New style antenna..

[1967KaiserM715]

Most modern electronics have built in suppresors to handle the noise from the ignition. And someone correct me if I am wrong but the plugs that are originally supposed to be in it are shielded, most of the plugs now are non shielded cause the electronics use suppressors now


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[bd]

...someone correct me if I am wrong but the plugs that are originally supposed to be in it are shielded, most of the plugs now are non shielded cause the electronics use suppressors now

Automotive spark plugs are not shielded.  They possess a resistor core that limits discharge current.  Resistor core spark plugs are still very much in use and cost effective for suppressing RF interference.

In contrast, shielded spark plugs possess a full metallic encasement that encloses the wire and spark plug from the source to destination.

[philo_beddoe]

Ok, so if the salesman in 1977 was showing a truck and you test drove it and wanted to hear the am radio and lived in a rural area, what would you hear, static?  Not a good selling feature? So car radios didnt work in the 60's and 70's?? Why is my wifes 2014 nissan radio sound crystal clear?  Will getting one of those retro looking modern radios solve my problem?

[1967KaiserM715]

...someone correct me if I am wrong but the plugs that are originally supposed to be in it are shielded, most of the plugs now are non shielded cause the electronics use suppressors now

Automotive spark plugs are not shielded.  They possess a resistor core that limits discharge current.  Resistor core spark plugs are still very much in use and cost effective for suppressing RF interference.

In contrast, shielded spark plugs possess a full metallic encasement that encloses the wire and spark plug from the source to destination.

Right, knew I was using the wrong word, and I guess I  am wrong with the use of resister and non resister plugs too. The non resistive plugs must be the ones harder to find now. The shielded were pretty common on military waterproof systems, I should have known that, just got new plugs for my m35

Either way technology has changed so much, that original radio probably sounded pretty good in 1977. But another possibility is some of the internal "parts" may be degraded some from age, that and analog radios are pretty hard to tune, I can remember playing with the tuning knob going to town in my parents vw just so the station would play clear


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[philo_beddoe]

Well that makes a little more sense, i will get a modern retro looking radio and try that.  Modern radio, speaker and antenna.  If that dont work then its a bluetooth speaker and my iphone!  That'll learn it!!

[BBM3]

Automotive spark plugs are not shielded.  They possess a resistor core that limits discharge current.  Resistor core spark plugs are still very much in use and cost effective for suppressing RF interference.

In contrast, shielded spark plugs possess a full metallic encasement that encloses the wire and spark plug from the source to destination.

bd is absolutely correct. Again.

The first thing you want to check is to insure your radio chassis has a solid ground to the body of the truck. The mounting bracket on the back of the radio if present should do assuming there is clean metal to metal contact at the radio and dash.
Don't rely only on the black ground wire of the power harness. If your radio is only grounded using the black wire a ground loop is possible which will lead to the problems you describe.
Second make sure you have resistor spark plugs. Normally there will be a "R" in the part number.

Don't throw the baby (radio) out with the bathwater unless you want to throw it my way. I need a period correct Delco for my truck.

[philo_beddoe]

I have no grounding whatsoever.  Will ground first thing in the morning and post results immediately. Good thing, was about to put a bullet through the center of it.

[BBM3]

Your radio is grounded otherwise it wouldn't work.
What you want to look for first is a metal bracket that is connected to the back or right rear side of the radio and is bolted to the underside of the dash.
 

[philo_beddoe]

I installed, there is no metal bracket.  So how shall i ground.  The metal frame of radio to metal dash?

[BBM3]

You are going to want some sort of support for the radio. Find a OEM bracket at the junk yard or fab one.
Relying only on the shafts is bad. They will fail and they don't offer an ideal ground.

If you want to test the ground loop theory make a solid ground connection with heavy gauge stranded wire or better yet a braided ground strap like the one you should have running from the engine block to the firewall.

http://www.summitracing.com/parts/aaf-all76330?seid=srese1&gclid=CPKLoMHyiMkCFQkyaQodwe0KuQ



I would also plug the windshield antenna back into the radio to eliminate the possibility that your powered antenna is not the cause of the ignition noise.

[philo_beddoe]

I am aware of the support the radio needs so i used a heavy duty spring from the back of the radio to somewhere on the dash, it is holding firm--no play or movement.  I will get going on the ground and try the windshield antenna again.  Standby....

[philo_beddoe]

Well i grounded radio frame, which didnt help with that antenna. So i hooked up the original window antenna and there was a huge difference.  Even with the vehicle running stations were very clear.   However, this piece came off the end of the window antenna, so i carefully inserted the coaxial wire into back of radio and was able to make connection.  How in the world do i replace this.  I am NOT removing my newly installed dash pad!

[BBM3]

http://www.vetco.net/catalog/product_info.php?products_id=8818

[enaberif]

Get a new antenna cable.

It honestly sounds like you are really trying to chase around a bunch of stuff have no idea how electronics work. Anytime you get ANY interference through the radio you have bad grounds somewhere. A good example of this is when you turn your radio on and rev the engine and you can hear a whine through the speakers.

The battery, alternator, engine, cab and radio all need a GOOD solid ground. Radios are also not made the same and will use different materials INSIDE that can really determine the quality of a radios.

If you are not using star washers and bare metal when doing grounds things will never run properly and regarding the end you found just run a new coax cable for the antenna.

[philo_beddoe]

Well, i dont hear any whining nor do i hear the wipers through the radio either.  I remember some cars you could hear the wipers going back and fourth.  I will get a new cable, just not sure how it attaches at the base of the windshield.