I'll start from the big end and work my way "forward" through the RCA ANT751.
There aren't any Hi-VHF Reflector elements, although whatever it is mounted to
might act as a reflector (although perhaps not at the "optimum" distance).
Obviously the Hi-VHF Elements serve as Reflectors for the UHF section....
and the UHF Elements serve as additional Directors for the Hi-VHF section.
1. Active Hi-VHF Element, fed from Element#2 by Crossover Feedline.
These two elements form a basic Hi-VHF Log-Yagi "Cell".
2. Active Hi-VHF Element, fed from Element#4 via Non-Crossing Feedline.
3. Passive Hi-VHF Director, bonded to metal boom.
4. Passive Hi-VHF Director, bonded to metal boom.
[Let's hope there is no connection via the short stub from Element #5.]
5. Active UHF Folded Dipole Driven Element, 300-to-75-ohm Balun connects via thumbnuts.
6. If it is connected via stubs to Element #5, then it's an Active Element forming a Log-Yagi Cell
for UHF....but separation seems too close....
If not, maybe it's a UHF Passive Director that also helps to control SWR (so why bother to insulate it.....)
7. UHF Passive Director, bonded to metal boom.
8. UHF Passive Director, bonded to metal boom.When someone gets one, let us know what the exact dimensions are so we can model it.
A Log-Yagi Antenna is a hybrid, taking a 2 (or 3) Element LPDA (Log Periodic Dipole Array)
and adding Yagi type Reflectors and Directors. More re LPDA:http://glendash.com/Dash_of_EMC/Log_...g_Periodic.htm
Advantage of a LPDA design is ability to cover extremely wide bandwidths, although at
the expense of max gain....and a large number of elements.
Advantage of Yagi is good max gain, but limited bandwidth.
Hence Log-Yagi Hybrid attempts to meet somewhere in the middle....with cost minimized...
Further info is available (requires FREE registration): www.cebik.com
If you're interested, a LOGYAG calculator can be downloaded:http://www.qrz.com/download/antennas/index.html
FYI: W-G YA-1713 LogYagi NEC Sim analysis:http://imageevent.com/holl_ands/wgya1713