The C3 uses two driven elements for bandwidth. Hence 3 elements.
Robert W5AJ wrote:
> Reading tribander report on C3 and it says 3 elements on 28mhz, however the
> forward gain seems somewhat lower on that band? Is it really close spaced?
> What happened?
> 73 Robert
>
> ----------
> From: MAERTZ, A REID <amaertz@oppd.com>
> To: towertalk@contesting.com
> Subject: [TowerTalk] C3/C3S
To: <towertalk@contesting.com>
> Date: Friday, October 02, 1998 9:36 AM
>
> Greetings:
>
> Thanks very much for your replies to my post.
>
> This is a summary of the many replies I received comparing the Force 12
> C-3 and C-3S to Mosley TA-33.
> Force 12 wins hands down. Positives include: lightweight, no trap
> design, exceptional mechanical construction, hears well, good SWR on
> 15/20 and will function on 17/12 well with tuner (not great on 12 with
> C3S). Negatives include narrow bandwidth (C3S) on ten meters and a high
> SWR (C3S) on 12 meters. A number of comments reflect dissatisfaction
> with customer service at Force 12.
>
> Excerpts of the replies follow. I've tried to lift the salient points
> and minimize redundance.
>
> I have a C3S I put up this summer, replacing a TA33jr. It seems to be a
> good antenna, but there are some wrinkles:
>
> 1. The F12 bandwidth numbers use coax loss to get those wide numbers.
> I wish my rig had an autotuner, but luckily it's good to 3:1 - I need
> it!
>
> 2. Monoband beams seem to be a lot fussier than trapped antennas -
> feedline problems that you didn't see before, etc.
>
> 3. If you're a cw/dx man, you may find 10m very disappointing - it's
> hard to pull it down below 3:1 at the low end of the band. Design is
> centred at 28.8 - best I could pull it down to was 28.400 centre
>
> My installation is not ideal - roof mounted on rowhouse in city centre
> on 15.5' wide lot. I feed antenna with quad shielded ethernet coax -
> the TA33jr was fed with heliax - I'm not a loss nut - the full shield
> really helps reduce QRN and TVI.
> _______________________________________________________________
>
> I bought a C4SXL which has as its core the C3S. On ten meters I have
> only been able to get 600 kHz bandwidth. They advertise 1.1 MHz. I
> emailed, faxed and called Force12 to try to resolve this problem and
> never got a response from them.
>
> Unfortunately, the SWR curve was such that the usable (2:1) bandwidth
> was from 28.5 to 29.1. I had to drill new holes to move the curve down
> to where I wanted it.
>
> To their credit, I broke an element on my 20 meter elements
> getting it down from the tower and they replaced it free of charge.
>
> The construction and performance of the antenna are very good. I had
> an MP-33, TA-33 and PRO67B before this antenna and it seems to
> out perform all of them. It is noisier than any of them but I think
> that is
> because it hears better. My SWR curves are excellent on 20 and 15 and
> it seems to work as well as the Pro67 (which covered 17 & 12) on 17 &
> 12.
>
> My suggestion is that if covering a lot 10 meters is important to you,
> go
> for the C3. Otherwise the C3S will work fine. At any rate the 18' C3
> will
> still be lighter than your TA-33.
>
> Don't count on customer support unless you flame them on TowerTalk.
> Looking back through the archives that seems to be the only way people
> get it.
> ___________________________________________________________________
>
> The C3S uses reflectors on all 3 bands and appears to offer the
> most gain for it's size. This would seem to be one of the best
> antennas for DXpedition / portable use due to it's light weight
> and low wind load and torque, allowing for a minimal support
> structure (i.e. push up mast). A full size 2L Yagi comes within
> 1 dB of a short boom full size 3L Yagi. With trap losses and
> other compromises, the full size C3S should have equal or
> more gain than most small 3L trapped tribanders
> ______________________________________________________________________
>
> Weighing in at only 25Lbs it (C3S) sure is easy to haul up the
> tower and install... For contesting I find the fact that it doesn't have
> that great a front to back an advantage as stations calling you off the
> back can be worked wiythout rotating the antenna. The design is simple,
> relatively rugged and should last forever and there are no traps to
> blow
> up.
>
> "Bad" things to keep in mind "Farce" 12 customer service
> At $500 the thing is over priced.
> ________________________________________________________________________
>
> I have used a stack of Force 12 C-4/C-3 for about two years now and all
> I
> can say is THERE GREAT. In the last two years I have ended up in the top
> ten
> box for every contest I have participated in. The antennas are at 73'
> and
> 40'. Spend the money and get the c-3 over the c-3s.
> ________________________________________________________________________
> ____
>
> I replaced a TA-33 with a C-3S and I am very happy with the new
> antenna....(just worked E31AA for a new one)
> It beats the pants off the TA-33 and is lighter and easier to install...
> 12M is so-so.....but 17 is great... 20 es 15 are very good...10 hasn't
> been
> open that much to try it out...
> ________________________________________________________________________
> ______
>
> I've used a C3s (well, actually the C4S) for 3 years now and am very
> happy
> with it. The 10 meter bandwidth is adequate with a tuner for the higher
> freqs
> ________________________________________________________________________
> __________
>
> I've put a C3 up as a replacement for my TH7DXS . The No TRAPS route and
> almost half the weight difference ( 31lbs. ) along with the pop rivet
> design
> as opposed to hose clamps has me convinced I made the right choice. The
> TH7
> has much better front to back rejection. However, the C3 performs
> equally
> and in some cases better then my circa 1989 TH7.
>
> In addition, I use the C3 on 12 and 17M with good results, this type of
> operation was
> not possible with the TH7. I only use a Rohn HDBX 48' tower so the C3
> sits
> at about a 53-54' height above ground.
> SWR spots.
> ________________________________________________________________________
> _________
> For a C3S:
>
> SWR on 12 sucks so far, but I need to change out a piece that f12 cut to
> wrong size on 20m ele, so we'll see then. 18meg swr is abt 4:1, again,
> we'll see. It fires "backwards" ON 18! What I understand is that it
> acts
> like a driven element and DIRECTOR rather than DE/Reflector 2 ele on
> other
> bands. SWR on 20/15/10 is fine (as it is on 40 -- I operate almost all
> cw
> there).
> ________________________________________________________________________
> __________
>
> I "think" the C-3S might be harder to stack, whereas the C-3 has a nice
> big
> gap between elements in about the right place. Otherwise, I agree, the
> C-3S would seem very competitive. Can't see for sure on the web page,
> but
> you might check this if it's a meaningful consideration for you.
>
> --
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
> Search: http://www.contesting.com/km9p/search.htm
>
> --
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: towertalk@contesting.com
> Administrative requests: towertalk-REQUEST@contesting.com
> Problems: owner-towertalk@contesting.com
> Search: http://www.contesting.com/km9p/search.htm
--
73,
Richard Thorne - N5ZC (ex KA2DSY, N2BHP, WB5M)
Amarillo, TX
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|