Radio Active Designs TX-8U User manual

SPECIFICATIONS
Operating Frequency Range
Number of RF Inputs
Nominal Input & Output Impedance
Input Power Range per Channel
Selectable Output Power per Channel
In-Channel Inter-modulation Products
Channel-to-Channel Inter-modulation Products
All Harmonic Levels
(Exceeds FCC Part 74 & Part 15 Requirements)
Antenna VSWR Indicator Threshold
Operating Temperature Range
AC Line Operating Voltage & Frequency
Power Consumption
Dimensions
RF Connections
Additional Options Available
470-698 MHz
8
50 Ohms
25-250mW
50, 100, 250mW
Better than -35 dB (typical)
Better than -65 dB (typical)
Better than -40 dB
Greater than 2:1
-20 to +60°C
90-260 VAC 47-63 Hz
<125 Watts
19” W x 1U H x 12 ¾“ D
BNC
Special Order
CONTACT US
Radio Active Designs
21 East Union Avenue
East Rutherford, NJ 07073
Phone: [phone]
www.RadioActiveRF.com
TX-8U
ANTENNA COMBINER
QUICK START GUIDE
TX-8U QSG Rev 10/17

MINIMIZING IM PRODUCTS
The TX-8U brings a new level of IM performance to combiner systems, using
advanced technology not found in any other system. While IM products are still
produced in any combined antenna system, they are at much lower levels with
the TX-8U.
There are well-known techniques for dealing with IM products caused by
combining, such as careful selection of transmit frequencies, judicious
adjustment of power levels, and minimizing antenna SWR. For additional IM
reduction, the following information may be useful.
Proper port selection is an additional way to minimize IM products
when using the TX-8U.
Because of the nature of combiners, some ports have more isolation between
them than others. The TX-8U is no different in this regard, and knowing which
ports have the highest isolation can be of benefit in reducing unwanted IM
products.
There are 8 numbered transmitter ports on the TX-8U.
The following port pairs have the least isolation between them:
• Ports 1-2, 3-4, 5-6, and 7-8.
Generally, you should use these paired ports for the widest spaced
frequency pairs, or alternatively, for pairs where the IM products will
not create problems.
Higher isolation is available between the following ports:
• Ports 1-3, 1-4, 2-3, 2-4, as well as 5-7, 5-8, 6-7 and 6-8.
These can be used for more troublesome frequency pairs, resulting in
better IM performance overall.
The highest isolation is found between the ports from 1 through 4 and the ports
from 5 through 8.
For serious IM issues, make sure the offending transmitter ports are
separated accordingly.
For example, if you have one transmitter on a port from 1 through 4, you would
need to put the other transmitter on any port from 5 through 8. This would
provide the highest level of transmitter to transmitter isolation.
INITIAL SETUP
1) Connect the IEC power cord to the AC power cord jack on the back of
the combiner.
The input range is auto-ranging from 90 VAC to 260 VAC.
2) Connect the antenna to the jack marked OUT.
3) Connect up to 8 transmitters to the various inputs before powering
on. DO NOT CONNECT PREVIOUSLY COMBINED TRANSMITTERS
TO ANY INPUT as performance will be compromised and damage to
the unit may occur. Terminate unused ports with 50
W
loads.
4) Turn the front panel power switch to ON prior to powering on
transmitters.
5) Set the power levels to desired output:
50mW, 100mW, or MAX (nominally 250mW)
NOTE: LOW indicates the unit is not transmitting power.
6) If an input channel is not in use, turn the output switch to LOW.
INDICATOR LIGHTS
POWER LIGHT
• GREEN: Combiner is powered ON.
• No Light: Combiner is OFF.
ANTENNA STATUS LIGHT
• GREEN: SWR optimal.
Antenna and cable are OK.
• YELLOW: SWR greater than 2:1.
Marginal antenna operation.
• RED: SWR High, greater than 3:1.
Indicates bad antenna and/or bad cable.
CHANNEL INDICATOR LIGHTS
• NONE: No power detected at input.
• GREEN: Input power present. Selected output power operating
correctly.
• RED: Channel amplifier fail.
• YELLOW: RF Input present. Channel OFF.