A VHF Magnetic Loop Antenna For 6m.
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- เผยแพร่เมื่อ 21 ต.ค. 2024
- Putting together a 6m magnetic loop antenna from www.vhfloop.com in Canada and a brief test with antenna analyser and Racal VRM-5080 military transceiver. The antenna covers the whole 6m band and then some, of course using any modulation mode. VHFLoop also makes a 2m circular dipole. The antenna seems to work well, but a field test is necessary to judge performance, which I will do as soon as possible. Get extra content and help this channel: / radioprepper DISCLAIMER: The Radio Prepper logo (depicting a microphone) is indeed inspired from a famous flag created in 1775. It is NOTHING BUT a symbol of freedom and independence. It does NOT imply support to any political group. It does NOT imply, represent nor support any ideology with an intent on harming anyone. Freedom means freedom from persecution based on any human trait or belief such as, non exhaustively, race, gender, religion, sexual orientation or nationality. The Radio Prepper channel is a technology and science channel with a focus on preparedness and use of radio technology for disaster relief and small group communications in times of need. It is apolitical and open to anyone sharing the same interests. .
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Nice quick review. Appreciate your well balanced approach!
Great Gil, I look forward to seeing it in action.
Thank you!
Clearly, with such a mechanically simple antenna, the thing to do is to make your own. Thanks for the demo. I think I'll build one to try, since it will cost next to nothing.
The first call, with lower initial wattage, and pointing the camera at the antenna showed that the camera was affected by the RF from the antenna. I bet that's why you then probably edited in a still image of the military radio after raising the wattage to 50 watts. Nice video.
No still, but I did notice the flickering!
What a cool antenna. Thanks for sharing. Searching for a 6m mag loop was on my To Do list. I have this crazy notion of using a fixed tuned mag loop for 6m JS8 so my local prepping group can text message without the internet or cell phones. Here in the US, Technician class operators can use 6m and 10m but none of the popular HF bands. 6m is a fairly wide band that's under utilized and the local group would probably have the band to ourselves. The mag loop is a small and efficient antenna, and the hassle of tuning it is not a problem for fixed frequency use on JS8. Now I need to find a QRP 6m JS8 transceiver kit.
I think it would work very well..
Really neat and interesting design. Thanks for the review.
I have this same antenna, but have not yet done any testing with it. It looks pretty cool in my shack, though. I have loaned my VNA to another ham, but once I get that back (so I can measure SWR, etc., and retune as needed), I'm going to do some testing.
This antenna look very nice, I'm making one by myself and I was thinking about use of aluminum strip, 2mm thick, bending forming the loop, but because of skin effect, the current flow just 1mm deep and this is right, but also 1mm deep just at both edges, making the flow of power like twin thin loops in parallel, decreasing a lot the efficiency of the antenna.
Find out what John portune w6nbc told about loop antennas.
Happy new 2024
You are correct. Mag loops are very much affected by all the metal in your building and deck. They are a compromise to begin with but work best away from all metal.
Thank you.
Hi Gil,
I wonder about the polarization (sorry if it is a mistake, "polarisation" in french) of this antenna : do it result of the location of the inner loop, or not, is it vertical, horizontal, circular ?
Sincerely yours, Milos F4IIP
A very interesting antenna.
Magloops are Awesome. Green radios and Magloops are even better 👍👍👍
Agreed! If only those green radios were lighter!
Radio Prepper Anyone got a spare Leopard 2 ? No, a Tiger tank is OK!
Thanks Gil.
Hi Gil,
Thanks for the nice video!
To adjust the capacitor, I use a pair of 40mm M5 screws mounted in the threaded aluminum part and wing nuts plus washers, all in nylon.
M5 seems a little tight (imperial thread?), but it works.
Interesting thanks.
It's Canadian so it should be metric.
Nice. I think it's a very elegant design (even if rough around the edges). There needs to be a bigger push for 6m usage!
Definitely!
Yes very interesting. I wonder how well it work with my yaesu ft 690...no mention of price on the website though. Look forward to your field test...
The price is on the site.. I am pretty curious as to how it will perform as well... Stay tuned...
Radio Prepper actually no the price is not given as I said not showing on my iPad anyway
The price is on the web site. $119.95 USD including shipping for the 6 meter version.
@@sasines oh yes clicking on products shows it...I just looked at the main page which shows the image but no price
Salve, sono IT9SKY, sono interessato a questa antenna. Posso avere info su costo, modo di pagamento e spedizione. Grazie IT9SKY Mimmo
Is there an advantage to having a loop edgewise on, rather than a flat section bent into a loop?
That I do not know... My intuition is that a tube would be better...
That's a nice antenna..
Je me souviens lorsqu' il était question d'ouvrir le 6m dans les Alpes maritimes , certains gueullaient parceque cela n était pas encore fait . Aujourd'hui je constate qu il n y a pas un chat sur la bande . Et les premiers que l on entendait brailler ont disparu .73 et bon courage pour vos prochains qso sur le 6m.
Oui, c'est domâge...
I just bought a 1979 Sanyo Betacord AKA Betamax player. It appears to have UHF & VHF tuning knobs on the front of the machine + uhf/vhf inputs on the back. I assume at one point this machine could record those frequencies to beta cassettes? That’s so cool
Never heard of that!
4 years after this video was posted, I tried the link, but it appears to be not working fully. Am very interested in this build. Anyone know where I might find it in May 2024?
Nice looking antenna. Have fun with it. 73 de K2CJB
I have the same one. I used the gamma match it was awesome. Little trick i did was to mount it on a lazy suzan so I can rotate it super quickly.
What's a lazy Susan?
@@RadioPrepper it's a type of serving device that spins around en.m.wikipedia.org/wiki/Lazy_Susan
@@RadioPrepper It's a rotating plate, commonly used on tables. Food is placed on it, and people can rotate it to get the food closer.
@@RadioPrepper you can get them fairly cheap and they do not have to be as ornate. Some are actually really simple.
Don't get too close to that. From what I have read about such loops, the near field RF gets pretty high with only a few watts input.
Definitely, I will only use it at no less than 30ft away..
I have just unpacked the 6M loop.
Did you need to bend the ends of the small coupling loop to fit on the SO239... mine is just a flat piece at present
Mine wasn't flat but I did bent it a bit..
@@RadioPrepper O.K mine is completely flat...
I need to bend it around a round object to form circle, then bend ends, what diameter is yours..??
Gil, I really got excited when you showed this antenna so I ordered one. How long did it take for yours to arrive after you ordered it? I am pretty anxious to get the antenna! Thanks
To the U.S. I'd think a week..
Bonjour... Je me souviens plus... La polarisation d'une telle antenne ?
Horizontale si je me souviens bien!
It would be very cool and sort of steam punk if it had been cut from copper but there you go with expense and weight. I wonder if you could put some form of dielectric material between the capacitor plates to perhaps make it easier to keep parallel and make it spring back out as you adjust that way, just a thought. Very cool device.
Good idea!
Hi from Australia.
Did you get around to further field testing of this loop to see how it performs?
I suspect that you'll find it works as well as your 6m end fed half wave antenna. Interesting video and I actually like their approach in the design of this antenna
Not yet, but it's on my list!
Hello.I have a question about the vhf handheld radio.I have a Kenewod TK-250 and TK-270 without batery packs and try to power them with lab linear power suply,the problem is when try to transmit the radio and the power suply enter protection
I also tried with analog power suply .My question is ???.There is a solution to solve this problem,or i must use only batery.I think they were not designed to go with external power suply instead of baterys.What do you think.
What voltage? I would think the battery is 8V (2S).
7.2V Ni-Ca but i dont have this batery pack.I use Elektro-Automatik EA-PS 2033-050 linear power suply.at 7.2v and max curent 5A
Hi Gil. My loop should arrive this week. It was posted over a week ago. I expect UK customs will ask for VAT 🤔 It certainly looks good. I am looking forward to getting out portable with this bit of kit & also using it when I give talks at radio clubs.
Do you have 6m only on your military radio?
Best 73
Hi, 30 to 76mHz. We don't have 4m so it's 6m only. Customs charged me 59 Euros!
Hi Gil, great antenna! Great video! I was actually wondering if loop antennas exist above 30MHz. What about UHF? 800-1000 MHz would it work for GSM-LTE? Do they exist? I would like to try out. I can just imagine loops for 70cm, 1800MHz dect and UMTS, 2.4GHz wifi....
I have heard of mag loops for up to 2m, but I guess above that it gets dicey, and really, above 6m there is no advantage in using a mag loop, as the main argument is small size..
The same guy who makes this 6m magloop also makes a 2m "circular dipole". Not a magloop, but it looks very similar. I have one that I've been looking for an excuse to test out. Maybe I'll be able to drive out to somewhere with some elevation soon, and try it with my IC-9700. If I do, I'll report results here.
@@AlGordon A Circular dipole is what they refer to as a Halo antenna. They work quite well. I've made them for various frequencies out of aluminum strip and a version of one which had a few copper tabs to capacitively load it just a little (reducing the size by about 30%) and make to it tunable. That was a very good performer too. You can run them vertical or horizontal which if you're into 2m SSB is something fun to play with
Does anybody have experience with the VHF version of this loop antenna that the company sells?
any dimensions or drwawings of this pieces?
No sorry.
Good video. Thank you. I was thinking about this antenna. I wonder if you can use it for CB (11m) and 10m as well.
I should try that, good idea...
I wonder if you could use double sided PCB material, and 'etch' something like that 🤔
Might cost more though...
I know you are probably aware because you seem to be some type of radio god but i feel I should tell you to be very cautious the nf rf from a antenna like that can be ridiculously strong even at low power. Another good video you have rekindled my interest in all things radio thank you sir
Indeed thanks. I am really no expert, but I always heard that mag loops could be dangerous..
Too damned expensive for a unfinished, bare, CNC project. The least they could do was to give it a cheap powder coat or an anodize at least. Aluminum corrodes all too easily.
I wonder if one could place a thin ceramic insulator for the dielectric in the capacitor in lew of the air gap, then crank up the voltage. . .
As it is this loop would be okay with 200W.
You are better really to stick with air dielectric for the lowest losses. Anything that heats up even slightly will cause the resonant frequency to drift.
However if you are interested in experimenting with dielectric materials for high RF usage, I have discovered that white plastic chopping boards (I presume they would be polyethylene) cut into pieces are impervious to the heating effects of high RF.
I found that nylon bolts (also uncoloured) from an industrial supplies store here heated up badly on around 10m with a mere 50W of RF and bad drifting was evident. The bolts were only being used to adjust an experimental capacitor arrangement too. Anyway warm regards from here in Australia
All else fails you could use it to crack nuts or toast a sandwich between the condenser plates. Just kidding! A nice looking antenna, just be careful to not bend it out of shape.
1 year no video on use of this antenna. How come?
Covid.. I will make more...
@@RadioPrepper stay safe and healthy my friend!
You too!
Yes, expensive... I have one in transit due any day now...
what handset are you using on the VRM5080 Gil ?
It's a Racal. They pop up once in a while on Ebay..
@@RadioPrepper do you have a type number,....and did you have to rewire it with an clansman audio connector?,....tnx, Ron G4FBC
No markings but it did come with the correct plug.
Is there a link to purchase?
Link in the description, printed twice and mentioned once in the video...
not for indoor tv?
LOL no.
Ça conception est originale en découpé laser.
Maintenant, si les Loop magnétiques sont à la mode. Leurs utilisateurs déchantent après quelques temps. Car dans certain cas, un bon dipôle épais, aura plus de bande passante qu'elles.
Par contre au QRA j'en utilise une en diversité, montée en dessous du dipôle et cela me permet de m'astreindre de certains QRN / QRM.
Après au niveau des signaux reçus ; il sont quasi identiques de l'une à l'autre
73's
Merci pour vos vidéos
Ayant un petit appartement de 23m2, le loop est la seule solution possible. Super performances, mais ajuster le condensateur tout le temps fatigue vite...
@@RadioPrepper Pourquoi ne pas réalisé un asservissement avec un moteur commandé par la valeur du ROS ?
Beaucoup le font... Un jour peut être..
@@RadioPrepper J'ai un ROS avec sa tête de mesure déportée qui ne me sert a rien... je vous l’envoi gratos (contactez moi en MP si vous voulez) il vous suffira a utiliser la tension issue de la sonde pour asservir un contrôleur de moteur pas à pas - Ainsi plus de crampes dans les doigts a ajuster le CV a air lol
73's F-10175 = F11DRE
Merci, j'apprécie beaucoup, mais j'ai vraiment trop de projets en cours! ;-)
Using a military term for a military radio, you are DANGER CLOSE to that antenna. Please do be cautious. Magnetic loops can be very dangerous in the nearfield proximity and 6M is a high exposure frequency. If you must be in close proximity always stay in the null to reduce your exposure to the massive H fields generated by the mag loop. The best advice is to keep a minimum of 2 meters away at lower power and further at higher outputs.
73
Indeed! I was in the null but still too close..
Efficiency equal to half wave dipol but magnetic field destroying your helth.
Just don't stay too close..
6 meter has no magic, thats a farce. 2 meter is more active and seems to perform better than 6m anyway.
Only because less people use 6m since most handhelds are 2m/70cm.
Radio Prepper I can talk simplex on 2m to friends 30-40mi away that can’t hear me or I them on 6m.
It's called the Magic Band because 1 minute you are talking local, next around the world...