Topband: FCP

[Guy Olinger K2AV]

Very kind, and flattering, but...

I'm really NOT expecting to be the loudest guy.  There is no reason
for me to expect that.  But I AM in play.  My station, including the
antenna wire + FCP, IS "working" and working well.  I have a K3, with
dual diversity RX, and an Alpha 8410. RX antennas are the limiting
issue at my station.  Working on that.

I'm using an FCP at 7 feet with an 84 foot vertical wire plus 104'
horizontal. It's strung in an open area in my narrow little private
forest over the driveway almost to the US 64 service road.  The
driveway splits the property there, thus no possibility for radials.
It's at 7 feet because I could do that and not have to clear some
stuff, and it was an EXPERIMENT when we first put it up.

I will be moving the FCP up to 15 feet, after clearing that stuff to
make it possible, and raising the wire a bit at the same time, so it
will be still be about the same wire above the FCP.  I have 425 feet
of WireMan #554 window line to the matching box plus about 80 feet of
coax getting from the shack out to the tractor shed where the balanced
line starts.

I have a 4:1 isolation transformer to step down to the FCP-antenna
feedpoint Z.  It's a trifilar winding on a T400A-2 monster powdered
iron core. Runs stone cold with 8410 in brick-on-key mode.  Vacuum
variable cap tunes out series inductive reactance in the nearly 3/8
wave length wire.  I use a duplicate of the isolation transformer to
go to coax at the tractor shed. That way I have a working duplicate
ready if the antenna end gets melted by a direct lightning. There have
been four close strikes to trees, and the isolation transformer
construction at both ends of the balanced line has stood up to induced
voltage without problems

My big maintenance headaches are parts of the forest falling on the
feedline and squirrels eating the window line material and exposing
the wire underneath to moisture. I have support weights on pullies at
the ends of the main run, The window line can slip through the
supports, which will also release with excessive pressure, and a tree
can take the window line to the ground and pull up the weights without
snapping or otherwise damaging the window line.

There are a couple sweet gums growing into the antenna clear space
that are going to be taken down shortly.  This antenna is now known
for sure to be the best 160m antenna I can get up on the property, so
it will be maintained, and I can justify the clearing activities.

As to FCP stories...

CQ160 CW certificates are now out there for Jan 2012 contest.  #1 SOLP
in NC (#2 in 4th call area) was over an FCP.  #1 SOHP in NC (#3 in 4th
call area) was over an FCP.

One Scot station with a new FCP in a 21 x 75 foot back yard (!!!), and
a 30 foot tower for supporting the bend in the L, was on 160 in the
CQWW SSB and worked into the US and all over Africa with 400 watts.
Was night and day for him versus his prior setup with necessarily
pathetic radials.  What radials could anyone put down that work in 21
x 75 feet?  And that's *SSB* across the pond, which is at a 10 dB
disadvantage to CW across the pond.

Yeah, FCP really works, but it is certainly not a replacement or a fix
for everything. Those without commercial radial fields, but who have
stuff that works and compares favorably with others' RBN numbers may
not get discernible performance boost by conversion. If you are
getting cr*p RBN numbers on 160, then examination of your setup is in
order, and you might get startling improvement with an FCP.  Others
already have.

The FCP is best replacing "miscellaneous" attempts at radials that are
a significant come down from commercial radials.  These are usually
because size restrictions prevent anything remotely resembling "full
size dense and uniform all around".  On the other hand, some are
making no-performance-change FCP substitutions because they didn't
lose anything and they got their back yard back. On fellow said he was
tired of tangling his annual radials in the lawn mower.

Some have put up their first real 160 antenna over an FCP because
there was no way they were ever going to use radials, including some
that clearly had room for the commercial equivalent.  I hear a range
of reasons (you've heard them all on this reflector) for not doing
radials.

73, Guy.





On Thu, Nov 8, 2012 at 3:00 PM, Guy Olinger K2AV <olinger at bellsouth.net> wrote:
> On Sun, Nov 4, 2012 at 12:36 AM, Charlie Young <weeksmgr at hotmail.com> wrote:
>> Rick, N6PE wrote:
>>
>>> The other question is does the thing actually work in the real world?
>>
>> I installed an inverted L over an FCP for 160M and compared it to 3 other
>> inverted L's over two elevated radials using RBN, real signal reports, and
>> DX pileup busting.  In addition, I attempted to compare it with field
>> strength measurements with a friend using a spectrum analyzer on a hilltop 5
>> miles from my hilltop.   All antennas were up simultaneously. During the
>> field strength tests, I floated the radiators of the unused antennas.
>>
>> In addition to my own antennas, I helped K8RRT commission an inverted L over
>> FCP.  The FCP replaced a single 1/4 wave elevated radial, with which Tim
>> worked 160 DXCC in two or three years.
>>
>> At my place, an attempt was made to quantify the difference in performance
>> between my FCP and a pair of inline elevated radials.  These are both
>> compromise radial systems compared to the ideal or near ideal.  My attempt
>> to quantify the performance difference was unsuccessful for two reasons.
>> First, I have towers and other antennas which are in close proximity to the
>> L's, close enough that I suspect coupling is impacting the performance.
>> Second, due to my rugged terrain and steeply sloping ground, I think the
>> antenna position on my hilltop relative to the ground slope is as important
>> as any other factor in determining how an antenna works in a given
>> direction.
>>
>> I believe at my location the FCP is roughly equivalent to two full size 1/4
>> wave elevated inline radials, based on the RBN reports and other tests.  DX
>> performance in pileups for the FCP seemed similar to 2 elevated radials,
>> given where the antenna was mounted on the hill.   I had no trouble breaking
>> any pileup, including  KH2, RI1ANF, VK6 and many EU stations., using the FCP
>> antenna.  This is anecdotal evidence and does not prove anything
>> scientifically, but I was unable given the circumstances to quantify the
>> performance difference.  With the recent wind and snow storm, I have run out
>> of time to do further testing.
>>
>> My 1/4 wave elevated radial tree supported inverted L's have been very
>> satisfactory for my use, and have resulted in Q's with  7O6T, TT8TT, NH8S
>> this year and South Sudan last year.  I would like to compare these minimal
>> elevated radials with antennas equipped with optimized radials, but this is
>> not in the cards at my rock cliff location.  Bottom line, from my
>> perspective, the FCP seems a viable alternative to two inline elevated
>> radials if one does not have space for the full size radials.
>>
>> Regarding K8RRT, Tim is having success this season in the relatively poor
>> condx, especially since his time is limited due to a heavy work schedule.
>> He has busted many pileups with his tree mounted L over an FCP, including
>> RI1ANF, NH8S etc.   A couple of days ago, Tim worked ZS1REC, one of only two
>> NA stations to make it on that night to Raoul.  In terms of DX pileup
>> success, Tim's FCP is working.  I realize this does not quantify or prove
>> anything, but it is additional evidence the FCP does work.   How and why it
>> works, I will defer to K2AV for explanation.
>>
>> It could be the FCP and two inline elevated radials are many db down from
>> the ideal or near ideal ground system, I have no way to determine that with
>> testing.  Given the simplicity of my setup, I am more than satisfied with
>> the DX results achieved with the elevated radials and believe the FCP would
>> generate similar results.  My location may have something to do with the
>> results but if so it is not due to good ground conductivity, because my
>> antennas are over thick sandstone.    It certainly seems the FCP is worth
>> trying if one wants to work DX from a limited space location.
>>
>> During the pre Stew, I did a lot of listening but attempted no Q's.
>> Consistently, K2AV had the strongest signal here in WV of any station I was
>> hearing, including many big guns.  Not sure how much power Guy was running,
>> but he was consistently over S9, at times up to 20 over, well above other
>> stations in S meter reading.   This does not prove anything, but I offer the
>> observation as another indication the FCP is worth considering for limited
>> space.
>>
>> I know the value of measurements and controlled tests but have no more time
>> to spend on this project.  Thus, it is back to working DX with the status
>> quo antennas.  I will leave it to the experts with more time, skill,
>> equipment, and space than I have to prove or disprove in scientific terms
>> the merits of various ground/radial systems.
>>
>> 73 Charlie N8RR