me know if you have any luck and I'll do th same for you.

Regards Nick R.

nik · 02 May 2005, 19:48

I think supressors may be fitted to the lt (low tension) side of the coil, but not to the spark plug leads (HT).
As an aside, I was on a boat with a yamaha o/b and it caused terrible interference on the radio. Then after a while it stopped. Electronic engine management maybe?
Nick.

Swifty · 02 May 2005, 21:00

Sounds like it might be easier to replace the crap radio

Tim'mers

Barry Montague · 02 May 2005, 21:09

Hi Swifty
yep carn't agree more but the brass is short
surley you fit things to sort out interfeerence rather than replace
things in your job

Swifty · 03 May 2005, 10:53

Quote:

Originally Posted by Barry Montague

Hi Swifty
yep carn't agree more but the brass is short
surley you fit things to sort out interfeerence rather than replace
things in your job

I understand your point. Generally in my industry we cannot afford to do cheap bodges as potentially alot of people will see the problem.

But as regards filters, I have found its better to cure the Interference at its source rather than cure it at the problem point, although this is not allways possible. If it is a power supply Interference then it will be strait forward to make a filter.

Tim'mers.

Scary Des · 03 May 2005, 11:04

Quote:

Originally Posted by Swifty

..... If it is a power supply Interference then it will be strait forward to make a filter.

Tim'mers.

Does it have to be a specific design or is a there general rule?

Des

Swifty · 03 May 2005, 14:58

Quote:

Originally Posted by Scary Des

Does it have to be a specific design or is a there general rule?

Des

Bit of both!

The typical frequencies you are trying to remove are varying (idle to WOT) so an AC blocking circuit with a capacity of around 5 Amps is required. Simplest design is a large inductor in series to the positive. Quite often on car radios they have a plastic 'thing' in the power lead near to an inline fuse. I would try one of them first. It is a fairly hefty inductor inside.

PS.
A quick rumage in my bits and bobs box revealed a 220uH 3.5A and a 100uH 5.4A coil. You are welcome to try these out. PM me with an address.

Tim'mers.

Biggles · 03 May 2005, 21:42

I bought an interference suppressor from Halfords today for £7.95 and will fit it at the weekend and see how it goes.

If it doesn't work they can have it back.

Hightower · 04 May 2005, 01:47

Had a similar problem with my S10 after an engine refit, dam squelch wouldn't work whilst outboard was running. All I did was to move the coax away from the power lines a bit, not much but if you bunch up your cables into engine and everything else bunches I think you also will get good results like I did.

Good luck,

Andy

Biggles · 04 May 2005, 20:38

Hi Andy,

Might seem like a stupid question but what do you mean by bunching up the cables.

Regards Nick R.

Hightower · 05 May 2005, 01:18

Seperating the ignition/engine control cables and cable tying these and channeling these bunched cables away from everything else.

In my case the coax was in close contact with the feed to the Tacho (electrical pulses from the ignition circuit) and it was this that was causing the interferance. I only moved them apart less that 6" and it sorted the problem.

You planning a sub 5m trip across to France then Nick?

Andy

Barry Montague · 20 May 2005, 21:15

hi biggles
did the £7:95 supressor work ??????
not had chance to look at mine yet

Biggles · 20 May 2005, 21:50

Barry,

I have tried the £7.95 suppressor and I'm not too sure of the results.

I don't really have anybody to talk to on it. I'm the only one of my crowd with the necessary licence. I use the radio mainly with safety in mind.

When I am listening to Solent Coastguard the reception is perfect. Some of the other calls, but not all of them still have a high pitched whine in the background.

I still need to do some work on it. It doesn't help that I can't even hear the radio over the sound of the engine or wind.

What I will say is that the Halfords bit of kit is in no way marinised. I don't give it much life if it gets wet or moist.

I really need to do some more research but then i need somebody with a radio to try it out.

Sorry,

Nick R.

Biggles · 20 May 2005, 21:54

Andy,

I'd like to do the sub 5m to France this summer. But legally I don't think I can satisfy the French requirements. I need to talk about this with my friends and see if the Channel islands is more appropiate.

I have done a little bit of planning with a view to landing at La Bretogne. But what I might do is aim for the channel Islands, refuel and then do a quick invasion of France before beating a hasty retreat.

Shaggy · 21 May 2005, 06:34

Hi
A good resource on RFI.

http://www.geocities.com/bill_dietrich/Radio.html

Shaggy

Hightower · 21 May 2005, 09:27

Nick, don't you need RYA, VHF, Insurance details for any kind of trip to "mainland Europe" inc of Ireland and Channel Islands of course.

That would count against me as I'm not RYA trained. This would surly have implications for a cruise if the unmentionable happened and you where rescued by French Air Sea Recuce for example.

Good luck with your planning though and if you want to test you VHF out PM me next time your down in this area.

Andy

Richard B · 21 May 2005, 09:47

Quote:

Originally Posted by Biggles

I'd like to do the sub 5m to France this summer. But legally I don't think I can satisfy the French requirements.

Nick, which bit(s) of paper don't you have?

You should have:
SSR for boat
Valid certificate of insurance
ICC
Passport
(E111)
Ship radio licence (if fitted)
VHF operator's licence
if your boat(s) is/are old then you probably won't need original invoice(s)

The French aren't usually too officious - I've been on trips without any of the above without a problem, although I wouldn't necessarily recommend it! There isn't a cordon of Gendarmes around each port