DX Engineering DU 1500 T User manual

DU 1500 T ANTNNEA TUNER
FEATURES
The DU 1500 optimizes the performance of your antenna and transmitter or SWL receiver
By providing adjustable impedance matching.The DU 1500 also measures the Power and
Standing Wave Ratio (SWR),which allows you to tune the indicted SWR to the lowest
possible ratio for the selected transmit frequency.
SPECIFICATION
FRONT PANEL INDICATORS AND CONTROLS
Meter…………………………Cross needle Power and SWR meter.
CONTROLS
Input Tuning………………….Continuous rotation 4,5kV capacitor 330pF
Antenna Tuning………………Continuous rotation 4,5kV capacitor 330pF
Antenna Switch Selector………Five position ceramic switch:COAX 1, Tuned and
COAX 2 Tuned and BYPASS,COAX 1 DIRECT,
COAX 2 DIRECT
Power Range Switch…………..Two position: 200W/2kW
!!1.8MHz SWR wors then 1:3 MAX 800W!!
REAR PANEL CONNECTORS
Coax 1…………………………...SO-239 Teflon connector
Coax 2…………………………...SO-239 Tflon connector
Balanced Line……………………Dual high voltage ceramic terminal
Include 4:1 balun
OTHER
Frequency Coverage……………...1.8-30MHz ,continuously tunable
Power Maximum…………………1500W max 2kW
Input impedance………………….50ohm
Output inoedance…………………25-600ohm and wire 2000ohm
Dimension………………………...H 330xW 330xD 120
Weight…………………………….10lbs.(4,5kg)
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CONTROL/CONNECTORS
FRONT PANEL FUNCTIONS
1. Output (Transmitter)
Continously adjustable input capacitor
2. POWER/SWR METER
Dual needle meter displays FORWARD and REFLECTED Power in Watts.
The SWR in measured where the two needles intersect on the red scale.
3. INPUT (Antenna)
Continuously adjustable output capacitor.
4. DIRECT-TUNED MODE SWITCH
Five-position rotary switch an output coaxial connector.
1.TUNED COAX 1 selects theCOAX 1connector trough the impedace matching
circuit.
2.TUNED COAX 2 selects the COAX 2 connector trough the impedance matching
circuit.
3.DIRECT BYPASS selects BYPASS COAX connector bypassing the impedanc
matching circuit but provinding SWR,FORWARD,and REFLECTED power
meter readings.
4.DIRECT COAX 1 select the COAX 1 connector bypassing the impedance
matching circuit but providingSWR,FORWARD, and REFLECTED meter
readings.
5.DIRECT COAX 2 selects the COAX 2 connector bypassing the impedance
matching circuit but providing SWR,FORWARD,and REFLECTED meter
readings.
6. TUNED WIRE/BAL selects the BAL.LINE+COAX 1 connector through the
impedance matching circuit.
5.RANGE SWITCH
Two-position switch selects the range (200W or 2kW) of FORWARD and
REFLECTED Power displayed ont he power meter.
When the METER ( power range) switch 200W the FORWARD meter
Scale reads 200W full scaleand the REFLECTED meter scalereads 40W
Full scale.
When the METER switch 2kW,the FORWARD meter scale reads 2kW
Full scale and the REFLECTED meter scale reads 400W full scale.
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REAR PANEL CONNECTORS
1. RF INPUT
Coaxial connector for input from SWL receiver or transmitter.
2 COAX 1
Coaxial connector for output to Antenna One.
3. COAX 2
Coaxial connector for output to Antenna Two.
4. BYPASS
Coaxial connector for output to dummy load or third coax output.
5. GROUND
Post/Wing-nut type ground connector.
6 BALANCED OUTPUT
Two ceramic post for output toRF balanced twin-lead antennas.
7. Install Jumper
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INSTALLATION
Select a location for the DU 1500 that allows the connectors to be free of any possible
Contact during operation.
WARNING:SOME BALANCED OR END-FED ANTENNAS WILL PRODUCE
HIGH RF VOLTAGES AT THE BANANA CONNECTORS.RF
BURNS MAY RESULT IF TOUCHED DURING TRANSMISSION.
INSTALLATION PROCEDURES
1. Connect a coax cable from your transmitter or receiver to the RF INPUT connector on
the rear panel.Keep the cable as short as possible. If you use a linear amplifier,connect
your transmitter to the linear amplifier output to the DU 1500.
2. Connect coax cable(s) from your antenna to COAX 1 or COAX 2 connectors ont he rear
panel.Thes connectors are either direct from the transmitter or trough the tuned circuit
depending ont he setting of the OUTPUT SELECTOR switch ont he front panel.
3If you are using a balanced feed antenna,connect the INSTALLJUMPER in the COAX 1
connector and switch band switch TUNED COAX 1.
4. If using a single wire antenna,connect itt o post COAX 1 without installing jumper.
5. Connect a dummy load to the BYPASS CONNECTOR using a coax cable.This
lets you select the dummy load from the OUTPUT SELECTOR switch.Any antenna
that does not require the use o fan antenna tuner may be connected to the BYPASS
connector,if desired.
BEFORE OPERATION
1. To avoid possible damage to the DU 1500,set INPUT,OUTPUT,BAND SWITCH
and POWER RANGE switches as outlined int he next section before applyng
transmitter power.(Tuning Section)
2. Begin tuning with your transmitter se tat a low power setting ( 50 to 100W)
WARNING: DO NOT OPERATE THE DU 1500 WITH THE COVER OFF!
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TUNING
1. Select the band and frequency of desired operation.
2. Set INPUT,OUTPUT,and BAND SWITCH controls to the suggested settings before
applyng transmitter power.Actual settings may vary from antenna to antenna.
3. Set up your transmitter to a low power output.If you transmitter has a TUNE
position,select that position.
4. If you use a linear amplifier,set itt o STANDBY. Do not use the linear amplifier
until the DU 1500 is tuned.
WARNING:DO NOT EXCEED 1500WATTS AVERAGE(SINGLE TONE).
5. Set POWER RANGE switch to 200W.
6. Set OUTPUT SELECTOR switch to BYPASS,or the position matching your antenna
connection.To tune your antenna,the switch selection must be set to:COAX 1 TUNED
COAX 2 TUNED,or BAL.LINE+COAX 1.Selecting COAX 1 DIRECT,COAX 2
DIRECT, or BYPASS.
7. Rotate the INPUT and OUTPUT controls for maximum noise or signal as heard
on your receiver.
8. Key your transmitter and adjust the power level for a reading of 50-100 watts on the
FORWARD scale.Adjust the INPUT and OUTPUT controls for
a minimum REFLECTED reading while maintaining a FORWARD reading of 50-
100 watts using your transmitter power control.
9. Read the SWR on the red scale at the point where the two needles intersect.Repeat step
8 until the lowest SWR reading is obtained. The SWR should be 2:1 or lower.
NOTE:This procedure takes patience the first time.The INPUT and OUTPUT
Controls vary the capacitors and provide fine adjustments.
5

NOTES
1. An SWR or 1:1 is best,buta n SWR as high as 2:1 may be acceptable. Check
you transmitter manual for details.
2. If you cannot get an acceptable SWR, lengthen or shorten you antenna and/
or feedlines and retune.
3. If you grt low SWR readings at more than one setting,use the setting that:
Gives the highest FORWARD power reading.
Gives the lowest REFLECTED power reading.
Uses the largest capacitance (highest number) ont he TRANSMITTER and
ANTENNA controls.
4. Any time a new or different antenna is connected,it is necessary to repeat the tuning
procedure for each antenna.
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