gtuson
New member
Any suggestions on how to reduce interference on portable radio from fridge. Radio not electrically connected so interference is transmitted from fridge.... I assume....
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intereference from fridge
- Thread starter gtuson
- Start date
Sea Devil
Well-known member
I stuck a load of those supressor maget things around the power cables and it helped.
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<A target="_blank" HREF=http://www.michaelbriant.com/sailing>http://www.michaelbriant.com/sailing</A>
<hr width=100% size=1>If you have time please visit my web site -
<A target="_blank" HREF=http://www.michaelbriant.com/sailing>http://www.michaelbriant.com/sailing</A>
pvb
Well-known member
Please, not magnets again! (nm)
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steve28
Active member
To expand on the post above ,they are ferite cores and work well when connected to power supplys and aerials.
They are used on computer and video equipment.
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They are used on computer and video equipment.
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Sea Devil
Well-known member
steve hi,
yes - couldn't remember what they were called - got them everywhere
<hr width=100% size=1>If you have time please visit my web site -
<A target="_blank" HREF=http://www.michaelbriant.com/sailing>http://www.michaelbriant.com/sailing</A>
yes - couldn't remember what they were called - got them everywhere
<hr width=100% size=1>If you have time please visit my web site -
<A target="_blank" HREF=http://www.michaelbriant.com/sailing>http://www.michaelbriant.com/sailing</A>
Benbow
New member
eek, don't connect them to aerials, they are designed to kill RF !
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bedouin
Well-known member
I would have thought that ferrites attached to the fridge wiring is unlikely to reduce the interference in a battery powered radio.
If it is a modern fridge then it should have some form of suppression fitted (often a capacitor IIUI) so if you are getting interference it suggests that that has failed.
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If it is a modern fridge then it should have some form of suppression fitted (often a capacitor IIUI) so if you are getting interference it suggests that that has failed.
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scarlett
New member
I seem to recall there was something in PBO a few years ago about 'stuff' from the popular Danfoss fridge compressors and the inability to get rid of its interference on the World Service on Shortwave. I recall the gist was we have to live with it.
I use WorldSpace during the day and turn the fridge off at night.
If a radio technican has the definative answer please post it.
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I use WorldSpace during the day and turn the fridge off at night.
If a radio technican has the definative answer please post it.
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bruce
New member
you might try using shielded wire to power the fridge, and ground the fridge body
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William_H
Well-known member
The expectation of the interference from the fridge is that the power wiring from the battery to the fridge is radiating the interference like a transmitting aerial. This is the mode of interference that has been discussed with the idea of ferite on the wires or in fact a failed in built filter. The frrite is a magnetically permeable material which increases the inductance of the conductor. It can increase the inductance by slipping the torroid over the wire however the inductance can be vastly increased by wrapping the wire around the torroid from middle to circumference as many times as the number of turns will fit through the hole. A simple source of ferrite is an old transistor portable redio where the aerial is in the form of a black rod 5 to 20 cms long round (6mm dia) or flat with 1 or more coils of fine wire wound over it. Take the existing coils off and wrap your power wire around the ferrite rod as many turns as you can fit or have spare wire. You can use another pierce of wire however it must be heavy enough to carry the fridge current and is inserted in the power wire. It is important to put the inductor as close to the fridge motor as possible to stop the high frequency AC before it can radiate. The iductor acts like a resrictiobn or resistance to the high frequency AC.
The next line of attack is to fit a capacitor from the power wire again near the motor to ground. (negative wire) (actual grounding of the negative and the fridge will help) The capacitor should be about .1 microfarrad ( 100 nanofarrad) although any value around or larger than that will help. If you use a large capacitor like 100 microfarrads then fit a small one in paralell as the large capacitors can exhibit inductance which maeans it won't work so well at high frequencies. Small capacitors may be salvaged from the same transistor radio and are frequently a green coloured shiny blob about 5mm across with two wires going in. You will have to carefully un solder from the board. Either wire can go to positive and any number can be fitted in paralell.
These two components should alleviate the power line radiated interference.
The other modes of interference can be direct magnetic field radiation which can only be stopped by a mild steel sheet around the motor or particularly between the motor and the radio. A somewhat similar mode is electrostic radiation from the motor which can be alleviated by a conductive foil lining of the fridge container which of course is connected together and to ground or the body of the fridge (negative). These are last resorts of course and the kind of thing you find in your computer box. good luck will
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The next line of attack is to fit a capacitor from the power wire again near the motor to ground. (negative wire) (actual grounding of the negative and the fridge will help) The capacitor should be about .1 microfarrad ( 100 nanofarrad) although any value around or larger than that will help. If you use a large capacitor like 100 microfarrads then fit a small one in paralell as the large capacitors can exhibit inductance which maeans it won't work so well at high frequencies. Small capacitors may be salvaged from the same transistor radio and are frequently a green coloured shiny blob about 5mm across with two wires going in. You will have to carefully un solder from the board. Either wire can go to positive and any number can be fitted in paralell.
These two components should alleviate the power line radiated interference.
The other modes of interference can be direct magnetic field radiation which can only be stopped by a mild steel sheet around the motor or particularly between the motor and the radio. A somewhat similar mode is electrostic radiation from the motor which can be alleviated by a conductive foil lining of the fridge container which of course is connected together and to ground or the body of the fridge (negative). These are last resorts of course and the kind of thing you find in your computer box. good luck will
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AndyL
Member
Isotherm make a Radio Interference Kit, part no SED00002BA, but it's about £70.00.
Cheers, Andy
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Cheers, Andy
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