Wonder if that FCP would be mo betta for my 43' vertical with three 25' top hat
wires mounted in a NORD sort of configuration, angled down at about 45 degrees.
I have 40 counterpoises- 25 are elevated about 3 feet above ground and 15 are
lying on the ground - and the length varies from 15 to 75 feet (I use the
antenna for 160 by switching a loading coil; switch it out for the other bands).
Thoughts? 72, Jim Rodenkirch, K9JWV
> Date: Fri, 9 Dec 2011 19:24:43 -0500
> From: kazeringue@aol.com
> To: topband@contesting.com
> Subject: Topband: K2AV 160m Folded Counterpoise Antenna - New Details Posted
>
>
> Hullo folks. FWIW.....
>
> I mounted the FCP on my "inverted J" which is about 60 up, 40 over, and
> another 40 to 50 over again. About 150 feet of wire on the radiator.
>
> The FCP and transformer box are mounted about 7 feet up. Sent photos to
> W0UCE since I still have the step ladder conveniently located.
>
> With 880pf of capacitance in series it is resonant right about 1830. The
> autotuner in my ft-920 can tune it easily down at 1800, and runs into
> trouble at 1860 up. Have not yet given the K2 tuner a look at the load.
>
> Using the Elecraft K2 S-meter as a field strength meter, sense antenna a
> dummy load on a 7 foot jumper, full attenuation/no preamp, the OLD
> antenna set up registered S5 on the K2 with 100w going into the antenna
> from the FT-920 at its 1:1 SWR point. [K2 in the shack about 75 feet
> from base of antenna and old antenna radials described below]
>
> After removing the elevated radials(they were in the way) and installing
> the FCP system, yesterday I found that:
>
> 20w into the antenna from FT-920 now registers S5 on K2
> 40w into the antenna from FT-920 now registers S5 plus one bar on K2
> 60w into the antenna from FT-920 now registers S5 plus two bars K2
> 100w into the antenna from FT-920 now registers S9 (S5 plus three bars)
>
> I'm pretty sure my K2's S-meter is not well calibrated so there is not a
> real quantitative measure there. But the new antenna is a lot better
> than the system it replaced. (Note: The K2 bar graph has three bars
> between s5 and s9.....> 5||9)
>
> There are still improvements I can make. There is a large coax
> choke/balun wound with rg-58 that I'll be replacing with a much shorter
> rg-8 jumper.
>
> The original crummy antenna(before FCP installed):
> The old radials consisted of 8 radials about 6 feet above ground, all of
> 35+/- feet in length. There were an additional 20 radials of various
> lengths from 16 to 30 feet long. All were tied together at the bottom
> of a coil, and the feedline ground tapped the coil where it provided the
> best match. The radiator was the same ~150 feet of wire with the same
> 880pf of capacitance in series. (A mix of 150pf and 82pf panasonic 3kv
> ceramics in parallel). The 82pf caps will be switched out to move the
> match should the relays prove capable of the task.
>
> The old set up allowed me to run US stations during ARRL 160m in 2010,
> but never worked much dx or west coast with 100w.
>
> I wanted to get it all installed before ARRL 160m this year, but that
> didn't happen. But maybe my 100w will be less like QRP for Stew Perry.
>
> For my own part, the 30 elevated radials were a maintenance nightmare,
> although they were producing better results than 8 uniform length
> radials. But every falling tree limb snagged one of them. The FCP
> lowers the odds of being hit by a factor of 15. That should cut down on
> radial repairs. Cha-Ching :)
>
> Other random thoughts......
> My installation of the FCP would have been easy to tune by trial and
> error. With the antenna long, a large value air variable could be used.
> Tune it to the sweet spot, measure the value of the air variable, and
> replace it with the fixed value. I expect my own spark gap to be between
> the vertical and the capacitors.
>
> Thanks very much to K2AV for his help with the project. Test drive
> for Stew Perry.
>
> 73 de w4kaz
>
>
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
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