OM0ET UltraLight Magnetic Loop Antenna v. 3.0 (MLA)
Welcome to my website about this very small and ultra compact UltraLight MLA antenna ver. 3 for HF bands.
This 3th version of home made QRP UltraLight MLA antenna has a new foldable construction for easy carry in common laptop bag.
The tuning box is made of thicker plastic and is slightly wider. For SWR measuring I used the QRP transceiver XIEGU X5105. The SWR on all bands is min. 1.1
This v. 3 MLA is working from 10MHz to 30MHz continuisly and CB band is covered too. Weight is only 872 grams. No switch is needed. It's a QRP version for 5 to 10W max. Please do not exceed the power limit of 10W! It may cause a fire on the capacitor plates or demage PA in your transceiver.
Large loop diameter: approx. 70cm ( wire lenght is 2170 mm )
Small loop diameter: approx. 18,8cm ( wire lenght is 578 mm )
Capacitor: air type with 380pF+320pF (700pF) with small gearbox reduction - used as split stator type
Large loop is made of Nordix MWC 10/50 microwave coaxial cable (can be used RG213U but it's not hold the shape of ring as Nordix)
Small loop is made of 2,5mm copper wire PVC isolated
The boom is made of 3 pieces 20mm diameter PVC pipe
Total weight: 872g
How to use this antenna:
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 frequency on your transceiver and tune antenna knob to resonant frequency until you will listen the noise peak.
2. After you listen the noise peak start measure the SWR and carefuly tune antenna for the best value ( SWR 1:1.1 ).
3. Now you can transmitting.
Some close metalic objects may disturb SWR, if so you have to place antenna more away from this object.
If you move from this frequency away you will need tune again (point 1-3).
The elevation will improve efficiency of your magnetic loop antenna.
This antenna no need counterpoise.
I wish you have fun with QRP and this antenna!
YouTube videos links ( my channel ):
Other MLA sources:
Want to buy one? Or any questions? Contact me here
Download schematic diagram PDF here (not yet available)