but the larger diameter is recommended for taller masts. Also, avoid installing
guy wires in close proximity to the elements. Finally,
never install where humans
or animals can come in contact with the elements.
Be especially attentive to
safety when conducting portable operations in public areas!
Important Warning: Contact with energized element wires can (and will)
cause severe RF burns or even death! Never install the MFJ-1835 where
humans or pets could make accidental contact.
Coaxial Feedline:
For best results, use new uncontaminated 50-ohm coax and
avoid making splices that could take on water and cause contamination. The
MFJ-1835 is light in weight and not designed for high power operation, so any
premium grade RG-8X (or Mini-8) should work well (RG-58 okay for short runs).
Larger cables such as RG-8 or 9914 have lower loss, but will add extra weight to
your installation. With lighter cable, you can safely mount the antenna higher in
the air which is normally more beneficial.
Antenna Grounding:
Always install a
Safety Ground
to protect your property
and your equipment from near-by lightning strikes. Connect the base of the
support mast to a suitable ground rod installation using one or more runs of #10
solid aluminum ground wire. Also, always install a barrel connector or junction
box where the cable enters your building and unhook it at the first sign of
threatening weather. Lightning arrestors may provide some protection from
nearby strikes, but a complete disconnect is your only real protection against a
very close or direct hit!
Theory of Operation:
The MFJ-1835 consists of five concentrically arranged
1/2-wave horizontal loops mounted on a fiberglass X-frame. The footprint is
square, with all five elements fed in parallel through a reactance-compensated
broadband autotransformer. The radiation pattern is virtually omni-directional (±
1.5 dB). A sleeve-style ferrite balun is installed at the feedpont to choke off
unwanted common-mode radiation. The balun also reduces receiver-noise
pickup and spurious RFI signals generated by consumer devices. Weighing just
over eight pounds, the MFJ-1835 installs easily on virtually any portable or
permanent mast from 1-1/4” to 1-3/4” OD.
Specifications:
Minimum SWR:
1.1:1 or lower all bands, measured at 20' AGL
Modeled Gain:
4.7 dBi at 20-feet AGL on 14.2 MHz with 37º TOA.
Modeled Pattern: Omni-directional, ±1.5 dB, max. gain on axis with feedpoint.
Power Handling:
300-W pep SSB/CW recommended, never exceed 600-W
Dimensions:
9’ x 9’ per side, 12' diagonally
Weight:
8.2 pounds
Mast Size
1-3/4" OD maximum
