2021-05-02, 12:23:22
I'm sure I've seen discussions on QRZ.com and eHam.net about the effects of carbon fiber masts. Some forum searches may yield useful information.
My opinion: I don't have one of those masts. I have read that some of the cheaper ones aren't carbon fiber at all, just fiberglass tinted black. A real carbon fiber mast is made from long fibers wound on the bias, thus will be somewhat conductive. I wouldn't expect any significant coupling into a vertical mast from a horizontal or near horizontal antenna due to the near 90° angle between the mast and the antenna. After all, people use steel & aluminum masts to hold up dipoles. On the other hand, if you tape a wire onto the mast to make a vertical antenna, RF will be coupled into the mast, which will degrade the antenna's performance (degree?). If you run the wire up inside the hollow mast, I would expect significant shielding.
Suggestion: buy one & do some measurements. It would make a good TCA article, RAC's always looking for material.
Re effect of trees on antenna emission: two detailed studies were published in QST in the last few years (by Dr. Steve Stearns K6OIK & Dr. Kai Siwiak KE4PT). If anyone is really interested let me know & I'll lend you the magazines.
73
Dave, VE3WI
My opinion: I don't have one of those masts. I have read that some of the cheaper ones aren't carbon fiber at all, just fiberglass tinted black. A real carbon fiber mast is made from long fibers wound on the bias, thus will be somewhat conductive. I wouldn't expect any significant coupling into a vertical mast from a horizontal or near horizontal antenna due to the near 90° angle between the mast and the antenna. After all, people use steel & aluminum masts to hold up dipoles. On the other hand, if you tape a wire onto the mast to make a vertical antenna, RF will be coupled into the mast, which will degrade the antenna's performance (degree?). If you run the wire up inside the hollow mast, I would expect significant shielding.
Suggestion: buy one & do some measurements. It would make a good TCA article, RAC's always looking for material.
Re effect of trees on antenna emission: two detailed studies were published in QST in the last few years (by Dr. Steve Stearns K6OIK & Dr. Kai Siwiak KE4PT). If anyone is really interested let me know & I'll lend you the magazines.
73
Dave, VE3WI