[TowerTalk] Re: C3E 10 M add on
Steve Zettel
zettel@homer.libby.org
Tue, 20 Oct 1998 12:27:46 -0600
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Content-Type: text/plain; charset="us-ascii"
>Steve,
>
>I saw your post on the tower talk archives and took your advice -- I
>ordered the 10M add on kit to my C3 order.
>
>How do you like your antenna? Does the SWR on 10 seem OK or did you tune
>it differently. I like to work CW also so 28.4 dip point would be about
>right.
>
>Anyway, thanks for the tip. The element is 60 bucks, but well worth it if
>they do all the work. Now, if it will just show up soon...
>
>73 and thanks in advance for any more info.
>
>Greg
>K0PJ EN43 SE Minnesota
Hi, Greg
I have gotten quite a bit of e-mail asking me about my experiences with the
10M reflector add-on to my Force 12 C-3's. I hope you don't mind if I post
to the group, since there seems to be such interest.
I really like the performance of the C-3E on 10M with the addition of the
10M reflector. For the amount of time/money/real estate I have available to
devote to amateur radio, the three-stack of C-3(E)'s I have on a 90' tower
represent the optimum in terms of light weight, low wind-loading, ease of
assembly and handling, etc. All of which translates into less $$$ or less
time/effort. No, they aren't long-boom, monoband stacks, but my life is a
series of compromises between wishes and realities. I am pleased with the
outcome of this particular set of trade-offs, so far.
For my application, I used the factory supplied dimensions for the
reflectors (mine did not have additional holes drilled for "tuning") and
found that the Force 12 recommended dimensions for the original C-3
elements that provide for tuning (the 10M and 15M driven, or
parasitically-coupled elements) gave almost exactly the VSWR curve you are
looking for. As I recall, this was with one rivet hole exposed on each
element tip, i.e. the "mid" setting. Of course, your settings may or may
not be the same as mine depending on your unique configuration of
tower/mast/guywires/proximity to other towers/antennas/metal roofs etc.
I have my C-3E's stacked at 30'/61'/92' with a Cushcraft 40-2CD 40M beam 8'
above the top C-3E. The lower two C-3E's are on "swinging sidearm" mounts
which allow rotation through 300 degrees of azimuth around the 45G tower.
The guywires at 29'/60'/90' are 3/16" EHS, broken with insulators near the
tower only.
I started out with a free-space model of a single C-3 to factory
dimensions, and have progressively added representative ground, the tower,
the 40-2CD (simplified into a two element 40M beam without traps) and mast,
the guywires, and ultimately, each of the C-3E's (simplified into taperless
files), and then rotated the antennas around the tower, firing into the
guywires and between them, to look for significant pattern/VSWR
disturbances. Brian Beezley's AO and GUY programs were used for this. The
pretty, smooth free-space patterns certainly did change as other conductors
were introduced into the model, but careful examination/comparison showed
the changes to be minor in nature. I am pretty pragmatic about this. In
uncontrolled, on the air listening and measuring, swinging beam headings
and looking at S-meters and VSWR's, I haven't found any gross degredation
of performance to suggest any really destructive interactions -- or maybe
I'm living in ignorant bliss. I certainly haven't found that my beams have
turned into isotropic radiators!
My subjective opinion (not having a tower of C-3's to A/B with a tower of
C-3E's, is that the addition of the 10M reflectors made an appreciable
increase in F/B ratio on 10M, and a very slight increase in forward gain
(maybe between the operator's ears). No affect on 15 or 20M. This shouldn't
be surprising, going from essentially two elements on 10M to three. Since I
ended up using the F12 kit/element dimensions/boom position for the add-on
reflectors, rather than rolling my own, installation and tuning was the
usual F12 piece of cake. Again, not surprising, since Tom has been testing
this configuration for several years.
Would I go to the trouble of taking my C-3's off the tower, installing the
10M reflectors, and re-installing them, again? Yes, I would. With the
elements ready to go, it was only the matter of one day's work to swap out
all three, including lunchtime, fiddling around with running them up the
tram to take and record VSWR readings, running them back down to set the
rivets I had initially taped in place, back up the tram, etc. working
entirely by myself. My next modelling project, when I get some time (ha!)
will be to play around with adding a boom extension and another 20M
reflector (not the optimum, I know) and/or another 10M reflector off the
front.
Hope this helps. Please feel free to continue asking me questions, but I
would suggest going right to Force 12 for pricing and availability
questions.
73,
Steve Zettel KJ7CH
near Libby, MT USA
--============_-1303214380==_ma============
Content-Type: text/enriched; charset="us-ascii"
<excerpt><fontfamily><param>Times_New_Roman</param>Steve,
</fontfamily>
<fontfamily><param>Times_New_Roman</param>I saw your post on the tower
talk archives and took your advice -- I ordered the 10M add on kit to
my C3 order.
</fontfamily>
<fontfamily><param>Times_New_Roman</param>How do you like your
antenna? Does the SWR on 10 seem OK or did you tune it differently.
I like to work CW also so 28.4 dip point would be about right.
</fontfamily>
<fontfamily><param>Times_New_Roman</param>Anyway, thanks for the tip.
The element is 60 bucks, but well worth it if they do all the work.
Now, if it will just show up soon...
</fontfamily>
<fontfamily><param>Times_New_Roman</param>73 and thanks in advance for
any more info.
</fontfamily>
<fontfamily><param>Times_New_Roman</param>Greg
K0PJ EN43 SE Minnesota
</fontfamily></excerpt><fontfamily><param>Times_New_Roman</param>
</fontfamily>Hi, Greg
I have gotten quite a bit of e-mail asking me about my experiences with
the 10M reflector add-on to my Force 12 C-3's. I hope you don't mind if
I post to the group, since there seems to be such interest.
I really like the performance of the C-3E on 10M with the addition of
the 10M reflector. For the amount of time/money/real estate I have
available to devote to amateur radio, the three-stack of C-3(E)'s I
have on a 90' tower represent the optimum in terms of light weight, low
wind-loading, ease of assembly and handling, etc. All of which
translates into less $$$ or less time/effort. No, they aren't
long-boom, monoband stacks, but my life is a series of compromises
between wishes and realities. I am pleased with the outcome of this
particular set of trade-offs, so far.
For my application, I used the factory supplied dimensions for the
reflectors (mine did not have additional holes drilled for "tuning")
and found that the Force 12 recommended dimensions for the original C-3
elements that provide for tuning (the 10M and 15M driven, or
parasitically-coupled elements) gave almost exactly the VSWR curve you
are looking for. As I recall, this was with one rivet hole exposed on
each element tip, i.e. the "mid" setting. Of course, your settings may
or may not be the same as mine depending on your unique configuration
of tower/mast/guywires/proximity to other towers/antennas/metal roofs
etc.
I have my C-3E's stacked at 30'/61'/92' with a Cushcraft 40-2CD 40M
beam 8' above the top C-3E. The lower two C-3E's are on "swinging
sidearm" mounts which allow rotation through 300 degrees of azimuth
around the 45G tower. The guywires at 29'/60'/90' are 3/16" EHS, broken
with insulators near the tower only.
I started out with a free-space model of a single C-3 to factory
dimensions, and have progressively added representative ground, the
tower, the 40-2CD (simplified into a two element 40M beam without
traps) and mast, the guywires, and ultimately, each of the C-3E's
(simplified into taperless files), and then rotated the antennas around
the tower, firing into the guywires and between them, to look for
significant pattern/VSWR disturbances. Brian Beezley's AO and GUY
programs were used for this. The pretty, smooth free-space patterns
certainly did change as other conductors were introduced into the
model, but careful examination/comparison showed the changes to be
minor in nature. I am pretty pragmatic about this. In uncontrolled, on
the air listening and measuring, swinging beam headings and looking at
S-meters and VSWR's, I haven't found any gross degredation of
performance to suggest any really destructive interactions -- or maybe
I'm living in ignorant bliss. I certainly haven't found that my beams
have turned into isotropic radiators!
My subjective opinion (not having a tower of C-3's to A/B with a tower
of C-3E's, is that the addition of the 10M reflectors made an
appreciable increase in F/B ratio on 10M, and a very slight increase in
forward gain (maybe between the operator's ears). No affect on 15 or
20M. This shouldn't be surprising, going from essentially two elements
on 10M to three. Since I ended up using the F12 kit/element
dimensions/boom position for the add-on reflectors, rather than rolling
my own, installation and tuning was the usual F12 piece of cake. Again,
not surprising, since Tom has been testing this configuration for
several years.
Would I go to the trouble of taking my C-3's off the tower, installing
the 10M reflectors, and re-installing them, again? Yes, I would. With
the elements ready to go, it was only the matter of one day's work to
swap out all three, including lunchtime, fiddling around with running
them up the tram to take and record VSWR readings, running them back
down to set the rivets I had initially taped in place, back up the
tram, etc. working entirely by myself. My next modelling project, when
I get some time (ha!) will be to play around with adding a boom
extension and another 20M reflector (not the optimum, I know) and/or
another 10M reflector off the front.
Hope this helps. Please feel free to continue asking me questions, but
I would suggest going right to Force 12 for pricing and availability
questions.
73,
Steve Zettel KJ7CH
near Libby, MT USA
--============_-1303214380==_ma============--
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