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Hi Gain SPT500 Super Penetrator


Well-Known Member
Jan 29, 2006

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.


Extraterrestrial Admin
Staff member
Apr 6, 2005
Sierras Near Yosemite National Park
If they are not angled down, they will be soon.
It's just not the quality that was seen in the past.
Not that anyone would see an actual signal difference but when you live in adverse weather areas, strength matters.


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