By Stana Horzepa, WA1LOU
Thanksgiving Eve, 40 degrees, breezy, overcast, rain in the forecast – a good day to put up a new antenna – NOT. But I was not to be deterred by Mother Nature.
Actually, I did not put up a new antenna; I put down a new antenna: a Loop on Ground (LoG) receive-only antenna as described by Matt Roberts, KK5JY: 60 feet of insulated wire stapled to the earth in a square configuration (15 feet per side).
I had prepared the wire the day before the install, so it only took about two hours to complete the install. The most time-consuming part was running the RG-6 into the radio shack from outdoors.
I was not sure how well the antenna would perform. Due to the Thanksgiving holiday, I did not have a lot of time to give the antenna a thorough test, but the initial results were very good. Tuning through the AM band for about 30 minutes Wednesday evening, nearly all the stations I checked were stronger on the LoG antenna than on my other antennas (80-meter dipole, Hy-Gain 18AVT/WB-A vertical, ICOM AH-7000 discone).
Loop on Ground Antenna Test
Over the long weekend following Thanksgiving, 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 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.
Loop on Ground Antenna Logging
A few days later, I logged my first new station with my new Loop on Ground (LoG) antenna: WWRK on 970 kHz in Florence, SC, transmitting 31 watts, 632 miles to my south-southwest!
How was the 80 meter dipole fed?
The difference in signal strength could have been in the feedline.
Approximately 45 feet of RG-58.
Please sign me up for this
What did you use for the “Isolation Transformer”?
For the isolation transformer, I used an inexpensive 300 to 75 ohm balun – the kind that often came with old VCRs and TVs that have F-connector inputs. I collected a few over the years and put one to good use.
Those TV baluns usually roll off drastically below 30 MHz. They are designed to pass VHF and UHF TV signals and block the other stuff. Also, the LoG antenna is not about signal strength, it is about signal to noise level, as seen on the meter or heard by the ear, so your signal levels are meaningless. Go back an re-read http://www.kk5jy.net/LoG/
Thanks Stana. That is clever and simple. I guess I forgot that its just a receive antenna and doesn’t need anything fancy.
Tony W8CDC
Hi guys 4 / 16 / 2021
I am entertaining using a 36 foot LoG to pick up 26 MHz. Four questions have come to mind so far:
( 1. ) Will higher frequency harmonics like 52 MHz, 104 MHz and 208 MHz also be tunable from the 36 foot LoG or does the wire length have to be 18 feet, 9 feet, 4.5 feet to pick up harmonics separately?
( 2. ) What is meant by “insulated wire” in this case? I am using AWG 16 well pump wire with 600V insulation that I had left over. Or does insulated mean something like enameled wire?
( 3. ) I am thinking of building a Passive Bandpass filter to pick out the 26 MHz from the rest of the frequencies the 36 feet will pick up. The filter center frequency is 26 MHz with contemplating 26 and 27 MHz as Low and High Breakover frequencies. Do I need a wider bandwidth?
( 4. ) Do I place the Filter near the Isolation Transformer or at the inside end of the 75 ohm coax. And why do I need an Isolation transformer if I am only receiving signal? If the Filter is inside the house, will the coax add length to the 36 foot LoG?
Please show mercy on me I am new to this. Thanks, Tom.
Remember the Alamo Tom and you will be ok.
I’m running a websdr using RSP1A and a Loop On Ground antenna. It is located about 60m from nearest buildings – you can hear how good it performs – https://so8oo.net/en/websdr/
It works really good from 160m up to 20m, but on 160m preamp is required.
This antenna is really a great performer when you consider used space, time and effort to setup.
But you _have_ to take care of common mode chocking. When you fail here – you will probably use coax shield as a antenna instead of loop itself.
In this family of antennas is also BOG (beverige on ground) antenna, but this is quite another story (it is far simplet to setup good working LOG, than BOG).
How good LOG is – you can check on pskreporter – search for SN0E station – it is my websdr monitoring ft8 24/h on 40m and 80m (sometimes 20m/160m also).
I built the LOG today. About 62 feet of insulated # 14 wire in an approximate circle on lawn. Used my commercial ( DXE ) Beverage transformer and 75-ohm coax line from it to radio (ICOM 7300). I have been a ham operator for more than 65 years and am pretty skeptical of most “new” things by now, but this is an Amazing antenna concept. I swept the loop with my antenna analyzer before using it with the transceiver — it has prominent, sharp resonant points (reactance zero) starting at about 4 MHz (lowest freq) and then about every 4 MHz thereafter up into the 10-meter band. How does one change the fundamental frequency here? Not a straightforward query.
Tnx de NK7B St Paul MN
I’ve been using a LoG at a couple of remote sites for some time. Recently I modeled it with 4NEC2 (NEC). I’ve put a quick summary of this at
https://www.dropbox.com/s/pcihl4jxwf6ulqk/LogModel.pdf?dl=0
Perhaps this may be of interest.
Glenn n6gn
Fort Collins, CO
Did anybody measure the feed point impedance of the 60′ loop on the ground itself across the entire LF bands?
Yes, I measured one. It is typically more or less centered on 600ohms or so over typical earth for loops less than a wavelength in diameter anway. I’d say the NEC model wasn’t a great match for what I measured.
Feed the preamp with a flux coupled transformer with on the order of 3.5:1 turns ratio to get to 50 ohm territory . If possible have the wire 100 diameters above earth.
20m of circumference will still work at 10m and will go down to 40m or so.
Follow the loop and transformer with a quiet preamp and VERIFY that when shorted at the loop terminals all signals really do drop >10 dB such that you are seeing the loop and not common mode or other ingress.
Symmetry and balance are important.
LIke the Beverage the loop-on-earth (I’ve been calling that to distinguish from the erroneous concept of ‘ground’) gets low angle shielding and generally is less responsive to local, near-field noise sources while still having response to ionospheric propagation.
I am looking for info regarding using a loop on ground for transmission. I understand it is a good listening antenna but will it work as both and on what bands.