12 MONTH LIMITED WARRANTY
MFJ Enterprises, Inc. Warrants to the original owner of this product, if manufactured by MFJ
Enterprises, Inc. and purchased from an authorized dealer or directly from MFJ Enterprises,
Inc. to be free from defects in material and workmanship for a period of 12 months from date
of purchase provided the following terms of this warranty are satisfied.
1. The purchaser must retain the dated proof-of-purchase (bill of sale, canceled check, credit card or
money order receipt, etc.) describing the product to establish the validity of the warranty claim and
submit the original or machine reproduction of such proof-of-purchase to MFJ Enterprises, Inc. at
the time of warranty service. MFJ Enterprises, Inc. shall have the discretion to deny warranty
without dated proof-of-purchase. Any evidence of alteration, erasure, or forgery shall be cause to
void any and all warranty terms immediately.
2. MFJ Enterprises, Inc. agrees to repair or replace at MFJ’s option without charge to the original
owner any defective product under warranty, provided the product is returned postage prepaid to
MFJ Enterprises, Inc. with a personal check, cashiers check, or money order for $7.00 covering
postage and handling.
3. MFJ Enterprises, Inc. will supply replacement parts free of charge for any MFJ product under
warranty upon request. A dated proof-of-purchase and a $5.00 personal check, cashiers check, or
money order must be provided to cover postage and handling.
4. This warranty is NOT void for owners who attempt to repair defective units. Technical consultation
is available by calling (662) 323-5869.
5. This warranty does not apply to kits sold by or manufactured by MFJ Enterprises, Inc.
6. Wired and tested PC board products are covered by this warranty provided only the wired and tested
PC board product is returned. Wired and tested PC boards installed in the owner’s cabinet or
connected to switches, jacks, or cables, etc. sent to MFJ Enterprises, Inc. will be returned at the
owner’s expense unrepaired.
7. Under no circumstances is MFJ Enterprises, Inc. liable for consequential damages to person or
property by the use of any MFJ products.
8. Out-of-warranty Service: MFJ Enterprises, Inc. will repair any out-of-warranty product provided the
unit is shipped prepaid. All repaired units will be shipped COD to the owner. Repair charges will
be added to the COD fee unless other arrangements are made.
9. This warranty is given in lieu of any other warranty expressed or implied.
10. MFJ Enterprises, Inc. reserves the right to make changes or improvements in design or manufacture
without incurring any obligation to install such changes upon any of the products previously
manufactured.
11. All MFJ products to be serviced in-warranty or out-of-warranty should be addressed to MFJ
Enterprises, Inc., 300 Industrial Park Road, Starkville, Mississippi 39759, USA and must be
accompanied by a letter describing the problem in detail along with a copy of your dated proof-ofpurchase.
12. This warranty gives you specific rights, and you may also have other rights, which vary from state to
state.
MFJ-916B & MFJ-916BN
Indoor Duplexer
Instruction Manual
Thank you for purchasing the MFJ-916B or MFJ-916BN duplexer.
Please read these instructions thoroughly prior to use.
The MFJ-916B has SO-239 connectors. The MFJ-916BN
duplexer has Female N connectors.
The duplexer is a series of inductance coils and capacitors that
acts as a band-pass filter. Your MFJ duplexer can be used two
different ways. Connection diagrams are on the next page.
In Connection Diagram 1 the duplexer combines the output of
the HF/VHF transceiver and the output of the UHF transceiver so that
both transceivers can be connected to the same antenna. In this
configuration, connect the antenna to the connector labeled
COMMON. Connect your HF/VHF transceiver to the connector
labeled 1.3~225 MHz. Connect your UHF transceiver to the
connector labeled 350~540 MHz. Be sure you connect the correct
transceiver to the correct connector.
In Connection Diagram 2 the duplexer separates HF/VHF
transmissions from UHF transmissions so that one transceiver can be
connected to two antennas. In this configuration, connect the multiband transceiver to the connector labeled COMMON. Connect your
HF/VHF antenna to the connector labeled 1.3~225 MHz. Connect
your UHF antenna to the connector labeled 350~540 MHz. Be sure
you connect the correct antenna to the correct connector.
Connection Diagram 1
Connection Diagram 2
Specifications:
Insertion Loss: 0.2 dB
SWR: Less that 1.2 to 1
Isolation: 60 dB
Power: 500W (1.3 to 35 MHz)
300 Watts (50 to 225 MHz)
300 Watts (350 to 540 MHz)
Notes / Cautions:
• If you need to use adaptors to connect your coax to the
duplexer, you will experience some loss through the adaptor.
Higher SWR level can be expected when using adaptors to
connect your coax to the duplexer.
• Do not exceed the power ratings listed in the specifications.
• Do not transmit outside the frequency range for the connection
used. In Connection Diagram 1, be sure your HF/VHF
transceiver is transmitting between 1.3 MHz and 225 MHz, and
your UHF transceiver is transmitting between 350 MHz and
540 MHz. In Connection Diagram 2, be sure that your multiband transceiver is transmitting between 1.3 MHz and 540
MHz.
• The MFJ-916B and MFJ-916BN are designed for indoor use.
If you use the MFJ-916B or MFJ-916BN outdoors, it should
only be used for short periods of time under good weather
conditions. Do not use the duplexer outdoors when there is any
kind of precipitation.