DENTRON MT-2000A ANTENNA TUNER
  

Of all the transmatches I own, this is my favorite. It consistently gets a 5 rating on eham reviews. It does not attempt to add "features" like a power or SWR meter or antenna selector, which I prefer to add separately. I am very picky about those items, and prefer to choose them separately. I have never found it lacking in performance. It matches any antenna I have ever connected to it. It handles all the power from my Heathkit SB200, about 700 Watts output with no signs of arcing or heating. All the internal components are super heavy duty compared to commonly available new units. This transmatch comes in a variety of flavors. The early Dentron Super Tuner is rated at 1 KW; I have run it at 100 Watts AM (equivalebnt to 400 Watts or more PEP) with no problems. A big brother is the 3000 Watt model, overkill for my station. These typically go for $90 to $300 depending on the power rating at swapmeets or better web sites. The suthoritative clunk of the switch speaks of the quality and dependability of this well built unit. I quickly became dissatisfied with the match range and reliability of the Ten Tec 238 transmatch reviewed elsewhere on this page. This Dentron is a definite keeper. 5 out of 5.

Have you ever seen a manufacturer dare to state the insertion loss in dB? Read the specs included later to see. QST often finds even 2 or 3 dB on recent transmatch product reviews.

See the interior photos to understand the detaiiled notes below.

The only problem I encountered was the breakage of the lucite plastic insulators beneath the tuning capacitors. Some glue corrected this easily. Everything else is built like a tank. This unit weighs 18 pounds due to the substantial cabinet.

The lightning protect switch was stuck in place when I bought it used after a long period in storage. I applied some WD40 and let it soak in several times. I removed the knob and used vise grips to carefully rock the switch shaft till it became operable. Since I have external grounding type antenna switches, this feature is not used at my station. I always disconnect the antennas outside at a grounding rod when not in use during lightning season.

The capacitor tuning shafts have plastic extensions. If these ever break, I plan to use a ceramic shaft coupler and add surplus vernier reductions to the stock knobs. At higher frequencies, the tuning is a bit touchy, but not to the point that you cannot use it in stock form.

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.

The long piece of buss wire attaching the rear of the capacitors might benefit from replacement with wide copper strap or heavier guage wire. I plan to experiment with this later when appropriate.

The coax wires inside the transmatch could be replaced by RG8 mini.

EXTRACT OF SALIENT SPECIFICATIONS AND INSTRUCTIONS FROM MANUAL:

Note - Full manual available at http://www.radiomanual.info/schemi/ACC_matching/Dentron_MT-2000A_user_WA0KKE.pdf

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

NOT INCLUDED:

  • SWR or POWER indicator
  • Antenna Selector

SUPPLEMENTARY TUNING INSTRUCTIONS:

  • 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.

73,
Janis
AB2RA
Text size:  +   –      Back to Transmatches
Back to the Home Page