Ok, I'm stumped.. WTH is this thing?

[GlocknSpiel]

This was mounted on the RV I just bought. Of course, I removed it for a PROPER antenna. But i've never seen one of these things before and curiosity is killing me. It appears to be some sort of induction coil that the coax from the radio is connected to --- INSTEAD of the 4FT Firestick itself!
WHY? What's wrong with just hooking-up the Firestick?


Yeah, that ancient truck stop coax is outta here too.

 

[BC Coyote]

Woah. Never seen anything like that before!
I wonder if it was someone's idea of a way to expand the notoriously narrow bandwidth of the firestik? Presumably by sliding the coil up and down you could adjust the resonant frequency of the antenna...... perhaps the RV's previous owner was a ham or freeebander and this was a quick and easy way to get higher frequencies or get on 10 meters without a tuner or separate antenna

 

[SuperLid]

This was mounted on the RV I just bought. Of course, I removed it for a PROPER antenna. But i've never seen one of these things before and curiosity is killing me. It appears to be some sort of induction coil that the coax from the radio is connected to --- INSTEAD of the 4FT Firestick itself!
WHY? What's wrong with just hooking-up the Firestick?
View attachment 72462

Yeah, that ancient truck stop coax is outta here too.

It's a GPS antenna on a mirror mount. Someone stuck it on the whip cuz they could

 

[BC Coyote]

It's a GPS antenna on a mirror mount. Someone stuck it on the whip cuz they could

LOL! Of course it had to be some dumb thing like that! My science-brain going all out when it's really some super simple explanation........

 

[GlocknSpiel]

LOL! Of course it had to be some dumb thing like that! My science-brain going all out when it's really some super simple explanation........

It makes sense, but here's a monkey wrench;
The old Radioshack mini CB it was hooked up to actually worked! I can't say, it worked WELL, but I did have ears and good SWR across the 40 (under 1.5).
Naturally, the toy CB was removed along with the rest, to make way for a REAL radio. Either the QT60 Pro, or an Icom IC-7000 (if I can find one for the right price).
I'm going to put a VHF/UHF/GMRS stick on the old mount, and an HF multiband along the rear fiberglass wall somewhere (to keep the tip outta the trees and overpasses). But outside of a quickie/temporary type QT60 install, and after just spending >$2K for new tires, not much more will be happening anytime soon.

 

[BC Coyote]

It makes sense, but here's a monkey wrench;
The old Radioshack mini CB it was hooked up to actually worked! I can't say, it worked WELL, but I did have ears and good SWR across the 40 (under 1.5).

Well then, the plot thickens........

 

[midnight special]

that is a no ground antenna,, used a lot on rv and motorcycles,,, it is mounted with whip to ground and moving the coax connection up or down to adjust swr,,,

 

[sunbulls]

It looks like that GPS antenna was mounted just below the CB antenna’s coil windings. That probably didn't impact the SWR much. Especially if the GPS mount is made of plastic like I think it is.

 

[Michael M]

finshin' pole with a strange reel ???

 

[NZ8N]

Midnight has it right, it is a No Ground Plane Firestick with the coupling coil clamp on the side, for fiberglass trucks or RV's, those were made in the late 90's. I quit CB tech'ing in 2000, so I can't say when they changed to another design. I can't find one on Google Images.

 

[brandon7861]

Smash it open and take a look!

I was thinking inductive coupling too, but that metal clamp has me wondering if there isn't a knife contact that slices into the coating and contacts the linear-loaded element. I was going to guess there might be a cap inside there and it is some kind of gamma match, but the shield return path has me questioning that too. If you have no plans on using it, why not see what its made of?

 

[NZ8N]

Just take the screws off of the clamp, detaching it from the antenna itself.

 

[GlocknSpiel]

It looks like that GPS antenna was mounted just below the CB antenna’s coil windings. That probably didn't impact the SWR much. Especially if the GPS mount is made of plastic like I think it is.

The Cb was actually hooked up to it instead of the antenna, and now that Midnight Special and NZ8N explained what it was, it all makes sense. It sure worked, but I couldn't seem to make any contacts with the toy that was in the RV. It probably would turn into a tiki torch in less than 5 seconds with a 'respectable' amount of RF runnin through it.
But yeah, I could see RV's and bikes using it for caravans and poker runs.