I wish to thank all people contributing to understanding the issue.

The discussion confirms me that precisely predicting what happens when using a carbon fibre rod is not easy. On the other hand that rod is so appealing for realizing a stealth antenna leaning on the balcony railing.... Imagine a 27-foot rod, coming down to just 4 feet, weighing just 2 pounds or so, having a diameter of less than 1 inch at the base and about 0.08 inch at the top.... and standing well straight!

So, what I plan to do is the following:
- buy the rod @ about 100$ (it will so also be possible to make more precise resistance measurements than those I can take at the store)
- quickly build a classic 20-meter ground plane test antenna, by extending the rod just as much as needed and taping an insulated copper wire on the rod, parallel to it. I will connect the copper wire only at the rod top and at its base which will be insulated from ground and connected to the coaxial cable center conductor. I will then put four radials on the ground, connected to the coaxial cable braid
- I will apply 1500W RF for some ten minutes. Assuming that the rod causes a loss of just 0.5 dB, this would mean dissipating 163 W on the rod that, considering its low mass, should become hot enough to detect it! Then, if the rod does not get hot at all, I can conclude that no virtually no power gets dissipated in it.
- I will repeat the experiment by keeping the copper wire fully insulated from the rod, though still taped on it
- finally, I will report the test results here.

73 to all

Tony I0JX