Hi JPZ and all,
First of all there's no such thing as a "loop dipole", it's one or the other. What you have is a T matched halo plain and simple. I'll fill in the blank for the benefit of the readers, it's a dipole bent into a circle. It has roughly 0.8 unity gain, that is somewhat less than a straight dipole. That's because the figure 8 polar pattern of a dipole is bent into a circle which contracts it a bit. That design is a favorite of contest rovers, it can be deployed quickly but I wouldn't recommend driving around with it for pretty obvious reasons.
Kokomo, that's where your dad's Cushcraft Saturn Six came in being considerably smaller due to it's capacitively end loaded design. That's what those discs were for, they form a variable capacitor. The rings were connected in parallel effectively increasing the radiator's diameter and subsequently the SWR bandwidth. Those were the days before FM when AM was king, about the time that Hallicrafters produced a neat (not so) little 15W crystal controlled transceiver also marketed under the Lafayette name. They also produced identical looking 2M and CB rigs, that one was the CD-5A.
Most of those commercially made halos have disappeared, I used to have a single ring. FM using vertical polarization is the most popular mobile mode now but there are still some horizontals made for SSB such as the Squalo, a square halo made by M2 if I'm not mistaken. They're often stacked for 6M, 2M and 70cM.
With any luck I'll have my gamma fed rigid dipole fixed and the stacked 2M halos up in time for the 'test, if the band happens to open we'll have a blast!
