Thank you very much for the informations. And by the way, I found very well choose the backtrack with the rag chew. That made it very grateful for HAM, I believe. Greetings from PY4SD, 73!
I have some smaller versions with 10mm copper tubing. Two types... one 5:1 version and also 6:1 version. Came out to be good performers. Amazed at the low SWR on both depending on wire lenghts. Now the one above is for 2KW??
"magic" is ironic here, nothing magic inside. This is a simple 1:6 unun transformer with lossy ferrite toroids, as you can see on the schematic at the end of the video. This presents wide band good matching and low swr, like the famous comet cha250. Not better than any balun, but can mask a high swr on the end of a piece of wire. You can find a lot of infos about this thing on the net, type "comet cha250 clone" in the google. 73dx!
you probably dont care but if you guys are bored like me during the covid times you can watch pretty much all the new movies and series on instaflixxer. I've been watching with my girlfriend for the last few days =)
Hm....a lot went into this. frankly I am not sure this works more effectively than to simply wrap the cable/wire around a single donut, or even a stack. Or not so good: simply pass the wire/coax thru the core. IOW: Why the copper tubing?
I got Q? maybe some can help me..I used both of this antennas the Comet CHA- 250B and the Diamond BB7V I will love to run more power tru it. now I sold my to KG2OZand he put around 600 watts to the Comet CHA250b with no problem of damage to the matching part! but the antenna said the power is a 250 watts. now can someone let me know if they put more power to the BB7V and what was the final result? and came someone let me know if anyone as building the same matching network for the BB7V that could handle more power. you I live in a HOD condominium and the BB7V from Diamond is easy to deploy because the design of the antenna telescopic style. I need to have the matching network build the same style but build to handle around 600 to 800 watts. can someone direct me to any information.thx....WB2WW..Ariel.
+Azzy M that might very well be true...but its not his design. Its taken from the drawings of G8JNJ who based his blog on VK5ZD's butchering of a Comet CHA-250B's 'network'. G8JNJ posted a blog detailing his experiments with such 'networks'. The drawings are directly from that blog. The 'network' is similar to that used on no less then EIGHT vertical antennas (according to the blog). Given that the element of the antenna isn't all that expensive, the $450 price tag is mostly for the 'network' (I'm assuming, because aluminum tubing isn't $300). The articles can be found at vk5zd.com and g8jnj.net
Explain why it's not a very good design. I hate when people have an opinion and cant even explan or take the time to explan why... How are people going to learn? may be it is a fine setup? maybe not.
it's a lossy dummy load like transformer which makes the PA FETs happy when you transmit on non resonant piece of wire, nothing more...but it's fun experimenting and building such things :D And again, It is not my invention, not my schematics, all credits to g8jnj and vk5zd!
Thank you very much for the informations. And by the way, I found very well choose the backtrack with the rag chew. That made it very grateful for HAM, I believe. Greetings from PY4SD, 73!
Ferrite costs more than radio?
😂😂😂😂yeahhh
I have some smaller versions with 10mm copper tubing. Two types... one 5:1 version and also 6:1 version. Came out to be good performers. Amazed at the low SWR on both depending on wire lenghts. Now the one above is for 2KW??
Broadcast level tx pwr no problem :D, efficiency is an other topic :D
Ok, besides the "magic" what is the impedance matching ratio on this beast, and why is it any better than a large toroid transformer?
Thanks, N4GA
"magic" is ironic here, nothing magic inside. This is a simple 1:6 unun transformer with lossy ferrite toroids, as you can see on the schematic at the end of the video. This presents wide band good matching and low swr, like the famous comet cha250. Not better than any balun, but can mask a high swr on the end of a piece of wire. You can find a lot of infos about this thing on the net, type "comet cha250 clone" in the google. 73dx!
Rob McCance www.g8jnj.net/cometcha250b.htm Go here Rob its a balun from the comet antenna It works fine as baluns go we have one in the club.
What exact ferrite rings are those ? Is this a Bal-Un or Un-Un tranformer at what ratio ?
unkown type russian ferrites from ebay similar to ft-xxx-31 mix ferrites from Amidon.
Ratio: 5:1 or 6:1 its your choice
Nice setup! I'd like to know the reference in Amidon site to get the same toroid rings to make it one. Best regards. 73s. PR7RC
you probably dont care but if you guys are bored like me during the covid times you can watch pretty much all the new movies and series on instaflixxer. I've been watching with my girlfriend for the last few days =)
@Travis Declan yea, been watching on InstaFlixxer for months myself :D
LOL ok can you put in the dacripshion what Toroid Core you used.???
Toroid cores: unkown type russian ferrites from ebay similar to ft-xxx-31 mix ferrites from Amidon.
Beautiful job!
i already made 4 antennas and they work very good
olá amigo , qual a especificação desse ferrite , ficou muito bom seu projeto
What's the "Q" value? Does it absorb the reflected waves or provide an impedance transformation?
Both of them, mostly absorbs due to lossy ferrites which are the base of this concept.
Hm....a lot went into this. frankly I am not sure this works more effectively than to simply wrap the cable/wire around a single donut, or even a stack. Or not so good: simply pass the wire/coax thru the core. IOW: Why the copper tubing?
I'd imagine its a way to maximise coupling for the limited "turns" of the primary.
Wonderfull
I got Q? maybe some can help me..I used both of this antennas the Comet CHA- 250B and the Diamond BB7V I will love to run more power tru it. now I sold my to KG2OZand he put around 600 watts to the Comet CHA250b with no problem of damage to the matching part! but the antenna said the power is a 250 watts. now can someone let me know if they put more power to the BB7V and what was the final result? and came someone let me know if anyone as building the same matching network for the BB7V that could handle more power. you I live in a HOD condominium and the BB7V from Diamond is easy to deploy because the design of the antenna telescopic style. I need to have the matching network build the same style but build to handle around 600 to 800 watts. can someone direct me to any information.thx....WB2WW..Ariel.
I have a similar antenna and i fill the network with sand e the power increase a lot (From Brasil PY2CYE)
Very poor audio on this video !!!!!
NOT a very good design.
+Azzy M that might very well be true...but its not his design. Its taken from the drawings of G8JNJ who based his blog on VK5ZD's butchering of a Comet CHA-250B's 'network'. G8JNJ posted a blog detailing his experiments with such 'networks'. The drawings are directly from that blog. The 'network' is similar to that used on no less then EIGHT vertical antennas (according to the blog). Given that the element of the antenna isn't all that expensive, the $450 price tag is mostly for the 'network' (I'm assuming, because aluminum tubing isn't $300). The articles can be found at vk5zd.com and g8jnj.net
Explain why it's not a very good design.
I hate when people have an opinion and cant even explan or take the time to explan why... How are people going to learn? may be it is a fine setup? maybe not.
it's a lossy dummy load like transformer which makes the PA FETs happy when you transmit on non resonant piece of wire, nothing more...but it's fun experimenting and building such things :D
And again, It is not my invention, not my schematics, all credits to g8jnj and vk5zd!
Its a good design for what it is, good enough broad band match across a wide range of bands. Lossy but its far from dummy load territory.