40M-4 WORLD CLASS EXTRA - 4 ELEMENT MONOBAND BEAM ANTENNA FOR 40 METERS
- GAMMA OPERATIVA: 7.0-7.3 MHz
- LARGHEZZA DI BANDA: 260 kHz
- GUADAGNO: 7.2 dBd
- FRONTE/RETRO: 20 dB
- R.O.S. MAX.: 1.5: l
- IMPEDENZA: 50 OHM
- BALUN: 4: l da 5kW
- LUNGHEZZA ELEMENTO 14 MT.
- LUNGHEZZA BOOM: 12.8 MT.
- RAGGIO DI ROTAZIONE: 9.75 MT.
- AREA ESPOSTA: 1.11 mq. (12 sq.ft .)
- PESO: 44.5 KG.
- DIAMETRO BOOM: 3 POLLICI (7.6 cm.)
- ATTACCO A PALO: 2 POLLICI (3 OPZ.)
WORLD CLASS EXTRA HF ANTENNAS ...
KLM's World Class Extra series of antennas are designed to satisfy the needs of the most serious DX operator. The
80M-3, 40M-4 and the 20M-15M-10M 6 element monobanders offer the ultimate in performance with no compromises.
The electrical designs are devised to achieve maximum gain, bandwidth, and front-to-back ratios. Construction materials
and techniques are selected for maximum strength and durability. All of KLM's World Class Extra antennas use
multiple driven elements. The average multi-element Yagi type beam antenna with only a single driven element is
essentially a high Q system. Maximum gain, maximum F/B ratios, minimum VSWR and cleanest patterns are possible
only over a very narrow frequency range; for example over the phone or CW portions of an amateur band. The Q of a
single driven element becomes extremely high in the presence of multiple parasitic elements when these elements are
adjusted tor optimum performance. The Q can be reduced and the bandwidth increased by manipulating the dimensions
of the parasitic elements, but at the expense of reduced gain and F/B ratios. This undesirable situation can be remedied
by the use of two driven elements fed in parallel and tuned to different frequencies - one frequency near the bottom and
one near the top of the amateur band. The parasitic elements can now be adjusted tor maximum gain and F/B ratios
rather than tor broad VSWR curves. This is the familiar "log-cell" driven element system derived from log-periodic
antenna design that is used in most of KLM's HF antenna designs. The response of KLM dual-driven element antennas
rolls off very rapidly outside the specified band coverage thus providing an added bonus in the form of lessened radiation
on adjacent frequencies. KLM uses boom-insulated elements throughout. This provides total isolation of the antenna
elements from the boom and minimizes possible interaction effects from the boom. Exclusive KLM designed insulators
are molded of a special glass-filled materiai which has excellent insulating properties and extremely high mechanical
strength. The form is webbed .... heavily reintorced at stress points to withstand high winds safely. To minimize unsightly
"droop" in long elements, the mounting angle is tilted slightly upward.
HF MONOBAND YAGIS ...
KLM high performance monobanders are the answer for quality installations where larger models are not practical or
necessary. Moderate in size, they can be easily stacked with other beams without overloading the tower/rotor capabilities.
KLM monobanders offer many of the superb performance and construction features of the World Class Extra
series. KLM's dual-driven element system provides full performance and broadband coverage, in many cases across
the entire amateur band! Matching problems are eliminated with the KLM 3-60-4:1 baluns which are rated to 5kW PEP.
6063-T832 aluminum alloy, massive insulators and stainless steel hardware (except U-bolts), along with swaged boom
sections assure years of trouble-free, consistent performance. The 40M-3, 40M-4, 20M-5, 20M-6, and the 15M-6 are
also available with a heavy duty boom (1/4" wall) at an additional cost. The 80M-2 and 80M-3 come with the heavy duty