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.

Thursday 7 July 2011

UK Propagation charts for July 2011

This month's predictions are based on a smoothed sunspot number of 43. Expect to see fair openings up to 20, 17 and possible 15m. The Sporadic E season is well under way too. Look for short skip on 15 and 10m. Note: have just redone the charts with the revised Smoothed Sunspot Number of 43 - probably makes little difference. Go to the charts