C2 antenna
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
Posts: 3,980
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From: Groton CT
C2 antenna
What is the proper way to check the antenna. I have a VOM and want to make sure I'm nnot trying to measure across a capacitor or something.
I spent a good deal of time under the car making sure the grounding plate was really grounded to the chassis, but if I check the outer sheild of the radio end of the cable to ground, I get nothing. Nothing from the mast itself to the center conductor of the radio end either.
I spent a good deal of time under the car making sure the grounding plate was really grounded to the chassis, but if I check the outer sheild of the radio end of the cable to ground, I get nothing. Nothing from the mast itself to the center conductor of the radio end either.
Burning Brakes
Joined: Feb 2000
Posts: 852
Likes: 112
From: Torrance California
Antenna lead continuity
You cannot check the antenna center wire with an Ohm meter on a '67'. Its got some kind of internal capacitance to it. You can check the outer sheild to ground though. Make sure the ground plane is grounded properly to the frame and that the radio is grounded properly also. If in doubt of the antenna cable itself, just replace it, about $28.
Desert Nomad
Desert Nomad
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
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From: Groton CT
I think that's the direction I'll be going anyway. Have all new grounding materials at the rear of the car and those grounds check ok to the frame and body, but at the radio end of the cable, there is no ground, so I think there's a break somewhere.
Burning Brakes
Joined: Aug 2000
Posts: 883
Likes: 2
From: Hilton Head SC
Go to Pep Boys and buy a $7 replacement antenna. Plug it in and see if it makes a difference. If you want to be really sophisticated, buy one with enough cable to use your engine as the ground plane. Cheapest "antenna checker" money can buy.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
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From: Going too fast over the hill. Iowa
What are you expecting to be grounded?
Both harness wires provide 12 volts when switched on. The coaxial antenna cable gets it's ground from the radio.
I'm confused. What is the problem??
Both harness wires provide 12 volts when switched on. The coaxial antenna cable gets it's ground from the radio.
I'm confused. What is the problem??
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
Posts: 3,980
Likes: 139
From: Groton CT
Originally Posted by magicv8
What are you expecting to be grounded?
Both harness wires provide 12 volts when switched on. The coaxial antenna cable gets it's ground from the radio.
I'm confused. What is the problem??
Both harness wires provide 12 volts when switched on. The coaxial antenna cable gets it's ground from the radio.
I'm confused. What is the problem??
But now I'm confused. I was under the impression that the antenna cable shield was grounded at both ends. One end at the radio, and the other end at the antenna ground plane that is grounded to the chassis. I am assuming that with an unbroken cable shield, I should be able to see a ground at either end of the antenna cable shield as long as either end is grounded (that make sense?)
My radio is out being rebuilt, so I was checking the antenna cable to make sure it was OK. I was able to verify that the exposed metal part of the antenna cable that is in contact with the antenna ground plane (and subsequent ground strap) was indeed grounded to the chassis. When I checked the radio end, it appeared as an open at the outer conductor.
I also tried to measure the antenna mast to the center conductor of the antenna cable at the radio end and that also indicated an open.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
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From: Going too fast over the hill. Iowa
The antenna ground plane plate is not electrically grounded. It establishes a base plane for the antenna, which (I will guess some Bessel function said it needed) to produce good reception.
As a side note, my asian power antenna works almost as well fully retracted below the plane as it does fully extended.
As a side note, my asian power antenna works almost as well fully retracted below the plane as it does fully extended.
Race Director
Joined: Jul 2002
Posts: 11,593
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From: Clayton NC
Originally Posted by magicv8
The antenna ground plane plate is not electrically grounded. It establishes a base plane for the antenna, which (I will guess some Bessel function said it needed) to produce good reception.
As a side note, my asian power antenna works almost as well fully retracted below the plane as it does fully extended.
As a side note, my asian power antenna works almost as well fully retracted below the plane as it does fully extended.
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Team Owner
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From: Washington Michigan
Originally Posted by magicv8
The antenna ground plane plate is not electrically grounded. It establishes a base plane for the antenna, which (I will guess some Bessel function said it needed) to produce good reception.
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
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From: Groton CT
Brand new ground strap was installed during my body drop. I have good continuity from the frame to the outer metal jacket of the antenna cable at the base of the ground plane. No continuity at the radio end. I'm pretty sure the cable is broken somewhere. I'll pull it out tonight.
Race Director
Joined: Jul 2002
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From: Clayton NC
I doubt it's broken anywhere.... The only way to measure the inner conductor is with as mentioned above a RF generator. If I were you I'd just wait until you get your radio back and plug it in and then continue.... Dave..
Le Mans Master
Joined: Nov 2000
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From: Going too fast over the hill. Iowa
Johnz - My car has the strap, but its connected to the antenna motor case, not the ground plate. I believe the 67s were the only year with the strap connected to the ground plate. Only 67 reinforcements have the tab for the bolt. I also believe the 64 that subfixer has does not have it connected to the gound plate (from the factory) either.
PS If it should have been grounded, it took the factory 4 years to correct the problem.
PS If it should have been grounded, it took the factory 4 years to correct the problem.
Last edited by magicv8; Jul 14, 2005 at 10:13 AM.
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
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From: Groton CT
Magic, my 64 does have the ground strap as well as the grounding plate and antenna re-enforcement plate. Also has a metal junction where everything ties together on the body just behind the #4 body mount.
It's shown in a good blow up view in the LICS catalog 23, section 29, 63-64 picture.
http://www.licorvette.com/catalog23.htm
It's shown in a good blow up view in the LICS catalog 23, section 29, 63-64 picture.
http://www.licorvette.com/catalog23.htm
Team Owner
Joined: Oct 2000
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From: Washington Michigan
Originally Posted by magicv8
Johnz - My car has the strap, but its connected to the antenna motor case, not the ground plate. I believe the 67s were the only year with the strap connected to the ground plate. Only 67 reinforcements have the tab for the bolt.
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
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From: Groton CT
Update... Swapped in a new cable (and all the hardware while I was in there) and it checks out fine now. If I use an ohm meter to check the outer conductor to ground, I now get good continuity.
The old cable and antenna mast were so corroded that there was no center conductor at the joint of the mast and cable.
The old cable and antenna mast were so corroded that there was no center conductor at the joint of the mast and cable.
