The hard question was -- what to do for a mast? The 1 1/2 inch rigid EMT I used worked ok for 15 years, but EMT isn't meant to be a mast product. Plus, it wasn't the right outside diameter to fit the mounting U-bolts for the antenna. A 12 to 15 foot piece of 2 inch galvanized, chrome-moly steel would have been ideal, but not easy to come by.
Top end of mast, showing R7000 attached. Notice the R7000 radials are not installed. They get in the way so it is easier just to put them on just before raising the antenna. |
The 1 1/2 inch nipple fit the mounting U-bolts much better than the old rigid EMT did. Close, but not as perfect as a 2 inch mast would be.
It just took a warm afternoon to put up the brackets, assemble the antenna and raise the mast. Unfortunately, the antenna did not show the characteristic low SWR on the ham bands. Some work with an antenna analyzer showed relatively high SWR on every frequency from 7 to 26 MHz. Only on 10m did it show a slightly lower SWR of about 3:1.
Uh-oh. Looks like this 15-year-old antenna needs a rebuild.
No comments:
Post a Comment