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Tuesday, December 3, 2019

Loop on Ground Antenna Test

I assure you that there is a Loop on Ground (LoG) antenna in this photo.
Over the long weekend, I tested my newly installed Loop on Ground (LoG) antenna.

I compared the LoG’s reception with the other antennas installed here at WA1LOU by noting the signal strength of 23 random stations across the AM band using the dBμ reading [absolute voltage (Terminated)] of my ICOM IC-R8600 receiver. (The other antennas here are an 80-meter dipole, a Hy-Gain 18AVT/WB-A vertical and a ICOM AH-7000 discone.)

The following stations were used in the comparison: WMCA on 570 kHz, WPRO 630, WFAN 660, WOR 710, WGY 810, WNYC 820, WCBS 880, WLAT 910, WPKX 930, WNTY 990, WINS 1010, WBZ 1030, WTIC 1080, WMRD 1150, WWCO 1240, WSPR 1270, WATR 1320, WFNW 1380, WVEI 1440, WFED/WFIF 1500, WQEA416 1670, WPTX 1690 and WRCR 1700.

I ran the test on three consecutive mornings and on one evening. In general, the results were the consistent during all four runs of the test. The only anomaly was hearing WFED loud and clear on 1500 kHz at 1447 UTC on 29 November. WFED is always loud and clear at night here, but is usually down in the mud under WFIF during daylight. Go figure.

After the first and second run of comparisons, I eliminated the vertical and discone antennas from the test to save time because the dipole consistently scored higher than the vertical and discone.

On average, the LoG performed 8.5 dBμ units higher than the 80-meter dipole. With a 22 dBμ unit difference, WSPR had the greatest signal improvement on the LoG. Right behind WSPR were WBZ, WWCO, WATR and WVEI with 17 dBμ improvement on the LoG.

The dipole performed equal to or slightly better (by 1 or 2 dBμ units) with WPRO (daytime only), WGY (daytime only), WCBS (all times), WLAT (all times) and WNTY (all times). WPRO and WGY were stronger on the LoG in the evening by 9 and 6 dBμ units respectively, which represents a 11 and 7 dBμ swing between day and night.

Overall, the LoG performed better at the top and bottom of the AM band and less so in the middle of the band (810 to 1150 kHz) except for one outlander: 50kW WTIC 1080, which is line-of-site from here. WTIC consistently scored in the low to mid 70’s dBμ-wise.

The first three tests were run under dry conditions, while the fourth test was run with the antenna covered with about six inches of snow. The snow did not seem to have any effect on the performance of the LoG.

In conclusion, I am very impressed with the LoG antenna. It is a keeper and I plan to install a larger version in the spring.

2 comments:

  1. Thanks for sharing Stan. Can you tell us what you used as an isolation transformer? Any attempt to install Common Mode Chokes inside the shack, and/or outside near the antenna? How does the signal to noise ratio compare with other antennas? On the AM band, that is usually the difference maker. S meter readings may be great, but it's S/N that puts new ones in the log.

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  2. This was not planned ahead. I read about the LoG one day and decided to try it the next day. Time was of the essence due to the weather and holiday, so I used what I had on hand.

    For the transformer, I used an F-type 300-75 ohm balun “TV connector.” I just had to add a female-to-female F-connector adapter so I could mate the balun with 75-ohm coax cable.

    I did not install any chokes.

    in general, S/N improved noticeably with most of the 23 stations I tested.

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