Tuesday 12 July 2011

The Wellbrook ALA330S active loop antenna

I have had one of the above to test. It is a 1m aluminium loop with a built-in preamplifier and covers 3MHz-30MHz with reduced performance on lower frequencies.

I was particularly interested in how it performed on LF and Medium Wave. Connecting it up in the shack (it has a BNC connector on the loop and a separate power supply that feeds 12v to the loop) I was initially disappointed as it seemed noisy.

But this is because my house is just buzzing with electrical noise. Putting it outside, even leaning against a tree, made a massive difference.

I was able to receive BBC Radio Wales from here in Norfolk on 882kHz at about S6-7 on my Icom 756 Pro 3. This was a perfect copy and far better than I can get it on any of my other antennas, including a W5GI 100ft dipole and a Western HF10 dipole outside and an array of dipoles in the loft.

It was also able to hear a lot of other weak AM stations that were in the noise on my other antennas.

I also had a listen for some NDBs (beacons) and heard loads – CWL (Cranwell) on 423kHz, WBA (Wolverhampton) on 357kHz, WCO (Westcott) on 335kHz and WHF (?)on 332kHz. The strongest was NWI (my local airport in Norwich on 343kHz). These were all in daytime.

Turning to HF the loop heard everything that I could hear on my outside larger antennas. Sometimes a little noisier - but it is tiny.

Its nulling capabilities were excellent and a rotator would obviously be helpful.

If your interest is in LF/MF you might be better off with Wellbrook's ALA 1530 which offers 6dB better performance at the low-end of the band.

If you are only interesting in listening, but don't want to put up lengthy wires I can recommend the Wellbrook. I might test it on transatlantic MW DX this winter.


  1. Hello ! What a funny antenna. How does it work ? You see i have little problem to remember all english words because i get a little stroke on the 4 of June 2010. Nice to read about your antenna experiments Hi Hi ! Good luck and welcome to visit my blogg. You will find a TRANSLATE button in the right Sidebar so you can understand the Swedish crap i writing hi hi !! 73 de Janne SM5VVS

  2. Hi, It is an untuned magnetic loop that reacts to the magnetic portion of the EM wave. It then has a broadband low-noise amplifier. This gives it the wide frequency response. If you rotate it you can null interference or interfering signals.

    You can find out more at www.wellbrook.uk.com