HG3 QRO Stepper Mag Loop Antenna


In Stock! The HG3 QRO currently has a 2 to 3 week lead time.

The HG3 QRO Stepper tuned Magnetic Loop Antenna delivers 1 KW power and unprecedented capability, performance and convenience. It employs a proven, accurate and repeatable stepper motor design.

3 in stock (can be backordered)

Shipped separately with added shipping charges

SKU: HG3-QRO Category: Tag:


>>> Read the HG3 QRO-B review <<<

>>> in the May issue of QST! <<<

Demo VideoSetup VideoUser GuideFacebook User Group

The HG3 is shipped in a sturdy foam padded package. The mast is shipped in a separate package.


All new orders now ship with the QRO-B. Improvements include:

  • Integrated capacitor to radiator connections with six times more copper surface area for improved efficiency
  • Optical isolated driver interface allows for a longer control cable and RFI rejection
  • Separate logic circuit and stepper motor power supplies allow for smoother and more precise tuning
  • Custom high voltage delrin motor to capacitor shaft coupler provides for greater high power and high voltage protection

The package includes everything you need to get going right away. Included are:

  • LMR 600 Radiator Loop
  • Loop to Mast Bracket
  • Copper Induction Loop
  • Aluminum Mast
  • HG3 QRO Tuner
  • HG3 Plus Controller
  • Illustrated User Guide
  • 50′ DB9 Controller Cable

The HG3 QRO is built to order. It is a premium Magnetic Loop Antenna (MLA) with unique characteristics. It provides a number of advantages over a simple wire antenna. However, to enjoy these advantages and use it, it is assumed you have a rudimentary understanding of radio principles and skills commonly practiced by ham radio operators. It also required some assembly and interconnection with your radio equipment. You’ll also need to complete the initial checkout, adjustment of the induction loop and position on the mast and setting the user band preferences. These steps are covered in the manual as well as the demo video. If you are not comfortable doing this yourself, before considering ordering the HG3 QRO, we strongly encourage you to review all the commonly asked questions (below), watch the demo video, review the manual and enlist the help of a knowledgeable ham (Elmer). If after doing so, you still are uncomfortable, the HG3 may not be for you.

The new HG3 QRO, our flagship magnetic loop antenna, is now available for sale. It delivers unprecedented capability, performance, and convenience. It employs a proven, accurate, and repeatable stepper motor design.  Band selection, remote tuning, including optional loop rotation, is controlled by a microcontroller driving a high-resolution stepper motor.  An integrated digital SWR bridge allows auto-tuning based on an SWR scan. This ensures compatibility with most radios. Manual tuning uses a convenient rotary encoder knob. The four-line LCD shows the band selected, SWR, ERP, Cap value, and more. It is ideal where an HOA restricts full-size wire antennas, or where there just is not enough room to erect a conventional antenna.

The small footprint is great for deployment or at your QTH. It works really well in attic installations or your backyard in HOA restricted areas. Start enjoying the many advantages of the magnetic loop antenna today. Watch the HG3 video (link above) to get a quick idea of just how much the HG3 MLA will improve your ham radio experience.

The HG3 Plus QRO is built to order. Our technicians calibrate the tuner and controller as paired units. Each band is shipped with a factory band setting. The user can custom set each band individually.

Conceptually, an MLA is a very simple antenna. It’s just an induction loop tuned to resonance by a capacitor. It is popular because of its performance and simplicity. But in practice, there is a lot more to it. High Q makes tuning challenging, band selection is tricky. Incremental capacitor positioning, motor selection, controller, and user-interface issues are just some of the factors that need to be considered. In addition, radiation efficiency must be maximized and of course, environmental factors must be addressed.

The internet is filled with all sorts of MLA projects and experiments. Some are quite elegant, yet proved expensive and time-consuming. Others are the bare minimum manifestations, cobbled together from parts at hand that worked – after a fashion. Still, others use experimental software with all sorts of tuning methods.  Some work well in concept, but when put into practice, unforeseen problems surfaced. As a result, they did not live up to their expectations. True, there is a large selection. The sheer number is mind-boggling.  Yet, none of these projects were available for sale as a ready-to-go product.

That’s where the HG3 QRO comes in.  It is a clean sheet of paper design, taking into account the myriad of pro and con factors. The result is the first turn-key, commercially available, microcontroller-based, stepper tuned antenna, combining auto-tuning and rotation into one integrated, high-performance package, ready to go on the air.

The MLA rejects locally generated noise due to its inherent magnetic field coupling and its relative insensitivity to the electric field. Most interference sources directly radiate in the near electric fields. That’s a big advantage for an MLA. When designed and constructed properly, an MLA performs as well or even better than a dipole antenna. According to the American Radio Relay League (ARRL) technical editor, Jerry Hall K1TD, in describing MLA gain, concluded: “in fact, it (MLA) considerably exceeds the gain of a dipole when the MLA is mounted close to the ground”. The bottom line – count on top-notch receiving and transmitting performance!



Q What is the HG3 QRO maximum power rating?
A: The maximum power ranges from 1,500Watts PEP to 800Watts PEP depending on operating modes and feed-line match. Common mode current is a factor that determines the maximum allowable input power. See page 45 in the user manual for details.

Q Can the HG3 QRO be mounted in the attic or other fixed locations?
A: You can deploy the HG3 QRO in a fixed location such as your QTH or the attic. Nearby objects (10-20 feet) will only change the directivity a little. Tile and asphalt roofing have little attenuation at HF frequencies. However, metal roofs tend not to work as well because of the shielding properties. The extra cable length will work well. They have been tested up to 75′. While a portable tripod may be OK, we recommend mounting the antenna to a structural object in the attic.

Q Can it be used on 80-60 meter?
A: Yes. The mast has provisions to attach a second radiator loop (external resonator). This loop is identical in size as the main loop. It is connected in series with the main loop. The added inductance allows it to be tuned from 3.5MHz through 7.0MHz.  The controller has an external resonator mode which must be used for 80m -40m use.

Q Should I use an antenna tuner such as a built-in or external tuner in some transceivers, instead of the HG3 QRO tuner?
A: Generally not. The HG3 QRO is designed to work into 50 ohms. It should be tuned to match the transmitter’s 50-ohm antenna impedance. An antenna tuner axiomatically transforms impedances to meet the transmitter’s current or voltage capability. Therefore, if misadjusted, it may present impedances other than 50 ohms to the HG3. As a result, this may create an impedance mismatch. Although once the HG3 tuner presents an SWR match of  2:1 or lower, touching up the SWR with an external or auto-tuner to 1:1 may provide a fractionally improved impedance match for the transmitter. That, in itself, may not provide more ERP.

Q How long may the coax feed-line and controller cable be?
A: The HG3 system has been tested up to 75 feet.

Q I want to mount the HG3 QRO as a permanent installation. How do I do that?
A: The sturdy aluminum mast is recommended. The mast should be clamped to a solid fixture using “U” antenna bolts and guyed.

Q Is the HG3 QRO waterproof and can I use it in rain or adverse windy conditions? 
A: Use common sense. The tuner enclosure is designed for outdoor deployment in a wide environmental range, but it is not submersible. These enclosures ensure that internal electronic components are protected in harsh environments. Durable weatherproof enclosures are specifically designed to meet and exceed various NEMA and IP requirements, making them suitable for both indoor and outdoor applications. See https://www.polycase.com/waterproof-enclosures. It is the best housing we could find short of an expensive marine grade, underwater nitrogen sealed enclosure. We have experienced excellent results in outdoor conditions. It is water-resistant, but not waterproof. See page 44 in the manual.

Q What is the primary HG3 QRO band coverage?
A: The HG3 covers all of the 40-meter band through the CW portion of the 10-meter band. The 10-meter phone segment is also available, but at a slightly higher SWR. When adding the optional second radiation loop, the 80m and 60m bands are covered.

Q How is the firmware updated?
A:  Firmware updating requires opening the HG3 QRO controller case. It can be done in the field by knowledgeable operators. We recommend the controller be sent back to us for firmware updating.

Q How does the HG3 QRO system work?
A: The HG3 user guide contains a system reference section starting on page 46. It includes a detailed circuit description along with a complete set of schematics.

Q What about the tripod?
A: The aluminum mast includes a 1/2″ female fitting on the mast’s base to provide for mounting it to conventional antenna stands/tripods having a male 1/2″ fitting. These antenna stands/tripods are available from a number of ham radio sources, including preciseRF.

Q How is the AR1 antenna rotator deployed?
A:  The optional AR1 Rotator is light weight and runs off 12VDC.  It is only recommended for temporary portable operation. Use the VH226E Rotator 120AC for fixed installations.  The AR1 has  has a female 1/2″ thread at its base for mounting on a conventional antenna mast or stand and a male 1/2″ threaded output shaft. The output shaft threads into the aluminum mast. When so deployed, care must be taken to allow for guying.

Q What are the environmental considerations I need to take into account?
A: The tuner is housed in a premium, water-resistant case, with a silicone rubber gasket, made in the USA by Polycase. It is made to UL Listed to UL508-4x specifications, constructed of durable, impact-resistant UV Stabilized Polycarbonate material, and is water-resistant. It is not waterproof. Under extreme conditions, water can enter the tuner and render it permanently unusable. Before use, ensure that all connections are secure from possible water incursion. This includes the sealed O-ring protected cover and all connectors.  If, after inspection, there is any doubt of the water-resistance integrity, follow these maintenance guidelines: Check all fasteners for a tight fit. If needed, apply a small amount of silicone sealant to each connector. Protect the antenna at all times from extreme weather conditions. THE AR-1 ROTATOR IS NOT WATERPROOF. IT IS INTENDED FOR TEMPORARY PORTABLE DEPLOYMENT OR SHELTERED AREAS. Under extreme conditions, water can enter the rotator and render it permanently unusable. Excessive weight can damage the rotator. Rotating a guyed loop antenna is difficult. The use of the AR1 Rotator in windy conditions must be done with caution. After establishing the desired direction, ensure the antenna is again guyed. Never leave the antenna unattended when not guyed.

Q  How do you check out the HG3 QRO for proper operation?
A: The user guide, starting on page 36, contains step-by-step check-out instructions.

Q How do you attach and release the radiation loop to the mast?
A: Check this video.

Q Who is preciseRF?
A: PreciseRF is a division of parent company Stenbock Enterprises LLC. It was founded by former Tektronix engineer, Roger Stenbock – W1RMS. It serves amateur radio, military, and industrial markets worldwide. Besides the high-performance HG series of loop antennas, preciseRF offers a full line of precision RF test instruments. These instruments include lab-grade RF couplers, samplers, power meters, computing TDR test sets, and ultrafast pulse generators.


The HG3 QRO is a built-to-order product. It may be returned within 15 days after the date of shipment, subject to a restocking fee. Because it is a built-to-order product the restocking fee is 25% of the MSRP retail price. Products must be returned in a new and unused condition in their original packaging to qualify for a refund.

If you have problems getting your PreciseRF kit to work, our support team will assist you. Contact us at preciserf.com. for spare or missing parts.  You can also reach us by phone at (503) 915-2490 Monday through Friday from 9:00 am to 4:00 pm PST. PreciserRF reserves the right to make the final determination of returned product condition. Any refunds will be less the original shipping charges from PreciserRF to the customer. If a product arrives in a damaged state we will either charge a higher return fee or return it to the customer. You must contact PreciserRF for a return authorization form, instructions, and return address before returning any products. You will be responsible for paying for your own shipping costs for returning items.  If you are returning an item, you should consider using a trackable shipping service or purchasing shipping insurance. We do not guarantee that we will receive the item that you are returning.

The basic term of the warranty is twelve calendar months from the date of purchase. The duration and conditions of warranty for this product may be superseded when the product is integrated into (becomes a part of) other PreciseRF products. During the warranty period, PreciseRF will, at its option, either repair or replace products that prove to be defective. The warranty period begins on the date of delivery or on the date of installation if installed by PreciseRF. The product is subject to being changed, without notice, in future versions. Further, to the maximum extent permitted by applicable law, PreciseRF disclaims all warranties of merchantability and fitness for a particular use.

For warranty service or repair, this product must be returned to a service facility designated by PreciseRF. For products returned to PreciseRF for warranty service, the Buyer shall prepay shipping charges and PreciseRF shall pay shipping charges to return the product to the Buyer. However, the Buyer shall pay all shipping charges, duties, and taxes for products returned to PreciseRF from another country.

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.  All rights are reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under copyright laws. PreciseRF 13690 Wisteria Dr, Aurora, OR 97002

The user and or operator understands that lethal voltages may be present in the operation and or use of this product. The operator or user assumes all risks associated with the deployment, operation, or use of this product. The operation of this product is dangerous. The operation may be harmful or fatally injure the operator, user, and or nearby people. Do not operate the product in an explosive atmosphere or in the presence of flammable gasses or fumes.  If necessary, return the product to PreciseRF for service and repair to ensure the safety features are maintained. Do not substitute parts or modify the product. For service, return the product to PreciseRF.


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