AM radio interference with '94 Range Rover.

I did i tune up on the beast replacing cap. rotor, plugs and wires and
now I get major iterference during AM reception, and actually no AM
reception now. Funny thing is, this is with the car NOT running. the
wires are suppsed to suppress noise, but this happens with the car not
running. when I open any door it's very loud. Did I bump a ground or
something?

Tim wrote:

> I did i tune up on the beast replacing cap. rotor, plugs and wires and
> now I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running. the
> wires are suppsed to suppress noise, but this happens with the car not
> running. when I open any door it's very loud. Did I bump a ground or
> something?

What position is the ignition switch in for this?

Also, where does the radio earth run to? It might be worthwhile taking an
earth straight from it to the body incase it's using the arial for an earth
just now.

Also, assuming your car has one, check the suppressor in the distributor and
see if it's good - the only useful way to do this is to replace it I'm
afraid.

Also you might want to try fitting a ground loop isolator to the radio, but
that's a long shot.

P.

Tim wrote:

> I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running.

Woo. If the engine is off then it is not engine interferance but I'd
go for a busted aerial connection. AM radio should be a big woosh
noise if no station is being recieved. (FM goes silent) On my '97
HSE the AM and VHF aerials are seperate connections so it's
probably either fallen out or something has chopped the cable.

nigelH

"Tim" <[email protected]> wrote in message
news:[email protected]
> I did i tune up on the beast replacing cap. rotor, plugs and wires and
> now I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running. the
> wires are suppsed to suppress noise, but this happens with the car not
> running. when I open any door it's very loud. Did I bump a ground or
> something?

Sounds like the aerial is disconnected or the wire is broken. It's picking
up what stray signal it can and opening the door lets in more of the signal.

The AM receiver will keep turning up the reception gain until it gets a
strong signal. If there's no signal it'll keep on increasing the gain until
either the background noise provides a strong enough signal or it hits
maximum gain.

There should be zero Ohms between the aerial itself and the centre pin of
where the aerial wire goes into the radio.
The radio needs to be earthed and so does the aerial mount.

--
FZS600 - Silver/Black
GS125 - Black/Rust
Ford 100E Prefect - Black, naturally
Whisky - Aberlour Cask Strength

I'm confused about where the AM antenna is. Not even sure about the FM
either. Could the FM antenna be on the left and right rear windows?
I'm thinking I bumped something while obsessing on window cleaning.


On Wed, 4 Aug 2004 18:42:24 +0100, "PDannyD"
<dan1970.nomeatproductsplease@nocannedmeat.scenicplace.freeserve.co.uk>
wrote:

>"Tim" <[email protected]> wrote in message
>news:[email protected]
>> I did i tune up on the beast replacing cap. rotor, plugs and wires and
>> now I get major iterference during AM reception, and actually no AM
>> reception now. Funny thing is, this is with the car NOT running. the
>> wires are suppsed to suppress noise, but this happens with the car not
>> running. when I open any door it's very loud. Did I bump a ground or
>> something?
>
>Sounds like the aerial is disconnected or the wire is broken. It's picking
>up what stray signal it can and opening the door lets in more of the signal.
>
>The AM receiver will keep turning up the reception gain until it gets a
>strong signal. If there's no signal it'll keep on increasing the gain until
>either the background noise provides a strong enough signal or it hits
>maximum gain.
>
>There should be zero Ohms between the aerial itself and the centre pin of
>where the aerial wire goes into the radio.
>The radio needs to be earthed and so does the aerial mount.

Tim wrote:
> I'm confused about where the AM antenna is. Not even sure about the FM
> either. Could the FM antenna be on the left and right rear windows?
> I'm thinking I bumped something while obsessing on window cleaning.
>
The radio aerial (I think there is only one) is built into the rear o/s side
window on later RRCs, looks a bit like a HRW element. I thought it was
built into the glass itself, but maybe it's on the surface and vulnerable to
damage like the HRW elements are. I don't know about the difference between
AM and FM reception, but perhaps you have damaged the aerial element and one
is just more tolerant of a crap signal than the other.

--
--
Rich

Land Rovers
Boat
Dog
Wife
Kids - in that order

"Richard Brookman" <[email protected]> wrote in message
news:[email protected]...
> Tim wrote:
> > I'm confused about where the AM antenna is. Not even sure about the FM
> > either. Could the FM antenna be on the left and right rear windows?
> > I'm thinking I bumped something while obsessing on window cleaning.
> >
> The radio aerial (I think there is only one) is built into the rear o/s
side
> window on later RRCs, looks a bit like a HRW element. I thought it was
> built into the glass itself, but maybe it's on the surface and vulnerable
to
> damage like the HRW elements are. I don't know about the difference
between
> AM and FM reception, but perhaps you have damaged the aerial element and
one
> is just more tolerant of a crap signal than the other.
>
> --
> --
> Rich
>
> Land Rovers
> Boat
> Dog
> Wife
> Kids - in that order
>
AFAIK all the later classic Rangies (mine did anyway) used the heated rear
screen as an aerial if you loosen off the rear edge of the headlining you
will find an aerial amplifier with the coax cable plugged into it close to
the speakers FM works quiet well even if this unit is U/S. I would suggest
you check for a power feed but the circuit diags I had looked buggerall like
the setup so in the end I had to forgo TMS and stick to FM only
thinks :- I really must sell my old manuals= haynes and electronic
Derek


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Outgoing mail is certified Virus Free.
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Tim wrote:

> I did i tune up on the beast replacing cap. rotor, plugs and wires and
> now I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running. the
> wires are suppsed to suppress noise, but this happens with the car not
> running. when I open any door it's very loud. Did I bump a ground or
> something?

What position is the ignition switch in for this?

Also, where does the radio earth run to? It might be worthwhile taking an
earth straight from it to the body incase it's using the arial for an earth
just now.

Also, assuming your car has one, check the suppressor in the distributor and
see if it's good - the only useful way to do this is to replace it I'm
afraid.

Also you might want to try fitting a ground loop isolator to the radio, but
that's a long shot.

P.

Tim wrote:

> I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running.

Woo. If the engine is off then it is not engine interferance but I'd
go for a busted aerial connection. AM radio should be a big woosh
noise if no station is being recieved. (FM goes silent) On my '97
HSE the AM and VHF aerials are seperate connections so it's
probably either fallen out or something has chopped the cable.

nigelH

"Tim" <[email protected]> wrote in message
news:[email protected]
> I did i tune up on the beast replacing cap. rotor, plugs and wires and
> now I get major iterference during AM reception, and actually no AM
> reception now. Funny thing is, this is with the car NOT running. the
> wires are suppsed to suppress noise, but this happens with the car not
> running. when I open any door it's very loud. Did I bump a ground or
> something?

Sounds like the aerial is disconnected or the wire is broken. It's picking
up what stray signal it can and opening the door lets in more of the signal.

The AM receiver will keep turning up the reception gain until it gets a
strong signal. If there's no signal it'll keep on increasing the gain until
either the background noise provides a strong enough signal or it hits
maximum gain.

There should be zero Ohms between the aerial itself and the centre pin of
where the aerial wire goes into the radio.
The radio needs to be earthed and so does the aerial mount.

--
FZS600 - Silver/Black
GS125 - Black/Rust
Ford 100E Prefect - Black, naturally
Whisky - Aberlour Cask Strength

I'm confused about where the AM antenna is. Not even sure about the FM
either. Could the FM antenna be on the left and right rear windows?
I'm thinking I bumped something while obsessing on window cleaning.


On Wed, 4 Aug 2004 18:42:24 +0100, "PDannyD"
<dan1970.nomeatproductsplease@nocannedmeat.scenicplace.freeserve.co.uk>
wrote:

>"Tim" <[email protected]> wrote in message
>news:[email protected]
>> I did i tune up on the beast replacing cap. rotor, plugs and wires and
>> now I get major iterference during AM reception, and actually no AM
>> reception now. Funny thing is, this is with the car NOT running. the
>> wires are suppsed to suppress noise, but this happens with the car not
>> running. when I open any door it's very loud. Did I bump a ground or
>> something?
>
>Sounds like the aerial is disconnected or the wire is broken. It's picking
>up what stray signal it can and opening the door lets in more of the signal.
>
>The AM receiver will keep turning up the reception gain until it gets a
>strong signal. If there's no signal it'll keep on increasing the gain until
>either the background noise provides a strong enough signal or it hits
>maximum gain.
>
>There should be zero Ohms between the aerial itself and the centre pin of
>where the aerial wire goes into the radio.
>The radio needs to be earthed and so does the aerial mount.

Tim wrote:
> I'm confused about where the AM antenna is. Not even sure about the FM
> either. Could the FM antenna be on the left and right rear windows?
> I'm thinking I bumped something while obsessing on window cleaning.
>
The radio aerial (I think there is only one) is built into the rear o/s side
window on later RRCs, looks a bit like a HRW element. I thought it was
built into the glass itself, but maybe it's on the surface and vulnerable to
damage like the HRW elements are. I don't know about the difference between
AM and FM reception, but perhaps you have damaged the aerial element and one
is just more tolerant of a crap signal than the other.

--
--
Rich

Land Rovers
Boat
Dog
Wife
Kids - in that order

"Richard Brookman" <[email protected]> wrote in message
news:[email protected]...
> Tim wrote:
> > I'm confused about where the AM antenna is. Not even sure about the FM
> > either. Could the FM antenna be on the left and right rear windows?
> > I'm thinking I bumped something while obsessing on window cleaning.
> >
> The radio aerial (I think there is only one) is built into the rear o/s
side
> window on later RRCs, looks a bit like a HRW element. I thought it was
> built into the glass itself, but maybe it's on the surface and vulnerable
to
> damage like the HRW elements are. I don't know about the difference
between
> AM and FM reception, but perhaps you have damaged the aerial element and
one
> is just more tolerant of a crap signal than the other.
>
> --
> --
> Rich
>
> Land Rovers
> Boat
> Dog
> Wife
> Kids - in that order
>
AFAIK all the later classic Rangies (mine did anyway) used the heated rear
screen as an aerial if you loosen off the rear edge of the headlining you
will find an aerial amplifier with the coax cable plugged into it close to
the speakers FM works quiet well even if this unit is U/S. I would suggest
you check for a power feed but the circuit diags I had looked buggerall like
the setup so in the end I had to forgo TMS and stick to FM only
thinks :- I really must sell my old manuals= haynes and electronic
Derek


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.734 / Virus Database: 488 - Release Date: 04/08/2004