Questions about antennas (1 Viewer)

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e9999

Gotta get outta here...
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I started to dig a bit -not much yet- into antennas and it is quite complicated I have to say. Looks like a lot of what I landlubber amateur electrician take for granted does not necessarily apply to RF. So much confusion ensues...
For now, I am trying to make sense of simple HT and mobile antennas and am already in trouble.
I have a vague idea of what monopole and dipole antennas are.
I looked at what I have. My little HTs have I am pretty sure helix monopoles under that chunky plastic coating. I verified continuity with the one I can remove and sure enough, no continuity between the 2 sides of the connector. Makes sense. Fine.
I checked my 1/2 - 2 x 5/8 dual band 2m and 70cm. This one appears to be a single solid wire. It is not plastic coated. It is about 1m long, so 1/2 the 2m, no surprise there, although it has a coil in the middle and I don't know what that is for (mechanical spring? center loading? both?). I have no idea what the 2 x 5/8 means since it does not appear that there is a connection in the middle of the whip. So maybe simply that it is twice the 5/8 wavelength for 70cm, but why say it that way then? Or does the coil electrically separates the whip in 2 separate 5/8 sections in phase? Any idea?
No connection between the 2 sides of the base connector, that makes sense. I'm thinking monopole on that one too.
One surprise was that the body of the NMO connector was in electrical contact with my ground plane sheet through the magnetic base, despite it being (lightly) covered in rubber /paint it seems. I can sort of see that there might some coupling at RF level, but at my meter's 9V DC? Odd if it's electrically insulated. Any idea?

But then the biggest surprise was that I also have a small flexible rubber-coated 1/4 - 1/2 NMO base whip (Comet SBB-1) also for the mag base. And that one shows continuity between the 2 sides of the base connector. What's with that? What kind of antenna is it?

TIA
 

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