Guy-- Thanks-- beautifully described. It is as I thought, but the diagram on the W0UCE page confused me, particularly with the connections to the Counterpoise. Bill--W4BSG
----- Original Message ----- From: "Guy Olinger K2AV" <[email protected]> To: "Bill Aycock" <[email protected]> Cc: <[email protected]> Sent: Thursday, December 08, 2011 1:56 AM Subject: Re: Topband: Best small space antennas > Bill, > > Instructions for creating a drawing of the basic configuration: 160 only, > no tuning inductors or capacitors. Tuning after construction by adjusting > the length of the top of the L. > > Start in the center of a blank piece of paper. Draw a transformer with a > completely separate primary and secondary. Draw the core bars vertical so > all of one winding is on the left and all of the other winding is on the > right. > > On the left side of the tranformer connect the upper end of the winding to > the inverted L. > > On the left side of the transformer connect the lower end of the winding > to > the folded counterpoise. > > On the right side of the transformer connect the upper end of the winding > to the feed coax center conductor. > > On the right side of the transformer connect the lower end of the winding > to the feed coax shield. Do not ground the coax shield until 30-50 feet > away from the transformer. > > That's the wiring diagram. > > Length of the inverted L is adjusted to prune to resonance at your choice > of center frequency. This appears to be centering in the vicinity of > 130-140 feet, **IF** you are using an isolation transformer built to our > specs, but we will know more when there are 100 of these up in the air and > reporting. > > The transformer is wound on an Amidon T300A-2 #2 material powdered iron > toroid. Twenty bifilar turns of #14 double polyimide insulated, sleeved > with AWG12 teflon standard wall no shrink sleeving. Requires 15 feet of > wire and 15 feet of teflon sleeve, cut in half to make the two winding > wires. > > 73, Guy. > > On Wed, Dec 7, 2011 at 11:33 PM, Bill Aycock > <[email protected]>wrote: > >> 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<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" < >> [email protected]> >> To: "Jim Miller Waco Texas WB5OXQ" <[email protected]> >> Cc: <[email protected]> >> 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 >>> <[email protected]> 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
