Topband: Going from 48 to 60 radials- Meas. Results

n4uk@mindspring.com n4uk@mindspring.com
Thu, 20 Dec 2001 19:07:44 -0500


Hello to all,
           I finally found the time to add the final set of radials to the 1/4wl tower vertical(122ft). I recorded the SWR changes after adding radials in groups of four. Here is what I was seeing(see below) on the swr meter of my FT1000MP. My original post showed up to 46 radials. I added two in the interim until today's additional 12 and recorded the swr measurements after adding an additional 4 at a time. A sidenote-
When I originally had only 12 radials I kept the radial connection point at the base of the tower "ungrounded". When I grounded the radial connection point the center frequency increased 6 KCs. When I repeated this test at 48 radials the center frequency increased 1 Kc.
Now that I am at 60 radials the center frequency does not increase at all when the radial connection point is grounded. I also noticed that the 1.2:1 points have also gotten wider as I added more radials even though the full 1.5:1 bandwidth has decreased. I think I have finally achieved ground radial "Nirvana". As the famous boxer Roberto Duran said; "No Mas". Too much trouble to add anymore radials and I don't think I'd get much more in the results department. What does this all prove? It proves that all you guys who told me that 60 radials was the minumum needed were right on target. Sure, I could have just believed everyone and went right to 60 radials and not taken measurements but if Christopher Columbus would not have had his doubts and had just gone along with the consensus about the world being flat I might still be tending my flock of sheep on some hillside in Spain. 
           The antenna seems to be working quite well based upon some of the reports I have been getting from the DX on 160. It helps that I have also improved my receive situation quite a bit too!  See you all in the pileups  73, Ken, N4UK


# of radials  1.5:1 points    Center freq.   Increase  Bandwidth
30              1778-1849         1813.5                   71khz
34              1784-1854         1819        5.5          70khz
38              1790-1857         1823.5      4.5          67khz
42              1791-1858         1824.5      1            67khz
46              1794-1860         1827        2.5          66khz
48              1795.5-1860       1828        1            64.5khz
52              1797.5-1860       1828.5      .5          62.5khz
56              1798.5-1860.5     1829.5      1           62 khz
60              1799.5-1861       1830       .5         61.5khz