MFJ MFJ-1835 User guide

MFJ-1835

10,12,15,17,20 Meter

Cobweb Antenna

Instruction Manual

Caution: Read All Instructions Before Assembling and

Using This Product!

MFJ

300 Industrial Park Road

Starkville, MS, 39759 USA

Tel: [phone] Fax: [phone]

Introduction: The MFJ-1835 is a compact five-band loop array especially

designed for limited-space installations. Using horizontal polarization, it packs a
3-4 dB gain advantage over ground-independent verticals plus superior immunity
to local noise and RFI. In addition, MFJ’s highly efficient Spider-Match® network
and adjustable tuning tabs guarantee low minimum-SWR on every band. The
MFJ-1835 only measures 9-feet on a side, yet it features a full half-wave element
on every band for no-compromise DX performance -- even when running QRP!
The MFJ-1835 is solidly constructed to take on extreme weather. With sky-gray
fiberglass spreaders and stranded-wire elements, it blends in with any backdrop.
Best of all, it’s omni-directional, so you can omit the rotor and mount it high in the
air using standard low-cost TV-antenna hardware.

Parts List: Before starting assembly, please check the package contents against
the parts list below to ensure all items have been included.

[ ] 2 8" x 8" Aluminum Mounting Plate (737-1835)
[ ] 4 72" Fiberglass Element Support Tube (811-1835-1)
[ ] 1 43" Fiberglass Feed Tube (811-1835-2)
[ ] 1 50-Ohm to 12.5 Ohm Match Box (10-1835-1)
[ ] 1 Mast-Mounting Bracket (735-1835)
[ ] 5 Element End-insulators, 12" x .5" (737-0115)
[ ] 2 Rolls, 10-Meter Element Wire (13-1835-10)
[ ] 2 Rolls, 12-Meter Element Wire (13-1835-12)
[ ] 2 Rolls, 15-Meter Element Wire (13-1835-15)
[ ] 2 Rolls, 17-Meter Element Wire (13-1835-17)
[ ] 2 Rolls, 20-Meter Element Wire (13-1835-20)
[ ] 1 Parts Pack (17-1835-1)

Parts Pack Contents:

[ ] 31 6-32 x 1" screw (656-1000S)
[ ] 14 6-32 x 3/8" screw (656-0375S)
[ ] 47 6-32 Kep Nut (705-0632S-K)
[ ] 21 #6 Flat Washer (561116)
[ ] 2 U-Bolt Assembly (758-9199)
[ ] 5 Cable Tie (745-2158B)
[ ] 10 Tuning adjustment strips (737-1615)

If any components are missing or damaged, refer to the warrantee for
replacement instructions.

Preparation and Site Safety: The MFJ-1835 is lightweight, but a second pair of
hands will always ensure greater safety during assembly and installation. Install
fiberglass spreaders on a flat level surface (driveway, garage floor, etc.) and
complete the assembly using a 5-6 foot temporary mast or pole. The mast will
allow you to string and tension wire element at eye level. Always wear safety
glasses when working with spreaders, and keep the assembly area clear of

people, pets, clutter and debris. Never assemble or install any antenna near
power lines or residential entrance cables!

Important Warning: This antenna is an electrical conductor and, if it comes
into contact with power lines, you can be KILLED. Never assemble or
install any antenna near power lines!

Tools: 7/16" and 5/16" nut drivers, #2 phillips-head screwdriver, diagonal cutters.

Assembly Instructions:

[ ] Locate one of the 8" x 8" aluminum mounting plates and install the mast­mount bracket using four (4) 3/8" screws and nuts. Insert screws so the nuts
install on the mast-mount side of the plate. This is the side that will be oriented
toward the ground during final assembly and installation.

Mounting Plate

Mounting

Bracket

Holes

[ ] Locate the second mounting plate and position it so all mounting holes align
with the first plate.

[ ] Install one of the fiberglass support arms as shown, inserting it between the
two plates and securing it with two (2) 1" screws and nuts. Insert screws so the
nuts install on the mounting bracket side of the plate. Finger-tighten for now –
they will be tightened later.

Mounting Plate

Install Tubes Between

the Two Mounting Plates

[ ] Install the remaining three spreader arms in the same manner.

[ ] Locate the matching-network support arm. Before installing, observe the
tube's mounting hole pattern closely. One set of holes will be closer to the end of
the tube than the set at the opposite end. Install using the pair of holes closest to
the end using two (2) 1" screws and nuts.