Force 12, Inc XR-5

The high performance and small size of the XR-5 have made it a clear winner. Before getting into the actual antenna, it might be good to address a common question these days. At the last three forums where I've been a speaker, I've been asked about the motorized Yagis in the market and how they compare. My surprise was that people in the audience answered the question for me - they don't compare. Some of the issues brought out by the audience are: a) the motorized antennas are much more expensive and they have the potential of a motor failure in the air (everything electrical has a mean time between failure); changing element lengths cannot make up for fixed element position; the gain and F/B ratios claimed cannot be done at the same time; if you do emergency work, you cannot afford to have something fail in the antenna (like a motor) - you are off the air; the power limitation gives a clue that there is loss in the design and system; and, you wait to change bands.

Taking 3 seconds to change bands wastes a lot of time when chasing DX and in contests (it all adds up). You can easily make 400 band changes in a weekend DX pile-up or contest to listen and call stations on other bands. 400 changes x 3 seconds = 1200 seconds -- a full 20 minutes you are off the air. This does not include extra time being sure the band change is complete so you don't trip off your amplifier or damage the antenna. If you are really active, 800 band changes is not unreasonable and that is at least 40 minutes lost.

The advent of the Force 12 C-3 in 1993 changed the landscape of amateur antennas. For the first time, the C-3 provided an efficient, simplified solution using a multi-monoband approach, void of the losses associated with traps and the complexities of log periodic designs.

This Force 12 design was a true breakthrough in antenna design and the performance improvement over conventional "tri-banders" was so good that the C-3 became an instant success. To avoid confusion with trapped antennas, the C-3 was properly labeled a "multi-monobander", because it utilized multiple monoband Yagis on a single boom. The C-3 covered the popular 20-15-10 meter bands and also offered service on 17 and 12 meters using a tuner, which was another "first." Further developments led to additional C-series antennas and also to the larger XR- series (up to a 49’ boom), which are dedicated to the 20, 15 and 10 meter bands. Customers asked for more performance on the 17 and 12 meter WARC bands to match the C-3 on 20-15-10 and many designs were used over the past 5 years. The response to our customers is the new, "XR-5."

The XR-5 uses technology from our C-series and XR-series multi-monoband Yagis. The boom was kept as short as possible without compromising performance. Much time was spent in developing the feed system so it was "plug and play" like the C-series and the jacketed feeds on the XR’s. The construction has been simplified with fewer element sections and the standard XR-5 is rated at a conservative 100 mph. There is no finer 5-band Yagi that the XR-5 (except the 33’ boom Force 12 5-BA!).

Force 12, Inc. XR-5 Specifications

Bands covered

20, 17, 15, 12, 10 (full coverage on all bands)

Boom Length

18’

Number of Elements

10 (2 full size for each band)

Design

Force 12, Inc. overlay and forward stagger, used on the C-3 (on all C-series) and C-31XR (and on all XR series)

Survival

100 mph (boom >160 mph, no truss)

Windload

8.5 sqft

Weight

57 pounds

Turning Radius

20.2’

Longest Element

36.5’ (20 meter reflector)

Feedlines

One, 50 ohm coax. Use Force 12 B-1 balun (1:1), or RF choke (always use a balun or choke to feed a Yagi antenna; the driver is balanced and the coax is unbalanced).

Match

Combination using Patented Force 12, Inc. Open Sleeve

VSWR

measured at antenna height of 40’

20 mtrs	14.000	1.3:1	14.350	1.4:1 (lowest VSWR in band is <1.2:1)
17 mtrs	18.110	<1.4:1 whole band		(18.068-18.168)
15 mtrs	21.000	1.6:1	21.450	1.7:1 (lowest VSWR in band is <1.4:1)
12 mtrs	24.920	<1.4:1 whole band		(24.890-24.990)
10 mtrs	28.000	1.5:1	29.700	1.9:1 (lowest VSWR in band is <1.3:1)

Forward Gain

4.4 – 4.8 dBd on all 5 bands, the same as the famous C-3 has on 20-15-10! (This is dBd, compared to a full size dipole at the same height - please see Force 12, Inc. Antenna Specifications found on this web site and in all brochures for full description of this accurate gain figure.)

F/B Ratio

14-20dB (Front-to-side >25dB)

Power Handling

>5KW, no time limit