Topic: Radio noise suppression


fsacht    -- 08-01-2010 @ 4:39 PM
  My 48's radio has suddenly acquired static that changes tone as RPM increases or decreases. I have a pictorial that describes noise suppression locations for our flatheads but can't find it. Was there a condensor that attacched to the coil to remove ignition static and how was it connected? I do have a condensor on voltage regulator and generator. The condition just cropped up when I changed my coil from the new cylindrical style to the original type for a car show last weekend. It is almost certainly ignition related due to change of intensity relative to RPM. Plugs are Champion H10C with no suppression gizmos attached to secondary wiring.


TomO    -- 08-02-2010 @ 7:59 AM
  Changing the coil should not have introduced static into your radio, unless there is arcing of the coil, internally or externally.

I would look into the grounding of the antenna shield at the radio and at the antenna. Next, I would check that the outside of the coil is not arcing, by revving up the engine in the dark.

Tom

This message was edited by TomO on 8-2-10 @ 8:02 AM


supereal    -- 08-02-2010 @ 8:11 AM
  Check the end of the high voltage lead that fits into the coil. It may not be tight, or may be arcing. Most old coils have serious internal breakdown of the insulation, and it isn't rare to have arcing between windings. It shouldn't be difficult to pin down the source, as you have already isolated it to the change in coils. There is no separate bypass condenser on the coil, as the regular ignition condenser on the side of the distributor on your car is enough.


fsacht    -- 08-02-2010 @ 6:07 PM
  Antanna cable loose to base of mast. Secondary coil lead secure at coil. Secured antenna cable to antenna base. Antenna cable secure to radio. Condition improved but not eliminated. Will live with improved condition. Thanks for input.


deluxe40    -- 08-02-2010 @ 7:46 PM
  Ford's answer to this problem was to supply an accessory "Interference Elimination" kit (see photo). The kit included condensers for the generator and regulator, a device to insert into the high tension wire between the coil and distributor, springs for the hubcaps, a ground strap for the fuel sending unit and, my favorite, five packets of "anti-static powder, Part No. 6A-18953". The powder was introduced into the tire tubes using an applicator that was provided. A friend recently found the remnants of such a kit in a collection of parts he acquired. The five packets of powder were not used. Perhaps the other items in the kit solved the problem.




fsacht    -- 08-03-2010 @ 6:37 PM
  Think I'll try to acquire a couple springs to insert into the hub nut caps. Thanks for the replies. There may be a few more out there who don't remember these remedies or who may not have a clue why their original AM radios have so much buzz. Resistor spark plugs was another rememdy if I remember correctly, like Rj14YC.


TomO    -- 08-04-2010 @ 8:08 AM
  The springs were put in the dust cover of the wheel bearings to compensate for the change in the materials used to make tires. They were not very effective and only reduced noise caused by static build up from traveling down the road.

If you go back to you old coil and do not have the static problem, have your stock coil rebuilt as it probably has some internal arcing and will fail soon.

Tom


supereal    -- 08-04-2010 @ 9:44 AM
  Fred: With the stuff available on AM radio today, I suspect the static is a welcome relief!


mvillebob    -- 08-04-2010 @ 6:35 PM
  Super,
Excellent point!
Best,
Bob


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