Question regarding FM modulators

**Scorpnstail** · 04-06-2005, 01:59 PM

I know there has been alot of disscussion in the past about these but I wanted to ask a quick question

I have heard FM modulators are not that good due to the fact that you will still get dominant radio waves trying to cut into your music.

However a friend of mine says that FM modulators that have a antenna hookup will make it so that when you are playing your music the antenna will be cut off and no more FM waves will be present to interfere with your signal.

Can anyone validate this or back this up as my knowledge of car audio is pretty nill.

**mox** · 04-06-2005, 02:41 PM

Originally Posted by Scorpnstail

I know there has been alot of disscussion in the past about these but I wanted to ask a quick question

I have heard FM modulators are not that good due to the fact that you will still get dominant radio waves trying to cut into your music.

However a friend of mine says that FM modulators that have a antenna hookup will make it so that when you are playing your music the antenna will be cut off and no more FM waves will be present to interfere with your signal.

Can anyone validate this or back this up as my knowledge of car audio is pretty nill.

The inline FM modulator that I've bought just recently contains a relay which indeed cuts the link from the car antenna to the HU as soon as 12V power is applied. I haven't tried it yet, so I have no idea about the overall sound quality. If it turns out to be really bad, I think I will sacrifice my cd changer and get an AUX-adapter from www.connects2.com.

**shotgunefx** · 04-06-2005, 02:47 PM

Originally Posted by Scorpnstail

I know there has been alot of disscussion in the past about these but I wanted to ask a quick question

I have heard FM modulators are not that good due to the fact that you will still get dominant radio waves trying to cut into your music.

However a friend of mine says that FM modulators that have a antenna hookup will make it so that when you are playing your music the antenna will be cut off and no more FM waves will be present to interfere with your signal.

Can anyone validate this or back this up as my knowledge of car audio is pretty nill.

My personal experience, wireless ones are pointless. Around here anyway (Boston). Every one I've tried had a strong signal on all of the available channels. I ended up with a inline Kenwood one that works perfectly. I don't believe they make it anymore though.

**cd25987** · 04-06-2005, 03:09 PM

Even the inline modulators let stonger interferance in. FM Modulators are not the way to go if you want good quality input. I learned the hard way....

**shotgunefx** · 04-06-2005, 03:11 PM

Originally Posted by cd25987

Even the inline modulators let stonger interferance in. FM Modulators are not the way to go if you want good quality input. I learned the hard way....

For me, so far so good. Though outside of replacing my HU or amp, it was my only option I could get working. I'm happy with my setup so I didn't want to replace it just to use my nomad.

**Scorpnstail** · 04-06-2005, 03:13 PM

Yea .. that is what I am refering to ( Inline modulators )

How would it be possilbe for something to get though if you basicly block the FM signal from ant. ?

**joelw23** · 04-06-2005, 03:28 PM

I have one for sale if anyone is interested...pm me...

**mox** · 04-06-2005, 03:59 PM

Originally Posted by Scorpnstail

How would it be possilbe for something to get though if you basicly block the FM signal from ant. ?

The modulator sits inbetween the outside aerial and the HU. Once power is applied, the aerial gets disconnected from the modulator so radio stations cannot interfere with the signal coming from the modulator (hopefully...).

Think of the modulator as a normal FM radio station with its own fixed frequency.

**Scorpnstail** · 04-06-2005, 04:07 PM

Originally Posted by mox

The modulator sits inbetween the outside aerial and the HU. Once power is applied, the aerial gets disconnected from the modulator so radio stations cannot interfere with the signal coming from the modulator (hopefully...).

Think of the modulator as a normal FM radio station with its own fixed frequency.

thanks for explaining that

.. I did understand how it worked but I was curious on if the aerial is disconnected how can any other signal other then the one from the FM modulator get through.

**mox** · 04-06-2005, 04:16 PM

Originally Posted by Scorpnstail

I was curious on if the aerial is disconnected how can any other signal other then the one from the FM modulator get through.

It can't

You are supposed to turn the modulator off if you want to listen to normal radio stations. It stops "transmitting" and the relay restores connection between antenna and HU.