MFJ | 2924P | manual | MFJ 2924M - 50 TO 75 OHM TRANSFORMER, LEGAL POWER, INDOOR Manual

MFJ-2924M and MFJ-2924P RF Transformers
Instruction Manual
Description: The MFJ-2924M and MFJ-2924P are in-line RF transformers that
transition between 50Ω and 75Ω loads, or transition from 50Ω sources down to
35Ω loads. The MFJ-2924M is designed for indoor use and is housed in a fully
shielded aluminum enclosure. MFJ-2924P is designed for outdoor use and is
enclosed in a weather-tight PVC enclosure for protection. Both feature a large
binocular ferrite-core transformer wound with silver-plated Teflon wire.
Input/output Impedance:
Power Rating:
Frequency Span:
Insertion Loss:
50Ω-75Ω, 75Ω-50Ω, 50Ω-35Ω
1500-Watts PEP SSB/CW, ICAS
1.8-50 MHz
< 0.05 dB
SO-239, Teflon dielectric
Suggested Applications: When raised high above ground, single or multi-band
dipoles may present loads closer to 75Ω, creating a mismatch with 50Ω cable
and reducing the antenna's 2:1 usable bandwidth. By the same token, 1/4-wave
multi-band verticals with effective ground systems, some Yagis, and loaded
antennas with shortened radiators may present loads down in the 35Ω range.
Better to correct these matches at the antenna rather than in the shack. Also, for
long transmission line runs, use transformers to feed surplus 75Ω cable-system
hard-line and save money. See example setups below:
75 Ohm Low-Loss Cable
50-Ohm Antenna
75-Ohm Antenna
75 Ohm Low-Loss Cable
50 Ohm Coax
50 Ohm Coax
75-Ohm Antenna
35-Ohm Antenna
Precautions: Note that the MFJ-2924M is not weather protected and may
sustain water damage if exposed to the elements outdoors. Also, note that all RF
transformers are subject to a small amount of loss which becomes dissipated in
the form of heat. As a result, the MFJ-2924 may exhibit excessive heat buildup
during sustained high-power operation due to limited air flow within the
enclosure. Avoid exceeding specified power limitations, and de-rate as
necessary if heating occurs. Finally, before applying RF power, always confirm
transformers have been installed in the right direction to yield the intended
impedance transition. Reverse orientation will result in elevated SWR.
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.
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, of forgery
shall be cause to void any and all warranty terms immediately.
MFJ Enterprises, Inc. agrees to repair or replace at MFJ's option without charge to the
original owner any defective product provided the product is returned postage prepaid to MFJ
Enterprises, Inc. with a personal check, cashiers check, or money order for $10.00 covering postage
and handling.
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 $8.00 personal check, cashiers
check, or money order must be provided to cover postage and handling.
This warranty is NOT void for owners who attempt to repair defective units. Technical
consultation is available by calling (662) 323-5869.
This warranty does not apply to kits sold by or manufactured by MFJ Enterprises, Inc.
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.
Under no circumstances is MFJ Enterprises, Inc. liable for consequential damages to
person or property by the use of any MFJ products.
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.
This warranty is given in lieu of any other warranty expressed or implied.
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.
All MFJ products to be serviced in-warranty or out-of-warranty should be addressed to
MFJ Enterprises, Inc., 300 Industrial Park Rd, 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 and a telephone number.
This warranty gives you specific rights, and you may also have other rights,
which vary from state to state.
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