[Bob B.]

I have a 70 Chevelle with the antenna in the windshield. I have had the car for 15 years and there has always been a whinning noise in the stereo,no matter what type of stereo it was. The system is simple,just a stereo and six speakers, no amps or equalizers.
While looking in Year One I see this windshield antenna ground, my truck has this but did not know it was for the antenna.The car has a fiberglass hood and no ground clip.Could this cause the whinning sound in my speakers?

 

[RussD]

Hey Bob-
Try getting a $5 dollar noise filter at the local parts store(pepboys Kragens autozone napa etc.) should fix it right away, it splices into the radio harness. Happened to one of my friends cars.

------------------
Steve
64SS-327-4spd-sold to Original owner!
65 Malibu 283/PG!!!
My 65's Homepage
Team Chevelle Member #71

 

[Coppertop]

How's your alternator doing? Sometimes when they aren't doing too good you can hear this annoying whine. Also check your grounds at the radio AND the antenna grounds where it plugs into the radio and the cowl connection(corrosion etc.). Are your speaker grounded to the car chassis? All these can cause problems.

 

[Shawn]

I've seen that ground thing too but how does it help the antenna? My Elky is missing the ground but the antenna works fine. ???

------------------
1970 Chevy Custom El Camino aka Kaileigh
Green Mist & Silver w/Green Vinyl Top
350ci/300HP 4bbl & Factory Dual Exhaust
Non-SS with Factory Rallies!
TH-350 Automatic - 2.73 Posi Rear
My El Camino Home Page - www.dreamelectric.com

 

[72chevelle350TH350]

Trial and error first!

Turn key to ACC. Play LOCAL radio station.... Does it hum now? if so your antenna may be at fault, or is your radio an old one?

Turn car over/ON. Play same radio station!....Does it hum now and vary in pitch with RPM?

If it's the latter, first buy the $10 dollar noise filter (at Walmart none-the-less). If that doesn't satisfy you, get a quality alternator.

I had the same problem, when people riding asked what that whining was... I told 'em it was my super-charger.

------------------
have now>>>>> am building
2.73 open 10bolt>>>>>>3.73 posi 12bolt
350>>>>396 w/nitrous
shooting for 12s in 1/4
college student budget!

 

[Rich-L79]

Do you have radio suppression spark plug wires? If not, this could account for the interference in your radio reception.

 

[Coppertop]

The whining is a tell-tale sign of electrical noise in the system. Typically from an alternator/charging system.

If the radio plays fine with the engine not running, the radio itself is not the trouble-maker.

If, when the engine is running, give it a couple good revs

Does the sound seem to correlate with the engine's rpms???

If so you have:

1)Charging problems (as described above)
2)Ground problems (see my earlier post)


A WHINE was stated, not any other noise. If it was spark plug related it would sound like a radio on AM with a hair-dryer close to it, crackling hissing popping noise.

I KNOW, I custom made tach for my '70 and got in a hurry and ran the coil input wire too close to the radio's antenna, now I hear the "sparkplug dance" on weaker AM stations.


Shawn (and to anyone else curious),

The hood ground is there to ensure the metal hood is in good contact with the rest of the body, "simulates" one whole piece of metal (the whole car body). This makes a consistant ground with optimizes radio reception, because the ground is the other element of a radio antenna system.

The radio is then "tuned" to the sheet metal of the car. How is this done?

The "trimmer" is adjusted. The tuning knob is removed and in the small hole is a trimmer capacitor that is turned until a weak station (near 1400 kHz on the AM band) is rec'd with the most output. This signals the antenna is "trimmed" to the vehicle for optimum performance.

You really don't need that hood ground, but reception and innerference may arrise. But the original question stated--a whining noise indicating a engine electrical source innerference problem.

I not going to totally rule out the fiberglass hood, but it really doesn't sound like it to me.

Joe

-auto radio repair tech
-creator of Team Chevelle's radio pages

 

[Philip]

Joe, The early plastic Chevy's had a metal shroud over the distributer and plug wires. Was this to shield interference from the radio? And would the use of a glass hood on a Chevelle allow ignition interference? I was considering putting one on my 64. It seems like those vettes also had rear mounted antenna.

------------------
Philip Valentine
Gold Member #42
"Perseverance is not a long race; it is many short races one after another."
[email protected]

 

[Bob B.]

Thanks for all the replies this is my set up:
Jacobs electronics wires ( not solid conductor).GM 12si alternator 2years old,Mallory unlite,stock coil,old regulator removed.My battery ground goes directly to the block and a strap from the block to the firewall then to frame.The radio is a JVC I have the same one in my truck with no problems both are about 1 year old.
The weird thing is that if I am sitting in the car motor off ,door open and radio on I get the same noise. Soon as I shut the door noises stops. I solder most of my connections and if I remove components I try and make sure they have a clean paint free surface to mount on and usually put a dab of grease there to keep out corrosion. Lots of humidity here in S.C. and dang cold these days

 

[Coppertop]

Hmmmm, Bob, try this stuff...

When you have your engine off, and radio playing, is the key in the ACC position???

Try connecting the power lead directly to a constant +12v source right to the battery.

See if you have any difference. The purpose of this is to rule-out any other power consuming accessories that could be receive current while the ACC positon is on.

Then disconnect the antenna plug from the radio itself, tune a VERY STRONG local station if you can and turn up the volume? Does the sound still seem to be in the background? Try both AM and FM bands. Then bend a piece of wire or coat hanger and stick it in the antenna jack (turn down the volume first!) see what kind of results then.

Also is this also a tape or cd player? Any noise while using the tape/cd portion of the deck?

You just have to try different things to track down the source(s) of problems.


-64elcamino,

anytime you see shielding on iginition component is usually to suppress radio noise.
Corvettes? Don't get me started. Those are quite a piece of work. Usually a Corvette has over 200 ground straps for the electrical system because of the lack of a metallic body. The antenna systems were a challenge for designers from the start. The radios and antennas but had to have special considerations to work. Early Corvettes used "screen grid" antennas and special ground plane shielding equipment. Not sure of all the means hows and whys...

 

[mrthomas]

Bob, my 70 elke has a "key in the ignition" buzzer that buzzes when the door is opened with the key on, yours may have the same, but so quiet that you can't hear it. It looks like a turn signal flasher can. Does youir dome lite work? you might have a bad dorr switch that is gounding all the time. Just a thought
Jim