Using 52 MHz for the design freq...your lengths are off. A typical 5/8wl ground plane is a total of 1 wl worth of vertical, matching/loading coil and gp radials all in series.
Feed point is shield to the radial set / bottom of coil point and the coax center to a tap up the coil at the 50 ohm point. Vertical should be 5/8 wl or about 11.5 feet. The matching / loading coil makes up an electrical 1/8 wl and the GP radials make up 1/4 wl or about 4.5 feet (54 inches). The coil turns/size/etc.can be figured using the ARRL Antenna Handbook and the charts for a loaded dipole of 50% length and coil at the center feedpoint...divided by 2. I have always found that 5/8ths systems are tricky to homebrew and get tuned....but that is just me. Use a GDO to see what your system resonance is. Once you get resonance to 52 (or so) MHz, then you can start matching the coax...but you got to get the lengths right first. Hope this helps.....GL and 73...W5RH Rick Hiller *The Radio Hotel* -- W5RH On Sun, Jan 8, 2017 at 4:16 PM, Gary Sitton via BVARC <[email protected]> wrote: > Get SWR at 3 freqs. to get a feel for where the lowest SWR freq. might > be. Then you can change the loading coil tap or antenna length. > Gary > > Sent with AquaMail for Android > http://www.aqua-mail.com > > On January 8, 2017 3:56:23 PM Gayle Dotts via BVARC <[email protected]> > wrote: > >> Almost finished my first home built 6 Meter antenna, 13.5 feet tall with >> 49" radials. This is coil loaded from the bottom 10 turns. The plans say >> 14GA coated wire and tap. I think the wire should be bare for the tap >> (aligator clip) to connect to. Plans don"t say this. By the way SWR is way >> high.3.0. Any advice. >> >> Thanks, >> Gayle >> KF5LVZ >> _______________________________________________ >> BVARC mailing list >> [email protected] >> http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org >> >> > _______________________________________________ > BVARC mailing list > [email protected] > http://mail.bvarc.org/mailman/listinfo/bvarc_bvarc.org > >
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