Die-Hard CW Fans may find that the 807-xx resonates too high in the 80m band when using the standard RMU (RMU-S).
The "RMU-CW" is currently not available due to component sourcing problems.
(Yes, it's just a piece of wire.)
Here is what its SWR curve typically looks like:
For Comparison: The 807-HD with Standard RMU (RMU-S):
Comments: If you think the lower SWR will improve your signal in the CW portion of the band, you are kidding yourself. The 'On-The-Air' performance of the antenna is exactly the same, regardless of whether you use the RMU-S or the RMU-0. Just use a good efficient matchbox if needed. However, if you absolutely want lower SWR for the bottom end of the band, use the RMU-0. (DJ0IP)