Just remember that an FCP is a SINGLE BAND device. If you use a 160 FCP on
80 meters, the field cancellation will not occur and it will be lossy.
Second, the gorilla in the room for QRP is eliminating loss. Wind the 160m
isolation transformer (ISOT) as specified or get the Balun Designs
commercial duplicate. Put the auto tuner right at the transformer, and it
will work. You will not need the loading coil if the tuner is at the ISOT.
You can put any kind of antenna on the other wire connection on the ISOT.
You just need to tune it right at the coax connection of the ISOT. If you
put more than 2-6 feet of coax between ISOT and autotuner you may start
running up losses. Put the coax to the shack on the tuned output side of
the autotuner so the shack coax is matched and losses are minimum.
An antenna like the one you describe has a very low radiation resistance on
160, therefore the current is very high in whatever counterpoise is in use.
A radial system used with this antenna that is NOT dense, AND uniform
length and spacing, will be that much more lossy and the FCP will make a
large difference. Critical with QRP. It is entirely possible that a
miscellaneous radial collection could reduce your 5 watts to a half watt.
For QRP, do the radials right, or use a counterpoise specifically designed
to minimize loss.
73, Guy.
On Sat, Dec 31, 2011 at 4:14 PM, James Rodenkirch <rodenkirch_llc@msn.com>wrote:
> 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: olinger@bellsouth.net
> > To: rgarrett5@comcast.net; w0uce@nc.rr.com; topband@contesting.com;
> press@thewireman.com
> > 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 <rgarrett5@comcast.net>
> 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
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