MattS
Well-Known Member
I don't suppose you know enough to explain why devices like this emit RF interference when they don't contain radio components? Is it just a common thing with electronic components?
Do you recognise this 'electronic' VHF interference?
- Thread starter MattS
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I don't suppose you know enough to explain why devices like this emit RF interference when they don't contain radio components? Is it just a common thing with electronic components?
Babylon
Well-Known Member
Matt, I note you replied that isn't your autopilot and that you've got an identified culprit , but just to say that on my boat it is definitely always the ST1000 tiller-pilot that somehow causes interference on the VHF (I've never however heard it on the hand-held).
But I do also have a cheap 12v socket adaptor with both socket and USB outlets near the VHF - so I wonder if the two are working in concert to amplify the interference? Might try disconnecting the adaptor next time I'm using the tiller-pilot and see whether that has any effect?
However, what with the interference, with DSC alarms constantly going off, plus the interminable number of radio-checks on Ch16 and official stuff exploding out the cockpit speaker from Northern France, I'm afraid to say that I now leave my VHF off a good deal of the time.
MattS
Well-Known Member
Well, you've given me cause to question myself, because the last time this happened to me in anger (preventing me from actually calling the harbour master), I did have the ST2000+ powered up (although it was in standby mode). I'll test this theory again next time I'm out.
I am fairly sure that, wherever the interference is coming from, I am definitely getting an amplification effect from the 12V wiring in the boat.
Daverw
Well-Known Member
Any electrical circuit involves high frequency digital switching can transmit RF, the skill in the design of stuff that is not supposed to is to filter these out. A radio transmitter is not much more than a turned voltage switching device, (maybe this is a bit simplistic but and a few filters and oscillators) This cost money so many lower end stuff omits these from design. It has been know for the original units to have all needed for CE and then production units seam to miss these bits out. LED lights and switch mode power supply’s are the most common source of issues.
any wiring around the device can act as additional transmitter/ antenna
ianat182
Well-Known Member
Just when I thought all was well with my phone yesterday it repeatedly broke up and crackled. Today I used the phone to call my son-in-law who was a Network engineer, just retired, He came round with his equipment and we tested all items separately then switched the tungsten light off and made a call to me from his mobile. the line was completely clear. He then phoned out to his home and still clear but the volume at both ends of the lines reduced a lot. I then tried to call the Surgery and switched the light on; ,again the crackling started so bad that no message could be made. What I have deduced . if right.is. the location of the phone base has 6 Switches and sockets within a metre of that base. When the lights or power sockets are in use as they are for Internet the crackling begins. and I'm going to move the phone though limited by the short lead of the line and power. So maybe I accidentally found the cause of the fault' We've lived here for 9years always the same phone . assume that when removed from the handset base the mobile phone then uses WiFi- not the hard wired line when on the stand/base unit so would not normally pick up distortion
of the type we've experienced= Fingers crossed!!
of the type we've experienced= Fingers crossed!!
William_H
Well-Known Member
With regard to the Yakker device emitting interference. I think it worth fitting the RF filter I described earlier into the positive supply wire. From there you could try encasing the device in cooking foil. With or without a connection to ground negative. If wifi function is in the box this may negate that function. Last resort hopefully not necessary is to fit it all into a steel box. (connected to negative power line) Top explain the foil alone will act like a radio antenna all round and hopefully soak up the radio interference. The steel box will do the same but also soak up (dissipate) any actual magnetic filed coming from device. good luck ol'will
William_H
Well-Known Member
To expand on daverw explanation. Any device switching on and off puts a square wave on the wiring. ie on then off then on. A sqaure wave contains harmonics at multiples of the original switching frequency diminishing in power but to 100s of multiples of original frequency. Digital devices switch at frequencies from .5 to thousands of megahertz. Hence frequencies are radiated at original and multiple harmonics. Hence a digital device can radiate signals which can emulate a proper radio transmission fortunately usually easily dissipated with good design and filters. with ianat182 tungsten lamp interference it is possible a corroded and bad connection at the base of the lamp or in wiring could produce this off and on effect and produce interference. (very rare but if possible clan contacts of bulb. might just fix it. ol'will
