Basically an 807-HD, without potting the Balun Enclosure with Epoxy:
I have selected the RMU-R1 for my antenna, which places the frequency of minimum SWR near the middle of the 80m band here in IARU Region One. (i.e., about 3.670 MHz)
Note: The details (above) show the basic antenna before installing the RMU.
The RMU used here (RMU-R2). raises the frequency of minimum SWR on 80m from 3.480 to 3.670 MHz, and j0 from 3.450 to 3.650 MHz.
'j0' = the fundamental frequency at which the antenna is resonant.