IMHO....
The SPT-500 should be adjusted to an OAL of 267" as a starting point for 11 meters and then fine tuned from there by adjusting length and beta match and/or grounding wire.
For the strongest vertical, if you overlap the joints by 4", the top radiator will have a 4 1\2" overlap and your OAL will be 267". Exposed lengths would be:
M1 = 71"
M2 = 48"
M3 = 51"
M4 = 49.5"
Top = 47.5"
Adjust the beta match and/or ground wire to tune R & X and the OAL for SWR.
The SPT-500 should be adjusted to an OAL of 267" as a starting point for 11 meters and then fine tuned from there by adjusting length and beta match and/or grounding wire.
For the strongest vertical, if you overlap the joints by 4", the top radiator will have a 4 1\2" overlap and your OAL will be 267". Exposed lengths would be:
M1 = 71"
M2 = 48"
M3 = 51"
M4 = 49.5"
Top = 47.5"
Adjust the beta match and/or ground wire to tune R & X and the OAL for SWR.