My sons 81 corvette has the factory digital am/fm 8 track in it. It only picks up 2 am stations, no fm stations and most all of the leds are burnt out.

I am going to buy him a new radio for Christmas. I am just worried about the reception.

I am wondering if the old antenna is not picking up and that is why he is not getting any stations or if the old radio is just seen its better days.

Is there a way I can test the antenna? It is not a power antenna, it is just a standard antenna. I was wondering how one could tell if it was picking up signals and sending them through the coaxial cable to the radio. I have an ohm meter, some extra wire and alligator clips if all I have to do is check resistance but I am not sure if and how that will tell me if the antenna is picking up a signal and transferring it to the radio.

Any suggestions would be greatly appreciated. I will be installing the new radio for him over the holidays so I have some time to check things. Hopefully I won't have to disassemble the whole car to check this out.

 

I know there is a way...but I am having 'brain fart' on what scale you need to use because it is a specific spot on my tester that can check antennas...like I do when I am checking the antennas in the doors of a PASS-KEY equipped C4 Corvettes.

I know that the antenna needs to be grounded back where it is mounted...and I have not seen a 1980 that was not equipped without a power antenna. Seems like someone has changed it out.

If in doubt....like I do....when I am installing an aftermarket stereo....before I put it in I do a quick mock up and get it working. Then I install if if all goes well.

DUB

 

yup have brain farts all the time but it is an OHMs test when testing the cable to see if it is still working there may be a little bit of resistance if the cable is old and corroded on the ends but very little if not Zero Ohms. If there is a break in the cable the OHMs test is supposed to find it. Zero Ohms says the antenna is working properly. If you have more then Zero then you need to check Continuity of the cable and test the Antenna.

Touch one lead of the multimeter to the metal part of the antenna and touch the other lead to the metal core of the cable. The ohms reading should be zero. If the resistance is greater than that, the antenna or cable is damaged, which is preventing a signal from reaching the reception device.


Touch one lead of the multimeter to the metal jacket around the antenna cable connector. Touch the other end to a grounded object. If you are testing a car, for example, touch a metal part of the car's frame. The reading should, again be zero; otherwise, the antenna is not grounded.

Hitting a ground under the dash is hard on a Corvette so look for metal that looks like a ground like the radio because it should be grounded.





The other test is do a Continuity test to see if the cable is not broken somewhere along the way. For Continuity test you need to test both leads to see if there is actual connection between both lead ends. Getting to them is best done by removing the passenger seat and the panel on that side. You may or may not need to remove the drivers side tire to get the antenna lead. Ramps will help if you have them.

http://www.ehow.com/how_12130900_mea...ultimeter.html

Aftermarket and original antennas also go bad. On my 1992 Miata I performed both these tests and all I needed to do is replace the antenna and not the wire running between the radio and antenna.

 

thanks for the info. I was not sure what the outer part of the cable went to. Hopefully I can check it tomorrow and see if I need to get an antenna and/or a wire before Christmas.

Dub, I will take your advice also when I put the radio in and make sure it works before I bolt everything back up

 

Mokey do you own a multi meter? Set it to OHMs and put in on both leads on the wire and check it. If it reads zero the Antenna and Lead is good then just the old radio that sucks. If you get anything other than that than the antenna or wire leading to the antenna are bad. PM and I can walk you through and I will give you my cell phone number. The test is easy with the right tool

 

Thanks Mako Joe. I am hoping to have time to check it out tomorrow afternoon. If I can't figure it out, I will take you up on your offer

 

People still listen to "radio" ?!?!?!?!
score him a new stereo with a usb port for mp3 and chances are if he ever does try to listen to the radio it wasn't the antenna but the old 8-track player...just grab that Foghat tape before you toss it.....

 

LOL I installed a 400 Watt amp and home built Speaker Box with 2 6 x 9 200 watt speakers and a 8 inch Sub into my Corvette last summer than used a Retro Sound head unit freaking thing rocks.

Yup Foghat Slow Ride

 

Using an ohm meter to check out the antenna is pretty gross. I once hasseled with a problem with a citizens band radio in my Corvette. I could receive pretty good, but I could not transmit for any distance. I took the car to a shop that specialized in mobile communications. They immediately diagnosed that I had a VSWR problem..Voltage Standing Wave Ratio problem. They inserted something in the co:axial cable to antenna (impedance matching circuit)...and voila..my citizens band radio was just booming out in power.

 

Bad news on the antenna. There must be a break in the coax somewhere. No signal from one end of the coax to the other.

So now I am thinking about going to a hidden antenna instead of dropping the gas tank, pulling up the carpet, etc to run a new antenna.

Any advice on the hidden antennas?

 

You do not have to drop the gas tank to change an antenna.

I would put a power antenna in it. But that is just me.

DUB

 

He thinks the problem is with the cable, not the mast.

 

Yes, the problem it the cable is broken somewhere between the mast and the radio. When I ohmed it out, I got an open loop meaning there was no connection between the two ends.

 

Not entirely sure about the antenna situation... haven't gotten that far with my project yet. BUT, I can recommend a good radio, and that's the RetroSound Model Two. Kind of pricey but they have other models as well. Installation is pretty easy and all you would have to do is remove the central cluster and install this new one. Wiring is an easy task too with these ones. Good luck!

Joshua

 

Depending on the antenna design....and if you want it stationary or power...I would get what is needed and replace it.

It is not that hard.

 

The antenna wire is fairly easy to trace front to rear of the car. It runs through the shift tunnel and than along the frame to the drivers side rear. You can reach the antenna just behind the tire and along the frame. It will take 2 people to change it out since you can only reach one hand up into the area where it is mounted and might need to remove the muffler. It is tight up there.

Did you perform both an OHMs test and a Continuity test?

here is what I would do in your situation......if you have not done this already to double check the cable.

I would reach up and disconnect the cable from the antenna and put an alligator clip lead on both contacts on the antenna cable than recheck the OHMs for 0 resistance and continuity. If this checks out or fails then I would consider replacing the cable. If this checks out then it is just a bad antenna. They do fail and I have just had to replace antennas in the past.

If you only tested the cable while attached to the antenna then you need to perform this other test I am suggesting. The open loop can be a bad antenna.

Explain to me the steps you took.

thanks

Joe

 

I have a Retro Sound in my 1977 Corvette as the head unit attached to a 400 Watt amp and a home built speaker box covered in material that matches my Torch Red interior than installed two 200 Watt 6 X 9 Pioneer 3 way speakers and a 8 inch Sub in the middle. I mostly use an 8 Gigabyte USB Drive to play music and have two of these filled in my car so I can switch back and forth. I am all for the Retro Sound but I had to install 2 filters on mine. One at the head unit and one at the amp to filter out the alternator noise.

 

if you want to get rid of the original 81 8 track let me know, I would love to get it, broken or not, like was previously mentioned you don't need to drop the tank to replace it, I would certainly go back to the power one, took awhile to get mine back into running order, but I am glad I did. just a heads up though no matter what you do the radio will never get reception like a modern head unit IMHO, even with everything working right and a new retro sound head unit and a signal booster that surprisingly are getting harder to find now a days, my reception sucks, about half the signal strength of a modern car

 

so the plan is to replace the cable and mast. Do I need to order one from a Corvette vendor or can I get one at either the auto parts store or somewhere like Best Buy? Looks like the cable length will be the issue unless there are other issues I need to be aware of. I plan to place the order this weekend if I have to go that route or if I can pick one up somewhere local, please let me know

 

I originally had and still have in a box the original AM/FM Stereo radio from my 1977 and I could never get it to stay in tune with a radio station and would have to play around with it all the time as i drove around. For like 2 months before installing the Retro Sound head unit. Speakers and Amp came a year later. Needed Tunes first even if it was only out of the 2 front dash speakers LOL.

These older radios are not in tune with today's tight band and even HD Radio Stations being broadcast the stations are so much closer together you get bleed over on older radios. The signal strength is stronger these days and the bands are closer together. Tech has passed these old radios by.