8 - The LOG (Loop On Ground) Antenna

[@hpbear101]

I put one of these together a few weeks ago and I am amazed at how well it works especially on 40 and 80 meters.

[@wkboggs5]

Holy cow! I’m DEFINITELY gonna try and home brew one asap! Thnx NR7K

[@M0NTVHomebrewing]

No worries. Hope it helps. 73, Nick

[@thormusique]

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!

[@M0NTVHomebrewing]

Thanks. Have fun. Merry Christmas! 73 Nick

[@HAMRADIO_QRP_and_more]

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

[@nickwood4367]

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]

unun 9: 1?

[@M0NTVHomebrewing]

@@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.

[@josehenriqueschossland485]

@@M0NTVHomebrewing Thank You 73” PU5IKE

[@M0NTVHomebrewing]

@@josehenriqueschossland485 You are very welcome!

[@nq0amark138]

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]

Thanks Mark. That sounds great. 73.

[@nq0amark138]

@@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. ;-)

[@M0NTVHomebrewing]

@@nq0amark138 Really pleased for you Mark :) 73

[@johnlew5972]

Was wondering if you can use a much larger gauge wire and improve reception? Thank you for the video.

[@M0NTVHomebrewing]

Hi John, I'm not sure about that. If you check out the guy I reference in the video I know he tried various configurations. I basically just built the standard one with the wire I had (Sotabeams heavy duty - the green stuff). 73, Nick

[@TalmidAndy]

I'm glad hams are smarter than algorithms as this came up when searching log (periodic) antennas. Good information though.

[@EdzashedFudwinkle]

I have a small Delta Loop just for fun and works great off a pole.

[@M0NTVHomebrewing]

Pleased to hear it. I built one for 6m once which worked really well. It was very directional though. 73, Nick

[@EdzashedFudwinkle]

@@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 🙂

[@bassdowg]

It is also a Perfect Stealth rcving antenna for Covert operation on the 160,80 & 40 M bands

[@AA5MC]

not sure if you are answer any more questions, but are you still suing this loop and if I understand this its only good for the lower bands like 40 nad 80 not the higher bands like 20 and 15 correct? nice video !

[@M0NTVHomebrewing]

Hi there. No this antenna is ancient history for me. I only had it for about a year. It was certainly effective at filtering the QRM on 80m but then the noise suddenly stopped and I didn't really need the LOG anymore. You are right that it is only used on the lower HF bands - 160 MHz, 80m and 60m. Certainly not above 40m. It does filter out a lot of noise but at the cost of significant attenuation of your signal too. I guess there is no such thing as a free lunch! 73, Nick

[@rs4425]

Very good explaination. thanks

[@M0NTVHomebrewing]

You are welcome. 73, Nick

[@brianfields4479]

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.

[@M0NTVHomebrewing]

Thanks Brian.

[@markramsay6399]

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 ?

[@M0NTVHomebrewing]

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.

[@shawnhornett]

Mfj 1708b. Automatic rf switch

[@TheArtofEngineering]

Did you put a common mode choke on the coax? 73 de VK2AOE

[@M0NTVHomebrewing]

I don't think I did! 73 Nick

[@BrekMartin]

Hello, it appears the dimensions you gave for the antenna Nat her for 80 meters. Would you simply halve the wire lengths for 40 meters?

[@M0NTVHomebrewing]

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

[@BrekMartin]

@@M0NTVHomebrewing I mustn’t have paid a lot of attention because I thought it was for transmission, even after seeing that tiny ferrite core!

[@M0NTVHomebrewing]

No worries! It is a RX only antenna and mine worked pretty well at my last QTH when I had a lot of QRM on 80m.

[@BrekMartin]

@@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.

[@OldSal-d8h]

Hello. What material is the box made of? PVC? Thanks de N9NY

[@M0NTVHomebrewing]

Just a plastic enclosure that is waterproof and with walls thick enough to drill and mount the connectors. 73 Nick

[@dazer123]

Wow what a huge difference

[@Aleziss]

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

[@M0NTVHomebrewing]

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

[@Aleziss]

@@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

[@Kd4stt.]

Thanks for sharing

[@M0NTVHomebrewing]

Thanks for watching! 73, Nick

[@Toxoplasmos]

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.

[@M0NTVHomebrewing]

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

[@digitalanaloguehamradio]

Interesting video thanks

[@M0NTVHomebrewing]

Glad you enjoyed it!

[@seventytrees73]

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?

[@M0NTVHomebrewing]

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

[@seventytrees73]

@@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.

[@M0NTVHomebrewing]

@@seventytrees73 No worries - but thanks all the same :) 73

[@franzliszt3195]

Wow, that works good.

[@M0NTVHomebrewing]

Hi! It did make quite a difference at a time when I had loads of QRM on half of the 80m band. Then the noise stopped suddenly and I never really needed the LOG antenna again. It is quite a cool idea though. 73, Nick

[@franzliszt3195]

@@M0NTVHomebrewing I guess it a 'try and see' situation. Some vids show that it made it worse. I wist there was a way to do a better test rather than listening to a guy talking 600 miles away and spend a bunch of times listening with the LOG in and out of use.

[@Nathan1975Liggy]

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.

[@GoA7250]

No, no tuning cap. As he said in the video. kzbin.info/www/bejne/l6rIooSqpJt-rLs Here is the author KK5JY's video on the topic kzbin.info/www/bejne/rX7FaZxrhsadjZI

[@Nathan1975Liggy]

@@GoA7250 Yeah sorry mate I replied before I had watched the whole video LOL

[@vincentstevens5048]

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)

[@nickwood4367]

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.

[@vincentstevens5048]

@@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.

[@m3hnl]

very interesting vid my earth is 9ft deep hustler 5btv ground mounted ft 450 512 ft asl it works 73 m3hnl

[@M0NTVHomebrewing]

Thanks James.

[@GoA7250]

Apparently, it works even better when it is just under the ground, a few mm is all. Here kzbin.info/www/bejne/l6rIooSqpJt-rLs 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 kzbin.info/www/bejne/rX7FaZxrhsadjZI

[@PatAutrey]

Would you please explain how you got it to turn on and off with your push to talk I have the same radio that you do and I’m very interested

[@nickwood4367]

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

[@PatAutrey]

@@nickwood4367 Thank you for your quick response all the best!

[@shawnhornett]

Mfj 1708b rf sensing switch

[@control5835]

I'll try it!

[@XPFTP]

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

[@rickdaniel1671]

Wait until you clearly hear a signal that doesn’t move the signal meter! My LOG is 500’ total length, fed where my property line allows.

[@M0NTVHomebrewing]

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

[@lizzyfan1986]

"How on Earth?"....pun not intended

[@T.M.G2014]

Could anyone make me a balun like one in video,

[@kellypaws]

The 'work around the problem' is attractive for those of us who may have neighbours who happen to be scum. Ergo, I shall be looking into this...

[@stevejoos8953]

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).

[@M0NTVHomebrewing]

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

[@Knarf14]

So youre saying if i use 75 ohm coax its 2 turns and 6 turns ?

[@M0NTVHomebrewing]

Hi there! No - if you're using 75 ohm coax I think it's 2:5. Check out Matt Roberts' page : www.kk5jy.net/LoG/

[@paulziminskin2ghr282]

You using noise reduction lets hear it with noise reduction off ,,,

[@M0NTVHomebrewing]

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!