ACOM 04AT | Remote Automatic Antenna Tuner and Switch

ACOM 04AT | Remote Automatic Antenna Tuner and Switch

ACOM 04AT is a remote automatic antenna tuner for HF + 6 m with integrated four-way antenna switch. The tuner automatically selects one of four available antenna outputs (as assigned in bands by the operator) and matches the impedance of the chosen antenna output by transforming it to 50 Ohm with SWR below 1.5:1 at the tuner input (typically below 1.3), providing an optimum load impedance for the amplifier.

The ACOM 04AT tuner is specifically designed and developed to work exclusively with the ACOM series of solid state (transistor) amplifiers, e.g., ACOM 500S, 600S*, 700S, 1200S or ACOM 2020S.
*Note: Some of the earliest produced pieces of 600S amps must be upgraded for use with 04AT tuner.

Easy set-up of user tuning presets
For a CAT transceiver a single press of the TUNE button on the amplifier front panel is all you need.

Transparent (invisible) operation
After setting up the user presets (auto tune) for the frequency segments and antennas, the operator will not be involved with tuner operation.

Three kinds of frequency segments, according to antenna bandwidth
The operator can choose according to the nature of each of the four antennas: Narrow band - Sharp, Normal - Regular, and Broadband - Wide).

Capability of operation at fixed frequencies
This capability is available also.

Non-volatile memory
Non-volatile memory for user presets (auto tune), independent for the four antennas, the three types of segment width, and more than 1000 random fixed frequencies for each antenna.

User presets
The user presets are automatically loaded, following frequency and antenna selection changes.

Export (backup) of preset memory
Backup of preset memory to a computer file, import of previously made backup files from a computer to the tuner memory.

Helpful information
Information about the setting age, and alerts for settings that reach a certain age, defined by the operator in 4 possible age levels.

Power supply and control to the tuner
Power supply and control to the tuner, as well as status return from the tuner are facilitated over the coaxial cable between the amplifier and tuner, no need for additional cables or special control signals from the transceiver (the availability of CAT control from the transceiver will give further advantages to the setup).

Improved electromagnetic compatibility
Full tuning can be completed within 5 seconds (typically 2-3 seconds), at 25 W at the tuner input and less than 6 W at the antenna output; quick tuning (from nonvolatile-memory presets) is completed in less than 0.05 seconds with zero emitted signals.

Input SWR during full tuning cycles
Input SWR during full tuning cycles - below 2:1, preventing activation of transceiver PA protection.

Input SWR after completing a tuning cycle
Input SWR after completing a tuning cycle - below 1.5:1 (typically below 1.3:1).

Relays with gold-plated contacts
Relays with gold-plated contacts for excellent receive characteristics.

Relay switching
Relay switching will only take place when no RF current is flowing, preventing contact arcing critical for preventing contact oxidation, surface melting and material transfer (otherwise resulting in poor receiving performance) and to avoid any unwanted widening of the spectrum of signals, emitted during the tuning cycle.

Air-core coils and high-quality ceramic capacitors
Air-core coils (no magnetic materials) and high-quality NP0 (C0G) ceramic capacitors usage throughout the matching circuit.

Harmonic suppression
Improves harmonic suppression - the matching network is a low-pass L filter.

Saves space on the operating position
ACOM 04AT can be located up to 100 m (330 ft) away from the shack.

Remote installation
Allows remote installation, including outdoors, close to the antenna feed point, minimizing losses.

Integrated antenna switch
Integrated four-way antenna switch - less coaxial cable, shorter unmatched sections, less losses.

Automatic and manual antenna switching
Antennas can be automatically and manually switched from the amplifier front panel. The last used antenna selection is memorized.

Customized antennas names and types
Indication and editing of names and types of antennas in editable freeform.

Protection mechanisms
Various protection mechanisms, including: antenna overvoltage, antenna overcurrent, excessive power during operation and tuning, extreme temperatures and power supply voltages, as well as relay hot-switching.

Safe power supply
Safe power supply voltage (26 VDC).

In BYPASS mode all components of the matching network are excluded, allowing direct operation of broadband antennas.

This menu allowing analysis of the tuner status and review of the used resource of coils and capacitors for all memorized and current tuning presets.

Lightning arrestor and bleeder resistor
Integrated lightning arrestor and bleeder resistor for protection against static discharges; automatic grounding of antennas on powering down.

The User's Manual is available as a PDF file only. The latest version of the User's Manual is available under the Download tab (see above).

Operating Frequency Range

  • Continuous from 1.8 to 30 and from 50 to 54 MHz;
  • Extensions and/or changes on request;

Minimum Range of the Matched Impedances (at Each of the Four Antenna Outputs)

  • All impedances with SWR from 1:1 to 3:1 towards 50 Ohm, any phase angle, unbalanced input and output;
  • For some frequencies and impedances, matching is possible at SWR above 3:1 at the antenna output (up to 10:1), but the maximum allowed power is reduced;

Maximum Allowed Input Power (PEP, Mean or Continuous Carrier, Without Mode Limitation)

  • At antenna SWR below 2.5: 1500 W;
  • At antenna SWR between 2.5 and 3: 1200 W;
  • At antenna SWR between 3 and 5 (provided matching is possible): 500 W;
  • At antenna SWR between 5 and 10 (provided matching is possible): 200 W;
  • Operation with SWR above 10:1 is not allowed;

RF Input Characteristics

  • Rated impedance: 50 Ohm unbalanced;
  • Input connector type: UHF/PTFE (SO-239A);
  • SWR during full tuning (basic cycle): No higher than 2:1;
  • SWR immediately after full tuning: No higher than 1.5:1 (1.3:1 typically);

Antenna Outputs Characteristics, Antenna 1 to Antenna 4

  • Rated impedance: 50 Ohm unbalanced;
  • Maximum antenna output SWR: 3:1 (up to 10:1 with RF power limitations;
  • Output connectors type: UHF/PTFE (SO-239A) - 4 pcs;

Full Tuning Duration (Basic Cycle)
Basic cycle for preparation of user full tuning settings, with automatic storage in the non-volatile memory:

  • In the range of 1.8 to 10 MHz: No more than 5 seconds (2-3 seconds typically);
  • In the range of 10 to 54 MHz: No more than 3 seconds (1-2 seconds typically);

Input Signal Needed to Prepare User Tuning Settings

  • Non-modulated carrier power 25 W +3/-3 dB (12.5 to 50 W);

Power Supply

  • +26 VDC, +10/-15%, consumption of 25 W at most;
  • Supplied by an amplifier of the ACOM transistor series over the input RF coaxial cable;

Remote Control

  • The remote control and indication from an amplifier of the ACOM transistor series is provided over the input RF coaxial cable of the tuner using a 60 kHz / 4800 bps bidirectional FSK modem;

Maximum Length of the Input Coaxial Cable

  • The maximum length of the RF coaxial cable between the amplifier output and the tuner input is 100 m (330 ft) for a cable of RG213 type or similar. The cable characteristic impedance should be 50 Ohm and the DC resistance should be below 1 Ohm for inner and outer conductors altogether;

Size & Weight (operating, excluding fastening elements and connected cables)

  • WxDxH: 345x250x190 mm, 4.2 kg (13.6x9.9x7.5 inches, 9.3 lbs.);

Shipping Size & Weight

  • WxDxH: Approx. 520x400x300 mm, 7.0 kg (20.5x15.8x11.9 inches, 15.5 lbs.);
  • Please, contact us for shipment details;

Operating Environment

  • Protection class: IP 53 (NEMA Type 3);
  • Temperature range: -40 to +65 degrees Celsius (-40 degrees F to 150 degrees F);
  • Relative air humidity: up to 98% @ +40 degrees Celsius (104 degrees F);
  • Height above sea level: up to 3050 m (10000 ft) without output deterioration.

There is one individual purchase option available:

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