Somewhere in my stuff, I've got the info for a 6m quadrifilar helix
antenna. I've been trying to figure out whether to build that or the
10m version first.
I have other 10m antennas, so I've been leaning toward 6m.
On 1/8/2017 5:15 PM, Rick Hiller -- W5RH via BVARC wrote:
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]
<mailto:[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
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On January 8, 2017 3:56:23 PM Gayle Dotts via BVARC
<[email protected] <mailto:[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
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Jonathan Guthrie KA8KPN
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