Difference between revisions of "Dentron MT-2000A and MT-3000A"

Revision as of 23:47, 12 April 2017

These are efficient antenna tuners capable of handling full legal limit power for use with amateur radio.

• Freq Coverage: 1.8 MHz - 30 MHz continuous
• Power Handle: 3000 watts P.E.P.

You should connect only one antenna at a time to the MT-2000A. The MT-3000A will accommodate multiple simultaneous connected antennas.

Although you can physically connect an antenna via the PL-239 and another antenna via the balanced line connector to the MT-2000A, you should not do this as there is no way to select between them from the unit and consequently you will have problems.

Specs

• 1.8 to 30 MHz Continuous
• Input Z : 50 Ohms resistive
• Output Z: Coax 50 Ohms nominal but may be a few Ohms to HI-Z
• Long Wire: High or Low Impedance
• Balanced Line (4:1 Balun inside tuner cabinet): 75 to 600 Ohms
• POWER RATING: 3000 Watts PEP
• INSERTION LOSS: 0.5 dB or less after tuning
• Dimensions: 5.5" H X 14" W X 14" D
• Weight: 18 lbs
• TRUE BYPASS SWITCH is an actual pass- through
• Antenna grounding switch included

Inductor Guide

Inductor selection is a starting point for you to tune to resonance with your own antenna setup.

Dentron recommends setting both capacitor selectors (Transmitter Matching) and (Antenna matching) to setting 5 before trying to locate the correct inductor setting for the frequency. Watch for the highest noise/signal level on the S meter. When the best inductor is located then fine tune using the capacitance tuning dials. If tuning for the higher bands 20, 15 and 10 set the "transmitter" capacitance to 8 instead of 5.

(A) on the inductor is the highest frequency and (R) is the lowest frequency on the inductor switch.

The following guide is for an Inverted V 66½' on each leg @ 45degrees for 75-meter

band       frequency    inductor      cap and ind select
-----------------------------------------------------------
160          1990          R          6.7, R, 5.0
 80          3980          K          4.0, K, 3.0          1:1
 60
 40
 20
 15
 10
-----------------------------------------------------------

FOR UP TO 10 MHZ: Set both capacitors for mid range (5). Adjust Inductor for maximum receive signal or background noise. Apply less than 100 Watts and adjust for minimum SWR.

FOR 14 MHZ AND ABOVE: Set both capacitors to 8. Adjust Inductor for maximum receive signal or background noise. Apply less than 100 Watts and adjust for minimum SWR.

MT-2000A specific

It is important to understand that you should not connect two antennas to this tuner at the same time. It was not designed to have you connect an unbalanced feedline to one antenna while also having a balanced line or long wire antenna connected. Use one or the other, not both at the same time!

Building a transmatch that covers 160 through 10 Meters is a challenge. The capacitors have to have a maximum capacitance sufficient to function at 160 Meters. This makes it difficult to achieve minimum capacitance values to work at 10 Meters. You may find that the small vertical coil in the front of the cabinet can be adjusted by spreading its top two turns. This may allow better match on 10, 12, 15, AND 17 Meters. Be very careful you do not stress the switch while making this adjustment. Support the connecting wire to the switch with pliers to remove the stress from the ceramic switch.

SPECIFICATIONS:

• 1.8 to 30 MHz Continuous
• Input Z : 50 Ohms resistive
• Output Z: Coax 50 Ohms nominal but may be a few Ohms to HI-Z
• Long Wire: High or Low Impedance
• Balanced Line (4:1 Balun inside tuner cabinet): 75 to 600 Ohms
• POWER RATING: 3000 Watts PEP
• INSERTION LOSS: 0.5 dB or less after tuning
• Dimensions: 5.5" H X 14" W X 14" D
• Weight: 18 lbs
• TRUE BYPASS SWITCH is an actual pass- through
• Antenna grounding switch included
• No AC or DC power required for operation

• SWITCH POSITION A for lowest frequency (160 Meters)
• SWITCH POSITION R for highest frequency (10 Meters)
• NEVER ADJUST ANYTHING WITH FULL POWER APPLIED except for tuning capacitors!
• NEVER APPLY POWER WITH LIGHTNING PROTECT SWITCH SET TO PROTECT. ALWAYS SET IT TO OPERATE BEFORE TRANSMITTING AT ANY POWER LEVEL!
• TUNER-BYPASS SWITCH ONLY AFFECTS COAX CONNECTOR. It does not function on open wire or balanced connections.
• NEVER CONNECT MORE THAN ONE ANTENNA TO THE MT-2000A.
• FOR UP TO 10 MHZ: Set both capacitors for mid range (5). Adjust Inductor for maximum receive signal or background noise. Apply less than 100 Watts and adjust for minimum SWR.
• FOR 14 MHZ AND ABOVE: Set both capacitors to 8. Adjust Inductor for maximum receive signal or background noise. Apply less than 100 Watts and adjust for minimum SWR

Notice above where it says, "The TUNER-BYPASS SWITCH ONLY AFFECTS COAX CONNECTOR. It does not function on open wire or balanced connections." How can this be accurate when you look at the schematic? It looks to me like the balun is still a factor whether or not the bypass is engaged, however, the capacitors and inductor are bypassed when using balanced line with the bypass engaged.

Dentron MT-2000A Schematic

The connection from S1A left to the so239 should have the line going to the center of the connector I believe.

Also, it looks like the balun could be bypassed using balanced line if one side of the balanced line was connected to the Single Wire connector while the other side of the balanced line was jumpered internally (using a wire with alligator clips) to the chassis.

references

• http://bama.edebris.com/manuals/dentron/mt2000a/