"Michael A. Terrell" wrote in message
m...

AZ Nomad wrote:

On Sat, 28 Nov 2009 23:47:31 -0500, mm wrote:

Thanks for the helpful replies about the car radio that would only get
a couple AM stations. The guy ignored my advice about trimming the
antenna, and just bought another antenna, even though the one he had
had worked fine with the previous radio.

The new radio worked fine with the new antenna. Did he just get
lucky?

No. He ignored your idiotic advice and replaced a defective antenna.

Did you propose he trim and replace metal every time he changes channels?


'Trimming the antenna' means to adjust a variable capacitor to
compensate for the capacitance of the coaxial cable. It affects the gain
on the upper end of the AM band, since the antenna is used as a voltage
probe, rather than a typical antenna design. It was standard procedure
whenever a car radio was installed or repaired to 'trim' it as the last
step of the job. Most US car radios allowed the adjustment by removing
the tuning knob and using a small screwdriver to adjust the capacitor. A
lot of cheap imported radios had no adjustment, and had very poor AM BCB
performance.

It has absolutely nothing to do with cutting metal.


___________________________
You forgot to mention that with age, the antenna coaxial cable would get
water in it, and
reception would suffer. Adjusting the trimmer would make little or no
difference in this situation. Replacement was the only fix.