Geo,
I think the main source of radio noise is the alternator. On Lucas
alternators(at least on mine) there is a capacitor to filter out most noise.
My ignition coil also has a capacitor on the positive side which is mounted on
the engine. I don't think its a ballast resistor in this case. I'm not sure if
it too is a noise filter or not but I suspect it is. I've got a '74 TR6. I
recently installed a 12 volt Lucas sport coil and I left the + side capacitor
in place and wired a new wire directly from the fuse box(12v). In my case the
old wiring was the 'ballast resistor'. Typically, round capacitors(with a uF
rating) mounted on the + side of a coil are indeed for radio noise suppression.
As with jonmac, I have seen(on my old 240z for instance) where the ballast
resistor is indeed a ceramic blocky looking inline resistor on the + side of
the coil. It does not, however, ground in anyway the + side of the coil like a
capacitor(high frequency noise filter). Its simply an inline resistor(to keep
the voltage down to 6-8 volts) for a 6-8 volt ignition coil.
Once again, most induced radio noise comes from an alternator(high pitched
weiring noise). A crackly popping type noise is what the ignition coil/wires
will induce into the electrical system of your car.
--
On Fri, 02 Jul 1999 15:39:57 George Hahn wrote:
>
>jonmac wrote:
>
>> Brian
>> Seems like you don't have a suppressor on the coil....
>
>The last time I bought a Lucas coil for the '3 it had a ceramic thing
>(about 2cm x 2cm x 7.5cm) mounted on the bracket and marked "+" and
>wired to the coil. Perhaps it's a ballast resistor but I'm unclear on
>it's purpose... noise supression? better spark?
>
>Anyway, I left it off and (naturally) saved it. Who can tell me what it
>is/does? Brian -- if it all it does is improve radio reception, it's
>yours if you want it.
>
>Geo Hahn
>59 TR3A
>
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