car stereo radio problem

[123hotchef]

Ok I have got to fix this issue now.

The problem is I loose radio signal in so many places.
I have fitted a new head unit and a new antenna and still have the same problem.
So it must be something else.

I can take my other car and get a strong signal all the way to work but not so with the Shogun.

What shall I check next.

 

[ajlelectronics]

The problem is I loose radio signal in so many places.

Have you tried re-tightening the loose signal?

I have fitted a new head unit and a new antenna and still have the same problem.

More details please. What radio is it and what aerial have you fitted?

So it must be something else.

I can take my other car and get a strong signal all the way to work but not so with the Shogun.

What shall I check next.

Does the original aerial use an in line amplifier / splitter unit?

Is the new aerial wired directly to the radio, or are you using the original loom?

I assume that the Shogun is all metal? Where is the aerial mounted?

 

[123hotchef]

ok so I replaced the old electric antenna with a new CB antenna and splitter box ran a new cable to the antenna. I have not fitted a CB yet.
The antenna is mounted in the original spot in the wing.
I may run a ground cable to the base nut of the antenna and see if things impove

 

[Melvyn Best]

Way to test aerials was to turn the radio on then touch the aerial, if the volume increased it normally had a bad earth, this was in the days before factory fitted radios etc , presume it still works?

 

[ajlelectronics]

ok so I replaced the old electric antenna with a new CB antenna and splitter box ran a new cable to the antenna. I have not fitted a CB yet.

Are you able to fit the old electric aerial as a test? Otherwise, even a random length of wire might give you a clue. My guess would be the splitter unit. Actually, you could perhaps just short it out because the CB aerial will work quite well for FM VHF reception.

The antenna is mounted in the original spot in the wing.
I may run a ground cable to the base nut of the antenna and see if things impove

Is the wing steel or fibreglass?

 

[skotl]

ok so I replaced the old electric antenna with a new CB antenna and splitter box ran a new cable to the antenna. I have not fitted a CB yet.
The antenna is mounted in the original spot in the wing.
I may run a ground cable to the base nut of the antenna and see if things improve

That's what I'm thinking - poor grounding at radio or antenna. Worth jury-rigging a ground cable direct to the battery to see whether that makes a difference...

 

[Kayos]

A lot of cb antennas do not need a dc ground, indeed they can be a dead short at dc

 

[123hotchef]

Are you able to fit the old electric aerial as a test? Otherwise, even a random length of wire might give you a clue. My guess would be the splitter unit. Actually, you could perhaps just short it out because the CB aerial will work quite well for FM VHF reception.



Is the wing steel or fibreglass?

Steel

 

[123hotchef]

But it was the same with the old antenna on the new stereo. And with the new antenna on the new stereo

 

[ajlelectronics]

But it was the same with the old antenna on the new stereo. And with the new antenna on the new stereo

Is the aerial going straight to the radio with its own cable, or are you using the original loom in the car to carry the aerial feed?

 

[123hotchef]

Is the aerial going straight to the radio with its own cable, or are you using the original loom in the car to carry the aerial feed?

No I replaced the cable to the antenna and have a splitter box now. To use the cb antenna for the radio

 

[123hotchef]

Here is the splitter box

 

[skotl]

No I replaced the cable to the antenna and have a splitter box now. To use the cb antenna for the radio

Huh.... so apart from the obvious concern about the splitter box reducing efficiency have you considered whether the length of the CB antenna is an appropriate multiple of the wavelength of the radio stations (presumably ~88-96Mhz)?

Antennae work best when they are a multiple of the wavelength they are operating in, so I presume your CB antenna is tuned for 27Mhz so won't be a great match for UHF/FM frequencies.

Edit: antenna length calculator, and a screenshot of a rough antenna size for ~90Mhz (you can the subdivide again to get to a reasonable length, so probably 16" or 8" for 1/8th and 1/16th wavelength)

Whip Antenna Length And Frequency Calculator (csgnetwork.com)

 

[123hotchef]

It's weird that the same problem existed with the old original antenna and wire and a different head unit though

 

[ajlelectronics]

No I replaced the cable to the antenna and have a splitter box now. To use the cb antenna for the radio

The only thing that I can say is that there has to be something different between the two vehicles. Quite what I can't say. However the aerial placement can make a little difference, the major lobe being across the largest area of groundplane. Without being there, it is hard to come up with anything concrete really, but I would start by shorting out the splitter temporarily, to see what losses it is introducing. Although the CB aerial is far from resonant, it will not make that much difference on receive across quite a wide frequency range.

 

[123hotchef]

When you say short out the splitter do you mean run a cable from the splitter to ground

 

[ajlelectronics]

When you say short out the splitter do you mean run a cable from the splitter to ground

No I mean bypass it as if it wasn't there. You may need some pieces of wire to connect the CB aerial direct to the radio, try with the inner core on its own first, then connect the earth and compare with the signals you get with the splitter in circuit. I would use a weak signal if you can find one for testing, because the FM limiter will mean no apparent change over quite a wide signal variation..

 

[123hotchef]

No I mean bypass it as if it wasn't there.

That I would need to get a adaptor to convert the pl259 to a standard antenna plug

 

[ajlelectronics]

That I would need to get a adaptor to convert the pl259 to a standard antenna plug

No, just cobble it for test.

 

[123hotchef]

That's the thing it works fine at home it's only on the drives it is in and out.