Wiring a powered car aerial

[Geo]

We had a member here a while back who stated that this was the case. Another member tried it and it didn't work for him. My opinion is that the area of 'contact' of a conventional car aerial is too small to get the capacitance anything like big enough.

 

Tony

 

That depends on the insulator and basic area. Was the member who tried it an RF engineer because it needs careful selection of materials.

 

What do you mean by "My opinion is that the area of 'contact' of a conventional car aerial is too small to get the capacitance anything like big enough."?

[MtB]

 

What do you mean by "My opinion is that the area of 'contact' of a conventional car aerial is too small to get the capacitance anything like big enough."?

 

Makes perfect sense to me. Capacitance is proportional to area and inversely proportional to separation, IIRC.

[WotEver]

 

Makes perfect sense to me. Capacitance is proportional to area and inversely proportional to separation, IIRC.

Spot on.

[1agos]

We have a dab radio made by Pure works perfectly inside the boat without the need for an aerial on the roof(it has its own pull out telescopic aerial). Sits on a shelf in the saloon - sound is very good except when I turn the light on over the dinette - then the sound disappears altogether.

[Geo]

We have a dab radio made by Pure works perfectly inside the boat without the need for an aerial on the roof(it has its own pull out telescopic aerial). Sits on a shelf in the saloon - sound is very good except when I turn the light on over the dinette - then the sound disappears altogether.

 

Sounds as if you have an LED light over the dinette

[WotEver]

 

Sounds as if you have an LED light over the dinette

And a cheap one at that - try a Bedazzled one.

[MtB]

And a cheap one at that - try a Bedazzled one.

 

 

My expensive Bedazzled LEDs do this too.

Odd, given I have an external DAB aerial.

[Geo]

 

 

My expensive Bedazzled LEDs do this too.

Odd, given I have an external DAB aerial.

 

In that case you should be returning them to Bedazzled for exchange to ones that don't. Think you will find digging deep enough in the regs anything of that nature sold in the UK has to be interference free.(EMI)

Edited September 10, 2016 by Geo

[1agos]

We do have the cheap ones - but its strange that it is only the one out of twenty one that effects the radio.

[Keeping Up]

My Bedazzled LEDS are fine with the FM radio but wipe out the DAB signal when it's weak. I think that is fairly typical. So far the only solution seems to be to switch to FM when I turn on the lights.

[Geo]

My Bedazzled LEDS are fine with the FM radio but wipe out the DAB signal when it's weak. I think that is fairly typical. So far the only solution seems to be to switch to FM when I turn on the lights.

 

I would suggest that you check the EMI regs. Think you will find they should not wipe out the DAB signal.

[MtB]

 

I would suggest that you check the EMI regs. Think you will find they should not wipe out the DAB signal.

 

 

There is a world of difference between 'should not' and 'do not'.

 

The EEC can write as many regs as it likes but they cannot change the the behaviour of the LED technology.

[bottle]

We had ones that did and now changed to Bedazzled and they do not.

 

Previous were SMD's new ones are LED's.

 

ps.

 

our aerial is FM and always able to pick up DAB. Perhaps just lucky.

 

Now actually working off log periodic TV aerial.

[Geo]

 

 

There is a world of difference between 'should not' and 'do not'.

 

The EEC can write as many regs as it likes but they cannot change the the behaviour of the LED technology.

 

No but the supplier can be made to only supply EMI proofed equipment

[Paul C]

DAB isn't the utopia of wonderful radio reception that some make out it is - by all means it would be nice if LEDs didn't interfere but remember its basically crap - the proof being that in areas where DAB is crap, FM still works.

[MtB]

 

No but the supplier can be made to only supply EMI proofed equipment

 

I started a thread on this subject a year or two ago. Someone posted a clear and thorough explanation of how the effect occurs and the fault is not the EMI-proofed Bedazzled lamps, but a weak DAB signal. When the signal is marginal the DAB radio either works perfectly of it turns off completely, and running LED lamps can tip it over into not working.

 

The solution is, obviously, to prevent the sale of all LED lamps because they all do this to a lesser or greater extent. The cheapo ones doing it to a far greater extent than the expensive Bedazzled ones.

 

If I return mine to Bedazzled for a refund I'll have to revert to incandescent lamps. For me its not a big deal because I use gas lights routinely. It's just that I also have electric lights and if I use one, the DAB radio sometimes turns off.

[Geo]

DAB isn't the utopia of wonderful radio reception that some make out it is - by all means it would be nice if LEDs didn't interfere but remember its basically crap - the proof being that in areas where DAB is crap, FM still works.

 

I appreciate what you are saying, however the difference between FM and DAB is the frequencies they are broadcast on. DAB is 220 Mhz to 226 Mhz FM Broadcast Radio is 87.5–108.0 MHz and thus the difference in frequency could well be causing the problems you experience, the LEDs could be interfering with DAB and not FM very easily

[Paul C]

 

I appreciate what you are saying, however the difference between FM and DAB is the frequencies they are broadcast on. DAB is 220 Mhz to 226 Mhz FM Broadcast Radio is 87.5–108.0 MHz and thus the difference in frequency could well be causing the problems you experience, the LEDs could be interfering with DAB and not FM very easily

 

Brilliant.....but ultimately irrelevant, because I can't change the frequency that DAB is broadcast on. If I want to listen to the radio, I want to turn it on and then moments later, hear the music. Oh I could change the frequency.....to the FM one. Problem solved!

[MtB]

 

Brilliant.....but ultimately irrelevant, because I can't change the frequency that DAB is broadcast on. If I want to listen to the radio, I want to turn it on and then moments later, hear the music. Oh I could change the frequency.....to the FM one. Problem solved!

 

 

Not if you want to listen to BBC 6 Music!

[WotEver]

 

 

Not if you want to listen to BBC 6 Music!

Next you'll be suggesting that Steve Wright isn't a self-opinionated <word that's not allowed>

[Geo]

 

I started a thread on this subject a year or two ago. Someone posted a clear and thorough explanation of how the effect occurs and the fault is not the EMI-proofed Bedazzled lamps, but a weak DAB signal. When the signal is marginal the DAB radio either works perfectly of it turns off completely, and running LED lamps can tip it over into not working.

 

The solution is, obviously, to prevent the sale of all LED lamps because they all do this to a lesser or greater extent. The cheapo ones doing it to a far greater extent than the expensive Bedazzled ones.

 

If I return mine to Bedazzled for a refund I'll have to revert to incandescent lamps. For me its not a big deal because I use gas lights routinely. It's just that I also have electric lights and if I use one, the DAB radio sometimes turns off.

 

DAB is only meant to work in areas where there is sufficient signal and quite localised areas, in those specific areas any interference from electrical equipment should not affect them. However there will be areas of marginal signal where interference from electrical equipment will affect them. DAB like any ether broadcast signal can never be the perfect signal. Oh and DAB will only work where the radio is getting sufficient data to put the sound back together again and thus it is either on or off whilst FM will give you what gets through with the crackle and pop.

 

Brilliant.....but ultimately irrelevant, because I can't change the frequency that DAB is broadcast on. If I want to listen to the radio, I want to turn it on and then moments later, hear the music. Oh I could change the frequency.....to the FM one. Problem solved!

 

Not brilliant just basic RF transmission but it should give you the reason why one works in one place and not the other.

[MtB]

 

DAB is only meant to work in areas where there is sufficient signal and quite localised areas, in those specific areas any interference from electrical equipment should not affect them. However there will be areas of marginal signal where interference from electrical equipment will affect them. DAB like any ether broadcast signal can never be the perfect signal. Oh and DAB will only work where the radio is getting sufficient data to put the sound back together again and thus it is either on or off whilst FM will give you what gets through with the crackle and pop.

 

Not brilliant just basic RF transmission but it should give you the reason why one works in one place and not the other.

 

 

Ah right.. So when I turn on my Bedazzled lamp and the DAB radio goes silent, I'm listening in the wrong localised area, yes...?

What's a localised area anyway? Is there a list of them?

[Geo]

 

 

Ah right.. So when I turn on my Bedazzled lamp and the DAB radio goes silent, I'm listening in the wrong localised area, yes...?

What's a localised area anyway? Is there a list of them?

 

Each transmitter is only designed to cover a specific location

 

http://www.ukdigitalradio.com/coverage/currenttransmitters/

 

http://www.ukdigitalradio.com/coverage/postcodesearch/

 

These two sites may help you

[Neil Walker]

When we turn on bedazzled lamps next to our DAB (same as MTB) I have no issues except the volume seems to go up?! Mind you... Hang on,I must have a word with the mrs, it only happens when she turns the light on

[Geo]

When we turn on bedazzled lamps next to our DAB (same as MTB) I have no issues except the volume seems to go up?! Mind you... Hang on,I must have a word with the mrs, it only happens when she turns the light on

 

Maybe the LEDs make everything quieter