microHAM ARCO

Intelligent antenna rotation controller with 7″ touch screen

microHAM sro, based in Galanta, Slovakia, is a manufacturer of a range of professional amateur radio equipment. One of its most technically advanced products is ARCO – Smart Antenna Rotator Controller. It is a fully standalone desktop rotator controller with a 7″ color touch screen that does not require a computer or any external device for normal operation. It also offers extensive remote control options via LAN, USB, RS-232 and direct connection of multiple units via the local LINK bus.

What is ARCO and what is it for?

ARCO is a motorized antenna rotator controller with a position sensor. It has been designed to be compatible with virtually any commercial or home rotator, including older types. The factory preset menu includes dozens of Yaesu rotators (the entire G series), Hy-Gain, SPID, Prosistel, TIC Ring, M2 Orion, Create, Daiwa, DX Engineering and others. For connection to Yaesu rotators, a direct 6-pin (2x3) connector is used, compatible with original Yaesu cables.

The main display shows the current antenna Azimuth on an azimuthal equidistant map (great circle map) centered on the rotator position, with day/night color schemes, gray line projection, Sun and Moon positions, and selectable distance circles. Antenna pointing is set using the Touch'n Turn function - touching the map instantly sets the target direction, the Rotator moves when you lift your finger.

Advantages over conventional controllers

Standard rotator controllers operate with analog position measurement, fixed calibration and no drive protection. ARCO brings several fundamental differences.

The motor is controlled by a 4-channel PWM driver with overload, short circuit and overheating protection. The rotator starts and stops using configurable ramp speed profiles - smooth acceleration and deceleration significantly reduces inertial force stress on the rotator, mast and antenna. The AUTO function dynamically adapts the minimum motor speed to changing resistance in wind or ice.

For position feedback, ARCO supports both absolute sensors (potentiometer, rheostat, PWM sensor, absolute encoder, geomagnetic sensor) and relative sensors (reed contact, Hall sensor, quadrature encoder). The D-SENSOR digital port allows the connection of RS-485 sensors, including quadrature encoders. With high-resolution sensors, ARCO achieves a positioning accuracy of 0.1°.

Motorized power supply is completely disconnected whenever the engine is not running – minimizing interference to sensitive receivers. ARCO also has an integrated function of automatic antenna parking before switching to Stand By mode.

Technical parameters

Direction input methods and display

The antenna azimuth can be entered in several ways. Touch'n Turn – touching directly on the great circle map – is the fastest method; the rotator moves when you release your finger. The Point and Shot rotary encoder on the front panel allows manual adjustment in steps; after three seconds the ARCO will move to the entered direction. The CCW and CW buttons on the front panel are used for manual rotation in a given direction. The Heading Dial Screen allows the azimuth to be entered numerically or by selecting by DXCC entity, WAZ zone, ITU zone or grid locator (QRB calculation). Six memory buttons on the display allow instant recall of preset directions.

Displej zobrazuje sunrise/sunset čas v UTC and counts down the time until the next event. Indicates overlap, SW limit and HW limit using traffic signs at the top of the display. BACK function returns the antenna to the previous direction. For dipoles or bidirectional antennas (SteppIR, UltraBeam) there is a BIDIR mode where the great circle displays a shortened bidirectional needle and the rotator rotates along the shortest path to the target.

LINK stacking, stack synchronization and remote control

A unique feature of ARCO is the two-wire LINK bus (CAN bus) for digital interconnection of multiple ARCO controllers. This function allows automatic synchronization of antenna stacks (SYNC GROUP), control of multiple antennas on the same tower in sequence (TOWER ID) and counter-rotation for rotating masts (COUNTER TO ID). The maximum length of the bus line is 1 km.

For remote control over the Internet, ARCO implements a CLIENT-SERVER architecture directly between two ARCO units – without the need for a computer on the rotator side. A home ARCO unit can connect to a remote ARCO server unit and control it in the same way as a local rotator. An internal VNC server allows direct display of the touchscreen on any device – Windows, macOS, Linux, iOS or Android – without proprietary software.

Related products: ARCO Junior and ARXC modules

ARCO Junior is a version of ARCO without a 7″ display in a more compact chassis. On the front panel it has a heading encoder, CCW/CW buttons and a small display showing azimuth. The entire functional set is identical to the full version of ARCO – including LINK bus, VNC server, internet remote and all sensor ports. To fully utilize the interface, a VNC Viewer is used on an external computer or mobile.

There are three optional ARXC (ARCO External Control) expansion modules:

ARXC RELAY adds a programmable relay output for switching antenna switches, polarization switches or mast preamplifier bypass. ARXC MAGNETIC adds an absolute digital compass (ARXC.MAG) and an antenna slip detection Watchdog - if the antenna on the mast mechanically rotates, ARCO automatically records it. ARXC LoRa consists of two LoRa communication modules for wireless connection of ARCO with ARXC modules (operating frequency 868 MHz).

Videos

The first video is the official presentation of ARCO by microHAM:

The second video shows ARCO in practical use in a real hamshack:

User ratings and experiences

On eHam.net, ARCO has 16 reviews with an average rating well above 4/5. Reviewers agree on several points.

Pascal Villeneuve, VA2PV, wrote in a review for QST (February 2023) that the ARCO is without a doubt one of the most advanced rotator controllers he has seen. He appreciated the intuitive Touch'n Turn controls, the ability to enter a direction by DXCC Entity or zone, and the full functionality of VNC remote access without proprietary software. He has been using the ARCO for seven months without a single error or bug.

"This is a complex unit, but it makes your operations very simple, and I just love it. I have used this unit for the past 7 months without any issues or bugs, so this one is a keeper for me." – VA2PV, QST, February 2023

N3CAL describes replacing the original Yaesu controller with ARCO on the G-450A rotator: he disconnected the cable, plugged the Yaesu connector into the ARCO, set up the LAN, updated the firmware, calibrated – and within 30 minutes it was fully functional. He considers the DXCC routing function to be extremely practical for DX hunting.

KP4AA uses ARCO in a Multi-OP contest environment with two operator stations. He displays the ARCO 20m antenna screen via VNC on station 2 and appreciates the time savings compared to the classic button-holding and waiting for the brake.

HB9AOO upozorňuje na špecifický problém pri kombinácii s Hy-Gain HAM IV: pri dlhom kábli (35 m) s tenkými vodičmi dochádzalo k chybe BRAKE ERROR. Riešením bolo zdvojenie prierezu vodičov brzdového obvodu na 2 mm². Po tejto úprave prebieha prevádzka bezchybne.

DK6WK reviews ARCO Junior: installation with G-1000 DXC and MacLogger DX on macOS went without a hitch, MacLogger DX recognized the ARCO serial port automatically and azimuth control based on QRZ data works immediately.

Where to buy

ARCO is available directly from the manufacturer microHAM sro, Matičná 28, 92401 Galanta, Slovak Republic (www.microham.com). For customers in the USA, the distributor is DX Engineering (www.dxengineering.com). The price of the 200 W version is US9.99, the 400 W version is US9. Firmware updates are free and available directly from the ARCO unit via the Internet or alternatively via USB. Flash disk.