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Antenna?

Started by SDGlenn, June 15, 2011, 09:24:06 PM

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chetbrz

Glenn,

Could you post a diagram of how things are wired and pay attention to what is positive and negative.  What if any wires are connected to your existing car wires ?

If you have a volt meter, measure the voltage across the power lines to the radio first on the DC volt scale then on the AC volt scale.  This would be very helpful in determining what is going on.  Do this first with the motor not running then with the motor running.  Radio on.

Chet...
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

SDGlenn

Chet, I will do that first thing tomorrow. After breakfast of course. lol I appreciate you taking the time to help me figure this out. There is a parade this coming weekend, about 100 mile north of me, but my grandson (8 year old)  may be going with me, he seems to have some interest in these older cars, and likes to wave at the people and throw candy. lol
Later, thanks
SD Glenn
SDGlenn

chetbrz

Quote from: Glenn on June 21, 2011, 10:35:27 PM
Chet, I will do that first thing tomorrow. After breakfast of course. lol I appreciate you taking the time to help me figure this out. There is a parade this coming weekend, about 100 mile north of me, but my grandson (8 year old)  may be going with me, he seems to have some interest in these older cars, and likes to wave at the people and throw candy. lol
Later, thanks
SD Glenn


Let's see:

100 mile drive north,
with grandson,
in an old Plymouth,

You are a brave man.

Chet...
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member

SDGlenn

LOL, no, we will be trailering the Plymouth. However, I am pretty confident the Plymouth would make the trip (along with AAA of course). I have put a lot of miles on and had no problems, of course problems show up when you area long way from home, or in an ackward place.
SD Glenn
SDGlenn

SDGlenn

Chet, We got it fixed, thanks a whole lot.
I followed your instructions, even drew up the diagram. (The radio is on its own circuit)
When I started the Volt meter testing, I started with the ground on the car body and positive lead to my 12V lead to the radio, the volt meter showed no voltage, then I started the car, immediately I had a spike of .08 volts, and the radio died. I took the switch down from the dash (I have a switch on the dash to shut off the 12V system to the radio) and dropped it on the floor, the radio came back on with the engine running. Surprised me. As I moved the switch back toward  the dash the radio would die. The switch was mounted only about a foot to the left of the coil, a little further away and there is no longer a problem.(there is about 4 inches difference of where it works or not) (The coil and Ignition Key are one assemble on the back side of the dash)
I would not have located this for a long, long time without your help. Thanks again.
SD Glenn

SDGlenn

chetbrz

#20
Good Glenn,

Early radio utilized a spark coil to generate radio waves.  Basically an ignition coil crudely serves the same function.  The long wire to the engine serves as the antenna.  The old coil and wire must be poorly shield so the closer your radio circuitry got to the coil the more RF induced into the power line and radio circuitry until it totally blacked out your radio.  This can happen to any radio in close proximity to a transmitter.

Lot's of thinks get fixed by serendipity.   Just ask Alexander Graham Bell and Thomas Watson.  "Watson come here I need you" !!! and the telephone is history.  They were actually trying to build a multi-tone telegraph that could transmit multiple telegraph signals on the same wire.  

Have fun, Chet...
http://www.1948Plymouth.info           Web Master - Forum Administrator - AACA member