Eliminating Niose on Ham Radio Jeep TJ?
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
http://www.k2bj.com/Pages/Noise/PowerSup.htm
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Nick ------ wrote:
>
> Hi Folks,
>
> Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> bypass caps on the fuel pump lead (to ground) and am still experiencing
> noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> still experiencing noise poportional to engine RPM.
>
> Any insight appreciated.
>
> Thanks,
> Nick
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/
Nick ------ wrote:
>
> Hi Folks,
>
> Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> bypass caps on the fuel pump lead (to ground) and am still experiencing
> noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> still experiencing noise poportional to engine RPM.
>
> Any insight appreciated.
>
> Thanks,
> Nick
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Hi ---- --- response follows...
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Hi ---- --- response follows...
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Hi ---- --- response follows...
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Hi ---- --- response follows...
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
---- wrote:
> Have you grounded the hood?
The factory has a large braid from the hood to the frame.
> What kind of antenna/mount are you using?
NMO, on the rear of the Wrangler, above the tail light. 70cm/2m Larsen
dual-band.
> Are you running both + and - directly from the radio to the battery?
No, only hot lead from the batter to the rear of the Jeep. I believe
it's 8 gauge wire. Negative lead goes directly to the chassis in the
rear of the Jeep.
> Do you have a direct ground from the radio to the Jeep chassis?
The radio's negative lead is grounded to the Jeep chassis, however not
the radio 'chassis' itself. I can try doing this also.
> Is the feedline coax grounded directly to the Jeep at the antenna end?
Yes. The coax grounds to the NMO mount, which in turn grounds directly
to the frame of the jeep (via screws).
> Do you know if the noise is from the ignition or the alternator?
>
Do you know how to distinguish?
Thanks for the help
> On 20 Aug 2005 17:46:26 -0700, "Nick ------" <nixon8890@gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> >2000 or later? I grounded the tail pipe to the frame, installed .1uF
> >bypass caps on the fuel pump lead (to ground) and am still experiencing
> >noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> >still experiencing noise poportional to engine RPM.
> >
> >Any insight appreciated.
> >
> >
> >Thanks,
> >Nick
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Response follows...
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Response follows...
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Response follows...
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
Response follows...
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Jerry Bransford wrote:
> Nick, where is your radio getting its power from?
10 guage wire directly from the battery. It runs from the terminal,
through a firewall, then to the rear of the Jeep.
> Does the noise go
> away when you disconnect the antenna?
I will try this.
> Have you replaced your spark
> plugs with non-resistor plugs?
Yes. They are Champion.
I may try moving an AM radio around the car. Hopefully, I can isolate
it further.
Thanks
>
> Jerry
> N6TAY
>
>
>
> Nick ------ wrote:
> > Hi Folks,
> >
> > Has anyone had sucess eliminating Jeep TJ RF noise? Specifically, year
> > 2000 or later? I grounded the tail pipe to the frame, installed .1uF
> > bypass caps on the fuel pump lead (to ground) and am still experiencing
> > noise on 2m/70cm. The bypass cap helped eliminate some noise, but I'm
> > still experiencing noise poportional to engine RPM.
> >
> > Any insight appreciated.
> >
> >
> > Thanks,
> > Nick
> >
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.***.net/jerrypb/
Guest
Posts: n/a
Re: Eliminating Niose on Ham Radio Jeep TJ?
On 22 Aug 2005 12:34:44 -0700, "Nick ------" <nixon8890@gmail.com>
wrote:
>> Are you running both + and - directly from the radio to the battery?
>No, only hot lead from the batter to the rear of the Jeep. I believe
>it's 8 gauge wire. Negative lead goes directly to the chassis in the
>rear of the Jeep.
The negative lead needs to go directly to the battery, either at the
battery terminal, or (as recommended by Chrysler) at the point where
the negative battery cable attaches to ground.
>
>> Do you have a direct ground from the radio to the Jeep chassis?
>
>The radio's negative lead is grounded to the Jeep chassis, however not
>the radio 'chassis' itself. I can try doing this also.
You haven't said where the radio is mounted. It sounds like it might
be installed in the rear with a remote head up front. In any event,
the radio chassis ground needs to find the most direct route to the
chassis. If you are using a remote head, you may need to use some
ferrites on the lead between the head and the radio.
>> Do you know if the noise is from the ignition or the alternator?
>>
>Do you know how to distinguish?
Ignition (spark plug noise) is a staccato, popping noise. Alternator
noise is a high-pitched whine. Both change with engine rpm.
----
wrote:
>> Are you running both + and - directly from the radio to the battery?
>No, only hot lead from the batter to the rear of the Jeep. I believe
>it's 8 gauge wire. Negative lead goes directly to the chassis in the
>rear of the Jeep.
The negative lead needs to go directly to the battery, either at the
battery terminal, or (as recommended by Chrysler) at the point where
the negative battery cable attaches to ground.
>
>> Do you have a direct ground from the radio to the Jeep chassis?
>
>The radio's negative lead is grounded to the Jeep chassis, however not
>the radio 'chassis' itself. I can try doing this also.
You haven't said where the radio is mounted. It sounds like it might
be installed in the rear with a remote head up front. In any event,
the radio chassis ground needs to find the most direct route to the
chassis. If you are using a remote head, you may need to use some
ferrites on the lead between the head and the radio.
>> Do you know if the noise is from the ignition or the alternator?
>>
>Do you know how to distinguish?
Ignition (spark plug noise) is a staccato, popping noise. Alternator
noise is a high-pitched whine. Both change with engine rpm.
----
