*very* strange RF interference ?!

Posted by: Nils

*very* strange RF interference ?! - 19/07/2000 03:12

Hi there !
It is not really a *bug* but this forum is my best guess to get help ...

-> Whenever my Mk2 is connected to the car sled ( no matter if it is in standby or playing music ), my radio controlled car key isn't working !!!!!!!
( I know this sounds mad, but i can prove & repeat it as often as i want )
At first i thought, the battarries of my car key transmitter is low, and i exchanged it, but it turned out that having the empeg in the sled is *the* main and only factor ...

Is it transmitting a very high level electronic noise ???

Do you have any idea ??

The car: Audi 80 convertible '97, standard AUDI radio controlled door (un)lock mechanism ...

Nils, ex #123, now #60000005



Posted by: Henno

Re: *very* strange RF interference ?! - 19/07/2000 03:25

Whenever my Mk2 is connected to the car sled, my radio controlled car key isn't working

This was reported earlier here. I believe the thread developed from someone having the same with a BMW.
German car / British electronics ??

Henno
mk2 nr 6
Posted by: Nils

Re: *very* strange RF interference ?! - 19/07/2000 03:48

Shame on me, you are right, Geoff was experiencing the same with his BMW ...
Strangely enough, i haven't had this problem with my Mk1, beeing installed in exactly the same location & manner ...

So what to do ???


Nils



Posted by: rob

Re: *very* strange RF interference ?! - 19/07/2000 04:20

The car player doesn't affect any of the Mercedes/BMW's/Audis/VW's that we've seen (I believe that CCA have installed empegs into all of those cars).

The player is FCC and CE approved, which involved a very thorough EMC test procedure. Of course, the player fully passed these tests. It seems unlikely that it's a radiation issue, but I'm not sure what else could cause it. Do you know where the door lock receiver is located in your vehicle?

Rob


Posted by: rob

Re: *very* strange RF interference ?! - 19/07/2000 04:24

One more thing.. does this happen when the player is powered down, or only when it's switched on or in standby? Note that it switches itself off completely 60 seconds after losing accessory sense, so try switching off your ignition, waiting a minute and then using your radio key. If it still doesn't work it can't be anything to do with radiation, as the player isn't powered up.

Rob


Posted by: Nils

Re: *very* strange RF interference ?! - 19/07/2000 05:14

Hi rob !
Im just downloading 12a to try this out, i let you know ...

Nils


Posted by: altman

Re: *very* strange RF interference ?! - 19/07/2000 05:38

Though they both passed CE & FCC testing, the mk2 is electrically quieter than the mk1 - so it should be *better*, not worse!

You could try taking one of the clip-on ferrites off the home PSU power lead and running the yellow, orange and blue (power, basically) wires through the ferrite (if you can get one turn through the ferrite, this would be good). This might help if the RF receiver is very susceptible to induced noise, though we passed CE and FCC on induced noise too...

Hugo


Posted by: Geoff

Re: *very* strange RF interference ?! - 19/07/2000 06:04

I'm sort of torn here... I'm glad I'm not the only one experiencing this anymore, but at the same time I wouldn't wish it on anyone else, if you know what I mean

I was hoping (I am still hoping) it will be cured when I get my Mk2 installed, but I am going to try to wait until the tuner module is available to minimise any installation hassles (I don't think I could live without a radio, even if I do only listen to it for a small percentage of my time in the car)

In my BMW, the alarm/door remote isn't completely disabled, but it will only operate from a couple of feet away from the car, and even then it may take a few (extended) presses of the button to activate.

I have a Haynes manual for the car, but I have lent it to someone so can't look it up right now to see where the alarm module is located. For the time being, if I have to leave the car temporarily, I just pop the empeg out of the sled by about 1/4" or so, just to remove the power, and then it works ok... so in my case, it only occurs when there is power to the Mk1.

Geoff
---- -------
Got one of the first Mark 2 empegs...
Posted by: jfranke

Re: *very* strange RF interference ?! - 19/07/2000 10:49

VW Golf IV + MK1 = No Problems
VW Golf III + MK2 = No Problems

Posted by: Nils

Re: *very* strange RF interference ?! - 19/07/2000 13:02

I tried it out, and ->
When the unit is powered off -> RF Remote works, if it is in standby, or working, RF Remote doesnt work ...

I will try out to use the ferrite thingies tomorrow ...

Nils



Posted by: mac

Re: *very* strange RF interference ?! - 19/07/2000 13:12

VW Golf IV + MK1 = No Problems
VW Golf III + MK2 = No Problems


VW Golf n + MKm <==> n + m = 5 ?

--
Mike Crowe
I may not be speaking on behalf of empeg above :-)
Posted by: Nils

Re: *very* strange RF interference ?! - 19/07/2000 13:35

>VW Golf n + MKm <==> n + m = 5 ?

Haha -> * Madness* :-)

nice one !

Nils

Posted by: jfranke

Re: *very* strange RF interference ?! - 20/07/2000 01:21

VW Golf n + MKm <==> n + m = 5 = wrong...
VW Golf n + MKm <==> n + m = 34 = right!
VW Golf IV + MK1 + VW Golf III + MK2 = no money in my pocket = entirely true :-(


Posted by: tanstaafl.

Re: *very* strange RF interference ?! - 20/07/2000 11:56

VW Golf n + MKm <==> n + m = 5 = wrong...
VW Golf n + MKm <==> n + m = 34 = right!
VW Golf IV + MK1 + VW Golf III + MK2 = no money in my pocket = entirely true :-(


Hmmm... never realized until now that you could add cars plus stereos and get a proper result. Of course, addition is a commutative function, so I suppose it's all right.

Just don't divide it by zero!

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"
Posted by: blairc

Re: *very* strange RF interference ?! - 21/07/2000 01:22

I may be totally off course here but, does your car alarm have current sensing i.e. will it sound if the interior light etc comes on. If so it might be sensing the current the empeg is drawing and not allowing you to arm it. It may not be RF interference it might just be your alarm refusing to arm while something isn the car is powered.

Blair

Posted by: Nils

Re: *very* strange RF interference ?! - 21/07/2000 02:54

Hi !
It is no alarm system, just the RF door lock !

By now i tried the trick with those ferrite thingies, but it still doesn't work :-(

Nils

Posted by: drakino

Re: *very* strange RF interference ?! - 27/07/2000 01:22

The alarm theory mat still hold true. My new car also came with keyless entry, and reading furthur into the manual revealed it to be a security system as well. One of the things that will set mine off is locking the car with the remote, then opening any door or trunk with the key. Try this with yours. Lock the car with the remote, then unlock it with just the key. Mine begins to sound a few horn chirps before going full blast to warn you that you forgot to use the remote.

Posted by: drakino

Re: *very* strange RF interference ?! - 28/02/2001 00:15

Well, it appears my car suffers the same problem described above. If the Mark II is powered in any way (Playing or standby), my factory keyless entry/alarm system will not work. I tried to arm mine while holding the remote inside the car, and also over various parts outside. Until the unit is powered down completly, no function on the remote will work.

I am going to try to find the exact position of the reciever in the car, and see how close it is to the empeg. For now, my workaround is to have the empeg completly power off only a few seconds after going into standby.

Oh, I suppose the car make and model would help. It's a 2000 Saturn SL2.

Posted by: tfabris

Re: *very* strange RF interference ?! - 28/02/2001 10:47

Well, it appears my car suffers the same problem described above.

I thought we got to the bottom of this a long time ago. And it was voltage-related rather than RF-related. The solution was to have the Empeg draw its power straight from the battery rather than going through the factory wiring. Am I right? Or is my memory failing me?

___________
Tony Fabris
Posted by: drakino

Re: *very* strange RF interference ?! - 28/02/2001 13:20

What was posted here describes my situation more then the voltage issue setting off someones alarm. By what I understand, there was 2 problems.

1. When the empeg is active or in standby, it becomes difficult or impossible to lock the doors with the remote.

2. When the empeg is docked, and is off, the occasional wakeup causes a voltage spike to set alarms off.

My car has the keyless entry and a basic alarm system. My problem is number 1, and I never saw a specific fix to it. I'm not sure if it's actual RF inteference or something else, it just seemed the right thread to tack my problem on.

Posted by: tfabris

Re: *very* strange RF interference ?! - 28/02/2001 13:28

Hmm. Maybe I was getting the two problems mixed up. They say the first two things to go are the memory and... I can't remember the other one.

So we never got to the bottom of the keyless entry stuff? For what it's worth, my Honda's keyless entry doesn't seem to be affected by it.

Wait a minute.

Now that I think about it, in the rare instances that I leave the empeg in the car (when I'm coming back so quickly that the sleep timeout doesn't even expire), there is a reduction in range. I have to be closer to the car than if I hadn't left the empeg in there. Not by much, though.

In fact, I had assumed it was just a low battery in my remote, so I replaced it. The new battery helped increase the range again. Have you tried replacing the battery in the remote?

___________
Tony Fabris
Posted by: drakino

Re: *very* strange RF interference ?! - 28/02/2001 13:56

In fact, I had assumed it was just a low battery in my remote, so I replaced it. The new battery helped increase the range again. Have you tried replacing the battery in the remote?

That was my first thought when I couldn't lock it. I went in my house, grabbed my 2ed remote, and the lock at the point worked because the empeg had gone to sleep. But later that night, holding the new remote over the hood didn't do anything until I opened the door and pulled the empeg. (I pulled it since at the time, the timeout was set to a few mins)

Edited by Drakino on 28/02/01 10:18 PM.

Posted by: loren

Re: *very* strange RF interference ?! - 28/02/2001 14:11

AH HA!! Maybe THAT's why my keyless entry is so damn finicky on my new Civic.... I ruled out batteries and the like... hmm..i'm going to have to do some tests tomorrow when i get some system work done...


|| loren.cox || 080000446 ||
Posted by: tanstaafl.

Re: *very* strange RF interference ?! - 28/02/2001 17:59

2. When the empeg is docked, and is off, the occasional wakeup causes a voltage spike to set alarms off.

That problem was mine, and it turned out to be completely unrelated to the empeg. The problem is it was a really cheap alarm and we think it was susceptible to temperature changes. All the electronics and the alarm siren were integrated and mounted under-hood. When the engine compartment cooled sufficiently the alarm went off.

The dealer installed a better (and far more costly) alarm at no charge to me, and I have no problems since.

I'll have to experiment and see if my empeg affects how easily my alarm/locks work. Fascinating... Of course, my empeg does say "Tested to comply with FCC standards for home or office use" :-)

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"
Posted by: MRHJr

Re: *very* strange RF interference ?! - 28/02/2001 19:28

I have expeienced the same problem, and have pinned it to the empeg.
It got to be a pain,so much so, I changed the timer to 10 seconds.

I have an old Ungo Box alarm with the door lock driver add on.

Mk2 #105 12g blue
Car install complete...........Boat forthcoming
Posted by: carrera84

Re: *very* strange RF interference ?! - 06/03/2001 07:54

I'm seeing a lot of new posts on this thread, but I've not seen anyone test blairc's 21/07/00 theory that the the alarm or keyless-locks may be sensing the empeg's current draw. I have no idea why they should do that, except maybe it has something to do with a circuit that disables the ignition when the car is locked up. If any of the tests below cause the alarm or lock to fail, then try connecting the constant voltage line directly to the the battery.

1) Does the system work if the interior lights are left on?
2) If so, does the system still work with a dummy load* plugged into the sled?
3) If so, the systems ARE interacting. More tests needed...

* A dummy load could be created by hooking up a 48-ohm, 3-watt resistor (or three 144-ohm, 1-watt resistors in parallel) to a spare blind mate connector. Maybe empeg could provide such a device to an owner with this problem hoping to exonerate their players.


-jim <MkII:080000260 18G blue>
Posted by: drakino

Re: *very* strange RF interference ?! - 01/05/2001 16:47

Just wanted to dig this thread back up as it's still a problem in my car. I haven't had enough time to look into it personally (since me poking at the car tends to take a big chunk of time). Has anyone else experiencing the loss of remote locking with the empeg found anything new?

(It's still an issue for me, as my empeg is rarley pulled from the car.)

Posted by: thinfourth2

Re: *very* strange RF interference ?! - 02/05/2001 01:18

i will give it a try as i have never actually left my empeg in my bmw yet.

Posted by: teemcbee

Re: *very* strange RF interference ?! - 03/05/2001 14:00

I haven't recognized this on my peugeot. At least not in combination with the empeg.
But I had this happen for 2 times (before I had the empeg) that my remote keylock didn't react to my unlock/lock from the remote.

Maybe stupid but maybe worth a try.. have you tried pulling out the empeg just a little bit of the docking sled (so that the connector isn't connected anymore).

Can you lock/unlock you car with the remote while sitting in the car? You could try if it really has something to do with the empeg quite easy this way...

If you find out that it has something to do with the empeg maybe some cabling is wrong.

VW's and Audi's make curious things when you combine some switches (e.g. when you switch off ignition, then switch on the heater from the back-window, then switch on the wiper and then switch on ignition again the back-window heater will be off again. after switching the ignition off and back on it will be on again... it was something like this.. i don't really know exactly how you got this effect in some Golfs...
And as I remember there was something about the air-condition, too...)


TeeMcBee
Got my Mk2! # 080000143
Posted by: drakino

Re: *very* strange RF interference ?! - 03/05/2001 16:37

Maybe stupid but maybe worth a try.. have you tried pulling out the empeg just a little bit of the docking sled (so that the connector isn't connected anymore).

But later that night, holding the new remote over the hood didn't do anything until I opened the door and pulled the empeg.

Can you lock/unlock you car with the remote while sitting in the car? You could try if it really has something to do with the empeg quite easy this way...


I did that once. I was specificially showing someone how the empeg was preventing the doors to lock, and it locked. I had to pull the empeg out to unlock and disarm the security system. That was the only time out of probably 200 presses of the lock button that it locked with the empeg either playing or in standby.

If you find out that it has something to do with the empeg maybe some cabling is wrong.

I really have no clue what to check on this. I'll have to probably pay an installer sometime to check it out again.

Posted by: tadzio

Re: *very* strange RF interference ?! - 06/05/2001 10:22

I experience the same symptom: the door lock remote decreases in range from 15 meters to 1 meter. My car is a Citroen CX with an aftermarket (which does *not* mean cheap and crappy here!) remote locking system which I installed myself. The car does not have an alarm system.


A few thoughts:


- the symptoms that I see are very, very similar to the symptoms others see, so I guess it's a valid conclusion that they have the same reason.


- as my car doesn't have any fancy electronics like an alarm system, and the remote locking system is connected to nothing else but the doors, ignition and 12V power, we can rule out interaction with alarms or other comfort electronics as a reason.


- the symptoms disappear as sonn as I pull out the empeg. Range is back to normal, even if I do not change the batteries in the remote. So we can rule out bad batteries as reason.


- my car's head unit (Kenwood TV/FM/Navigation system) draws its power from the same point as both the empeg and the remote lock system. However, leaving the Kenwood running does not have an impact on the range. The Kenwood uses a big backlit LCD, so I'm very sure it draws more power than the empeg, which would cause a much bigger drop in voltage on the power lines. Btw, the current an empeg draws in standby mode should cause only *minimal* voltage drops, if any. So we can rule out voltage drops as a reason.


- In Germany, the only radio frequency that is available for things like remote door locks is 433MHz. So, as my remote door locking system is EU certified, I strongly assume (couldn't verify, unfortunately) that is operates at that frequency. I just performed an interesting experiment to check if the empeg has any influence on 433MHz devices: cordless mice use the same frequency, so I placed the base station of my Logitech cordless optical mouse on top of the empeg (the empeg running on AC). The distance between the base station/empeg and the mouse was around 1 meter. And indeed: as soon as the empeg was running or in standby mode, the mouse behaved erratically! When I disconnected the empeg from AC power without moving the base station, the effect went away.


Moving the base station more than a few centimeters away from the empeg also cured the problem, so the empeg doesn't radiate much. However, as the remote door locking sender uses very tiny batteries, it sends a *very* low power signal, which means the receiver in the car has to be *very* sensitive.


In my car, the receiver's antenna is some 50 cm away from the empeg. If I remember correctly, the power of an electromagnetical signal drops with distance to the second power. So, if I use the remote from 10 meters distance to the car, which is 20 times the distance the empeg has to the antenna, then even if the empeg sends with only 1/400th of the already very low-power remote signal, the antenna would receive them both with the same strength. This (admittedly not very detailled) calculation leads me to the conclusion that despite the empeg being FCC certified, it it very possible that it still interferes with weak remote door locking signals.


So, the next steps would have to be:

- find out with which power a remote usually sends. Can anybody who experiences the problems try to ask their car manufacturers or even try to find that in your manuals?

- try to get access to a measuring receiver to actually measure the radiation (frequency and power) of the empeg. Empeg folks: do you have any data from your FCC tests that could be helpful here?

- based on that data, do a more thorough calculation to see if my theory can be proved or disproved.

Daniel

---
"My software never has bugs. It just develops random features."

Posted by: pca

Re: *very* strange RF interference ?! - 06/05/2001 19:29

- In Germany, the only radio frequency that is available for things like remote door locks is 433MHz. So, as my remote door locking system is EU certified, I strongly assume (couldn't verify, unfortunately) that is operates at that frequency. .

It will be, 98% probability. This is the European standard low power license exempt frequency for telemetry systems

And indeed: as soon as the empeg was running or in standby mode, the mouse behaved erratically! When I disconnected the empeg from AC power without moving the base station, the effect went away.

This does seem to show that there is some interference from the empeg, I have to admit.

Moving the base station more than a few centimeters away from the empeg also cured the problem, so the empeg doesn't radiate much. However, as the remote door locking sender uses very tiny batteries, it sends a *very* low power signal, which means the receiver in the car has to be *very* sensitive.

It is. The receivers for the 433MHz band data transmission system often have quoted sensitivities of around -107dBm, witch is technical speak for absolutely sod all power. Bear in mind this is for receiving a good signal, as well. Much less power on the right frequency will cause interference, if the transmitter is close enough.

- find out with which power a remote usually sends. Can anybody who experiences the problems try to ask their car manufacturers or even try to find that in your manuals?

The output power varies slightly with application and country. However, in the UK this band is regulated under the MPT1340 exemption, covering both 418MHz and 433MHz, and limits the output power to less than 1mW effective radiated power. One TX module I have used had a power output with a 1/4 wave antenna of something like 500uW. This really isn't a lot.

- try to get access to a measuring receiver to actually measure the radiation (frequency and power) of the empeg. Empeg folks: do you have any data from your FCC tests that could be helpful here?

This has been done. Believe me, this has been done. Ad nauseum. It's a pain in the arse, the tests you have to go through to be able to sell any electronics nowadays. And, unless you have access to (1) an electromagnetically clean isolation chamber, and (2) a good RF spectrum analyser and probes (the one the RF test company kindly lent us for a few days cost them in excess of $30000, and that was the cheap spare), you won't even be able to find the emissions of the empeg over the RF hash produced by everything else around you, never mind measure it properly.

The MK1 was a bit of a bugger due to the USB controller. It radiated dozens of harmonics of the 16MHz fundamental oscillator, with peaks at multiples of 48MHz, all the way up to at least 2GHz. I had a hell of a time trying to kill off these parasitic oscillations during the original design phase, and even though we got it under the EEC and FCC limits, I couldn't stop it completely. The manufacturer of the chip finally admitted they had a problem with the thing, but couldn't really suggest any good complete fix.

However, the Mk2 uses a different USB chip, with a completely different oscillator, and doesn't suffer from the same problem.

That said, any complex computing device will produce spurious emissions. All you can do is try to keep the output level down to whatever standard the thing has to meet. Unless we went to something like Tempest classification shielding, a little RF will leak. In the case of most PC equipment, a lot will leak.

I suspect it's only because of the close proximity and extreme sensitivity of the receivers being affected that allow them to in fact BE affected. The frequency they use isn't one that the empeg intentionally produces, but is either a harmonic of one of the oscillators, the bus clock, or the core clock, or a mixing product of two or more of them.

I don't recall any peaks in the emission spectrum around that frequency, but it might be that a multiple of the 200MHz or so CPU core clock is to blame. It in fact probably isn't a signal on the same frequency, but a fairly broadband one near it, at extremely low power. The box is pretty well shielded, and unfortunately there isn't a lot you can easily do to make it any better at that part of it's job. Most of the RF leakage will be through the front panel, and covering that with a stainless steel sheet rather defeats the object, I'm afraid.

Look on the bright side. If your in-car entertainment system used, for instance, a 433MHz intel processor, you'd have no chance.

One thing does occur to me now that I think about it. Does this effect occur when the empeg is completely shut down, ie with the ignition off? Under these circumstances the only thing that should be active is a small part of the PSU, the PIC that controls it, and the RTC, none of which should produce harmonics anywhere near 433MHz at power levels above the nanowatt range.

When the empeg is running or in standby mode with the light flashing the CPU is active, and if it's that producing the putative interference it shouldn't occur when the unit is off.

This only applies to the MK2 of course. The MK1 is completely dead when the ignition is off, as it uses a different PSU circuit.

Patrick

Opinions expressed in this email may contain up to 42% water by weight, and are mine. All mine.
Posted by: rob

Re: *very* strange RF interference ?! - 07/05/2001 05:09

I believe it was reported that this only occurs while the empeg is in standby. If you configure the shutdown time to, say, 5 seconds that gives you time to switch it back on manually if you want to but also ensures that it is fully powered down by the time you exit the vehicle and use your remote.

if you do have this problem, given that the car player operates well within both FCC and (the much stricter) CE guidelines, chances are your vehicle would suffer from any high speed in-dash computer. Since the regulations also specify that a product must be immune to EMC radiation well beyond the levels that the car player produces, I have to wonder as to the design quality of the receivers in question. We certainly don't have a problem with any of our demo or staff owned vehicles.

Rob




Posted by: drakino

Re: *very* strange RF interference ?! - 07/05/2001 15:12

One thing does occur to me now that I think about it. Does this effect occur when the empeg is completely shut down, ie with the ignition off?

It only happens when the empeg is either playing or sitting in standby. If it's completly off, or pulled, the problem goes away.

I'm going to dig into it a bit more. Xanatos here on the board has a RioCar installed into a 2000 LS series Saturn, and dosen't see the problem, so something different between the LS and SL that I have might be what is causing it. I'm going to see him later this week to look into a remote problem, so I will probably try a swap of the units to see what happens.

Posted by: drakino

Keyless remote problems - 11/05/2001 12:44

Ok, as an update, I tried Damien's Rio Car last night in my sled. Whenever his player was playing or in standby, the door locks worked just fine. I probably unlocked and locked the doors about 25 times with his player, and only occasionaly it wouldn't work, and was probably a matter of not pushing the button all the way. Putting my player in his car did not show the problem there, possibly due to differences in the dash design between the LS and SL. (I'm still looking into where the system is in my car...)

After putting his player in my car, then putting my empeg back, mine seems to be causing the problem less and less, but is definitly still there. About 75% of the time, the locks won't respond now.

What differences were there in the Mark 2 and Mark 2a? Could the serial cable issue in the origional batch in any way be affecting this? The serial cable is tucked behind my dash in a place I can get to it easially, and happens to sit right next to an electrical fuse box in the car. Last night I remember moving the cable to show Damien, so thats the only thing I can think of that changed last night with my player install. I suppose another test I could do would be to try another Mark 2 in my car. I am heading to E3 this year, and will be bringing my car, so anyone in the LA area want to meet up with me to test this?

Posted by: pca

Re: Keyless remote problems - 11/05/2001 13:54

What differences were there in the Mark 2 and Mark 2a?

Very minor PSU tweaks, very minor audio input tweaks, and a change of RAM layout. It now has 2 x 64Mbit chips, rather than 6 x 16Mbit chips.

I'm getting the feeling that this problem, in the rare occasions it occurs, may be down to extremely low-level RF emitted by bus activity being picked up by insufficiently filtered receivers. The apparent fact that the 2A doesn't seem to cause it in a car where the 2 does might support this, as the smaller number of ram chips also requires less bus wiring length. This would have the effect of radiating somewhat less RF, since the effective antenna length would be completely different for bus signals. Also, if it's some sort of RF mixing process that's generating the offending frequency, different circuitry would be resonant at different frequencies. It seems feasible, anyway.

The serial cable is tucked behind my dash in a place I can get to it easially, and happens to sit right next to an electrical fuse box in the car.

That may be your main problem. The serial lead might act as a feeder, coupling any interference into the car wiring more inductively than any other way.

I have one suggestion that might be worth trying. Get a biggish ferrite toroid, about an inch and a half across, and wind a couple of turns of the serial lead through it near the back of the docking cage. Do the same thing with the main empeg wiring, ie disconnect the ISO connector, feed it through a toroid a couple of times, and reconnect it. See if this helps in any way. You should be able to get suitable toroids from Radio Shack or a similar electronics supplier.

Rob is right, though, the problem is most likely down to bad (cheap) RX design on the part of the car manufacturers.

Patrick.

Opinions expressed in this email may contain up to 42% water by weight, and are mine. All mine.
Posted by: Jazzwire

Re: *very* strange RF interference ?! - 11/05/2001 16:17

If my empeg (Mk2) is powered up (can be in standby, or playing) the FM reception on my JVC head unit becomes very weak. Sometimes it cannot pick up a signal at all.
Pulling the empeg from the sled fixes the problem.

Could be releated?

Jazz
(List 112, Mk2 12 gig #40. Mk1 4 gig #30. Mk3 1.6 16v)