The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop.
Control unit is seperated with 8 meter cable from main unit and is
mounted underneath the ashtray

D-

My guess is that the whistle is alternator whine, as others have suggested. If
so, it is probably not coming in through the antenna, but through the power
connection to the audio amplifier.

I would suggest using a pair of 10 AWG wires directly from the battery
terminals to the main unit (Fused, of course). Either alternator or ignition
noise might be coupled through the control unit's ground, so try isolating it.
Let it obtain audio, power and ground through the 8 meter cable.

If the antenna is ground independent, make sure you didn't ground it by
accident. There could be noise conducted through its shield back to the radio.

73, Fred, K4DII

(D.) wrote in message . com...
Hi,
I am beginner .. sorry if some of this seems like stupid question(s):

I have installed a ICom F2010(2020) into my Jeep.
The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop.
Control unit is seperated with 8 meter cable from main unit and is
mounted underneath the ashtray (so basically it is sitting above the
gear box).

The antenna is mounted on the roof the car:
A GME 409L (ground independend), mounted on a spring S004

Frequencies used are in the 460Mhz-490Mhz range.

The problems I am experiencing now:
- Whenever the unit is Rx ... I can hear a whisling sound, which is
only audible if I accelerate (there seems to be a relationship to the
RPMs ?)

Alternator noise. Rock on down to your local car radio shop and buy a
noise filter for the alternator.

(D.) wrote in message . com...
Hi,
I am beginner .. sorry if some of this seems like stupid question(s):

I have installed a ICom F2010(2020) into my Jeep.
The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop.
Control unit is seperated with 8 meter cable from main unit and is
mounted underneath the ashtray (so basically it is sitting above the
gear box).

The antenna is mounted on the roof the car:
A GME 409L (ground independend), mounted on a spring S004

Frequencies used are in the 460Mhz-490Mhz range.

The problems I am experiencing now:
- Whenever the unit is Rx ... I can hear a whisling sound, which is
only audible if I accelerate (there seems to be a relationship to the
RPMs ?)
- If the car is stationary I can Rx ok, once the car is moving (maybe
50 kmh) the Rx is braking up

Is above normal, if not .. any ideas how to fix it ?

I am aware that I should shorten the antenna cable, rather than
looping it.
Could the transmition be causing the whisling noises ?
Is the antenna I am using a piece of s(*^&(^ and should I use a
different one ?
Thanks, D.

Where are you getting the power from? The battery direct, or from a
receptacle?
Sounds like you are getting alternator whine, or ignition noise.
Probably alternator. You can try directly hooking the power direct to
the battery. Both positive and negative wires, "use both + and - fuses
at the battery". Or go to rat shack and buy a noise filter. I think
they still sell them. It's possible to need the filter even with a
direct battery connection in some cases I bet. MK

In article ,
says...
Hi,
I am beginner .. sorry if some of this seems like stupid question(s):

I have installed a ICom F2010(2020) into my Jeep.
The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop.
Control unit is seperated with 8 meter cable from main unit and is
mounted underneath the ashtray (so basically it is sitting above the
gear box).

The antenna is mounted on the roof the car:
A GME 409L (ground independend), mounted on a spring S004

Frequencies used are in the 460Mhz-490Mhz range.

The problems I am experiencing now:
- Whenever the unit is Rx ... I can hear a whisling sound, which is
only audible if I accelerate (there seems to be a relationship to the
RPMs ?)
- If the car is stationary I can Rx ok, once the car is moving (maybe
50 kmh) the Rx is braking up

What you're hearing is alternator whine. I'm curious how you hooked up
the power leads. If you did the one through the fuse panel, another to
ground you're going to get noise.

The way you should install amateur radio gear is a positive and negative
lead connected to the battery, being sure to put suitable fuses on both.

I've used this method on half a dozen vehicles over time and never had a
problem. But it's very important to fuse both leads.

"D." wrote in message
om...
Hi,
I am beginner .. sorry if some of this seems like stupid question(s):

I have installed a ICom F2010(2020) into my Jeep.
The radio unit itself is installed in the back where the CD changer
was, the antenna cable is a bit too long, so it is stored in a loop.
Control unit is seperated with 8 meter cable from main unit and is
mounted underneath the ashtray (so basically it is sitting above the
gear box).

The antenna is mounted on the roof the car:
A GME 409L (ground independend), mounted on a spring S004

Frequencies used are in the 460Mhz-490Mhz range.

The problems I am experiencing now:
- Whenever the unit is Rx ... I can hear a whisling sound, which is
only audible if I accelerate (there seems to be a relationship to the
RPMs ?)
- If the car is stationary I can Rx ok, once the car is moving (maybe
50 kmh) the Rx is braking up

Is above normal, if not .. any ideas how to fix it ?

I am aware that I should shorten the antenna cable, rather than
looping it.
Could the transmition be causing the whisling noises ?
Is the antenna I am using a piece of s(*^&(^ and should I use a
different one ?
Thanks, D.

I had the same problem but with a PRM8010,
On Transmit you could hear an alternator noise, so all i need is a noise
filter?
Where abouts can i get one and how much??