HG3 Stepper Mag Loop Antenna

(2 customer reviews)


In Stock! The HG3 Pro currently has a 1 to 2 week lead time.

The HG3 Stepper tuned Magnetic Loop Antenna delivers unprecedented capability, performance and convenience. It employs a proven, accurate and repeatable stepper motor design.  It is available in the EXPRESS and PRO models.

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DeploymentDemo video  | User guide | First time set up | QST Jan 2021 Review

The HG3 Express and Pro MLA are built to order. They are 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 Express and Pro MLA, 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. [hr]

The package includes everything you need to get going right away. Included are all cables, mast, and even a tripod adaptor and a comprehensive illustrated user guide. The HG3 was designed by hams and is manufactured in the USA with premium components selected for durability, ease of use, and long life.

  • LMR 600 Radiator Loop
  • Loop to Mast Bracket
  • Copper Induction Loop
  • Three-section PVC Mast
  • Universal Tripod Adaptor
  • HG3 2K Stepper Tuner
  • HG3 Stepper Mag Controller
  • 9V DC Power Supply
  • Illustrated user guide
  • 50′ 50-ohm feed line
  • 50′ CAT6 controller cable
  • (PVC Mast not shipped when purchasing Aluminum Mast)


Note: The HG3 Express and Pro now comes standard with the new HG3 plus controller. It replaces the previous all plastic HG3 controller. Also it now comes with a new  User Guide





Q1 : Is the HG3 compatible with the HG1 or HG WR MLA?
A: No. The HG3 uses a completely new controller and tuner.

Q2: Can I use my existing HG1 WR tuner, it looks the same?
A: No. While they share a similar case, the radiator, induction loop, and tuning capacitor with the HG3, the controller, motor driver, and motor are completely different.

Q3: Can I upgrade my HG1 WR Mag Loop to the HG3 Stepper Mag Loop?
A: Yes. We have an upgrade program for existing customers who have purchased their products in the previous 12 months. It provides for a discount and consists of upgrading your exiting HG1 tuner and controller. The upgrade is only available for units in good working condition. Call us for price and more details.

Q4: Can I purchase the HG3 controller separately to use the optional LAB tuner kit or another tuner?
A: No. The HG3 controller is only available with either the EXPRESS or PRO tuner. However, the LAB tuner kit is fully compatible with the HG3 controller.

Q5: Why is the LAB version only available as a kit?
A: The LAB tuner was designed for those users wanting ultra-fine capacitor positioning. This fine control is occasionally wanted by engineers and homebrew operators. The LAB version uses a micro stepped NMEA 17 stepper motor with a 40:1 low backlash worm drive and limit switches. This allows up to 8000 discrete steps over the 180-degree range (.0225 deg) of the tuning capacitor rotation, as opposed to 2000 steps (.09 deg) for the EXPRESS and PRO stepper motors. As a result, the tuner is more complex and more expensive to assemble. Providing it as a kit makes it more affordable.

Q6: Can the HG3 be mounted in the attic or other fixed location?
A: You can deploy the HG3 for portable operation or in fixed location such a your QTH or the attic. Nearby objects (5-10 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 50′. While a portable tripod maybe OK, we recommend mounting the antenna to a structural object in the attic. Check this link Deploying the HG3

Q7: What is the maximum power for the QRO version, and when will it be available?
A: While the HG3 controller is designed to be compatible with the QRO version, maximum power and availability have not yet been determined. It is still in the engineering and testing phase. Please stay tuned for more information as it becomes available.

Q8: What is the HG3 maximum power rating?
A: The maximum power ranges from 22W to 100W depending on operating modes and conditions. Modulation mode, duty cycle, feed-line match, and common mode current are all factors that determine the maximum allowable input power. See page 22 in the user manual for details.

Q9: Should I use an antenna tuner such as a built-in or external tuner in some transceivers, instead of the HG3 tuner?
A: Generally not. The HG3 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 autotuner to 1:1 may provide a fractionally improved impedance match for the transmitter, that in itself may not provide more ERP.

Q10: How long may the coax feed-line and controller cable be?
A: The supplied cables are 25 feet. The HG3 system has been tested up to 50 feet.

Q11: I want to mount the HG3 as a permanent installation. How do I do that?
A: The optional sturdy aluminum mast is recommended. The mast should be clamped to a solid fixture using “U” antenna bolts and guyed. See Deploying the HG3

Q12: Is the HG3  waterproof and can I use the HG3 in rain or adverse windy conditions? 
A: Use common sense. The case used in the HG3 uses the same case as the HG1. We have experienced excellent results in outdoor conditions. It is water-resistant, but not waterproof. See page 21 in the manual.

Q13: What is the primary HG3 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.

Q14: Can the MLA be used on 80 and 60-meter?
A: Yes. You will need to plug in the optional external 80 and 60-meter resonator.  See page 19 of the user guide.

Q15: How is the firmware updated?
A: See page 26 in the user guide. Firmware updating requires opening the HG3 controller case and moving some jumpers. It can be done in the field by knowledgeable operators. We recommend the controller be sent back to us for firmware updating.

Q16: How does the HG3 system work?
A: The HG3 user guide contains a system reference section starting on page 23. It includes a detailed circuit description along with a complete set of schematics.

Q17: What are the tripod options?
A: The HG3 is shipped without a tripod. The package includes a PVC tripod adaptor that allows it to be mounted on a camera type tripod (25mm). We do offer a lightweight tripod that allows the HG3 to be mounted for portable and temporary deployment. The optional 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.Deploying the HG3

Q18: Will older AR1 antenna rotators fit the new optional aluminum mast?
A: No. The original AR1 rotator had a smooth friction fit with a locking pin output shaft. It was designed to fit the black PVC three-section masts. The new optional aluminum antenna mast has a female threaded fitting at its base. The newer AR1 Antenna rotator output shaft has male threads that thread into the aluminum mast’s base. This provides a more secure attachment. We also recommend attaching the AR1 rotator to a securely mounted steel mast via “U” bolts. You can have your original AR1 rotator upgraded to the newer AR1 rotator which fits the new aluminum mast. The price for this upgrade $150. You must return your original AR1 rotator only, in working condition. You keep all cables and the original HG-2 controller.

Q19: How is the AR1 antenna rotator deployed?
A: The optional AR1 antenna rotator 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 optional aluminum mast. When so deployed, care must be taken to allow for guying. The AR1 rotator can also be secured via “U” bolts to a sturdy fixed rail or mast. The AR1 antenna rotator is compatible only with the PRO and LAB options. Check this link Deploying the HG3

Q20: 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, the CAT 6 cable gland, PL239 connectors and the banana 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 PVC mast is not intended for unattended outdoor use. Use the optional metal antenna mast and attach guy wires to the two guying ears at the top of the mast. Deploying the HG3  THE AR-1 ROTOR 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.

Q21: How do you checkout the HG3 for proper operation.
A: From time to time, we publish anddenda to the user guide. One such addendum is the trouble shooting guide. Click here HG3 Trouble shooting.

Q22: 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 small footprint is great for field deployment or at your QTH. Works really well in attic installations or your backyard in HOA restricted areas. see Deploying the HG3. 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 new HG3, 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 – no more finicky push buttons. 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.

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 were the HG3 Stepper Mag Loop 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.

Many operators favor the MLA for Field Day and SOTA (Summit On The Air) operations. 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 topnotch receiving and transmitting performance!





PreciseRF factory-assembled products and unassembled kits may be returned within 15 days after the date of shipment, subject to a restocking fee. 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. Products must be returned in a new and unused condition in their original packaging to qualify for a refund.  On kits, all kit parts bags must be unopened and the product manuals and boxes must be in a new, undamaged state. Note: Partially built and completed kits may not be returned for credit. 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. We also charge a 15% restocking fee on each returned product. 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 which 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 the 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.

Additional information


PVC, Aluminum

2 reviews for HG3 Stepper Mag Loop Antenna

  1. Bob McCuskey. W7BV

    After using the new HG3 Stepper Tuner and Mag Loop, Pro Controller, and AR-1 Rotator with the new aluminum mast for the past two weeks, I am very impressed with the new tuner and controller, especially the auto tune feature. I tested and/or operated my KX2 in CW mode with its antenna tuner bypassed on all bands from 40 through 10 meters and always was able to rapidly obtain a SWR below 1.5:1! Manual tuning also was easy. Rotating the loop also was rapid and easy.

  2. Dan Zdanowicz. K1YPB

    I have the HG-3 with the AR-1 rotor. This Is a really nice antenna. The ability to steer the direction of the antenna, and QSY and retune remotely makes this the perfect stealth antenna for condo and portable use. The stepper motor controller easily grabs a match. When you QSY, it’s easy to regain a match as you follow your rig Up or down the band with the microprocessor controller. The antenna easily handles 40 to 50 watts PEP at resonance. 20 to 25 watts on FT8 no problem. I leave the antenna assembled, and bring it In and out of the house when I want to use it. So for me the set up just takes minutes and I’m on the air. The antenna is made of quality materials. I had a small issue with the AR-1 rotor, but Roger took care of it with a replacement unit, and even paid the postage both ways. That is five star customer service! That says a lot when a company stands behind their products and Is committed to customer satisfaction. Yes, it is expensive, but as the saying goes… “You get what you pay for”. Considering the engineering behind the design and implementation of the product, the quality of materials, the workmanship, and the customer service, there definitely is value for your money.

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