A lot of assumptions are made in this post for the sake of simplicity of Schematics to working value and ranges to work with - so no flames needed - just trying to open up a discussion with a ball that has been hit so hard it's missing half it's cover - don't ask about what is still left for the rest of the playfield to work with...just open dialogue helps.

Well, need a better photo - but from what I see you've got, is the Loading for a 1/4 wave ACROSS the 1/2 wave - with it's own loading coil. So between the winds, which needs a better photo to count those winds - the ƛ -1/4 wave provides a working impedance for the ƛ- 1/2 Wave to Parallel against - like two coils with one tuned with a capacitor and an air gap to change the "reluctance" coupling the 1/4 wave loading and the 1/2 wave loading - together into one package.

I can see the Red coil winds are possibly that 1/4 wave - but the "capacitor" to load the 1/2 wave element must be located around those tuning rings, this cap / sleeve combo provides an Air Gap for the coil load (your 1/2 wave) and Capacitor so the tuning rings work as the "slug" for the tuning - the 1/4 wave just "loads" the matching network to offset the impedance mis-match of the 1/2 wave being much higher than 50 ohms - so more than likely it's a 1/4 wave or 72 ohm inductive impedance load - parallel with a ~1kOhm 1/2 wave whip tuned to offset the impedance so the 72 ohm and the ~1kOhm 1/2 wave - matches close to 50 ohms...per your schematic...

Xr = 1/(1/R1 + 1/R2)

So 72 ohm (expected from 1/4 W/L Dipole Impedance = 72 ohms and the tuning range of the 1/2 W/L with tuned impedance ~1kOhm....

Solving for 1/4 W/L = 72 or 1/72 = 0.01389

Solving for 1/2 W/L = 1,000 = 1/1000 = 0.001

So = 0.01389 + 0.001 = 0.01489 or 1/0.01489 = 67.2 ohms ...

So the 1/2 W/L (ƛ) expected of 1K ohm and 72 ohm of a dipole 1/4 w/l (ƛ) gives 67.2 ohms expected. or about 1.3 SWR based upon 50 ohm unbalanced impedance to 67 ohm loading impedance.

So amongst the ruins of this post, the 1/2 W/L (ƛ) radiator element and its' airgap tuning rings then provide a much LOWER impedance adjustment than the 1/2 W (ƛ) "high impedance in the Kilo-ohmic range" to lower the SWR - against what looks to be a steady 1/4 wave "shorting coil" load that should give the tuned expected of 72 ohms (or less)

The 72 ohms is what a typical 1/4 wave dipole -center fed - exhibits - and that's being forgiving.

So since the LENGTH of 27MHz (at 1/2 ƛ) wavelength is TAD longer than 18 feet - Velocity versus Free air - still can't truly compensate for the shortened length - so it's apparent the capacitor and air gap - offset a length of radiator just under 1/2 wavelength in this package - so the impedance workout is about 900 ohms or just under 1kohm which would fool most meters into thinking you're at a close to 1:1 SWR - but the RESONATE length

ht seems to be a little too short. So, to compensate that - they use a "capacitor" for coupling to the 1/2 Wave - the Inductive Coil added offsets this shortened length. Refer to photo - there's room in length to compress it in there...

There I said it...

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I'd like to think all I need to do is update my notes...

"Don't beat me up too Much Scotty...

Uh, Scotty, I said Beat - not Beam...

Oh heck, pass the "Jim Beam" - we all need a shot.."