Poor Radio Signal
#1
06-12-2014, 03:31 PM
Poor Radio Signal
Can anyone please tell where I would look to solve my poor reception problem with my standard incar radio.
I'm guessing the antenna is in the back window and somewhere there is an ariel amplifier, but not sure where that is to confirm it has power.
Cheers guys
I'm guessing the antenna is in the back window and somewhere there is an ariel amplifier, but not sure where that is to confirm it has power.
Cheers guys
#2
06-13-2014, 05:59 AM
Some time ago, manuf. started using rather short-ish aerials on cars for the car radio, sometimes indeed cast into the rear window.
At the same time-ish, the BBC went onto circular polarization for FM instead of vertical. This made reception for cars very much better.
The aerial on the car was fitted with an FET (field-effect transistor) to amplify the weak-ish signals from the short aerial. This needed a DC power supply of 12volt nominal, and different arrangements were used to send the power up the co-ax aerial lead to the aerial, depending on the manuf., even sometimes separate DC wiring.
1) If you have fitted a different radio to the one supplied by the car manuf., these arrangements could be at cross-purposes. If you've fitted an old radio, it may be intended for a plain aerial, not an FET-powered one.
2) These FETs are very susceptible to nearby lightning discharges. Because the aerial sticks up in the air, (it wouldn't be much good if it didn't...) and because the FET has a very high input impedance, like a thermionic valve, just a few induced volts here can damage the FET. In the security business, I had a few cameras every week to fix that had been damaged by lightning discharge magnetic field inducing a power spike into the camera, rendering o/c the output load resistor.
Hope this can help you investigate further your weak signals.
Case #2 could be your answer.
Leedsman.
n.b
Antenna and aerial are same, one US and t'other UK.
At the same time-ish, the BBC went onto circular polarization for FM instead of vertical. This made reception for cars very much better.
The aerial on the car was fitted with an FET (field-effect transistor) to amplify the weak-ish signals from the short aerial. This needed a DC power supply of 12volt nominal, and different arrangements were used to send the power up the co-ax aerial lead to the aerial, depending on the manuf., even sometimes separate DC wiring.
1) If you have fitted a different radio to the one supplied by the car manuf., these arrangements could be at cross-purposes. If you've fitted an old radio, it may be intended for a plain aerial, not an FET-powered one.
2) These FETs are very susceptible to nearby lightning discharges. Because the aerial sticks up in the air, (it wouldn't be much good if it didn't...) and because the FET has a very high input impedance, like a thermionic valve, just a few induced volts here can damage the FET. In the security business, I had a few cameras every week to fix that had been damaged by lightning discharge magnetic field inducing a power spike into the camera, rendering o/c the output load resistor.
Hope this can help you investigate further your weak signals.
Case #2 could be your answer.
Leedsman.
n.b
Antenna and aerial are same, one US and t'other UK.
#3
06-13-2014, 10:52 AM
What Jason may not realise, is that the aerial is part of the rear side window. If you're UK based then it's the rear window on the drivers side.
#5
06-14-2014, 04:23 AM
Thats the bit hopefull I needed to know, hopefully the amp is there too so I can confirm its getting its necessary voltage to work.
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