Bill:
Functionally both FCP configurations shown on my website K2AV Antenna Page
produce the same results. The sketch showing the Inverted L portion of the
antenna system indicates how my 160/80m antenna is configured. The matching
unit diagram is unique to my system.
If your needs are only for 160m you will just need the Feed Point Isolation
Transformer Guy specifies in order to FORCE the antenna to use the FCP
versus feed line coax shield as a counterpoise.
A 1:1 Current Balun or Off the Shelf Line Isolator will not provide the
required degree of isolation and as much as 80% of the applied RF power will
be lost as was proven with my system during initial FCP field trials. It
will be a waste of time, money and effort to attempt using any Isolation
Device other than what Guy specifies.
Guy is in process of preparing a list of materials, sources and instructions
how to wind the FCP Isolation Transformer. I'm not sure when he will be
ready to release the information but when it is available and with his
permission, I will include his list, material sources and instructions on my
website.
Believe me... this is worth waiting for. You will be amazed what you can
work on top band with Guy's FCP based antenna be it an Inverted L or
Inverted U.
The vertical portion of my quarter wave Inverted L is only 46.5 feet, the
rest is horizontal due to available tree supports yet I have worked JA, VK,
ZL and lots of other DX from my QTH in NC with the antenna and FCP Guy
designed.
73,
Jack
Guy--(and others who may contribute)
I have been following your posts, and have some questions, brought on by a
view at the W0UCE diagrams, at:
http://www.w0uce.net/K2AVantennas.html
The top figure seems to match what I understood from your post, but the
figure that includes the Inv "L" confuses me, particularly with regard to
the connections. I need a more simplistic description, including the
connections to the transformer
Thanks- Bill--W4BSG
----- Original Message -----
From: "Guy Olinger K2AV" <olinger@bellsouth.net>
To: "Jim Miller Waco Texas WB5OXQ" <wb5oxq_1@grandecom.net>
Cc: <topband@contesting.com>
Sent: Wednesday, December 07, 2011 7:57 PM
Subject: Re: Topband: Best small space antennas
> Note: the following is not a theoretical or untested antenna. There
> are working antennas in the field using the folded counterpoise
> described below, scoring well in contests**, in use up to a year and
> more. Contest scores of the sort attained are not made using antennas
> with significant deficiencies or fundamental flaws.
>
> A miscellaneous end-fed inverted L or end-fed inverted U over an
> elevated 5/16 wave single wire folded counterpoise (FCP) will have
> good radiation from a small lot, with the ability to put out a strong
> signal not usually associated with small lots. In the simple
> implementation of this antenna (160 only), the length of the L or U is
> adjusted for zero reactance, usually resulting in a 50-60 ohm feed Z
> at resonance.
>
> There are NO radials. The main design point of the antenna is to
> minimize lossy currents induced in the dirt and confine TX signal
> current to the FCP and the radiating wire. This is a real, and lossy
> issue for a few short or miscellaneous radials. Enough of an issue to
> kill 15 dB.
>
> The radiating wire first goes up as much vertical as you can manage,
> then out as far as manageable, and then down if length is still needed
> to prune to resonance. The main point is to pick a feed point on the
> property that has your best vertical rise and then get the rest of the
> length for resonance however you can. For some properties this has
> meant putting extra angles in the up+over+down radiator. Some
> properties will not need the "down" part.
>
> The antenna uses a REQUIRED isolation transformer at the feed point
> because the counterpoise is NOT resonant, and the feed would really
> rather use the much lower Z but hugely lossy coax shield current as a
> counterpoise. The folds in the FCP are designed to maximally reduce
> counterpoise fields at the ground, reducing lossy currents in the
> dirt.
>
> The isolation transformer's leftover inductive reactance, a
> disadvantage in many applications, in this case helps to tune out the
> capacitive reactance of the FCP and reduces the length of the
> radiating wire needed to achieve simple resonance for the antenna.
>
> The counterpoise extends plus and minus 33 feet from the feed point,
> 167 feet folded into 66 linear feet occupied on the property. The
> middle 20 feet of the 66 should be straight, but either end can be
> bent away from the straight line to accommodate the property. Up 8
> feet or higher is recommended. Lowering the counterpoise increases
> the coupling to dirt, increasing losses.
>
> The isolation transformer uses the same physical components as a
> balun, but the unlike the balun there is NO connection of any kind
> between the primary and secondary windings. This is accomplished with
> twenty bifilar turns of double polyimide insulated #14 with teflon
> sleeving wound on an Amidon T300A-2 #2 material powdered iron toroid.
> One wire is the primary, and the other is the secondary. The low MU
> powdered iron toroid was picked over time to avoid heating, still
> provide required coupling, with other choices sometimes failing in
> spectacular fashion. We have no information of our currently-used
> winding method on the Amidon T300A-2 ever failing for any cause,
> though we would not expect it to survive a direct lightning strike.
>
> With the isolation transformer, the antenna and FCP is entirely above
> ground and not connected to anything else. We use a 5 megohm resistor,
> in parallel with a non-resistor lawn mower spark plug, from the FCP to
> ground as a static drain. The gap drains lightning induced voltage to
> protect the resistor, the resistor drains wind, snow, rain static.
> The resistor and gap protect the winding from a voltage puncture that
> will grow into a carbon track to ground.
>
> 73, Guy.
>
> ** As reported in Dec 2011 CQ, Jan 2011 CW160CW contest, USA low
> power unassisted, the 29 scores over 100K out of 335 scored logs in
> class:
>
> Station, state, score, QSO, ST+PROV, DX
>
> K9AY WI 259,346 991 58 36
> W0UO TX 250,716 882 58 44
> K1EP MA 232,750 909 56 39
> K2AV NC 223,908 907 57 37 << No radials, 5/16 FCP
> K8BL OH 203,328 819 58 38
>
> KU1CW KS 197,885 795 58 37
> N2WN TN 191,090 640 55 42
> WB8JUI OH 190,372 852 58 38
> N7IR AZ 183,855 856 58 27
> W2TZ NY 178,633 723 56 35
>
>
> NA8V MI 177,030 793 59 31
> W4AA FL 173,619 494 56 45
> K1HTV VA 172,956 733 55 32
> W1WBB RI 161,550 654 55 35
> KU8E GA 152,613 615 58 35
>
> W7RH AZ 135,369 500 55 34
> K4WI AL 128,520 509 55 30
> N9NCK WI 126,162 516 55 31
> KV8Q OH 125,741 674 57 20
> N9AUG OH 125,330 608 55 28
>
>
> W2TX FL 121,800 504 52 35
> K9QVB IL 120,120 641 56 21
> WW3S PA 119,848 706 55 16
> K2UF NY 119,392 541 53 29
> K0PK MN 118,400 678 58 16
>
> WF4U UT 114,239 664 56 15
> W1BYH MA 106,444 404 54 35
> W5WMU LA 106,020 574 54 22
> N4JF AL 101,920 493 54 26
>
> ** 3830 claimed scores listing of Dec 2011 ARRL 160 contest, North
> America low power unassisted, top 20 of 119 listed as of this writing:
>
> Station, state, score, QSO, ST/PROV, DX
> 2011 ARRL 160 - 3830 Claimed Scores 06Dec2011
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Call QSOs Sec Cntry hr Score Club
> NA Single Op LP
> K8FH 920 74 18 27 175,076 Medina 2 Meter Group
> NE9U 978 75 14 172,927 MWA
> K4FT 976 75 9 28 166,236 KCG
> WB8JUI 940 71 9 21.32 152,560
> K0TI 920 76 5 21 150,255 MWA
> K0DI 875 75 8 28 146,495 Lincoln ARC
> K2AV 788 65 9 21.5 119,066 PVRC << No
> radials, 5/16 FCP
> W0DLE 725 74 3 21 112,343 Grand Mesa
> K9MMS 653 74 10 16 112,224 SMC
> K0PK 657 72 6 19 104,130 MWA
>
> K3PA 618 74 7 101,817 Kansas City DX Club
> WA1FCN 645 68 7 99,864 ACG
> K2ZR 695 64 4 20.0 90,112 Western NY DX Associ
> K0AD 584 75 6 10 88,500 MWA
> W0UO 519 71 9 14 85,680 NTCC
> K0CN 478 73 11 83,076 MWA
> N1IX 516 60 10 13 78,540 YCCC
> VE3OSZ 442 68 15 77,854 CCO
> W9ZRX 492 69 8 20.5 77,616 SMC
> W7RH 437 72 8 76,869 Arizona Outlaws Cont
>
>
>
> On Sun, Dec 4, 2011 at 8:18 PM, Jim Miller Waco Texas WB5OXQ
> <wb5oxq_1@grandecom.net> wrote:
>> With limited space what is the best antenna for 160? The only room
>> available is a 130X50' area. Ground radials will be nearly impossable to
>> put in large enough to be of much value. 1/4 wave antenna tried, very
>> narrowband and interfeared with every receiving device in a block. I may
>> just be out of luck. wb5oxq
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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