Power Antenna - Rehab

Justwondering

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This new project was caused by 1) ugly, hot weather and 2) Darth Car's lack of tunes...

I should be working on replacing hoses on my 87 Fifth Avenue but each time I get out enough household chores done so I can get outside the heat index is over 100. So I need an inside project.

The garage has no windows yet and is completely boarded up to try and keep the heat from telegraphing upstairs to the rest of the house since I don't have the downstairs walls finished. But there is just enough work area that is reasonably cool.

Last month Darth Car sent me his broken power antenna and his universal antenna.
IMG_4879.jpg

To use the new antenna would require several mods:
1. take the old antenna to radio line out and run a new one
2. change the mounting location on the inside fender well
3. cut and crimp several leads to get the power to feed to the new unit

Not terribly complicated but exceptionally tedious and time consuming.

The old radio line:
The old radio line runs through the dash and above/behind the glove compartment. Pulling the dash to run a new line is ugly. Course, you could leave the old line and just run a new line. Only run the new line down low under the glove box and across then up to the back of the radio. Leave the old line in there and confuse the hell out of the next repair person.

Get/make an adaptor cable
The old radio line uses a banana plug at the back of the radio but a reverse polarity, not quite standard size uhf-like plug at the antenna. The new antenna uses a current standard radio plug (sma /smb type). Darth Car checked in his world (motorola chippies) and I checked in my world (electrical geek chippies, kick-ass current auto stereo chippies, on-line chippies, mcmaster-carr, grainger, etc.) No one has the old, non-standard connector. Can't make an adapter cable.

Put a new mast in the old antenna
The new, universal antenna mast is larger diameter than the old antenna mast. This means you can't thread the new mast up through the center of the old antenna 'inner' tube. The new mast is the same size as the tube.

Well fudge bucket.
 

Justwondering

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Never one to give up when I have yet to take anything apart ... ;)

Call Brian and ask one more time if its okay to kill the old antenna and his new universal antenna..
Why yes, he's game!

So lets take a look:
IMG_4880.jpg

The old plug. The line from the back of the radio comes to this connector on the antenna. Its not a standard size and most places don't have 30 year old parts.

IMG_4881.jpg

This is the new antenna and a bad shot of the current radio antenna connector. Much smaller center pin in the barrel.

Here are the two antennas showing the mast ends:
IMG_4882.jpg
 

Justwondering

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IMG_4883.jpg

The body of the old antenna housing is held together with rusted c-clips. Look at the top center (12 oclock ) and the 2 oclock positions.

IMG_4884.jpg

Realize that low bid wins and no wonder everything is wonky -- assembled in Mexico using parts sourced from who knows where.

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Take all top bezel and fiddly bits off the antenna tube.
IMG_4887.jpg

And a somewhat worn locking ring
IMG_4890.jpg
 

Justwondering

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There is an obvious seam, so I'm thinking there must be a way to separate the two sides of the body housing the motor.
IMG_4891.jpg

Nothing much happening here
IMG_4892.jpg

Tried a putty knife and that worked better.
IMG_4893.jpg

About this time I realize there are rivets holding things together. I had to use the wire cutters to nip the edges so I could push it through.
IMG_4896.jpg

Do that to the one in the center as well
IMG_4902.jpg

Til you get all the rivets out.
IMG_4903.jpg
 

Justwondering

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Take a peak inside:
IMG_4904.jpg

Nasty - dirty
IMG_4905.jpg

Use isopropyl alcohol, q-tips and toothpicks to clean gunk
IMG_4907.jpg

IMG_4908.jpg

I did remove all the gunk, cleaned the contacts, and removed all the grease.
At this point, I put the body sides back together and checked to see if the motor worked.
It did.
Course, there was a 10 hour delay because I was using the battery by the door.
The 12 year old - we need to turn this in - i need to replace this - battery.
I put it on the charger - zippo results.
This morning I find out there was a 2nd battery that I should have been using. Ahhhh.
Using the new battery, the antenna motor works.
 

Justwondering

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IMG_4909.jpg

Don't use this old battery. lol

At this point I take lots of measurements and realize the new mast will not fit in the old antenna body.

I can't use the old antenna mast because it has been cut off so the entire length of the mast is 4 inches.

I want to have the old antenna connector so I don't have to run a new line to the radio.

I can easily take the new antenna apart.
Aluminum housing, plastic insert, its easy.

So at this point, I'm thinking the old antenna outer tube is nearly double the diameter of the new antenna tube. How about, I remove the antenna mast from the old unit and see if there is a way to remove the guts to the old antenna tube without killing the connector to the outer tube.

I mean, Brian already said I could kill the antenna.. ...

I first tried a dremel ... What a laugh. That old antenna tube is made out of tank steel.

IMG_4910.jpg

IMG_4911.jpg

See that bump on the top? Thats a tack weld. There are 4 of them down the length of the tube. The dremel can't even touch it.

Now where is the grinder?
 

Justwondering

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I need to figure out how this old antenna is constructed.
Get the grinder!
IMG_4913.jpg

Old antenna seems heavy so it may take a bit to grind .
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Lots of effort to get the welds ground down. Beginning to rethink this approach.
IMG_4915.jpg

Major, major time and effort just to get through the metal of the collar at the top.
This is definitely not going to work.
The metal is much too thick and strong. I won't be able to pull it off the tube.

I have to shorten the original tube. It is much longer than the new antenna tube. My thought here is to shorten the original tube just enough so that when I put the new tube inside it the total length will be the same.

The length being the same means the mounting bracket will not have to be modified.

So its time for another tool.
IMG_4923.jpg

Hacksaw!
 

Justwondering

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I'm going to cut off the top collar.
IMG_4924.jpg

Brian - enjoying the destruction of your antenna?
IMG_4925.jpg

Was a little off but I managed to mangle it enough to get the top collar off.
IMG_4926.jpg

Top collar is off.
The outer tube is empty below the collar.
I'm going to cut another 3 inches off the tube til I get down to the plastic insert.
IMG_4929.jpg

Okay, here we go with the plastic insert at the top.
Apparently its only purpose is to hold the inner tube in position so it doesn't wobble inside the outer tube.

Next, remove the inner tube.

IMG_4941.jpg

Using a hammer, I could encourage the inner metal tube to exit the bottom of the outer tube BUT I can't get the it past the plastic insert.

Need to think about this and get a new plan.
 

Justwondering

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Maybe I should try to remove the plastic insert at the bottom and push everything out.
IMG_4933.jpg

But there are 4 dimples at the bottom that are pressed inward to discourage the plastic insert from backing out.

Lets drill them out.
IMG_4934.jpg


Try twisting out the insert.
IMG_4938.jpg

Not gonna happen.

Well then, while I think up a new plan, lets see how hard it is to get the two-prong collar off the tube. I believe it is used as a stabilizer and to ensure the orientation of the antenna tube remains steady.

IMG_4930.jpg

The first easy thing I have done on this project.
Just slipped a small, flat bladed screwdriver under the edge. There are two holes in the outer tube and the black collar has two protrusions that sit in the holes.
Just popped it off.

IMG_4938.jpg
 

Justwondering

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I still need to get the stub out for the connector off the inner tube.
Lets assume it is screwed into the inner tube and try twisting it.

IMG_4940.jpg

Nope - not screwed on. It was soldered it looks like. Either way, its off now.

IMG_4942.jpg

So now I'm back to how to get this inner tube out.
I'm thinking it will twist out.

IMG_4943.jpg


IMG_4945.jpg

In fact it will twist out now.

So I have the inner tube out.

Check to see if the new antenna will thread through the holes in the plastic inserts.

IMG_4946.jpg

Yep.
It will thread through.

Can it extend?
IMG_4947.jpg


Yep, it will extend.

Now I remember that there needs to be an inner tube that the old connector post can be soldered to.

And of course, the new tube is too large to get through the plastic inserts. So I wind up yanking out the top one, crushing it in the process.

This lets me thread the antenna through the bottom, drop the tube through the top, and marry everything up together. I can always add another plastic insert at the top.

Its time to check the beauty rings at the top and make sure all that looks good.

IMG_4948.jpg

Well of course not.
On the left if the old collar. The outer diameter of the bushing is the size of the hole through the quarter panel.
The bright brass on the right is the top of the new antenna. It is too large to fit through the bushing and too small to fit correctly on the frame. It could be made to work, but it wouldn't look stock.

This week, I'll look for a bushing that has the same outer diameter but a larger inner diameter. I want to use the original beauty ring.
 

BudW

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In ‘84, all but M-body passenger cars (not sure about trucks), went to a much smaller antenna base/hole (power or manual antenna).
‘83 and down all had the bigger fender hole (FMJ size).

I suspect the replacement aftermarket power antenna that Darth-Car obtained, might not fit his existing fender hole, without modifications.

BudW
 
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BudW

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I mostly removed the power antenna from an ’88 5th Ave this morning at a pull-a-part and got hung up on the antenna cable itself. This one does not have the screw onto side of motor cable like I’m used to seeing.

I should have taken a picture this morning, but forgot.
I thought the antenna cable just pushes in (like how the antenna plugs into the radio) but it wasn’t budging (this connector was about 6" from motor).
Breaking it wasn't an option, so will go back in morning for round two. The plan is to get the entire antenna cable, so leaving the connector by motor alone and dissembling dash next (which I need to do, anyway).

88 Power Antenna.JPG

The power wires to antenna do match.
 

Darth-Car

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Yes those later antennas are different in how their antenna cable connects to the antenna mast.
 

lowbudget

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I think I have my old one from my 87, it just wouldn't go up and down so the mast is still good.. I grabbed a NOS from Marty. My 84 has the old solid F body type. If you need it let me know as I head back to the desert Sunday.
The newer ones have an extension cord on them to make it easier to change out as I have 2 NOS aftermarkets but didn't want to deal with the threading of all off the cables through the dash.
 

Justwondering

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Send me any antennas you don't want. I've practiced with darths to figure out the internals and how to retrofit a new mast in them.

New masts are too big in circumference so there be magic involved to get it to work
 
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BudW

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Another pic.
20160805_092403.jpg

Will do what Justwondering mentioned to it, soon.
 

Justwondering

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I'm guessing the one I have from Darth is the older Fbody style.
The one in your pictures is smaller diameter tube and the connector for the radio is a very different mount.

Let the games begin.
 
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