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#1
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![]() Does anyone have a good link or design for a 6:1 balun ? I bought some 420 cores and am stacking 2 of them to handle 1.5 kw. I wound one using # 14 magnet wire and measuring the return loss showed not too good of a match with a 300 ohm load. I though the cores may not be what was advertised, so as a check I wound a 4:1 and the RL was very good with a 200 ohm resistor. The 4:1 was wound just on a single core. I had ordered 3 cores instead of just 2. I later tried several other types using some small scrap wire and none of the 6:1 seemed to work where a 4:1 would. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#2
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On 7/22/2016 11:44 AM, Ralph Mowery wrote:
Does anyone have a good link or design for a 6:1 balun ? I bought some 420 cores and am stacking 2 of them to handle 1.5 kw. I wound one using # 14 magnet wire and measuring the return loss showed not too good of a match with a 300 ohm load. I though the cores may not be what was advertised, so as a check I wound a 4:1 and the RL was very good with a 200 ohm resistor. The 4:1 was wound just on a single core. I had ordered 3 cores instead of just 2. I later tried several other types using some small scrap wire and none of the 6:1 seemed to work where a 4:1 would. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus http://www.spirat.com.au/vk5zvs/pic32.htm This page shows one. Depending on your cores adjust the turns but not the ratios. http://tinyurl.com/zx7co7f Mikek |
#4
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Ralph Mowery wrote:
In article , says... On 7/22/2016 11:44 AM, Ralph Mowery wrote: Does anyone have a good link or design for a 6:1 balun ? http://www.spirat.com.au/vk5zvs/pic32.htm This page shows one. Depending on your cores adjust the turns but not the ratios. http://tinyurl.com/zx7co7f Mikek I saw that one. It looks to be for low power. One thing I did not understand is why they used 3 windings in parallel. Seems like just a waste of wire. I know I should be able to use larger wire and a larger core as long as the number of turns are the same. Perhaps it is the same logic as Litz wire. I haven't done the arithmetic, but if skin depth at the frequency of operation is comparable with the radius of the wire, or less, then it might make sense. -- Roger Hayter |
#5
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On 07/22/2016 12:44 PM, Ralph Mowery wrote:
Does anyone have a good link or design for a 6:1 balun ? Hello, and are you sure of the required impedance ratio? What operating frequency range (bandwidth) is required? The 6:1 ratio seems oddball since in most practical applications integer-squared values suffice. A 6:1 broadband balun using tapered transmission lines (no ferrites required) is realizable but I think the fabrication required is not something most hams would want to tackle. Having said all that a quick Google results in a number of hits including how-to U-toob videos. Sincerely, and 73s from N4GGO, -- J. B. Wood e-mail: |
#6
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In article , says...
On 07/22/2016 12:44 PM, Ralph Mowery wrote: Does anyone have a good link or design for a 6:1 balun ? Hello, and are you sure of the required impedance ratio? What operating frequency range (bandwidth) is required? The 6:1 ratio seems oddball since in most practical applications integer-squared values suffice. A 6:1 broadband balun using tapered transmission lines (no ferrites required) is realizable but I think the fabrication required is not something most hams would want to tackle. Having said all that a quick Google results in a number of hits including how-to U-toob videos. Sincerely, and 73s from N4GGO, Yes, I want a 6:1 balun. It is for an off center fed antenna that is up around 50 to 60 feet. To be used from 80 to 10 meters. I have had one up for a number of years and used a 4:1 bought balun that is suspose to be good for 5 KW. It heats up and the SWR goes up after several minutes of SSB usage with about 1200 watts. Works fine at 600 watts. My research seems to incicate that at that height a 6:1 is a beter match. I have seen a few that seem to use way too many turns for the core and size of wire I am using (number 14 enamel type). I tried one that had 2 windings of 11 turns and tapped at 9 turns and it was not any good at all when I tested it. Found another design that used 5 wires and 5 turns each. I am now in the process of building it. Layed out on the bench hooked to a RLB it looks good. So now to get it into a box and hooked to the antenna. I built one using the same lengths of wire for field day and at 25 feet the swr looks a lot beter than mine at 60 feet. Thought I would try a 6:1 as that is what some research seems to indicate at that height. I agree, 6:1 does seem to be an odd ball number and info hard to come by. I did see some info on one that used two seperate cores and the winding on each core for a 4:1 and then paralled or something for the 6:1. I just did not like that design. I don't think a tapered line would work over a broad range,and even if it did, I would not want to try to build and use one. Sort of comes under the open wire feeders. I just would not want to use them due to getting the feeders into the shack. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#7
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On 07/25/2016 10:10 AM, Ralph Mowery wrote:
I don't think a tapered line would work over a broad range,and even if it did, I would not want to try to build and use one. Sort of comes under the open wire feeders. I just would not want to use them due to getting the feeders into the shack. Hello, and again, while not advocating these for ham use, decades ago J.W. Duncan and V.P. Minerva in the February, 1960 issue of Proceedings of the IRE described a hundred-to-one bandwidth tapered-line balun. The one constructed for the article provided for interfacing a 50-ohm coax to a 15O ohm open wire line. VSWR never exceeded 1.25 from 43 MHz to 2200 MHz (50:1 bandwidth). Sincerely, -- J. B. Wood e-mail: |
#8
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On Monday, July 25, 2016 at 6:55:50 AM UTC-4, J.B. Wood wrote:
On 07/22/2016 12:44 PM, Ralph Mowery wrote: Does anyone have a good link or design for a 6:1 balun ? Hello, and are you sure of the required impedance ratio? What operating frequency range (bandwidth) is required? The 6:1 ratio seems oddball since in most practical applications integer-squared values suffice. A 6:1 broadband balun using tapered transmission lines (no ferrites required) is realizable but I think the fabrication required is not something most hams would want to tackle. Having said all that a quick Google results in a number of hits including how-to U-toob videos. Sincerely, and 73s from N4GGO, -- J. B. Wood e-mail: 300 Ohms is the typical impedance of a folded dipole at it's resonant frequency. I converted a used Terminated Folded Dipole to a simple folded dipole by removing the termination resister and the 12 to 1 balun. I used an SGC antenna coupler with it with great success. I wanted to use the build in antenna tuner in my Yaesu FT-1000 with it but that was futile until I bought a 6 to 1 balun and connected it to the antenna with 300 Ohm window line. Now the built in tuner has no trouble obtaining a match from 160 to 6 Meters. I was told by many on an antenna usenet group that I could use a 4-1 balun and 450 ohm ladder line rather than bothering with the 300 ohm stuff and the 6 to 1 balun. In each case using the 450 LL and the 4-1 balun both separately and together the internal tuner would fail to match the load on many frequencies. Once I changed to a complete match at resonance the internal tuner could manage the rest. -- Tom |
#9
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#10
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In article t,
Ralph Mowery wrote: Yes, I want a 6:1 balun. It is for an off center fed antenna that is up around 50 to 60 feet. To be used from 80 to 10 meters. I have had one up for a number of years and used a 4:1 bought balun that is suspose to be good for 5 KW. It heats up and the SWR goes up after several minutes of SSB usage with about 1200 watts. Works fine at 600 watts. My research seems to incicate that at that height a 6:1 is a beter match. Since the feedpoint impedance of an OCF is a function of the feedpoint location (how far off-center it is), could you reduce the impedance towards 200 ohms and use a 4:1 balun by simply moving the feedpoint some distance towards the center? |
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