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thanks - 73

The loop antenna works better for receiving than transmitting but is still very directional and has to be retuned every time you change bands and frequencies. A long wire antenna does not have that issue. I will say that this antenna has a very sharp Q and is good at reducing interference from other signals around the station you’re trying to listen to. I will also say that there are larger loop antennas on the market which work better than this one.

The wire would be much cheaper and less directional.

All good information. Thanks for taking the time to share the information. I do agree that this is slop detection and you can even remove one of the transistors. At some point I want to try re-doing this video as I did it a number of years ago. Thanks for writing - de N1KRB

Prego. Questa antenna funziona meglio per CW. Visiterò l'Italia ad ottobre e porterò una radio. Spero di lavorarti. 73 de N1KRB

I also use that key for code practice. I can connect the key to the battery and a buzzer to practice. Thanks for asking

@@rbashta Brilliant, thank you for the super fast reply. 73

@@union310 - you're welcome - 73

Thanks for your note. Yes, trying to figure out the correct pinout for a number of devices seems to be a constant struggle in this hobby. It seems no two mic, earphone or key jacks work the same on each radio. Thanks for letting me know this video was of some help. 73

Merci de me le faire savoir. J'en ai entendu d'autres utiliser un seul transistor.

Thanks for the info. I actually had it working - sort of - at about a third of a meter. Anyhow, thanks. I'll try 10 meters ( 33 feet ) next time I experiment with this.

My apology for not getting back to you sooner. There are a number of very simple one-transistor circuits available online. The only problem is that with a one-transistor amp, you can only use an earphone. The output is not enough to drive a speaker. To find a circuit, just Google schematic for one simple one-watt audio amplifier. For a transistor, I prefer a 2N2222 but most NPN audio transistors will work. Gook luck

Thanks for your note and apologies for not getting back to you sooner. The only thing I would do is cut off the connector from the new key you bought. Then buy a three-ring connector and connect the two wires to the recommended contacts. If you come up with a better idea, let me know.

That's great to hear. Having the height of your antenna and using a signal like the Digital modes /CW, is ideal for an antenna like this with its tight Q. I was able to make some SSB contacts but it was a struggle. Thanks for letting me know.

Is this circuit working in Sri Lanka ?

Hi there, I also reside in Sri Lanka. Does it work?

It depends on the overall SWR on the band being measured. If the SWR is high, the tuner will only bring down a certain segment of the band to around 1 or below. However, if the SWR is in the middle of the range, most of, or the whole band, will be brought down to around 1. This tuner is about the best I've worked with. Try it for yourself. Find an antenna really out of range. Hit the tuner button and the display the readings. You will see only a part of the band is corrected. Thanks for asking.

@@rbashta Thanks for the quick reply! This was a well done video and very helpful. I did notice that the SWR is sometimes really good on only a portion of the band and this happens on many of the bands. I'm running an end fed wire antenna with a 9:1 balun and was trying to test my new antenna across all the bands. My question was if the autotuner focuses its tuning for some bandwidth around the currently tuned frequency in a chosen band or tries to tune across the entire band?

@@billguzek9743 - Hi Bill - sorry I could not get back to you sooner. As I might have mentioned before, if a band is only slightly out of whack, the auto-tuner can bring in most or all of the band. But if your SWR level is very high, the auto tuner really has to work and is only able to bring in a smaller portion of the band. The lower the SWR, the more of the band can be tuned. By the way, I use a 49 to 1 un un with 66 feet of wire and my antenna is resonant from 40 to 10 with very little auto tuning needed. That is really the key ... make the antenna resonant for the bands you want to work.

thanks for letting me know

Thanks for letting me know

As you can imagine, not having a proper Demodulator circuit, hampers the audio. This type of radio uses the poor-sounding 'slope detection' circuit, not known for quality. Thanks for watching.

Thanks for your comment

There is not a true FM demodulator in this circuit. However, the angle of the RF signal across the transistors creates a changing voltage drop at the base which mimics an audio signal. That distorted signal is then amplified by the LM386. This is known as slope detection. There are other videos on RUclips that use a similar circuit. Easy to make and fun to play with.

Thanks for asking. The top button is used to activate the the tuner when you hold it down it LONG. You will hear the relays clicking. When you do the tuning, there will be a small icon that will appear in the top-left corner of the display, indicating your radio has been tuned. It looks like the schematic symbol for 'antenna', If you should do a SHORT press on that same button, the antenna icon will disappear and you will be back out of the tuner mode. Push it one more time, the icon will re-appear and you are back being tuned. The second button, if pushed LONG, will show you the sweep. I hope this helps. I've had very good luck making contacts with my G90. I also have a Xiegu G1M, which runs 5 watts, and I do well with that radio too! With your QRP Guys antenna, you should do great. I took my G90 and QRP guys antenna to Florida last year and did several Parks on the Air outings and did great each time. Of course, the propagation makes all the difference.

Thanks for your comment. That is why I put out this video ... I went through the same thing. Finally, I sat down one day to figure it all out. This also works with my Xiegu G1M.

The type of capacitors this uses is the the polyvaricon (sp?) variety. You're right, it can't handle much power. About 5 to 10 watts CW and 10 to 20 watts SSB. And because of the size of the loop, it is better at 20 meters than 40. I have a G90 which has SWR reading capabilities - very easy to use - making tuning a little easier. But, this was not the best loop antenna which is why I sold it. It was interesting to play with and I'm glad I had it for a while but I have moved on. Thanks for replying.

@@rbashta Thank you very much for buying this loop and sharing your experiences. To get good performance from small transmitting loops requires meticulous attention to design, construction and materials. Otherwise, loops will prove to be less efficient radiators. Coupled with low power, there may be stations that you can hear when they cannot hear you.

Ну, на счёт переменных конденсаторов вы совершенно правы. Эта антенна представляет собой параллельный колебательный контур, при чём с относительно высокой добротностью. По этому, при резонансе, Э.Д.С. там может достигать единиц киловольт, при мощности передатчика в десяток ватт. Да, лучшим решением будет вакуумный КПЕ. Но, а на счёт антенных анализаторов, то это лишне. Обычно такая антенна настраивается следующим образом - в режиме приёма, по максимальному уровню шумов или сигнала корреспондента. А потом даётся малой мощностью несущая и окончательная настройка по минимуму КСВ. Такие антенны узкополосны - полоса пропускания 15...30 килогерц и на ось конденсатора надо установить хотя бы простейший верньер с передачей 1к3 или 1к10. Я экспериментировал с такими антеннами и лучшие результаты это рамка с петлёй связи. Удачи, 73!

Alex - thanks for your note. These loop antennas are quite interesting with their good points and bad ones. I enjoyed playing with this antenna but eventually sold it. I mainly use an end fed for a lot of my work. 73

Thanks for the comment. I would re-do the video but I have sold the antenna. To be honest, there are some plus and minuses to this antenna. It works the best when outside and close to the ground. But it needs constant tweaking to get on frequency. I do best with my QRP Guys end fed which requires only a 25 foot wire.

Thanks - the 3S rule is the best - short, sweet and simple - something I learning in working radio many years ago.

That works no nonsense Thankyou.

For me, I found this antenna worked best outside - away from buildings - and with the antenna sitting close to the ground, to take advantage of the earths magnetic presence. I have seen these antennas work inside a building but only if it is close to a window. Good luck.

Not only is the tuner a great feature for the G90, it is about the best tuner available anywhere. It works better than my LDG and my ATU 40.

I feel like I'm not getting my signal out? I'm using the g90 tuner and a QRPguys UnUntenna Plus with 5-10watts. I've been really low on the SWR meter but I don't seem to be getting out? I'm totally new with this stuff... any suggestions

Hi Boris - At the bottom of the Control Box with the 2 knobs is a Coax that connects between the antenna and the radio. It is kind of hidden in the video but if you look close, you will see it. Thanks for your question.

@@rbashta You didn't understand my question! I didn't ask you about the connecting cable.Such antennas have a communication loop with which you can go on the radio. There is no loop in this antenna. I don't understand how this antenna works! Does she have the opportunity to go on the radio? 73

Hi Boris - my apology. I think you were asking about the small inner loop antenna some magnetic loop antennas use. This design does not need one. I have another video showing me operating this magnetic loop antenna and how it works - ruclips.net/video/bJsmxDhlhzY/видео.html - . I have tried using the inner loop antenna with this but there wasn't performance difference. I hope this helps to answer this question

Борис, вы удалили все видео и связь с вами пропала. Удалось ли вам заставить работать антенну? У меня есть интерес к Mag Loop, думаю о покупке. Я знаю что во второй коробке )) Игорь

@@RadioFromMoscow Приветствую Игорь. Жду лета да испытаний на улице. В квартире рамка работает только на приём. Что же в коробочке?

Thanks for the question. Only two wires are used for a straight key operation ....one wire from what I call the Base ... and one wire from the Ring. The wire from the Tip is not used at all for the Straight Key set up. Make sure you set up in the Manual Mode. The Q90 instructions does not cover this.

Thanks for the question. I had the same one originally. This antenna can handle up to 20 watts SSB and 10 watts CW. However, this amount of power is right at the threshold of causing the capacitor plates from arching over. To operate at a safe amount of power, I would use 10 watts SSB and 5 watts CW.

Well, no, see my request for clarification, please.

If you 'click' on the link in the comment section, you will see the exact schematic I used. The two transistors form a closed loop circuit where the output of the transistor on the right feeds the input of the transistor on the left. The output of the left transistor then feeds the input on the right. The exact frequency seen by the transistors is determined by the incoming radio station signal developed across the L-C tuning circuit.

Thank you and yes 👍🏻 I managed to figure that part out, circuit works great.

Thanks for letting me know. Good to hear.

Like all simple circuits circuits, the performance is "iffy". This circuit's ability to work depends party on the antenna and the strength of nearby FM stations. Also, just like a simple diode radio used for AM broadcast reception, the sound quality is limited. But, technically, this circuit will work. The schematic is very similar to others posted on You Tube.

Click on the link posted below the video

The diagram I show is pretty much the schematic of the loop antenna. The loop uses the shield of the loop cable with a variable capacitor attached to the ends. The variable capacitor is actually two. When using 40 meters, one side of the variable capacitor is shorted. And then when using 20 meters, the switch is open, both variable capacitors are used. There are wires connected to both ends of the cable which go to the radio antenna connection. There is one variable capacitor connected in series with one of the leads to the radio. This capacitor is for matching the SWR of an antenna. I hope this helps.

According to Google - Because the collector current of the 2N3904 is 200mA and the collector current of the BC547 is 100mA, you can replace the 2N3904 with BC547 if the load you're driving is less than 100mA, but you can't use BC547 if the load is greater than 100mA

I sold it a month ago. It was fun to use but I had better luck with an end fed antenna I use for QRP POTA work. Just remember to use it near a window or on a balcony. Tune for the loudest signal and make sure your SWR is below 1.5. Also, it is very directional. And don't touch it when transmitting. You will get a shock. You don't need that. It will work decently if the propagation is good. I did make an inner loop which you do see on a lot of mag loops and that can work a bit better. Good Luck.

The AlexLoop is a much better loop antenna than the one I once owned. And you are right - its all about turning and getting the best SWR level. I have another video reviewing the loop antenna I bought. I finally got rid of it. It did not have a very tight Q and the loop was too small for it to be very effective. Thanks for sharing the results.

From the datasheet I saw, it can be. The s9018 works over over a high frequency range. I'm not sure about gain. The 2n3904 and the 2n2222 - both very generic - works great, too.

The 9014 and 9013 might work but they are designed for a lower frequency range. That is why I suggested the 2n3904 and the 2n2222. They both have twice the frequency range than the ones you mentioned. The 9014 has an operating range of 150 MHz where as the 2n3904 range is 300 MHz. FM radio operates from 88 to 108 MHz.

There are larger mag loops on the market, like the Chameleon or the Alex Loop, which have a diameter of 1 meter. They can do 80 meters. The larger loops can also handle up to to 100 watts. This QRP mag loop has a diameter of less than 3/4 of a meter - 70 centimeters to be exact. It is one of the smallest mag loops out there. Those larger loops go for about $ 500. This one cost $ 139.

@@rbashta What you've got there is about $50 in parts, if all need is longer coax for the loop, then we might get up to $60. I was considering this loop as it is pretty cheap. I have not seen inside the little box but I suspect it will contain two cheap polycon variable capacitors, a switch and a pair of SO239's. MFJ make a cheap nasty loop tuner and it is very much the same. IE a handful of cheap parts and a tin box. It seems that hams have forgotten how to make make things and your credit card is an essential tool as they seem to have forgotten how to MAKE the gear they use.

@@G7VFY Unfortunately peoples use to pay tons of money for something that they can make on theyr own , involving 1/5 of the money . Alot peoples buy the alexloop and somm like that for $500 and up wich is totally insane and NO sense to me . They pay loads of money for a lenght of a shielded cable and a cheap variable cap ..this is because they don't know about the skin effect of the rf ..so by this everyone can understand that a solid copper tube is one thousand times better than a coax . Oh yes, but the coax version is for portable use . LOL and you pay $500 because you won't make it yourself ? Hey, it's a 1m of coaxial cable and a cheap boxed variable cap ! To me, those hams really should woke up .

@@adrianoragazzo1321 People still do. They MAY pass an exam, but they still seem to have no clue or interest in making some of the most basic and common tools and station accessories. A coax loop pocket money parts, assuming that you don't have the parts already. Appliance operators, the credit card is the only tool they've mastered.

@@adrianoragazzo1321 A lot of hams have physical limitations and are unable to even do the soldering so back off!! I hope that you never have a debilitating condition to the point where you need help to take a piss or are unable to perform any ham related tasks.