On Monday, December 30, 2019 at 2:52:49 PM UTC-8, wrote:
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And since you asked about different style 1/4 wave dipoles. The rods, blades etc. should all behave the same from a RF viewpoint. They are effectively the same internally. Rods/single attach point style antennas may be easier to attach/mount on curved surfaces, but have higher drag than a blade if that small drag worries you. I've also seen A&Ps recommend the rod style so that if you do manage to crunch it will bend and hopefully do less damage to the fuselage/finish.

Transponder rod antennas spec drag at .41 lbs at 250 MPH and blade antennas at .09 lbs at 250 MPH. That seems to be a big difference but anyone have a comment to what this measures in the gliding world?

The simplest answer: parasitic drag ~ V^2. So at (100mph/250mph)^2 * 0.4 = ~0.07 lb. = ~1 oz.

I suspect this has been flogged to death on r.a.s. before.

"Honey I need a new glider with a tail mounted transponder antenna because it's lower drag. And I'll win more contests. Honey?" :-)