First partly copy from the message I wrote to Jan, maybe it is
intresting to others:
About the FC40 testing, this summer was somehow more busy and not
enough time for one vawelenght loop testing, some tests I did but not
enough to store results to the web. You should member from my
messages that I am doing tests in the summercottage, not useful in
the wintertime.
One tricky test I did when camping at SRAL summerhappening (SRAL is
like ARRL here in OH country ). I got thought abt G5RV what I have
been using all my RadioTime.. abt 25 yrs, idea was to use the
standard G5RV length 31,5 meters straight from the FC40 and it was
working nicely with several bands, I didnt write up the results
because test was done in the bush.
I didnt hear enough OH stations with that G5RV mod and I made
horisontal one vawlength loop to 3,7 MHz , that one didnt work, I
dont know why ? Tuner did his work and SWR was OK, but no QSOs,
it still questionmark.
When I was in ZamBia ( 9j2bi) , I got better results with temporary
G5RV, than with 23 m long wire what I told in my earlier messages.
but it still good idea jusgt to throw wire over tree and start QSOs.
should be realistic.. it is not so easy ****
... and the ground is needed too
One thing more I have to tell you, at town qth I have inv L antenna,
horisontal length abt 42 meters and vertical part 21 meters,
horisontal part abt 18 meters high , free space.
After coming back from that camping I told, I was thinking maybe
something wrong in FC40. I installed FC40 instead of my AH3 (icom
similar stuff) and FC40/FT897 was working OK
all bands.. not so good as IC706/AH3, but good anyway.
--------
Now back to Reply itself.
Ok Jan, good reply.
OCF Dipole can be fed different ways as you described, always
have to find best way to fit your needs and what are possibilities.
I did some OCF tests, but they were not perfectly documented,
thatswhy I didnt wrote results here. It was working OK in some bands,
the 23m wire is better, Maybe because of better ground.
Longer wire was connected to FC40 output and shorter wire to Ground
connector, the "real" ground connection was only in my ground bar,
where all my stuff is grounded, FC40 was not connected there during
this test. Suppose to do more testing with OCF..
Once I made windom to my AH3 / IC706 so that feeding was one third
from "shorter" side and single feeding wire length abt 8 to 10 m .
Cottage ground was there in the AH3 gnd connector. Whole system was
like inverted V, shorter line to town direction and longer part to DX
direction. It was GOOD antenna, but also no documentation. I did it
abt 8 years ago. What to learn from this:
DOCUMENTATION IS IMPORTANT !!!!
After years you can member just something !
73s de rami, oh6bi
--- In YaesuTuner@..., "fil_jds" <fil_jds@...> wrote:
Hi Rami,
I am also "forced" to use the FC40 and in reality I regret not
having
bought the SGC-230 instead...
The FC40 seems to have only a limited impedance and reactance
tuning
range and therefore is rapidly 'running out of breath" with more
demanding antenna systems.
As you will have found out, it is quite difficult to find an end-
fed
wire length that it will tune all-band.
A 23m inverted L with goud ground system it will tune.
On my sailing boat it is really giving me a headache.I use a
sloping
backstay wire as wire antenna, with a halyard running down from
mast
top, sloping to port sisde aft, with heavy duty isolator through
the
deck and 40 cm extra wire untill the FC 40. As RF ground I use wide
copper tape running to engine mass and also to an underwater bronze
strut underwater. Via copper tape also coupled to the stailess
steel
lifelines that run on both sides of the boat, + 2 radials cut for
40m
and 2 cut for 20m.
I can only tune all band (and still miss bottom part of 80m) with
9.6m total wire length till FC40. 12.5 or 13m does not work.
The FC 40 is also very very sensitive to length even some distande
away from 1/2 waves.
I tried to insert a 1:9 Unun at bottom just before tuner, with
12.5m
wire. Works more or less but this is lossy.
Now why do you try to tune an OCF dipole? Do you mean installing
the
FC40 AT the antenna, just where the 2 uneven dipole halves meet?
Normally the impedance there should be around 300 Ohms for most of
the usable bands (since normally a 1:6 balun + good choke is
installed there before running down coax).
The FC40 should be able to handle that 300 Ohms!
But why don't you justhook the FC40 at the end of the coax at your
transceiver, and install the normal 1:6 balun at the antenna? The
FC40 should easily tune-up the slight SWR you will find with and
OCF
dipole on some bands.
Another idea: run down a twin lead (450 Ohms of 1/2 electrical wave
on lowest band, then a 1:1 current balun and this into your FC 40?
I
would guess this would be a very losless system?
In a field situation like the Zambia, I would use 20m, 17m and 15m
simple wire vertical dipoles (no tuner needed) and maybe an 80m
horizontal loop, hanging at leats 10m high, fed with twin lead out
of
corner, to a 1:4 balun at the tuner.
Jan
ON3ZTT
--- In YaesuTuner@..., "oh6bi" <oh6bi@> wrote:
Hello All after long winter !
Yesterday I put my boat to sea and today goeing to summer
cottage with FT897 and FC40..
If you dont know about me, just read some earlier messages
from oh6bi in this group.
OK, last messages during autumn I told to start testing
FC40 and OCF dipole, yes I will do that.
During this winter I spent 3 months in Zambia (9J2BI)
and I didnt get good contacs to Europe with 23m long Wire.
I installed The Wire four times to different directions
to get better EU signals, but no good success, only some
QSOs to Europe, none to OH. JA and UA9 where the best.
Also local QRM and QRN where strong with The Wire.
After that I did some tests with 7 MHz deltaloop and that was much
better. QRN and QRM where lower and receiving signals better.
Unfortunately work was disturbing The Hobby and not enough
time for the loop. That means I will start this summer experiments
with 7 MHz Delta Loop.
You will see what happens..
By the way, does anyone have information how FC40 really works ?
I mean would be nice to build "universal control box" same way
as many has done with Icom AH4(and AH3, what I am using with
IC706).
Check in AH4 section from
AA7OL Niko Takahashi: "AH4 connetion to any Radio".
Best Regards and 73s de rami, oh6bi
