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EFV-8 Club Forum / General Ford Discussion / RADIO NOISE

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Posted By Discussion Topic: RADIO NOISE -- page: 1 2     supereal 12-20-2010 @ 2:54 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Ferrite beads do a good job on higher frequencies, but not much on AM noise. In old radios, much of the noise is due to the mechanical vibrators that generate the higher plate voltage from the 6 volt input for tube type radios. There are solid state "vibrators" that help with that, and don't create "hash". Another common fault is old filter capacitors. They are mostly electrolytic type, and become weak due to aging. One method of noise reduction tried years ago was to use the speaker coil as a choke by running the input thru it. They are rare today. Old Henry 12-20-2010 @ 11:21 AM reply profile send p.m. Senior Posts: 738 Joined: Apr 2010 Here's a photo of one of my wires going through the larger ferrite core. You can see in the photo two other smaller choke cores with smaller wires going through them. Old Henry (The older I get, the better old looks.) rogbell 12-20-2010 @ 11:21 AM reply profile send p.m. New Member Posts: 106 Joined: Dec 2009 Thanks for all the help everyone. I will try each of the suggestions and hopefully eliminate the problem. Old Henry 12-20-2010 @ 11:09 AM reply profile send p.m. Senior Posts: 738 Joined: Apr 2010 It looks like it wouldn't hurt to put condensers in all of the possible places (but not another between the coil and the distributor.) Might not do any good but can't hoit. Something I did to try to eliminate spark plug noise in my indepentent CD player (run by it's own battery not connected to the car except to the speaker) is to put choke cores on all lines that would fit in them. Here are the ones from Radio Shack I used: http://www.radioshack.com/product/index.jsp?productId=3012599 Here's ferrite core for larger wires: http://www.radioshack.com/product/index.jsp?productId=2103222&clickid=prod_cs The way those work is to run the wire through them then back around and run through again. That eliminates a different kind of noise that capacitors to not. Capacitors (condensers) reduce low frequency interference, coils reduce high frequency. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-20-10 @ 11:22 AM supereal 12-19-2010 @ 9:59 AM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 OH: Putting a condenser on the battery post of the regulator has the same effect as putting one in the power wire to the radio. There is no problem with putting a condenser on the input side of the coil, but putting it on the distributor side will affect operation. The ignition condenser does dampen arcing of the points, but it also provides a method of assisting the charging and saturation of the coil, itself, so the capacity is important. All the Ford radio installation information I have shows the regulator condenser is attached to the ARM terminal if it is not actually on the generator. As said above, there is no harm to put one on the BATT post, but it won't suppress the arcing at the commutator, a major source of noise. For a couple of decades, I was employed as an engineer for a group of radio stations, and spent a lot of time trying to clean up AM interference on a variety of receivers, including vehicles. We could usually reduce it, but seldom eliminate it. The spread of FM radio made life a lot easier. 4dFordSC 12-18-2010 @ 4:22 PM reply profile send p.m. Member Posts: 266 Joined: Oct 2009 "One more question for 4dFordSC: Do you know the NAPA part equivalent for the suppressor explained and shown in the radio manual as part number 63-1273?" Sorry, I don't. Old Henry 12-18-2010 @ 3:16 PM reply profile send p.m. Senior Posts: 738 Joined: Apr 2010 One more question for 4dFordSC: Do you know the NAPA part equivalent for the suppressor explained and shown in the radio manual as part number 63-1273? Old Henry (The older I get, the better old looks.) Old Henry 12-18-2010 @ 3:09 PM reply profile send p.m. Senior Posts: 738 Joined: Apr 2010 Two responses to Supereal: 1. As I said before, I don't have any radio noise and have no condensers anywhere so don't know the difference between putting one on the ARM terminal of the regulator and putting it on the BAT terminal. All I know is that Ford recommended the BAT terminal as per my attached illustration. 2. The condenser by the distributor is to give the current trying to go through the points when they open an alternate route so that the points don't arc so much and burn out. Ford's recommendation is to put one on the other terminal BEFORE the current goes through the coil to dampen any static being picked up by that wire. (See illustration) What is unclear from those instructions and illustration is whether to put that condenser before the coil mounted resistor or after. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 12-18-10 @ 3:13 PM supereal 12-18-2010 @ 2:55 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 If it does the job, that's OK, but the condenser at the regulator should be on the ARM terminal. The coil already has a condenser, usually at the distributor. It is part of a tuned circuit, and adding capacity may affect operation. We used to install condensers on the oil pressure sender and the gas gauge sender as part of the kit that came with the radio, but unless there is an intermittent "scratching" sound, they usually are not necessary. A condenser on the input wire to the radio may help, but we usually substitute a piece of RG-59 coax for that wire, such as used in TV systems, and ground the shield. Any part of the wiring in a car can pick up radio noise. That is why the Corvettes have shielded ignition systems. 4dFordSC 12-18-2010 @ 2:18 PM reply profile send p.m. Member Posts: 266 Joined: Oct 2009 My '40 with a stock Roto-Matic AM radio has RC-1 Condensers attached to the "Batt" terminal of the voltage regulator, the oil pressure sending unit, and the circuit breaker under the dash. The installation instructions also call for one on the coil in addition to the ignition condenser, but I omitted that one. I have no engine noise in the radio, but don't listen to it that often, since about all we get on AM in this market is talk radio and gospel music. Used to have a good Golden Oldies R&R station, but it went Hispanic several years ago:-(

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