I am converting my club members to ground loops I even had a QSO transmitting 100 watts on a ground loop if you can believe it LOL 600 miles a 3-5 received signal at the other end so funny they could not believe it. Anyway I have left some comments on your site. Nice video presentation keep up the good work regards 73's VK4ZOW
Hi Bob! Thanks very much for getting in touch. What kind of transmitting loop did you use? Presumably it was tuned. I've heard that some people have had surprisingly good results from a transmitting ground loop. It seems counter-intuitive but - hey - if it works!!! Thanks again. 73.
Excellent video, thanks very much! Now I'll definitely have to try one. I do live in a very rural area, so I may play with loop length a bit, as described by Matt on his site. Cheers!
Great video, amazing antenna. Never expected this result. We are members of Denby Dale Amateur Radio Society and heard the announcement of your upcoming lecture on the Zoom clubmeeting today. Looking forward to seeing you soon on Zoom! 73s de Adriane DL8BDT and Mike DL1BJW
Thank you both very much. Yes it is a surprising antenna! I'm looking forward to joining you on Zoom next month. I'll be going back to basics and talking about homebrewing a direct conversion receiver - another thing which works surprisingly well! 73.
@@josehenriqueschossland485 No it's not an UnUn - which is a transmission line transformer - it is a genuine isolation transformer with no DC path to ground and no DC connection between the primary and secondary windings. So the loop is completely isolated from your connecting coax from a DC point of view. It is a 3:1 voltage transformer and so a 9:1 impedance transformer. Please check out Matt Robert's page for the schematic (www.kk5jy.net/LoG/). Thanks for your interest.
Very cool ! I'm building two of these this week, one broad side east / west and one broad side north / south with a coax switch in the shack to switch between the logs and my receive only mag loop, which then go to my receive only port on the IC 7600. A guy can never have too many antennas to play with ! hihi.. 73 from NQ0A in Utah.
@@M0NTVHomebrewing Wow ! Wanted to let you know I got this project done and I am amazed ! They are directional for sure and boy do they work well. If hams knew about LOG antennas they could use the low bands again in T storm season. This was a great project, truly amazed. ;-)
The transmitting (Log ) composed of insulated earth wire held in place with plastic rods using a ferrite yolk from a VGA monitor (high cut off freq and handles 100 watts no problem) tuned the yoke and loop with a Nano Vna to around 720 ohms balanced ,slowly increased the power on my rig to a safe SWR.
At 02:50 you mention having a LoG (receive) and a transmit antenna that can "...switch in-and-out with the PTT." How did you achieve this with the IC-7300? Thanks.
Hi! I said that I was investigating having a separate RX antenna - one that I could switch in and out. In truth I never got this far. The interference I was encountering on 80m seemed to vanish as quickly as it came and so I had no real need of the LOG antenna any longer. In the end I pulled it up and have moved house since then. Also, the commercial rig I was using in this video was a Yaesu FT991A. I've never used an Icon rig so I can't be much help I'm afraid. Sorry! Thanks for watching. 73, Nick
Thanks for the interesting video. How does the loop perform on mediumwave? And should i go with one slightly larger than yours? I read that 15% of the intended rx wavelength is the optimal length, which equates to about 45m if i use 300m as the midway point of the mw band (=1000khz)
Hi Vincent, I'm afraid I've no idea how it will perform on MW. I only ever used mine on 80m. The size is a funny business because some have made larger loops but ended up with worse performance. I think I'd go with your gut and be prepared to experiment a lot! All the best.
@@nickwood4367 thanks Nick. I have a large plot 100x42m and I've tried a few experimental LOGs but strangely enough they seem noisier than my delta loops. But its fun to fiddle around with all kinds of antennas so i might have a crack at a smaller one, 11m per side.
Interesting video. So how practically would you swap between RX on the loop (which does sound much better for 80M) and TX through your other antenna, given that the loop is receive only ?
That's an excellent question Mark! As yet I've not come to a satisfactory answer. I have played around with RF switches etc. but I could do with something that will handle a bit of power i.e. more than QRP. There are probably some fine solutions out there but I've moved on to other projects I confess.
Just watched this after your talk at Denby Dale. I’ve built a LOG and it is definitely more quiet, but when I scan it with my rig expert I get dips on 40/20/15+10 but 80 has no dip. That’s where I have the biggest noise problem and could use the most help. Any ideas where I should start investigating? It’s 15ft per side and a 9:1 transformer at the feed point.
Hi Dave, thanks for watching and well done for building a LOG antenna. I wouldn't get too concerned about the SWR - incidentally mine shows a similar pattern on a RigExpert analyser. I'm no expert in this but from my understanding the antenna is not intended to be resonant on any particular frequency. A high SWR is simply an indication of impedance mismatch and reflected signal. This is obviously bad news for a transmitter but for a receiver - where the received signal level is magnitudes weaker - it is not such an issue. What it will mean is that you will get attenuation of the signal from your antenna - but (and here's the important bit) that attenuation is applied to both the received signal AND THE NOISE too. So your signal will be weaker but the noise floor will be lower. This is why in the video I was able to switch on the RF preamps and still get a cleaner signal than if I used my EFHW and no preamp. Hope this helps! 73.
@@M0NTVHomebrewing I think this is around 20ft or 3.6m x3, told to put balun high, and bottom 2 opposite the direction of path, so West is east south is north, something I will have to try and find out, great video btw 🙂
I find most of my rx ants are not resonant , but a small rx atu does peak sigs on different bands, main test is with weak sigs, and how well the log pulls them out of the noise.
Out of curiosity do you still need the smaller 15% loop and tuning cap. What size to cover the full HF spectrum. Will mostly use this for my bedside SDR.
No, no tuning cap. As he said in the video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ayeqQto6KvY.html Here is the author KK5JY's video on the topic ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wMb8i5QajW0.html
I'm not doubting that the loop on ground gives a better signal to noise ratio, but I wasn't entirely convinced by the video, because it sounded like the rig had some dsp noise reduction. With the large signal from the efhw the audio peaks were dipping the background noise, but with the lower signal from the loop it sounded like the audio was noise gated. It was definitely more pleasant to listen to, but does it truly demonstrate the s/n advantage of the antenna if the rig's DSP is skewing the results?
Possibly not but I was simply running the rig with the same settings that I commonly used at that time. By all means build one and judge for yourself. I've moved house since then and probably won't need to resort to a LOG antenna as my noise floor is now much lower. Thanks for watching and commenting. 73
@@M0NTVHomebrewing I have used low dipoles, just a couple of feet off the ground, a loop on a fence, and a mini-whip. They definitely show a s/n improvement over a high dipole, so I have absolutely no doubt that the loop on ground also works. If my comments sounded nasty, I apologise wholeheartedly. Thanks for the videos! 73.
14:54 I notice your tuner is still engaged on the LOG, that might have an effect on the receive since it is far from being the same loading than you transmit antenna
Hi there! Well-spotted. I hadn't noticed this! The tuner doesn't actually kick in unless you transmit a tuning tone through it. It was only there because of my particular setup. But you are right, it could have an effect on receive if it was already held in a 'tuned state' but frankly I don't think it makes much difference when you are just receiving (unless the 'tuned state' was way out). All it will do is present a different impedance to the incoming signal which will result in a higher SWR. This will mean a bit of loss but not much. Since the antenna attenuates the signal in any case it's probably not worth worrying about. Obviously on a receive-only antenna you can get away with a lot more! Thanks for watching and for commenting. 73 Nick M0NTV
@@M0NTVHomebrewing ok I thought it could have been why you had such results with the log antenna, here I have two transmit antennas that are totally different systems and when one is tuned and I switch to the other one, the reception is greatly degraded, I thought you might have got the same result on your end with a mismatch antenna. 73 de Claude VA2CST
Hi! I think the loop I built is good for 160, 80 and 40m but I advise you check out the original author's website: kk5jy.net/LoG Hope this helps. 73 Nick
@@M0NTVHomebrewing I only work camping. There’s no gear at my QTH anymore. I thought I’d found a way to be lazy! Due to back problems, I’m probably going to have to make an air bazooka to fire the throw sack with line over the branch.
Sounds great. Mine was useful when I suffered a lot of QRM on half of the 80m band. The antenna is now long gone and I'm at a new QTH. Thanks for watching. 73, Nick
I didn’t - I only built it as an experiment and used it for receiving only. I did think about some form or relay switching but never got around to it. It shouldn’t be too difficult to do I should think. All the best, Nick
Apparently, it works even better when it is just under the ground, a few mm is all. Here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ayeqQto6KvY.html you see a group of HAM radio enthusiasts, you may even know a few, talking about the LOG. Here is the author's video on the topic ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wMb8i5QajW0.html
hahahah... i have a end feed. no balun no unun. just wire off center of coax 1 ft off ground. to 35ft in tree. shield is 2 60ft #12 soild .. got sick of moving it for mowing. so i rolled the grounds up. about 5ft diameter. hugh on tree works a charm. i hear better on it then i do tx on it hahahha.. tho i do use a manual tunner for 75. antenna is only used for it... tho i need to put up a proper diapole someday
You comment about the #73 material being good through 30 Mhz and the entire HF band is incorrect. If you look at the graph from the manufacturer shows if drop completely at 10 Mhz. The KK5JY article even says that this core is only good to 30 meters. And you can see this on your RigExpert too: put a 8 Ohm resistor on the loop side of a 5:2 ratio binocular core, and run a RL (Return Loss) sweep on each band. You see 20 meters has a RL of less than 10 (8).
Thanks for watching. Certainly that particular mix is designed for lower frequencies but according to www.toroids.info/BN-73-202.php 73 mix is good for wideband transformers from 0.2 - 30 MHz. As I only ever used the loop for 80m it wasn't really an issue for me. 73
Sorry Paul. I did the tests simply as I would normally use that particular radio on that particular band i.e. with digital noise reduction on. If I'd thought about it before then I'd probably have done as you suggested!
