Just wondered if anyone has ever had an issue with a DAB radio and interference from the heater fan?
I wanted to enjoy the full experience of having an 80's car with having 80's music.....as I'm an 80's kid!
Thought carefully and purchaed a retro looking Blaupunkt Valencia with DAB and Bluetooth phone connectivity. It really looks in keeping with the car.
On our recent charity classic car run, we spent most of the time cursing the lack of reception until we stumbled across something.
We had spent 90% of the journey with the heater fan blowing as the missus is always moaning she's cold!
It was only at the end of the journey when I switched off the fan, the signal returned and the music came on.
Switched on the fan and the reception dropped out!
I imagine that the cable shielding isn't that great on the X1/9 and the interference is coming from the fan's switch live cable when turned on.
I've ordered some ferrite magnet cable suppressors to clip onto the power cables and see if that eliminates it.
I just wondered if anyone else has had any experience with this type of thing?
Gotta admit, I have yet to try the DAB + heater trick that's tomorrows job.
I have a Pioneer medialess radio with DAB but I mainly stream Spotify via blutooth from my phone.
The best option would be to try - first, connecting a capacitor from the +fan motor to chassis
try a standard 1uF (same as the one at the hinge to the coil +12v), your ferrite clip on could then
be placed on the +12v feed to the motor.
Another thing to try is clean the base of the aerial to body and check the aerial lead is in good condition.
I fitted a top quality Algon fixed mast 35years ago and it seemed to work just fine.
Remember that the DAB band is around 174MHz to 240 MHz in the UK wheras FM is 88MHz to
108MHz so the coax cable from your radio to the aerial will be more lossy and signal may struggle.
Any further questions, just ask me, I spent a lot of time at work on RFI and EMC in vehicles over the years!
The following user(s) said Thank You: Gareth Lloyd
……thanks Alan. It’s funny, the DAB works fine until the fan heater is switched on. I have a DAB antenna fitted which I’ve fed behind the glove box interior and then adhered to the bottom windscreen corner discreetly.
I’ll try the ferrite magnet cores first. I also have some silver tape that the ductwork guys use in work. It maybe useful. If that doesn’t work, I’ll come back to you!
Ok, tried my DAB and turned the fan on, no interference heard. DAB is soo much more robust than FM or AM because it has digital error correction, having said that the transmitted power is less so the signal weaker.
The following user(s) said Thank You: Gareth Lloyd
......hmmmm.....weird. I don't get intererence as such. More the signal just disappears.
I'm still waiting for my ferrite cores to arrive. I bought a pack of 10 so I'll put them on as many black/red power cables as possible!
I assume then that what is happening is the electrical noise from the fan motor is just completely swamping the broadcast DAB multiplex and if beyond a certain signal to noise ratio the DAB processor mutes rather than giving noise.
As DAB is completely digital, you either get very good sound or its completely digital nonsense that the error correction cannot correct and that data would be awful with no programme content at all. It either works or is just doesn't - as you have found!
I would guess you may require a capacitor in addition to your ferrite cores?
Anything like a 1uF or even 10uF plastic type capacitor - voltage rating doesn't matter here 50V or more and definitly not an electrolytic capacitor (their ESR is just too high at 100MHz +) like the eBay capacitor from Switch below.. (I have used them several times)
If so the capacitor would go directly across the motor terminals, the ferrites downline after the motor +12V.
Could always just rev beyond 6,000 rpm then the DAB situation becomes irrelevant!!
Switch Electronics eBay Shop (759852)
Metallised Polyester Film Capacitor £7.49 for 10off
Capacitance: 4.7uF Voltage: 250V
......LMAO!.....yes, I prefer to switch it off and listen to the engine!!
Some great information there Alan, many thanks.
(I haven't looked into how accessible the fan motor terminals are yet)
I'm determined to get this sorted.
Would the silver ducting tape help shield anything or would that be a waste of time Alan?
Metal Tape - I would say (its = screened cable) that would come 4th on the list and as it would be so hard to do a good job (RFI is very finicky, needs earthed at one end too. You would be as well to replace those wires with screened cable! so, no. You list of most effective still goes:-
1. Capacitor across the motor
2. Ensure your antenna is grounded and as far away from the fan motor, possibly new high quality rf cable
3. Ferrite on the motor leads (close as possible)
The following user(s) said Thank You: Gareth Lloyd
……I have a confession to make!
I checked over everything again and I realised that I had installed the new DAB antenna without grounding it to the chassis!
After grounding it, the radio works perfectly!
I have also installed a few ferrite magnet suppressors to the cables but I suspect it was my mistake that was causing it.
Thanks to everyone that contributed and I hope this thread helps someone else!
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