Wrong! - But thank you for playing.

I've had both the Avanti Sigma5/8 & the Hy-gain Penetrator 500 on the same mast, radio, coax, etc., and the Sigma only outperformed the Penetrator in terms of receive, and then only by a tiny amount, as in 1/2 needle width, and only until I removed the 10", 45* downward-bent top-hat radials on the Penetrator, leaving the top simply a small point of aluminum, just like that of the Sigma5/8 design, and extended the overall length of the P500 radiator to reclaim the lost 10", at which point it received the same as, or slightly better than, the Sigma5/8.

At all points the Penetrator outperformed the Sigma5/8 on TX, albeit only by a full needle width. This is due to the slightly better efficiency of the Penetrator's Beta match and the fact the radials nullify a small percentage of the out-of-phase bottom 1/8wave of the antenna, which on a 5/8 is reverse current phase from the next 1/8wave up on the antenna, thus providing a slightly lower radiation angle than that of the Sigma5/8.

The high current node on a 5/8 is ~13.5' above the bottom of the radiator, therefore, what happens at the bottom 1' is almost insignificant and not a reason for anything other than superstition in believing this is a negative in the design of the P500.

In addition, the construction of the Sigma5/8 is SH!T in comparison, ie: weak, smaller and much more easily bent tubing material for the radials, wimpy radial ends made from 1/8 solid aluminum rod mounted to smashed & drilled tubing ends which bend easily in wind or under the stress of even a large bird landing / take-off, weak and brittle radial hub which tends to crack under tightening and spins easily, wimpy too-thin wall fiberglass radiator insulator which cracks and snaps off in decent wind, too-heavy non-suaged radiator tubing making the radiator heavy and more whippy in the wind than the P500.

All-n-all, I had purchased both because I decided the best of the best was one of those two awesome looking antennas, tested them, one against the other, and sold the Sigma5/8 but kept the Penetrator 500 - for many obvious reasons.

I got the Sigma5/8 back from the guy I sold it to and have it today... 4sale, that is.

Sigma5/8