<From: MGAdrvr @ aol.com @ USDESMTP
<Date: 10/14/96 02:55:46 PM
<Subject: A great day in St. Louis!
<
<It's 75 degrees & clear, the Cardinals are up 3 to 1 on Atlanta, and my
<American luxury sedan puked its' power steering pump yesterday so I have to
<drive my 35 year old MGA all day...I could not ask for more (except maybe the
<fourth win tonight)!
<
<On the practical side, I am about to atempt to install a new radio in my
<positive ground car. Since I have a wood IP and the case & mounting bracket
<will be insulated, I intend to wire it as suggested by the radio
<manufacturer: positive on the radio to the positive(ground) of the car,
<negative of the radio to the negative(harness) of the car. Why should it
<matter to the radio how the current flow gets there? I will have a line fuse
<head of the radio. Any experience out there? Any suggestions?
< don't want to let any smoke out of the harness since everything has been
<erfect since the restoration.
<Thanks in advance.
<GO CARDINALS !!!!!!!!!!!!!!!!!!!!!!!!
<Tom McCarthy
The only problem with the wiring you propose is the antenna. The outer
shield of your antenna cable needs to be well grounded at both the radio
chassis and the car body (to minimize static noise pickup). Unfortunately,
this will short out your power. I haven't tried this, but it may be possible
to isolate the 12V DC from the car body by connecting the cable shield to
the car body through a capacitor (maybe something like a .1 microfarad rated
at 25 volts or more). It would probably be easier to to put the capacitor
at the radio end of the cable, it doesn't matter which end as long as the
capacitor is blocking the DC current. The idea is that the capacitor
blocks the DC current but passes the RF noise (which is AC current). If you
only intend to listen to strong stations, you may get by just leaving the
shield unconnected at one end.
If you do decide to hook the radio up without a power inverter, I suggest you
put a fuse in line with the negative power lead of the radio since that is
the "hot" wire on a positive ground car. Your new radio probably has the fuse
on the positive wire. Good luck.
Bob Donahue, Still Stuck in the '50s
53 MG-TD, under DIY restoration
71 MGB, still in the shop, 11 months and counting
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