User`s Manual - Unified Microsystems

UM
Unified
Microsystems
BT-75 Beverage Transformer
User's Manual
Revision 1.00
September 2014
Specifications
Size: 3.75” X 2.25” X 1.5”
Feed line impedance: 75 ohm
Antenna feed impedance: 450 ohms
Connector type: F
Overview
Beverage antennas are excellent low noise receive only antennas. Properly built, Beverage antennas
have excellent rejection of signals and noise from the non-favored direction. For information on
constructing your Beverage antenna ON4UN's Low-Band DXing or the ARRL Antenna Book are
recommended.
Beverage antennas have a typical impedance of 450 ohms. For best performance this must be matched
to the coaxial feed line. The BT-75 is designed to be with 75 ohm RG-6 coax cable. RG-6 is designed
for TV use. Because of this, it is produced in very large quantities and thus inexpensive. Coax
designed for TV must have low loss at VHF and UHF frequencies. Because of that, it will have very
loss loss at the 160, 80 and 40 Meter band frequencies. For this reason RG-6 is the most popular feed
line for Beverage antennas.
The BT-7 has a gas discharge tube across the antenna terminals to help protect the transformer from
lightning strikes in the area. While this provides protection, it will not protect against direct or close by
hits.
Warning!
Always disconnect your Beverage antenna from the radio when storms are possible!
Never transmit into the BT-75!
Installation
1. Mount the BT-75 on the support for the feed end of the Beverage wire.
2. Attach the Beverage wire to one of the screw connections with the wing nut. The wire should have a
strain relief before connecting to the BT-75. It does not matter which screw the wire is connected to.
3. Attach the ground wire to the remaining screw.
4. Connect the RG-6 F connector to the BT-75 F connector. Cover the connectors with electrical tape
or other weather sealing method.
Warranty Information
Unified Microsystems warrants the components workmanship of the BT-75 for a period of 1 year from
the date of purchase. A copy of the receipt must be included with any units returned for warranty
repairs.
Unified Microsystems will, at its option, repair or replace defective units returned during the warranty
period. Unified Microsystems reserves the right to change specifications of it products at any time
without notice.
If you have questions or need help, email w9xt@unifiedmicro.com. Please put “BT-75” in the subject
line for fastest response.
Unified Microsystems
PO Box 133
Slinger, WI 53086
www.unifiedmicro.com
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