Offset Antenna Install Instructions + Parts List

[Wire Fox]

All, this was a question I had asked a while back and a member was kind enough to provide me his instructions he had floating around, but they were limited and suffered from the reprint-of-a-reprint syndrome. While browing some TMs for equipment I probably will never own (GRC-240), I just happened to notice that an offset antenna mount was standard equipment with this kit, plus it had an excellent write-up on how to install this antenna assembly and a list of all parts used. The best part was that it is all in excellent, vector quality from a non-scan PDF. I've gone ahead and extracted all of the pages relating to the offset antenna installation and put them in one PDF for you guys to reference. It starts out with installation instructions and several drawings to show the assembly. It's followed up by the same drawings again (the number labels were slightly different in the two sets of drawings) and closes with a list of parts used in assembly.

Installation notes: If you have a cargo cover installed, you're going to have to remove the rear-corner tie-down loop, since it will get in the way of the offset antenna (it mounts high). I also don't think we'll ever see the proper spacers and reinforcement plates again, so I'll try and measure out what thickness of spacer will be needed to clear the "top cap" of the rear fender and its rivets. The reinforcement plates aren't quite as critical, as that should just be a slightly oversized, thicker piece of metal that has the same hole pattern drilled through it. This exists purely so that the antenna mount won't tear through the thin aluminum during high wind or a strike against a tree or other object. I personally plan to buy the same thickness and material that's used for the troop seat supports, as that should be more than sufficient to support an antenna.
View attachment Offset Antenna Extract Diagram.pdf

 

[General Hood]

All, this was a question I had asked a while back and a member was kind enough to provide me his instructions he had floating around, but they were limited and suffered from the reprint-of-a-reprint syndrome. While browing some TMs for equipment I probably will never own (GRC-240), I just happened to notice that an offset antenna mount was standard equipment with this kit, plus it had an excellent write-up on how to install this antenna assembly and a list of all parts used. The best part was that it is all in excellent, vector quality from a non-scan PDF. I've gone ahead and extracted all of the pages relating to the offset antenna installation and put them in one PDF for you guys to reference. It starts out with installation instructions and several drawings to show the assembly. It's followed up by the same drawings again (the number labels were slightly different in the two sets of drawings) and closes with a list of parts used in assembly.

Installation notes: If you have a cargo cover installed, you're going to have to remove the rear-corner tie-down loop, since it will get in the way of the offset antenna (it mounts high). I also don't think we'll ever see the proper spacers and reinforcement plates again, so I'll try and measure out what thickness of spacer will be needed to clear the "top cap" of the rear fender and its rivets. The reinforcement plates aren't quite as critical, as that should just be a slightly oversized, thicker piece of metal that has the same hole pattern drilled through it. This exists purely so that the antenna mount won't tear through the thin aluminum during high wind or a strike against a tree or other object. I personally plan to buy the same thickness and material that's used for the troop seat supports, as that should be more than sufficient to support an antenna.
View attachment 683948

Good stuff Wirefox

 

[desmodromic]

Thanks, Wirefox. I have a pair of offset mounts I need to, well, mount. This will certainly help.

 

[juanprado]

The directions and parts break outs are also in different flavors of sincgars radio tm's.

The rear facing reinforcement, I could not find anywhere. I used large fender washers. The side fender reinforcements are "right" and "left". They have a slight triangle shape is the best way to describe them with 3 bolt holes. Flight Source in Pa had them. They are the parent company of Equipment sales. They do have a min order but they are my to go to source on not common stuff. You need to provide nsn's .

I do have an extra cover access plate if anyone is in need, pm.

 

[Wire Fox]

The directions and parts break outs are also in different flavors of sincgars radio tm's.

The rear facing reinforcement, I could not find anywhere. I used large fender washers. The side fender reinforcements are "right" and "left". They have a slight triangle shape is the best way to describe them with 3 bolt holes. Flight Source in Pa had them. They are the parent company of Equipment sales. They do have a min order but they are my to go to source on not common stuff. You need to provide nsn's .

I do have an extra cover access plate if anyone is in need, pm.

Are they really directional? I know you can orient that large external plate to face either side, so the offset mount can be driver side or curbside, but I didn't think that inner supporting plate was going to be unique to be LH/RH. Do you have any pictures of them to showcase how they're actually different?

 

[juanprado]

It has been a monsoon here lately. I finally went and found the one I had not installed yet as I only have the left one mounted now and the standard mount on right. It must work for both sides. I was confused (easy to do) as I had ordered a bunch of parts a while ago before actually getting to it. I must have confused it with other stuff. Too many irons in the fire...

Here are the pics with nsn and part number in case anyone needs to order.

 

[Wire Fox]

I've shot over an inquiry to PartTarget to see if they could source the whole set of reinforcement plates for me. I know I've used as enough of a reference point for long enough...it's about time I actually give them some business in return.