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Classic C Series | Multi Mono Triband Yagi Beams

Force 12's venerable C Series has well-earned the title "Classic" however you should not assume this means "dated"! In fact, from the beginning, these ground-breaking antennas were referred to as such due to their coverage of the 'classic tribander' bands - 20, 15 and 10 meters - not their age. The C Series are compact designs but don't let that fool you: the landmark head-to-head tribander testing by Silver and Morris showed the C-3 to have the best performance per foot of boom of all the antennas tested (see below).

C-4 models add our new high-efficiency, shortened 40 meter Delta-C element(s) to the core C-3 elements on the same boom and with a separate feedline.

C Series Models
6 Element Trapless Tribander for 20 / 15 / 10 Meters info & order here
C-3 7 Element Trapless Tribander for 20 / 15 / 10 Meters info & order here
C-3E 8 Element Trapless Tribander for 20 / 15 / 10 Meters info & order here
C-3E-CON C-3 to C-3E Conversion Kit info TBD
C-3SS Discontinued, replaced by XR3-C XR3-C info & order here
Delta-C-4SXL C-3S plus Delta-C 240 2 Element 40 Meter Yagi on same boom | replaces Delta-4SXL info & order here
Delta-C-4 C-3 plus Delta-C 140 40 Meter Rotatable Dipole on same boom | replaces Delta-4 info & order here
C-4-CON C-3 to C-4 Conversion Kit info TBD
Delta-C-4XL C-3 plus Delta-C 240 2 Element 40 Meter Yagi on same boom | replaces Delta-4XL info & order here

















For those desiring high performance on 40 and/or 30 meters but wanting to maintain the smallest possible antenna footprint, all C Series antennas stack well with newly upgraded Delta-C 140 (40 meters, info & order here) and Delta-C 130 (30 meters, info & order here) rotatable dipoles, this is an excellent alternative to the C-4 models which add 40 meter capability on the same boom which does increase the antenna rotating diameter.

You can find the C-19XR, C-31XR, C-49XR in the Strike Force section on this Website, info TBD

The C Series designs were all ahead of their time when introduced and still are! Don't just take our word for it! There are a very few 'level playing ground shoot-outs' between multi-band antennas. The most thorough and comprehensive testing is detailed in the "HF Tribander Performance Test Methods & Results" by H. Ward Silver, N0AX, and Steve Morris, K7LXC available from Champion Radio here.

Silver and Morris, in their concluding remarks, said:

"Big Overachiever - The Force 12 C-3 squeezes an enormous amount of performance out of short-boom design.

"Loudest - the C-31XR is clearly the big tribander to beat on the market today.

"Best Front-to-Back - The C-31XR also had the best performance here."

(C-31XR info & order TBD)

Other antennas in this test, the "bridesmaids," were the TA-33, PRO-57B, TH-7, TH-11, X-9 and KT-34XA.

The C Series introduced a number of ground breaking technologies: (1) Multi Monoband and (2) Forward Stagger element geometries, (3) Open Sleeve Feed System, and (4) Fast Taper lightweight element structural designs.

(1) Each C Series design is comprised of three individual monoband Yagis stacked horizontally on a single compact boom with each element in an optimum position - unlike trapped and SteppIR-style designs - and completely free of power robbing, bandwidth destroying, weather- and age-at-risk, and insect sheltering traps (and free of potential stepper motor failures, too).

(2) Forward Stagger element positioning where, for example, the positioning of 20 meter elements provide a boost to the higher frequency bands and conversely the positioning of the 10 meter elements help the lower frequency bands. In addition to boosting performance on the three classic bands, this has a secondary benefit of delivering gain and pattern on 17 and 12 meters with the use of an antenna tuner making the C Series five band antennas for those who also like to DX on the WARC bands.

(3) All C Series antennas use a single feedline using Force 12's patented Open Sleeve Feed System. The 20 meter driver is directly fed with the 10 and 15 meter drivers parasitically excited, a highly efficient approach. The C Series antennas are all native 50 Ohm designs and thus do not employ lossy matching devices such as gamma matches or hairpins.

(4) Fast Taper element structures optimize wind load, weight and survivability.


  • Proven Designs: thousands of C Series antennas are on the air every day cracking pileups and running up 'Top Ten Box' contest scores
  • Multi Monoband design puts each element in an optimum position, unlike trapped and SteppIR-style designs (and there are no potential stepper motor failures to worry about).
  • Forward Stagger design enhances gain and pattern on all three primary bands and delivers gain and pattern on 17 and 12 meters with an antenna tuner
  • Single feedline using Force 12's patented, high efficiency Open Sleeve Feed System
  • Small Footprints - all booms 18 feet long or less
  • No traps to rob power, destroy bandwidth, age, weather and provide insect shelter
  • 2 inch OD round booms; round booms have 33% less wind loading than square booms and superior strength for the same weight
  • Fast Taper element structural designs optimize wind load, weight and survivability
  • Boom-to-Mast hardware for 1.5 to 2.0 inch O.D. masts standard; larger sizes available on request
  • 5 kW CCS power handling subject to balun and coax feedline power handling


  • We recommend the Texas Antennas EB-1 (info & order here), EB-2 (info & order here) and EB-3 (info & order here) 1:1 ferrite bead baluns for use with C Series antennas
  • Turns great with medium duty rotators such as the AlfaSpid RAU, info & order here
  • All C Series antennas are potent contest antennas and work great with the 4O3A Signature Triplexer System allowing simultaneous three band, high power operation, info & order here


  • Each antenna is handmade one at a time in our Grand Junction, Colorado workshop from the best available materials
  • Each antenna fully assembled to ensure fit then partially disassembled for shipping
  • All boom-to-element brackets pre-aligned and boom mounted before shipping
  • High Tensile Strength (< 42,000 PSI ultimate) aircraft and architectural grade drawn aluminum tubing (6061-T8 and 6063-T832 alloys); drawn tubing has higher precision than extruded tubing and assembles into telescoping antenna elements with superior fit
  • Stainless Steel hardware standard, not an extra-cost option
  • Genuine Stauff Polypropylene industrial grade insulators
  • Famous Force 12 riveted construction; rivets hold skyscrapers, aircraft, Humvees and Airstream trailers together, and they will keep your antenna intact year in, year out (stainless bolts used in lieu of rivets on larger tubes)

C Series antennas are great for DXpeditions and portable operation, contact us for info on custom lightweight versions for your next trip.