I was working a 200w station at a friends house he had a vertical and didnt believe in grounding. The heli mic touched my lip wile transmitting and man that hurt had me jumping out of my chair.
Hello!. Im new to HF and was recommended to purchase this antenna. If you have time, what do you think of this. (I got the 155-foot with a 100-foot coax and instructed to choke at 95ft from antenna connection. Supposed to be good from 160m-6m..Thank you!
Hi, thanks for the video! Curious why you chose coax and not bifilar? And also, is 140 size good for QRP only? I use 240 size rings for 100 watt chokes. 73!
You what a common mode choke on every antenna because no antenna is perfectly balanced. Yes some antennas have much more unbalanced than other but there is always some stray currents. So use a good common mode choke and you will happy that everything works.
Nice job! 👍🏻 I will never forget the feeling when common mode current at 100W on 40m into a short Vertical has hit my fist while started keying 🤯...learning by pain
@@RadioPrepper 1981, using an FT101ZD and a long wire....Ouch! is the correct term, I can confirm. Luckily, it has never happened since. Great vid Gil. 73 Keith
For a RF shoke it's simple. Independent of the both materials that you recommend put as much turns around as you can. For QRP power RG174 or RG316 is perfect as you can put a lot more around. It's simple as that. Despite a choke I prefer a 1:1 wired BALUN directly connected to the feedpoint of the antenna. If using balanced ladder line for feeding the dipole I place it on the junction between ladderline and coax feed. Every time as close to the antenna feedpoint to avoid coax loss and detuning of the antenna due to the coax feed. Also the ATU, directly behind the choke (1:1BALUN) to have low coax loss and best impedance matching between antenna and the 50 ohm coax.
Hot glue the hell out of it, just imagine in the 40s what the hell the French resistance could have done if issued with hot glue guns ha ha A tip from an expert select your ferrite material and cores with the inside diameter of the coax you are going to use as close as possible , from your coax feeder line take the rig side end and the antenna side end and slip say 8 coresconto the cable at each end , solder the plugs on and heat shrink with 3 layers the cores to the cable with 10mm spacing between the cores. If you work in an ems lab you know the tricks its far more professional than using little plastic boxes and such bnc rf rubbish bins ha ha We HS0ZOG
Hello ! oui, bien dommage que ce soit en anglais, même si avec tes dessin on arrive +ou- a comprendre un peut. Pourquoi ne pas faire une autre chaine en français avec tes vidéos en double ? ou un sous-titrage en fr ? merci quand même pour ton partage et 73 51 !
pour les sous titre en francais ...Clic en bas a dte sur parametre...lire sous titre desactivé /clic dessus...puis clic anglais automatiquement...Clic a nouveau sur titre Anglais automatiquement...choisir Francais...Voila et en cliquant appuyé sans lacher sur la barre soustitre on peut la deplacer puis relache ..bonne lecture en francais
I was wondering, after winding a choke yesterday, can you put the choke in the same casing as the balun (or unun) or will that have unwanted side effects ?
I thought about that issue and am guessing that a bit of separation, at least a few inches is better. Maybe just using a longer box and putting the toroids at opposite ends might work.
While placing the choke in the same box as the balun at the feed point should do no harm and should help, typical practice is to place the choke away from the antenna. The idea of the choke is attenuation of common-mode current. One theory is to put the choke one quarter wavelength back from the antenna feed point. Just as an example, if you had, say, a doublet with a 9:1 balun at the centre feed point and it was fed with RG-58U co-ax. If you were operating on 20m band, you can calculate the wavelength as 300/14.1 = 21.28m. The quarter wavelength is the 21.28/4 = 5.32m. However, you have to take the co-ax velocity factor into account. This is usually 0.66. So, 5.32x0.66 = 3.51m. You would put the choke 3.51m back from the feed point. Simplify the above by using one formula for RG-58U: (75 x 0.66)/(frequency in MHz) = quarter wave distance in metres. If you have a different type of co-ax, just replace 0.66 with whatever it's velocity factor is. For longer runs of co-ax, you can place the choke at odd multiples of a quarter wavelength (one, three, five, etc.).
@@Steve-GM0HUU I'm not sure why you wouldn't want to place it as close to the transmitter as possible? Isn't the feed line considered part of the antenna if it's some fraction of the wave length you're using? I've got EFLW's on the brain, so I'm pretty sure what ever I say my be wrong here.
@@Steve-GM0HUU In certain cases you may be correct Steve but in most cases I would suggest that people use common mode chokes to stop ANY part of the coaxial cable becoming part of the antenna. Allowing your coax to radiate for any multiple of a wavelength will only serve to alter your radiation pattern. That's why common mode chokes are placed at the antenna feedpoint, to stop RF currents coming back down the outside of the coax and effectively becoming part of the antenna.
I have 240-43, can I wind one that will cover 160 to 6 meters using that 240-43 and RG58? How many turns would I need? Thank you for the information. 73 de W4DES
Concerning the RF chokes on the ferrite toroids you HAVE TO read excelent paper of G3TXQ ( now SK) on the page: www.karinya.net/g3txq/chokes/ where uou can find many answers to the questions like: how many turns...., what type of ferrite toroids to use for some frequency and so on. Stan OM8ST
Oh yeah,the mighty random/longwire. I've been using one as my main antenna for 5years now,I couldn't even count how many ridiculous anomalies I've experienced with it :D I will definitely try a choke in the future
Maybe you can help please. How many turns have a RFC coil for FM tube radio with ECC81 and what is the diameter of wire in mm and the diametere of the core? i have found that i use 37 turns of 0,8mm wire and 8mm core bat i think its not right. Have any one an idea?
I leave my portable connected to my random wire antenna and today I noticed none of the buttons worked. I took out the batteries and it worked for a few seconds and locked up again. I unhooked the antenna and now its fine. I wonder if this was an rf issue or because it's a cheap radio? It is stormy out today if that'd matter.
@@RadioPrepper - and those sources are dead wrong. You should remove this video, because a.) wrong number of turns and b.) such a core 'FT-114-31' does not exist. So, what you show in your video is just 'believe'. ;-)
Gil, nice info! Congrats! Can a FT-114-43 be used as a choke? How many turns? I've made a 49:1 with 2 x 140-43 and like to know which choke fits better. 73 de PT2YW
Hi Gil, I hope you are doing well! I’d like to ask for your option about something I would like to try. Do you think would be possible to combine this antenna: qrpguys.com/qrpguys-mini-80m-10m-no-tune-end-fed-half-wave-antenna With these traps: www.sotabeams.co.uk/pico-traps-kit-pair/ To create a resonant antena for 20, 30 and 40 meters? Do you have any advise for someone that wants to try?
Thanks for your videos they are some of the most useful on U tube for the Ham types especially beginners like me. Your English is great thank you again. KI7RJS
Sir great video! I am new into HF. I got one of those Sigma Euro-Comm Vertical antennas that don't use radials. Do you recommend I use an RF choke with this?
Gil you have convinced me to put up a half wave antenna for 20 meter cw. I need your advice. My shack is on the 2nd floor of my house. I have access to a water pipe earth ground. Do you think I need a counterpoise? If yes, where should it start ? Thanks for your videos.
Bonjour gil de radio prepper. Est-il possible d'accorder l'impedance d'une antenne dipole "pour le 11m "de 71 ohms au centre avec un coax 50 ohms en utilisant un balun à air.ou la desadaptation mineure ne nécessite pas vraiment ce genre de montage.
Great video - thanks! So - if I have my FT-891, I'm outside (not trying to operate QRP in a hotel room as I often am) and want to go full 100 watts, what has to change? The toroid? The coax? Both? I love the idea of the small size and I can both pack in a bag for travel on in my saddlebags when on my motorcycle. Thanks in advance for the help. 73
Thank you for the nice video. I want to make some RF chokes for 'listening' on the VLF and LF bands. How can I determine which toroid I need, and especially, how many windings are the right amount? -Thanks.
After watching your videos on the Minion I got to wondering if some of the problems I experience with my homebrew radio and random wire are due to common-mode currents. That made me wonder what you use as a choke. Then you do this video to explain! Merci beaucoup Gil!!! (are you a mind reader as well as a radio prepper?)
Do you think you still need an RF Choke when using a End Fed Random Length wire with a 49:1 balun? I haven't seen RF Current, however, I can't say that I'd know what I'm looking for since currently all my work is SSB or FT-8.
@@RadioPrepper Interesting, I'm making and using 49:1 for EFRW antennas and getting really good SWR's across all the Ham Bands from 30Mhz down. Normally I get SWR's in the low 2's
@@TheDgdimick Curious. What cores are you using? for a 49:1 I've found -43 to be pretty good however -2 (powdered iron) is very lossy and you might see a decent SWR but all your energy is just heating up the core. Build two identical transformers and hook them back to back. Transmit into one end and connect the other to a 50 ohm dummy load via a power meter. Measure the power at the far end versus the power you put in. If you put 10w in and get 5w out like i did with -43 cores then each transformer is losing about 25% of your power as heat. I did this with -2 cores and could barely measure any power at the far end they were so lossy.
@@binky_bun Thanks for your reply, and bare with me here: I'm using 240-43, for the 1.5Kw (3 of them) 49:1 baluns, and 140-43 (1 of them) for the 100w or lower baluns. Now, I'm not disagreeing that there is some lose, I just have an issue/question about your test when using a dummy load. Most dummy loads are 50ohms, when you use a 49:1 balun your only going to be seeing an input of 1.0 ohms = 50/49 = 1.02 ohms, and a 9:1 balun will see 5.56ohms, into the transmitter. The BAD SWR you're feeding into the transmitter should/will cause the transmitter to decrease the power the transmitter outputs. I see your test as not really being valid. If I was going to run your suggested test, I would need to build a 3300 ohm dummy load, however I don't have 10watt resistors to do this. If I'm wrong here, please correct me. Did you have power meters on both the Transmitter output as well as on the output on the balun? Just because you dial in 10watts out on the transmitter doesn't mean your going to really get that 10watts out.
I wonder if it would make winding the toroid easier if you hot glued the first wire wrap to the toroid. Thanks for the videos. I'm always learning something new from them.
Euh... super de bon vidéo, Gil, mais tu sais-tu pas skeu ça veut dire en tête-carré « étrangler sa poule »? (Je te parle en pepsi pour pas que ça te gêne...) En tout cas, merci pour l'explication de ce machin. Je vais m'en faire kks uns. Bonjour!
I think I can do that if I slow down the video and spend an afternoon studying. One question I have is where o you get those neat little boxes? Who knows, I may build one of these. I have hand tremors and had an awful time with Anderson connectors, an awful time. Thank you for your video. Looks like there were a lot of people who needed this information. It was kind of you to help so many. N4KBM
Gil, you rock. Question, is that toroid providing enough resistive impedance for 80 meters, without the inductive impedance? I just finished a 240/31 w/17 turns, but always looking to save ounces. This choke is now the heaviest thing in my kit except for the radio. 🙂
@@RadioPrepper A perfectly reasonable reason :-) I just don't have any thin coax like that, but I have some flat, four-conductor single copper stuff from Radio Shack; I'll split some of that of into two pairs: it'll probably wind easier and flatter anyway. Keep 'em comin', Gil, I look forward to seeing notifications of your new posts in my inbox. Anecdote: I miss France, too: an ex-pat Brit in the US now for 36 years, I used to travel around western Europe for my job back in the late 70's, back in my machine tool controls days. The inside of a French tool & die shop is the same as any other, but the surrounding countryside was beautiful. Do you guys still have yellow headlamps? I always though that was smart... (priority to entry onto a roundabout not so much ... ;-) )
Hi Gil, can you advise on an EFHW transformer using 140-43 cores? What size wire did you use and was the turn ratio still 14:2? And did you use the standard 100 pF capacitor?
@@RadioPrepper I've travelled for robotics job for over 21 years all around all continents, now I'm retired because of my legs and wheelchair user. hope to meet u on air soon 73 51 de iw4dbx
![ผัวเถื่อน - ยูริ โตเกียวมิวสิค [ OFFICIAL MUSIC VIDEO ]](http://i.ytimg.com/vi/P08ORRVDGl8/mqdefault.jpg)
I love videos on RF suppression. Big fan of RF chokes. Good work Gil!
Thanks Josh, it's a really simple choke, aren't they all, and I just hope it will work well..
I was working a 200w station at a friends house he had a vertical and didnt believe in grounding. The heli mic touched my lip wile transmitting and man that hurt had me jumping out of my chair.
Hello!. Im new to HF and was recommended to purchase this antenna. If you have time, what do you think of this. (I got the 155-foot with a 100-foot coax and instructed to choke at 95ft from antenna connection. Supposed to be good from 160m-6m..Thank you!
I used FT240 cores with 14 turns of RG58 for my home brew chokes. I have no problem with 100w, and could probably go much higher. --de N3TS
But did anyone else laugh at his RF choking his chicken picture in the video thumbnail?
Hilarious! Thumbs up for great information and some fun too!
Great project ! Thanks for info Gil .....
Hi, thanks for the video!
Curious why you chose coax and not bifilar?
And also, is 140 size good for QRP only? I use 240 size rings for 100 watt chokes.
73!
It's just simpler and bifilar is more finicky, requiring more attention to detail..
Use 21 winding with RG316 to make a good CMC. Toroid used is FT240-31. Handle easy 500 watt !
Thanks. FT-240 is too big for me. That's a lot of turns!
You what a common mode choke on every antenna because no antenna is perfectly balanced. Yes some antennas have much more unbalanced than other but there is always some stray currents. So use a good common mode choke and you will happy that everything works.
I only use mine when needed...
Nice job! 👍🏻
I will never forget the feeling when common mode current at 100W on 40m into a short Vertical has hit my fist while started keying 🤯...learning by pain
Ouch! I never want to feel that!
@@RadioPrepper 1981, using an FT101ZD and a long wire....Ouch! is the correct term, I can confirm. Luckily, it has never happened since. Great vid Gil. 73 Keith
Always a good idea to test a new antenna on low power first. That way, you only get a little shock.
For a RF shoke it's simple. Independent of the both materials that you recommend put as much turns around as you can. For QRP power RG174 or RG316 is perfect as you can put a lot more around. It's simple as that. Despite a choke I prefer a 1:1 wired BALUN directly connected to the feedpoint of the antenna. If using balanced ladder line for feeding the dipole I place it on the junction between ladderline and coax feed. Every time as close to the antenna feedpoint to avoid coax loss and detuning of the antenna due to the coax feed. Also the ATU, directly behind the choke (1:1BALUN) to have low coax loss and best impedance matching between antenna and the 50 ohm coax.
Very good thanks!
Nice simple stay at home project, thanks Gil!
Can i use this on fm transmitter?
Hot glue the hell out of it, just imagine in the 40s what the hell the French resistance could have done if issued with hot glue guns ha ha
A tip from an expert select your ferrite material and cores with the inside diameter of the coax you are going to use as close as possible , from your coax feeder line take the rig side end and the antenna side end and slip say 8 coresconto the cable at each end , solder the plugs on and heat shrink with 3 layers the cores to the cable with 10mm spacing between the cores. If you work in an ems lab you know the tricks its far more professional than using little plastic boxes and such bnc rf rubbish bins ha ha
We HS0ZOG
Hello ! oui, bien dommage que ce soit en anglais, même si avec tes dessin on arrive +ou- a comprendre un peut. Pourquoi ne pas faire une autre chaine en français avec tes vidéos en
double ? ou un sous-titrage en fr ? merci quand même pour ton partage et 73 51 !
Ce serait bien oui, mais je ne suis pas retraité et je n'ai pas vraiment le temps.
pour les sous titre en francais ...Clic en bas a dte sur parametre...lire sous titre desactivé /clic dessus...puis clic anglais automatiquement...Clic a nouveau sur titre Anglais automatiquement...choisir Francais...Voila et en cliquant appuyé sans lacher sur la barre soustitre on peut la deplacer puis relache ..bonne lecture en francais
@@RadioPrepper Après tu as aussi la possibilité d'en faire une sur deux ! lol
Je n'ai qu'un faible pourcentage d'auditeurs francophones...
@@pheliciadirssen7940 Merci c'est bien cool ! 7351 a toi !
🇧🇷🇧🇷🇧🇷👍👍👍
I see it. I see the inside of the box.
Always remember what my school teacher told us when doing homework or taking a test.
Neatness counts.
😄
I was wondering, after winding a choke yesterday, can you put the choke in the same casing as the balun (or unun) or will that have unwanted side effects ?
I thought about that issue and am guessing that a bit of separation, at least a few inches is better. Maybe just using a longer box and putting the toroids at opposite ends might work.
I was thinking the samething.
While placing the choke in the same box as the balun at the feed point should do no harm and should help, typical practice is to place the choke away from the antenna. The idea of the choke is attenuation of common-mode current. One theory is to put the choke one quarter wavelength back from the antenna feed point. Just as an example, if you had, say, a doublet with a 9:1 balun at the centre feed point and it was fed with RG-58U co-ax. If you were operating on 20m band, you can calculate the wavelength as 300/14.1 = 21.28m. The quarter wavelength is the 21.28/4 = 5.32m. However, you have to take the co-ax velocity factor into account. This is usually 0.66. So, 5.32x0.66 = 3.51m. You would put the choke 3.51m back from the feed point.
Simplify the above by using one formula for RG-58U:
(75 x 0.66)/(frequency in MHz) = quarter wave distance in metres.
If you have a different type of co-ax, just replace 0.66 with whatever it's velocity factor is.
For longer runs of co-ax, you can place the choke at odd multiples of a quarter wavelength (one, three, five, etc.).
@@Steve-GM0HUU
I'm not sure why you wouldn't want to place it as close to the transmitter as possible? Isn't the feed line considered part of the antenna if it's some fraction of the wave length you're using? I've got EFLW's on the brain, so I'm pretty sure what ever I say my be wrong here.
@@Steve-GM0HUU In certain cases you may be correct Steve but in most cases I would suggest that people use common mode chokes to stop ANY part of the coaxial cable becoming part of the antenna. Allowing your coax to radiate for any multiple of a wavelength will only serve to alter your radiation pattern. That's why common mode chokes are placed at the antenna feedpoint, to stop RF currents coming back down the outside of the coax and effectively becoming part of the antenna.
Well, you were right 👍 It's a good first project! Thanks for the information
Good project Gil, thank you. I think it is definitely a good idea to have one of these.
Tu es sûr que c'est ft114-31 et pas ft114-43? Je ne trouve rien sinon...
Ou 140-31, pas sûr, le miens est un "made in China," pas standard..
Tnx. 73.
Thanks for this Gil, I'm shack building at present so the timing was perfect!
Just ordered my toroid on Ebay, curiously from a french seller...
And I order from the UK!
Thanks again. Very informative video. I have
an endfed antenna. Was getting RF feed back so bad that it blew my GFI in another room. Come to find out my coax was bad.
Thanks again. Clark KG7LOI.
Great video. Thanks.
73 de Kevin, VK4KK
Oke 73
I made a 4:1 balun, didn't know what I was doing and it works,hi hi
Vidéo fantastique! La réponse à mes problèmes! Merci beaucoup!
Another good practical video Gil.... Cheers
I have 240-43, can I wind one that will cover 160 to 6 meters using that 240-43 and RG58? How many turns would I need? Thank you for the information. 73 de W4DES
I would try a dozen... I have seen sites online with netter information though, worth a bit of a search...
Just a little bigger box, little bigger and a ton of hot glue. Lol
Concerning the RF chokes on the ferrite toroids you HAVE TO read excelent paper of G3TXQ ( now SK) on the page: www.karinya.net/g3txq/chokes/ where uou can find many answers to the questions like: how many turns...., what type of ferrite toroids to use for some frequency and so on. Stan OM8ST
Yes! Thanks.
Good demonstration, many thanks for sharing.
Oh yeah,the mighty random/longwire.
I've been using one as my main antenna for 5years now,I couldn't even count how many ridiculous anomalies I've experienced with it :D
I will definitely try a choke in the future
LOL, indeed. I wonder how many radios went back to the manufacturers that way..?!
Maybe you can help please. How many turns have a RFC coil for FM tube radio with ECC81 and what is the diameter of wire in mm and the diametere of the core? i have found that i use 37 turns of 0,8mm wire and 8mm core bat i think its not right. Have any one an idea?
Sorry no idea.
Salut Gil, as tu une idée des performances de ton choke comparé à ces graphs (trouvés via DX commander)?
Non, je sais juste que ça marche. Il y a certainement moyen de faire mieux.
can you just wrap a sma cable around a toroid, no soldering? also how does this suppress DC? Wouldnt you want a 1:1 isolation transformer?
Hi, sure. It does not suppress DC, just Comm9n mode currents. Not sure which of the two works best..
Jai rien compris, mais j'ai regardé comme même.
The doctor is doing fine, too. Many thanks!
what would be the max power on this, I would imagine the smaller coax couldn't handle 100w.
No, definitely not..
Explain what you understand to be an unbalanced antenna. In what way makes it unbalanced. You seem to think unsymmetrical is unbalanced?? Not so.
Correct, I meant not symmetrical.
Hi Gil, Can I use the same principal and turns for the 11 meter band 27/81 FM ?
Bonjour, oui.
Nice and simple project, but is the hot glue necessary?
You have to secure the toroid one way or another...
@@RadioPrepper Thad makes sense. Thanks.
Well done, nice project 👍
I leave my portable connected to my random wire antenna and today I noticed none of the buttons worked. I took out the batteries and it worked for a few seconds and locked up again. I unhooked the antenna and now its fine.
I wonder if this was an rf issue or because it's a cheap radio?
It is stormy out today if that'd matter.
Hi, that sure sounds like it... Try with a choke, you'll know right away..
Why the heck would anyone give this video a thumbs down!? Good coin Gil. Thanks for sharing.
Thanks Julian. Some people disagree with that design. Some aren't gonna be happy if it can't handle a KW..
Toujours chouette. Merci! :)
This must be for a qrp transmitter ? I've seen more and more recommend the 31 material.
Hi, yes, and yes :-)
shouldnt the test check for the S21 attenuation? SWR doesnt say much
S21?
Is it correct to wind coax cables at radius smaller than datasheet explained ? I mean bending radius.
Not the best...
Nice. What antenna analyzer is in the video ?
EU1KY model.
A sign of RF issued would be when TXing on HF your computer speakers start buzzing? (Using a 20m EFHW antenna)
Put your tongue on the coax shield?
@@RadioPrepper not sure thats a good idea :-)
That was very informative and useful.
Thanks. How do you know/calculate the correct number of turns, or is this purely trial and error?
There is a calculation but I just got the info from a few different sources...
One source, I have used and think is very good is G3TXQ's findings on common-mode chokes. It can be found here:
karinya.net/g3txq/chokes/
@@RadioPrepper - and those sources are dead wrong. You should remove this video, because a.) wrong number of turns and b.) such a core 'FT-114-31' does not exist. So, what you show in your video is just 'believe'. ;-)
Thank you.
Great stuff 👍👍
Great videos Gil.
Salutation gilles.c est bien ce le tu fais -ancien f-60194 hugues
Merci. Gil.
Such a good learning video, I watched it again.
Hi! I have a question for you. When using an End Fed Half Wave antenna with a 1:49 unun, do I need a choke balun, or is it not necessary in this case?
Generally not necessary. You would need one for a 9:1 with a random wire though..
@@RadioPrepper Ok, thanks. 73!
Gil, nice info! Congrats! Can a FT-114-43 be used as a choke? How many turns? I've made a 49:1 with 2 x 140-43 and like to know which choke fits better. 73 de PT2YW
I would say yes. I would actually use a few more turns, say, eight to twelve, experiment...
How could epoxy disturb the magnetic field... unless you used filled epoxy like JB Weld.
I wish I knew... I tried twice...
Great information!!👍
Hi Gil, I hope you are doing well! I’d like to ask for your option about something I would like to try.
Do you think would be possible to combine this antenna:
qrpguys.com/qrpguys-mini-80m-10m-no-tune-end-fed-half-wave-antenna
With these traps:
www.sotabeams.co.uk/pico-traps-kit-pair/
To create a resonant antena for 20, 30 and 40 meters? Do you have any advise for someone that wants to try?
I believe they will. It probably will reduce the length of your antenna also.
Thanks for your videos they are some of the most useful on U tube for the Ham types especially beginners like me. Your English is great thank you again. KI7RJS
Thank you Don, much appreciated!
Sir great video! I am new into HF. I got one of those Sigma Euro-Comm Vertical antennas that don't use radials. Do you recommend I use an RF choke with this?
Only if you notice problems...
9:1 unu. Work on non-restence freq. Bc u want this bc u don't want Short of open . Bc mine has 55 135 141 203 are lenght it dose 10 to 160m.....
I didn't quite get that sorry...
How many turns for 30 - 10 meters for FT114 31?
No idea...
@@RadioPrepper thanks
Is the number of turn very significative ?
some poeple are sujesting 14 turns.
Is there a way to measure it with a VNA ?
73 et merci d'avance
I think more would indeed work better. You can measure its impedance yes.
Gil you have convinced me to put up a half wave antenna for 20 meter cw. I need your advice. My shack is on the 2nd floor of my house. I have access to a water pipe earth ground. Do you think I need a counterpoise? If yes, where should it start ? Thanks for your videos.
No.
Thank's
Bonjour gil de radio prepper.
Est-il possible d'accorder l'impedance d'une antenne dipole "pour le 11m "de 71 ohms au centre avec un coax 50 ohms en utilisant un balun à air.ou la desadaptation mineure ne nécessite pas vraiment ce genre de montage.
En effet pas besoin, c'est assez proche..
Great video - thanks! So - if I have my FT-891, I'm outside (not trying to operate QRP in a hotel room as I often am) and want to go full 100 watts, what has to change? The toroid? The coax? Both? I love the idea of the small size and I can both pack in a bag for travel on in my saddlebags when on my motorcycle. Thanks in advance for the help. 73
The toroid, FT-240-31, bigger...
Are these types of filters ONLY for unbalanced antennas or will they remove rf noise picked up from power lines also?
Not from powerlines. You'd need a specific filter for that, not sure what kind...
Hi Gil, do you have a video about that magnetic loop behind you? I would like to build one for my balcony, mainly for 20m.
Yes, search in my videos..
Thank you for the nice video. I want to make some RF chokes for 'listening' on the VLF and LF bands. How can I determine which toroid I need, and especially, how many windings are the right amount? -Thanks.
There is a document floating around with all that info... Not sure where it is though. I think it was posted on one of my videos..
where can you order the FT-114-31 core? I tried ali-express but could not find. any hints?
Ebay, but the FT-140-43 is easier to find..
Thank You!
Can't find an FT-114-31, google shows nothing, any sources?
FT-140-43 are easier to find..
Tnx👍🏻
Where can you find the FT-114-31? Cant seem to find it anywhere.
Apparently I got a non-standard Chinese-made one.. Get the 140 size..
Is a choke/1:1 balun necessary for a random wire antenna with a 9:1 unun for 80-10 meter 'receive' only?
No.
je pensais que tu étais francais..?
Je le suis :-) J'ai juste vécu très longtemps aux USA.
is these better than 4-5 ferrite beads?
I haven't tested...
Good morning, is this worth using when shortwave listening? Thank you. Stay well, 73 Lee
Yes, absolutely, though the tuning button is a bit small, but great using CAT control with a computer.
After watching your videos on the Minion I got to wondering if some of the problems I experience with my homebrew radio and random wire are due to common-mode currents. That made me wonder what you use as a choke. Then you do this video to explain! Merci beaucoup Gil!!! (are you a mind reader as well as a radio prepper?)
If only I could read mine sometimes ;-)
Do you think you still need an RF Choke when using a End Fed Random Length wire with a 49:1 balun? I haven't seen RF Current, however, I can't say that I'd know what I'm looking for since currently all my work is SSB or FT-8.
49:1 is for half-wave wires. 9:1 is for random. You never use a random wire with a 49:1. A half-wave wire should not require a choke.
@@RadioPrepper
Interesting, I'm making and using 49:1 for EFRW antennas and getting really good SWR's across all the Ham Bands from 30Mhz down. Normally I get SWR's in the low 2's
@@TheDgdimick Curious. What cores are you using? for a 49:1 I've found -43 to be pretty good however -2 (powdered iron) is very lossy and you might see a decent SWR but all your energy is just heating up the core. Build two identical transformers and hook them back to back. Transmit into one end and connect the other to a 50 ohm dummy load via a power meter. Measure the power at the far end versus the power you put in. If you put 10w in and get 5w out like i did with -43 cores then each transformer is losing about 25% of your power as heat. I did this with -2 cores and could barely measure any power at the far end they were so lossy.
I should mention I use -2 cores for chokes because unlike an autotransformer you actually want the core to burn off any common mode energy as heat
@@binky_bun
Thanks for your reply, and bare with me here:
I'm using 240-43, for the 1.5Kw (3 of them) 49:1 baluns, and 140-43 (1 of them) for the 100w or lower baluns. Now, I'm not disagreeing that there is some lose, I just have an issue/question about your test when using a dummy load. Most dummy loads are 50ohms, when you use a 49:1 balun your only going to be seeing an input of 1.0 ohms = 50/49 = 1.02 ohms, and a 9:1 balun will see 5.56ohms, into the transmitter. The BAD SWR you're feeding into the transmitter should/will cause the transmitter to decrease the power the transmitter outputs. I see your test as not really being valid. If I was going to run your suggested test, I would need to build a 3300 ohm dummy load, however I don't have 10watt resistors to do this. If I'm wrong here, please correct me.
Did you have power meters on both the Transmitter output as well as on the output on the balun? Just because you dial in 10watts out on the transmitter doesn't mean your going to really get that 10watts out.
I wonder if it would make winding the toroid easier if you hot glued the first wire wrap to the toroid. Thanks for the videos. I'm always learning something new from them.
Maybe a tie-wrap temporarily...
Bonjour Gil! Where do you buy your toroids from?
Kind regards, Simon
Ebay..
Euh... super de bon vidéo, Gil, mais tu sais-tu pas skeu ça veut dire en tête-carré « étrangler sa poule »? (Je te parle en pepsi pour pas que ça te gêne...) En tout cas, merci pour l'explication de ce machin. Je vais m'en faire kks uns. Bonjour!
Bien sûr je le sais ;-)
@@RadioPrepper ha ha! J'aurais dû savoir! Cheers!
"I'll be amazed if I don't burn myself" ....me, every time the soldering iron comes out lol
LOL yup.
Great vlog Gil, can you post a link for your electrical boxes you are using for your kits, please. Thanks for sharing.
Hi, they are Hammond cases..
@@RadioPrepper Thanks for the reply Gil. Excellent.
I think I can do that if I slow down the video and spend an afternoon studying. One question I have is where o you get those neat little boxes? Who knows, I may build one of these. I have hand tremors and had an awful time with Anderson connectors, an awful time. Thank you for your video. Looks like there were a lot of people who needed this information. It was kind of you to help so many. N4KBM
Hi, I get them on Ebay for the cheap stuff, and the good ones, the Hammond brand.
@@RadioPrepper What size is the box?
Gil, you rock. Question, is that toroid providing enough resistive impedance for 80 meters, without the inductive impedance? I just finished a 240/31 w/17 turns, but always looking to save ounces. This choke is now the heaviest thing in my kit except for the radio. 🙂
I think around 900KOhm...
Oops, 900 Ohms sorry.
What's the model of the CW paddle shown in 3:35 and where I can buy it?
www.americanmorse.com/dcp.htm
Gil, how about a video on using a nano-vna for antenna analysis? (Please)
I would but I can't really afford one right now..
Must one use coax? Is there any reason one cannot use, say, twin speaker wire, or a manually closely coupled bifilar winding?
Coax is just simpler and bifilar is more finicky, requiring more attention to detail..
@@RadioPrepper A perfectly reasonable reason :-) I just don't have any thin coax like that, but I have some flat, four-conductor single copper stuff from Radio Shack; I'll split some of that of into two pairs: it'll probably wind easier and flatter anyway.
Keep 'em comin', Gil, I look forward to seeing notifications of your new posts in my inbox.
Anecdote: I miss France, too: an ex-pat Brit in the US now for 36 years, I used to travel around western Europe for my job back in the late 70's, back in my machine tool controls days. The inside of a French tool & die shop is the same as any other, but the surrounding countryside was beautiful. Do you guys still have yellow headlamps? I always though that was smart... (priority to entry onto a roundabout not so much ... ;-) )
Hi Gil, can you advise on an EFHW transformer using 140-43 cores? What size wire did you use and was the turn ratio still 14:2? And did you use the standard 100 pF capacitor?
14/2:for upper HF, 21/3 or even 24/3 (64:1) for lower bands. 100pf 3KV.
Wire: 1mm.
@@RadioPrepper TNX ES 73!
french OM have a lot of things to say, and if they speak english is really awesome
Pronunciation is difficult for most French people. In any case it's always better to spend at least a year in-country..
@@RadioPrepper from me (italian on jn54wj locator ) your accent is very very good
Thanks, 22 years in Florida ;-)
@@RadioPrepper I've travelled for robotics job for over 21 years all around all continents, now I'm retired because of my legs and wheelchair user.
hope to meet u on air soon 73 51 de iw4dbx
Looking forward to it :-)
What would happen if I hooked this up to a 2m radio?
Not sure but why would you?
@@RadioPrepper say if I threw a random wire up a tree and got heavy swr???
You never use a random wire for 2m and it would not help SWR anyway. Look into a coax colinear.
@@RadioPrepper was just thinking of a hypothetical where you may try it to get an emergency call out
It might work but I would guess no better than the rubber ducky the radio came with. A ladder line Slim Jim would also work much better...