Would that FCP work with my 43' vertical, three 25' top loading wires that drop at a 45 degree angle (patterned after the NORD antenna model) and have a 160 meter loading coil that I put in series with an auto tuner at the base???
Using a less than complete counterpoise "field" - about 40 radials, not symmetrical and not even in lengths. Max power is 20 watts out of a Ten Tec Argonaut V 516 but run QRP most of the time. Thank you, in advance, for comments, suggestions or escape plans! 72, Jim Rodenkirch, K9JWV > Date: Fri, 30 Dec 2011 20:50:48 -0500 > From: [email protected] > To: [email protected]; [email protected]; [email protected]; > [email protected] > Subject: Topband: K2AV 160m Folded Counterpoise (FCP), parts and > winding for isolation transformer. > > As requested. > > Parts: > > http://thewireman.com/wirep.html#631 #635 Double polyimide insulated > #14 AWG, 15 feet. > > https://www.amidoncorp.com/categories/15 #12 AWG standard wall teflon > tubing, 15 feet. > > https://www.amidoncorp.com/items/26 T300A-2 #2 material powdered iron > toroid. > > You can also use Micrometals T300-2D, or a PAIR of Micrometals T300-2 > stacked and taped together with fiberglass tape, which are the same as > Amidon T300A-2. You can often find the Micrometals cores on eBay. > > Note: The core material, bifilar winding turn count, and core dimensions > are chosen to facilitate a "simple" 160 installation that has approximately > 1/4 wave wire, a toroid wound balun-sized isolation transformer feeding the > coax, and a folded counterpoise attached, that delivers an impedance that > is close enough to 50 ohms resistive to reasonably use regular coax as a > feed. If you change the turn count, or the core material, or core > dimensions, this balance for the "simple solution" is defeated, and the > conditions which were tested in our two year research period no longer > apply. You might substitute configurations which we put up ourselves, > tested, and specifically rejected for cause. Like burned it up, was lossy, > wouldn't stay tuned, was worse than the original antenna, etc, etc > > You can't use a stack of smaller diameter cores with the same total of A > sub L numbers because you can't get the required 20 bifilar turns on the > inside diameter of the smaller cores. 20 turns fills up the inside diameter > of the T300x-x form factor. If you don't use 20 turns, then you will get > less inductive reactance to cancel the FCP's capacitive reactance for the > simple installation and need more wire in the radiator to compensate. > Dropping only one turn on the core will add 12 or 13 feet to the "pruned" > length for resonance you would have had otherwise. > > The #2 powdered iron core material has been very carefully chosen for 1.8 > MHz QRP and QRO, drawing on advice and published work by W2FMI. Do not > substitute ferrite or other powdered iron materials. #2 powdered iron cores > are always painted red and easily identified. A core without paint or a > different color will not work. > > > Winding: > > First, have a look on W0UCE's site for a good picture of one of these > correctly done . (Pix worth 1000 words and all that...) > http://www.w0uce.net/K2AVantennas.html > Scroll down for the pictures. Note the appearance of the bifilar pair when > done right. Think of the bifilar pair as an exotic "zip cord". You will > be winding the PAIR as if you were winding with zip cord. > > The professionally wound version from Balun Designs with enclosure and > hardware can be seen at: > http://www.balundesigns.com/servlet/the-108/1-cln-1-High-Isolation-Balun/Detail > > > > Cut wire and tubing in half and slip the wire inside the tubing to create a > pair of parallel 7.5 feet teflon-sleeved wires. Some find it easier to > handle the wires in winding if you tape them together. > > Tightly wind twenty bifilar turns around the core. This will use all the > space in the inner diameter. Keep the bifilar pair turns separate and > uniformly spaced on the outside. ALL the wires should be laying flat on > the toroid, with NO twist flips where the wires do an "over-under". > > IMPORTANT: When properly connected there is NO connection between the > antenna/FCP side and the coax side. CAUTION: If you get that WRONG when > you hook it up, you will STILL be able to hear on it, but the system won't > work right and you will loose valuable dB's. > > !!! VERIFY THE SEPARATION !!! with an ohmmeter BEFORE you start pruning the > antenna wire or hurling electronic curses at dog, family, neighbors, or me. > > To wind one of these for a 16+16 version FCP for 80 meters, and you are > doing the "simple" version with 67 feet or so radiator above the FCP, > evenly space *fifteen* bifilar turns around the toroid. > > 73, and I'm looking forward to a lot more 160 QSO's in the contests, > > Guy K2AV > > > On Sat, Dec 10, 2011 at 1:38 PM, Bob Garrett <[email protected]> wrote: > > > Hello Guy, > > > > When the dust settles, will you post a list of parts and sources so we can > > duplicate this antenna and the unique matching network? 73, Bob K3UL > > > _______________________________________________ > UR RST IS ... ... ..9 QSB QSB - hw? BK _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK
