During last IOTA contest, a couple of weeks ago, we had occasion to test “on field” @IO3M the AZILOOP supplied by Quietradio.
The location was Pellestrina Island, a sandy strip between Venezia’s lagoon and the Adriatic sea.
The configuration of the antenna was a double loop, triangle shape, with elevated ground radials on a 4,4 meter high fiber glass pole. You may have better details about the antenna at page 114 of the AZILOOP user guide, available for the download from the producer’s website www.quietradio.co.uk
The set-up took around 1 hours, including the laying down of 130 m of 7mm 50 Ohm coax cable.
On the shack side the ICU (Internal Control Unit) was connected via USB to a laptop where the AZILOOP software was installed. The ICU was connected to the antenna, one side, and to the RX ANT socket of the Kenwood TS590, other side. The LCU (Loop Control Unit) was “muted” when the radio trasmitting to avoid damage to the electronics and high RF levels through the RX ANT socket of the RTX. The muting is obtained setting the software and connecting the ICU between the PTT-out of the TRX and the PTT-in of the linear amplifier.
On Friday late afternoon – evening we tested the AZILOOP on “loop mode” on MW. Receiving the local broadcasting from Veneto inland and from Slovenia (QRG 100-200 Km), we was impresssed from the directivity of the system: the broadcastings were audible on the expected directions, in a space of 30°. At 20°-25° of differen heading, the broadcast was not received at all. To be clear: the beaming of the antenna is obtained with the software only, the antenna itself remains still.
The PBF, pre-amplifier and the attenuator were effective.
During the contest, on 40 and 80 m bands, the AZILOOP system was used on K9AY mode because it is better working on HF (likewise the beaming, the mode change loop/K9AY is obtained via software).
Expecially on 80m, where the other available RX option was the TX vertical antenna, with AZILOOP on K9AY mode, the operators reported a much better S/N ratio. The directivity was not the same obtained with loop configuration, as described before, but still we was able to reduce a local QRM. Probably the reason of the lack of directivity of the AZILOOP on K9AY configuration was because the most part of correspondants were from Europe (means: high angle of arrival): the K9AY works well on LOW ANGLE (DX) signals.
Varying the termination load (through software) had not appreciable effect on F/B.
Summary: The antenna is very light and the set-up is really fast. On MW (loop mode) the directivity is just impressive, while on HF (K9AY mode) we obtained good S/N but not enough directivity on the medium-high arrival angles signals (stations from Europe).
More test on HF DX signals, K9AY mode, are needed, but, so far, the AZILOOP deserved his ticket to Bioko Isl.!