Saturday, October 06, 2012

Saturday Oct 6 Report

Not much to report, really. The plasma blob on the sun yesterday certainly had its impact and conditions went quite auroral with few if any North American stations audible. Some stations from Brazil and Argentina had ok signal levels but nothing really "DX-able". Instead I did some more comparisons between the omnidirectional Mini-Whip active antenna and my directive beverages. This time I had connected a Kiwa 10 dB preamp to the Mini-Whip feedline to put the antennas on equal terms with regard to gain.

The Mini-Whip fares quite well when signals are above a certain level. Weak but audible X-band stations, such as AM Restauración, Argentina on 1630 isn't heard on the Mini-Whip, while the 50-degree beverage backlobe hears it quite well. When it comes to monitoring more powerful stations in-band, the difference is much less pronounced.

This 20-second recording of Buenos Aires on 1270 should illustrate my point. The first 10 seconds is from the Mini-Whip, the last 10 from the 50-degree beverage (pardon the unintended difference in audio gain). While the latter is definitely stronger, the Mini-Whip does a very decent job. Add to the equation that the NetSDR which hosted the Mini-Whip is a few dB less sensitive than the Afedri SDR-Net which was connected to the beverage.

I experienced roughly the same difference when I compared with Brazil 4885 kHz.

During the day I will ground the Mini Whip feed line to see if there is any difference in noise levels.
UPDATE: After grounding the coax braid, there was no difference. The SDR-Radio waterfall was identical before and after the grounding, so I presume that the noise level is as good as it gets.

Misty but relatively calm, 8 degrees Celsius at 7 am local, this is in the "Warm" category for October and 71 degrees north.

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