title: MC-20 MAGLOOP ANTENNA | OM0ET Ham Radio Aerials
source: https://om0et.com/
author:
published:
created: 2025-07-02
description: "The MC-20 Magnetic Loop is a 7-band(+CB) Ham radio, QRP, bi-directional antenna foldable construction. Dimensions are: 1m in diameter and 1,3m tall."
tags:
- HamRadioMC-20 MAGLOOP ANTENNA | OM0ET Ham Radio Aerials
First Look at the HF Signals zBitx QRP Transceiver
Ideal solution for vacations QRP indoor or outdoor portable activities
Quick assembly, Multiband, 1kg weight
Amount = EUR €295 Converted to USD $346.49
Our current rate€1 = $1.1746
The MC-20 magnetic loop is a multiband tunable antenna for reception and transmission, which can be continuously tuned between 6,3 MHz - 30,3 MHz. The laws of physics cause this antenna to transmit in a narrow frequency spectrum - a few kHz, say 10 kHz (5 kHz on each side). After detuning, the SWR is no longer usable and the antenna needs to be retuned. If the antenna is only used for reception, it is enough to leave it tuned in the middle of the selected band. Sometimes it can be a bit annoying, but with a little practice it is easy. On the other hand, this is also a great advantage, since such an antenna behaves as a natural bandpass filter for the input of the receiver and transmitter. Interference from nearby strong stations will no longer overflow the receiver, and even in the case of using a poor-quality transmitter, the antenna will naturally attenuate parasitic harmonic products.
It is necessary to note a very important thing! The magnetic loop is most effective when tuned to the best possible SWR! It is never recommended to use an additional antenna tuner as compensation if you are transmitting on an untuned frequency!
Reviews For: OM0ET UltraLight Magnetic Loop Antenna on eham.net
The MC-20 Magloop Antenna description
Why choose this antenna?
The UltraLight Magnetic Loop Antenna MC-20 is a 8-band(40m/30m/20m/17m/15m/12m/CB/10m) Ham radio QRP antenna. Antenna is foldable construction, designed for easy transfer in the special designed cardboard box or any 17" laptop bag. This antenna was designed mainly for 40m to 10m bands + CB. The main loop is almost 1m in diameter and antenna itself is almost 1,3m tall(without tripod - is not included). Foldable boom is made of a solid thick-walled 25mm PVC tube.
MADE FOR INDOOR AND OUTDOOR USE
LIGHTWEIGHT AND STURDY
Its small dimensions and weight (only 1kg) makes this antenna a perfect buddy for your vacation, trip to the nature or just working QSO's right from your living room, balcony or garden by enjoying your coffee and having relax at any time.
Despite its low weight, the antenna is sturdy, made up of several parts that fit into your bag for easy transport.
Assembling the antenna takes only 2 minutes with a little practice!
NEW MC-20 TUNING UNIT
HAND MADE TOP QUALITY
The heart of all the Magloop Antennas is a Variable Capacitor, which is located in the Tuner box. In my antennas was used the enclosure made of ABS plastic with sealing against the rain shower or dust (but the Tuner box it self is not fully waterproof). The Main Loop is connected to the Tuner box with two SO-239 connectors (sockets) and two PL-259 on Main Loop with goldened center poles, which improves connection and reduce loses. Tuner box is also equipped with two clamps for very quick installation on the antenna boom.
HIGH CAPACITY VARIABLE AIR CAPACITOR
WIDE FREQUENCY RANGE
New dual gang Air Variable Capacitor is connected in serial fashion because of the very low resistance in a whole antenna circuit what is very important to secure a high Q and high efficiency of my loops.
Combination of a new variable capacitor and custom made PCB inside the box improves the frequency range of this Magloop antenna from 6,3 MHz - 30,3 MHz!
Due to its wide frequency range, quiet reception bi-directivity and selectivity is this Magloop great solution also for Short wave radio listeners.
EXPLORE MORE DETAILS
ANTENNA COMPONENTS
Let's take a closer look at what components this antenna consists of
The Tuner Unit
The heart of all the Magloop Antennas is a Variable Capacitor, which is located in the Tuner box. In my antennas was used the enclosure made of ABS plastic with sealing against the rain shower or dust (but the Tuner box it self is not fully waterproof). The Main Loop is connected to the Tuner box with two SO-239 connectors (sockets) and two PL-259 on Main Loop with goldened center poles, which improves connection and reduce loses. Tuner box is also equipped with two clamps for very quick installation on the antenna boom.
The Main Loop system
The Main Loop is made of an excellent quality coaxial cable BELDEN H1000 (made in Holland) which is 10,3mm thick in outer diameter.
Inner conductor is made of solid Bare Copper 2,62mm thick core which allows to hold the perfect circular shape of the loop without deformation of gravity. In all my Magloops is connected only the inner core. Outer shield is disconnected for improve the SWR results and less sensitivity of nearby objects.
The Air Variable Capacitor
New variable capacitor used in my Magloops is connected in serial fashion due to a minimal loses in the antenna circuit, which has three positive advantages:
1. improves Q-value and efficiency of the Antenna on all bands
2. allowes to work with higher power up to 20W on 40M band
3. antenna will not change the SWR value when human hand is close to the tuning knob and is easier and faster to final tune.
For more comfortable tuning is this Capacitor equipped with the 1:3 gear reduction and larger plastic knob. In the MC-20 is for the first time used a high quality custom made PCB.
The Coupling system
Quick installation of my Magloops is my priority and therefore I made the small Coupling Loop with a BNC socket. The clamp on the Coupling box allows you to attach the small loop on antenna boom in a second.
The Plastic Holder
In the middle of the Main Loop lenght is located the mark (heatshrink) which inform you where the Loop have to be inserted in to a Plastic Holder on top of the Magloop Antenna Boom.
Modification Ready
The "small" Coupling Loop is made of 3,4mm thick solid copper wire attached with a mounting eyes on both ends, which allows you anytime to do your own modifications or easy exchange to the other size of experimental Loops (Main+Coupling).
New flexible Clamps
New flexible clamps for easy and firm mounting of components on the antenna boom. For a firm grip, it is necessary to tighten the clamp to two clicks. Releasing the clamp is easy (see picture), pull both rings apart from each other to the sides
A Mounting Adapter
A CNC machined1/4' camera tripod Mounting Adapter. Is compatible for any standard 1/4 threaded camera tripods. With this adapter is very easy to mount entire antenna on the tripod and also very comfortable 360 degree rotating this antenna on it.
A Feed line
Connection between the Antenna and Transceiver is done by the soft and flexible Coaxial cable HELUKABEL C/U RG58 with BNC male (clamp system) connector. Usable length of this cable 4,5m is sufficient to operate in the safe zone of 2 or 4m away from the Magloop when we are transmitting (If we use max. 20W).
The mc-20 magloop
Antenna Dimensions
-
Large loop diameter: approx. 1m ( coax lenght is 3000 mm )
-
Small loop diameter: approx. 23cm ( wire lenght is 720 mm )
-
Capacitor: air type 380+320pF with a small gearbox reduction 1:4 - used in split stator fashion
-
Large loop is made of the Belden Venlo H1000 high quality microwave coaxial cable
-
Small loop is made of 3,4mm thick solid copper wire (black PVC isolation)
-
The foldable boom is made of 3 pieces, 25mm in diameter, PVC tubes
-
Feedline usable length of this cable 4,5m of the HELUKABEL C/U RG58 with BNC male plug
-
Total weight: +/- 1kg (without tripod)
instruction guide
How to tune this Antenna
Important information! Never transmit in to the antenna before you don't listen the background noise peak while tuning, it may demage your transmitter!1. Set the desired frequency on your transceiver and rotate antenna knob to resonant frequency until you will listen the noise peak.2. After you listen the noise peak start measure the SWR in carrier mode (FM/AM) with 5 - 10W and carefuly tune antenna for the best value ( ideally SWR 1:1,1 or 1:1,5 ).3. Now switch to desired modulation mode and you can transmitting.4. If you move from this frequency away you will need tune the antenna again (point 1-3).Download the instruction manual PDF hereSome close metalic objects may disturb SWR, if so you have to place antenna more away from this object or rotate the main loop to the another direction.The elevation will improve efficiency of your magnetic loop antenna. Higher - better. Please consider the hight of your tripod stand.This antenna doesn't need the counterpoise.This Magnetic Loop is a wideband tunable antenna that can be used continuously from 7MHz to 31.7MHz. But that also doesn't mean that you tune it somewhere in the middle of the band and will fully tune to SWR by 2. NO! because the laws of physics cause this antenna to transmit in a narrow frequency spectrum - a few kHz, let's say 10kHz (5kHz on each side). After this de-tuning, the SWR is no longer usable and the antenna needs to be re-tuned. If it is only used for reception, then there is no need to fine-tune it and you just need to leave it tuned in the middle of the band. It may be a little annoying sometimes, but a little practice can do it. On the other hand, it is also a great advantage, as such an antenna behaves like a natural bandpass for the receiver input. Interference from nearby strong stations thus no longer overwhelms the receiver, and also in the case of using a poor quality transmitter, the antenna naturally attenuate the parasitic harmonic products. It is necessary to note a very important thing! The magnetic loop has the highest efficiency when is tuned to the best possible SWR! It is never recommended to use an additional antenna tuner as compensation if you are transmitting on an untuned frequency!Let's watch the following instructional video:
MC-20 Assembly Guide
How to properly assemble the MC-20 Antenna
Completed
Fully assembled antenna. Click on the blue button below to download the Guide in PDF format.
Top side
The coaxial feedline RG58 must exit from the front towards the Coupling Loop BNC connector.
Loops Holder
Insert the Coupling Loop into the holder first, then the Main Loop. Then slide the holder cover on from the side.
Bottom side
The Tuning Unit connects just below the bottom plastic clutch. At the bottom of the antenna, the RG58 coaxial feedline must run from the bottom rear of the antenna to the transceiver.
Order The MC-20 MagLoop Antenna
is a 7-band(+CB) Ham radio QRP antenna based on very popular Ver.4 with the same dimensions, but completely new tuner. The antenna has a foldable construction, designed for easy transfer in the special designed cardboard box or any 17" laptop bag. This antenna was designed for 40m to 10m bands + CB. The main loop is almost 1m in diameter and antenna itself is almost 1,3m tall(without tripod - is not included). Foldable boom is made of a solid 25mm PVC tube.