Re: [Elecraft] KAT 500 and open wire
Electric fence insulator tubes 4" long. Drill each end for #14 THHN stranded. 3.5" spacing gives Zo= ~550 ohms. Box of 200 on Amazon for $16. 73, K0DTJ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Be careful with black hose/tubing/pipe. Cut a small length of it and put it into a microwave oven along with a cup of water for varying lengths of time, checking each time. If it comes out cool when the water is about to boil, it's probably OK. It seems some ABS and black drip tubing has some semi-conductive ingredient(s) like carbon? I've also seen white PVC fittings that failed this test. 73, Fred ["Skip"] K6DGW Sparks NV DM09dn Washoe County On 1/19/2019 7:45 AM, Victor Rosenthal 4X6GP wrote: Today I'm using homemade open wire line, no. 12 (2 mm dia) spaced 4.5 inches (11.4 cm). Insulators are cut from black irrigation hose. Wire is ultra flexible type from The Wireman. 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
You can buy spacers for #14 insulated house wire that would also work wonders and be a cheaper but best solution. 73, Bill K9YEQ https://wrj-tech.com/ -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of Al Lorona Sent: Friday, January 18, 2019 8:08 PM To: Elecraft Subject: Re: [Elecraft] KAT 500 and open wire G3TXQ's work here is awesome, as is N7WS's before him. I'm thinking two things: Thing 1 is that, clearly, water really messes up window line's loss. However, I'm guessing that a/ in a place like southern California, where perpetual drought is the new normal; and b/ in an installation where the window line, rather than running perfectly horizontally so water can pool, has a slant, allowing it to shed water; a ham would probably be fine using it. All one would have to do to discourage pooling on a horizontal run is twist the line once every few meters. Thing 2 is that G3TXQ shows matched loss at 6.72 MHz in heavy rainfall increasing from 0.2 to 1.1 dB per 100 feet, which seems totally acceptable for worst-case rainfall. In moderate rainfall the loss increased to only 0.34 dB/100 ft. That's lower than any coax out there. I myself would never use it (for reasons other than water loss), but window line seems like an okay choice for those hams who can't or won't use coax. Al W6LX Glossary: "Window line" = Wireman 551 or 552 or equivalent >>> http://www.karinya.net/g3txq/wet_ll/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k9...@live.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
When I used to use ladder line I noticed a significant detuning effect when wet. It was worse with older line, probably because the weathering made the water more likely to stick. I never tried to measure the loss. I tried waxing the line with automotive wax and saw an improvement. But I don't know how long it would have lasted, since I switched to other feedlines. Today I'm using homemade open wire line, no. 12 (2 mm dia) spaced 4.5 inches (11.4 cm). Insulators are cut from black irrigation hose. Wire is ultra flexible type from The Wireman. It works great with no noticeable weather effects. It's very easy to make: I made a jig from a piece of tubing to cut the insulators to the same length. The jig has holes to drill near the ends of the insulators; then I snipped a cut from the edge to the hole to enable the wire to snap in. The holes are just big enough to grip the wire but to let me slip the insulators a bit to get them in the right place. In a few locations I made insulators out of fiberglass that could be attached to brackets to hold the line in place. 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco/ On 19 Jan 2019 16:45, Bob McGraw K4TAX wrote: I didn't measure significant increase in loss with clean water i.e. tap water sprayed on the entire length of the line from a hose. I did make a solution of dish washing detergent and water and , using a spray bottle, sprayed that on the line. This caused much more water to cling to the line. While the loss did not appreciably increase, I did notice the electrical length of the line changed a measurable amount. Measurements were made such that the line was operating at its characteristic impedance. The source was the tracking generator in my Spectrum Analyzer, sweeping 1 MHz to 50 MHz. 73 Bob, K4TAX On 1/18/2019 11:56 PM, Walter Underwood wrote: On Jan 18, 2019, at 6:08 PM, Al Lorona wrote: Thing 1 is that, clearly, water really messes up window line's loss. However, I'm guessing that a/ in a place like southern California, where perpetual drought is the new normal; ... Clean water isn’t a problem. Dirty water is a big problem. When I first moved to the SF Bay area in the early 1980s, I was surprised by the number of power outages, compared to where I grew up in Louisiana with heavy weather. The first light rain would be accompanied by outages. With six or more rainless summer months, dust and grit would accumulate on the power line insulators. The first light rain would create conductive mud and trip breakers. So perpetual drought is just a way to build up more dust on the line. I think we take coaxial cable for granted. It was a brilliant invention and a real gift to people who love radio. Maybe I’ll start celebrating December 8th as Coaxial Cable Day. https://www.wired.com/2009/12/1208coaxial-cable-patent/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k2vco@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I didn't measure significant increase in loss with clean water i.e. tap water sprayed on the entire length of the line from a hose. I did make a solution of dish washing detergent and water and , using a spray bottle, sprayed that on the line. This caused much more water to cling to the line. While the loss did not appreciably increase, I did notice the electrical length of the line changed a measurable amount. Measurements were made such that the line was operating at its characteristic impedance. The source was the tracking generator in my Spectrum Analyzer, sweeping 1 MHz to 50 MHz. 73 Bob, K4TAX On 1/18/2019 11:56 PM, Walter Underwood wrote: On Jan 18, 2019, at 6:08 PM, Al Lorona wrote: Thing 1 is that, clearly, water really messes up window line's loss. However, I'm guessing that a/ in a place like southern California, where perpetual drought is the new normal; ... Clean water isn’t a problem. Dirty water is a big problem. When I first moved to the SF Bay area in the early 1980s, I was surprised by the number of power outages, compared to where I grew up in Louisiana with heavy weather. The first light rain would be accompanied by outages. With six or more rainless summer months, dust and grit would accumulate on the power line insulators. The first light rain would create conductive mud and trip breakers. So perpetual drought is just a way to build up more dust on the line. I think we take coaxial cable for granted. It was a brilliant invention and a real gift to people who love radio. Maybe I’ll start celebrating December 8th as Coaxial Cable Day. https://www.wired.com/2009/12/1208coaxial-cable-patent/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
> On Jan 18, 2019, at 6:08 PM, Al Lorona wrote: > > Thing 1 is that, clearly, water really messes up window line's loss. However, > I'm guessing that a/ in a place like southern California, where perpetual > drought is the new normal; ... Clean water isn’t a problem. Dirty water is a big problem. When I first moved to the SF Bay area in the early 1980s, I was surprised by the number of power outages, compared to where I grew up in Louisiana with heavy weather. The first light rain would be accompanied by outages. With six or more rainless summer months, dust and grit would accumulate on the power line insulators. The first light rain would create conductive mud and trip breakers. So perpetual drought is just a way to build up more dust on the line. I think we take coaxial cable for granted. It was a brilliant invention and a real gift to people who love radio. Maybe I’ll start celebrating December 8th as Coaxial Cable Day. https://www.wired.com/2009/12/1208coaxial-cable-patent/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Using matching transformers and my spectrum analyzer with tracking generator, I measured a 100 ft length dry and I measured it wet. My measurements indicated the velocity factor changed when wet, i.e. the electrical length of the line changed. Thus explains to me the reason to "retune" when the line is wet or covered with frost, ice or snow. With my tuner, that means I must push a button. Oh geez. I agree the loss does increase a wee bit when wet in a horizontal position. Considering we have less than 100 days with recorded or measured precipitation in my area, it is no big deal. My window line is mostly vertical and that which is horizontal has about 5 twists per 10 ft. Still worst case, I find it has less loss than coax and less expensive than coax which has equal or less loss. 73 Bob, K4TAX On 1/18/2019 8:08 PM, Al Lorona wrote: G3TXQ's work here is awesome, as is N7WS's before him. I'm thinking two things: Thing 1 is that, clearly, water really messes up window line's loss. However, I'm guessing that a/ in a place like southern California, where perpetual drought is the new normal; and b/ in an installation where the window line, rather than running perfectly horizontally so water can pool, has a slant, allowing it to shed water; a ham would probably be fine using it. All one would have to do to discourage pooling on a horizontal run is twist the line once every few meters. Thing 2 is that G3TXQ shows matched loss at 6.72 MHz in heavy rainfall increasing from 0.2 to 1.1 dB per 100 feet, which seems totally acceptable for worst-case rainfall. In moderate rainfall the loss increased to only 0.34 dB/100 ft. That's lower than any coax out there. I myself would never use it (for reasons other than water loss), but window line seems like an okay choice for those hams who can't or won't use coax. Al W6LX Glossary: "Window line" = Wireman 551 or 552 or equivalent http://www.karinya.net/g3txq/wet_ll/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
G3TXQ's work here is awesome, as is N7WS's before him. I'm thinking two things: Thing 1 is that, clearly, water really messes up window line's loss. However, I'm guessing that a/ in a place like southern California, where perpetual drought is the new normal; and b/ in an installation where the window line, rather than running perfectly horizontally so water can pool, has a slant, allowing it to shed water; a ham would probably be fine using it. All one would have to do to discourage pooling on a horizontal run is twist the line once every few meters. Thing 2 is that G3TXQ shows matched loss at 6.72 MHz in heavy rainfall increasing from 0.2 to 1.1 dB per 100 feet, which seems totally acceptable for worst-case rainfall. In moderate rainfall the loss increased to only 0.34 dB/100 ft. That's lower than any coax out there. I myself would never use it (for reasons other than water loss), but window line seems like an okay choice for those hams who can't or won't use coax. Al W6LX Glossary: "Window line" = Wireman 551 or 552 or equivalent >>> http://www.karinya.net/g3txq/wet_ll/ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Guys - we've long since passed he max posting limit for the list on a single topic. Let's wind this one down at this time. 73, Eric /Moderator (hopefully not for life!..)/ /elecraft.com/ On 1/7/2019 7:45 AM, Wes Stewart wrote: Then there must be less signal too:-) Wes N7WS On 1/7/2019 6:48 AM, Bob McGraw K4TAX wrote: ... less noise on receive... 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I use the "window line" for 3 of my antennas. We have less than 125 days/ yr with precipitation of all types. The "loss wet" is a non issue in my thinking as I'm sure would be about the same for most folks. Still with extreme loss, under most conditions, coax will have greater loss. Bob, K4TAX Sent from my iPhone > On Jan 7, 2019, at 11:34 AM, Walter Underwood wrote: > > I think “window line” is less ambiguous for the stuff separated by plastic > with squares cut out. I see “ladder line” being used to mean either window > line or open wire line. > > DX Engineering uses ladder line to mean the plastic dielectric line: > https://www.dxengineering.com/search/part-type/ladder-line > > W7FG uses ladder line to mean 600 Ohm open wire line: > http://trueladderline.com/w7fg-design-600-ohm-open-wire-feedline/ > > wunder > K6WRU > Walter Underwood > CM87wj > http://observer.wunderwood.org/ (my blog) > >> On Jan 7, 2019, at 8:39 AM, Don Wilhelm wrote: >> >> There is a BIG difference between ladder line and open wire transmission >> line. >> >> Even low loss ladder line can have significant loss, especially when wet. >> >> Open wire feeders can truly be low loss even when operated at high SWR. >> >> So how do you construct proper open wire line? It is most easily done when >> the 2 wires are under tension and spaced about 6 inches apart with as few >> insulators between them as possible - the tension keeps the spacing >> relatively constant - that is practical over a long horizontal run of the >> transmission line. Then bring it up to the antenna feedpoint with wires >> spaced apart with insulators, and likewise on the run to the house entry or >> better yet to the shack - the more insulators, the greater the loss can be. >> You can use ladder-line from there into the shack, or you can put a good >> current mode balun at the house entry and from there run a short length of >> coax to the tuner. >> >> As I have mentioned before, whether a 1:1 balun or a 4:1 balun will work >> better has to be determined - it depends on the feedline length, the >> frequency, and the feedpoint impedance of the radiator for that particular >> frequency. If the feedpoint impedance at the tuner end of the feedline is >> already low, a 4:1 balun will make it 4 times lower and difficult for your >> tuner to deal with. >> >> A G5RV antenna on 160 meters will not be very efficient (the high current >> point will be somewhere down the transmission line and not at the center of >> the antenna). One thing is true, the RF voltage at the ends of the antenna >> is the highest, and the highest current is 1/4 wavelength away from the end, >> even if that is at a point well down the feedline. The equal and opposite >> currents on the feedline will cancle making that highest current point not >> useful for radiating a signal. >> >> Radiator lengths greater than 1/2 wavelength can be efficient, but shorter >> than 1/2 wavelength will be less efficient because the balanced currents on >> the feedline cancel each other out. That is just plain physics. >> >> 73, >> Don W3FPR >> >> >> >>> On 1/7/2019 10:49 AM, Wes Stewart wrote: >>> Try running that 102' long "G5RV" up 50' on 160 meters. Feed it with 100' >>> of Wireman 553 "low loss" ladderline. The 0.1 dB matched loss turns into >>> over 13 db at the input and that's without considering tuner loss. (Source: >>> EZNEC and TLDetails) >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to wun...@wunderwood.org > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
A pre-publication copy of the N7WS QST article from 1999. http://k6mhe.com/n7ws/Ladder_Line.pdf Independent verification of the N7WS experiments, with some nice graphs showing loss when dry, with rainwater, and with frost. The results are fairly similar. http://www.karinya.net/g3txq/wet_ll/ wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Jan 7, 2019, at 10:33 AM, Jim Brown wrote: > > On 1/7/2019 8:39 AM, Don Wilhelm wrote: >> Even low loss ladder line can have significant loss, especially when wet. > > N7WS is the guy who did that research and published it several decades ago. > It's in one of those excellent ARRL Antenna Compendiums. > > 73, Jim K9YC > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
On 1/7/2019 8:39 AM, Don Wilhelm wrote: Even low loss ladder line can have significant loss, especially when wet. N7WS is the guy who did that research and published it several decades ago. It's in one of those excellent ARRL Antenna Compendiums. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Re: "...what is the old dual air coil Heathkit B-1balun, a current or voltage type? If I remember correctly, they are 4:1 ratio." From the Heathkit manual: "The Heathkit Balun Coil Set, Model B-1 is a convenient transmitter accessory which has the capability of matching unbalanced coax lines, used on most modern transmitters, to balanced lines to either 75 ohms or 300 ohms impedance". The manual discusses its use with a dipole (~75 ohms) or a folded dipole (~300 ohms), and the analogy of using a line transmission line to get the desired impedance transformation. It is a very short but interesting read. The assembly manual shows how to wire it in 1:1 or 4:1 configurations. The schematic is identical to the Elecraft BL2 , except it uses air core coils instead of ferrite coils, and there is no switch to easily change between impedance ratios. I have never used my BL-2, so I cannot vouch for its effectiveness. I have often wondered if it might be compromised by the 2 bifilar wound "non-self-shielding" air core coils tightly packed into a metal enclosure resulting in enough capacitance or magnetic coupling to each other and the enclosure to reduce its effectiveness. I do, however, open it up occasionally and admire those beautiful inductors! Mark KE6BB null __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I think “window line” is less ambiguous for the stuff separated by plastic with squares cut out. I see “ladder line” being used to mean either window line or open wire line. DX Engineering uses ladder line to mean the plastic dielectric line: https://www.dxengineering.com/search/part-type/ladder-line W7FG uses ladder line to mean 600 Ohm open wire line: http://trueladderline.com/w7fg-design-600-ohm-open-wire-feedline/ wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Jan 7, 2019, at 8:39 AM, Don Wilhelm wrote: > > There is a BIG difference between ladder line and open wire transmission line. > > Even low loss ladder line can have significant loss, especially when wet. > > Open wire feeders can truly be low loss even when operated at high SWR. > > So how do you construct proper open wire line? It is most easily done when > the 2 wires are under tension and spaced about 6 inches apart with as few > insulators between them as possible - the tension keeps the spacing > relatively constant - that is practical over a long horizontal run of the > transmission line. Then bring it up to the antenna feedpoint with wires > spaced apart with insulators, and likewise on the run to the house entry or > better yet to the shack - the more insulators, the greater the loss can be. > You can use ladder-line from there into the shack, or you can put a good > current mode balun at the house entry and from there run a short length of > coax to the tuner. > > As I have mentioned before, whether a 1:1 balun or a 4:1 balun will work > better has to be determined - it depends on the feedline length, the > frequency, and the feedpoint impedance of the radiator for that particular > frequency. If the feedpoint impedance at the tuner end of the feedline is > already low, a 4:1 balun will make it 4 times lower and difficult for your > tuner to deal with. > > A G5RV antenna on 160 meters will not be very efficient (the high current > point will be somewhere down the transmission line and not at the center of > the antenna). One thing is true, the RF voltage at the ends of the antenna > is the highest, and the highest current is 1/4 wavelength away from the end, > even if that is at a point well down the feedline. The equal and opposite > currents on the feedline will cancle making that highest current point not > useful for radiating a signal. > > Radiator lengths greater than 1/2 wavelength can be efficient, but shorter > than 1/2 wavelength will be less efficient because the balanced currents on > the feedline cancel each other out. That is just plain physics. > > 73, > Don W3FPR > > > > On 1/7/2019 10:49 AM, Wes Stewart wrote: >> Try running that 102' long "G5RV" up 50' on 160 meters. Feed it with 100' >> of Wireman 553 "low loss" ladderline. The 0.1 dB matched loss turns into >> over 13 db at the input and that's without considering tuner loss. (Source: >> EZNEC and TLDetails) > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
On 1/7/2019 10:39, Don Wilhelm wrote: Radiator lengths greater than 1/2 wavelength can be efficient, but shorter than 1/2 wavelength will be less efficient because the balanced currents on the feedline cancel each other out. That is just plain physics. Actually, a short antenna CAN be very efficient, as long as the resistance of the antenna itself is low and the losses in the matching network are low. I didn't say it was easy, though. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
There are limits, of course, as your example shows. A center fed quarter wave is a very low impedance. I'd expect the feedline loss for that G5RV system would be less than a couple dB on 80 through 10 meters, generally acceptable. 73, Scott K9MA On 1/7/2019 09:49, Wes Stewart wrote: With all due respect, you don't say what acceptable loss is. Of course, you can match whatever the impedance is, most tuners will match an open circuit because their internal losses allow it. But it can be a fallacy that, "The line loss is so low it doesn't matter." Absent voltage breakdown, line loss increases because of the increased circulating current resulting from operating at elevated SWR. That increased current is an issue in some baluns and tuners as well. *All* of these components must be considered when evaluating an antenna "system." Considering only one part in isolation is fraught with danger. Try running that 102' long "G5RV" up 50' on 160 meters. Feed it with 100' of Wireman 553 "low loss" ladderline. The 0.1 dB matched loss turns into over 13 db at the input and that's without considering tuner loss. (Source: EZNEC and TLDetails) Wes N7WS On 1/6/2019 3:15 PM, K9MA wrote: The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k...@sdellington.us -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
There is a BIG difference between ladder line and open wire transmission line. Even low loss ladder line can have significant loss, especially when wet. Open wire feeders can truly be low loss even when operated at high SWR. So how do you construct proper open wire line? It is most easily done when the 2 wires are under tension and spaced about 6 inches apart with as few insulators between them as possible - the tension keeps the spacing relatively constant - that is practical over a long horizontal run of the transmission line. Then bring it up to the antenna feedpoint with wires spaced apart with insulators, and likewise on the run to the house entry or better yet to the shack - the more insulators, the greater the loss can be. You can use ladder-line from there into the shack, or you can put a good current mode balun at the house entry and from there run a short length of coax to the tuner. As I have mentioned before, whether a 1:1 balun or a 4:1 balun will work better has to be determined - it depends on the feedline length, the frequency, and the feedpoint impedance of the radiator for that particular frequency. If the feedpoint impedance at the tuner end of the feedline is already low, a 4:1 balun will make it 4 times lower and difficult for your tuner to deal with. A G5RV antenna on 160 meters will not be very efficient (the high current point will be somewhere down the transmission line and not at the center of the antenna). One thing is true, the RF voltage at the ends of the antenna is the highest, and the highest current is 1/4 wavelength away from the end, even if that is at a point well down the feedline. The equal and opposite currents on the feedline will cancle making that highest current point not useful for radiating a signal. Radiator lengths greater than 1/2 wavelength can be efficient, but shorter than 1/2 wavelength will be less efficient because the balanced currents on the feedline cancel each other out. That is just plain physics. 73, Don W3FPR On 1/7/2019 10:49 AM, Wes Stewart wrote: Try running that 102' long "G5RV" up 50' on 160 meters. Feed it with 100' of Wireman 553 "low loss" ladderline. The 0.1 dB matched loss turns into over 13 db at the input and that's without considering tuner loss. (Source: EZNEC and TLDetails) __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
With all due respect, you don't say what acceptable loss is. Of course, you can match whatever the impedance is, most tuners will match an open circuit because their internal losses allow it. But it can be a fallacy that, "The line loss is so low it doesn't matter." Absent voltage breakdown, line loss increases because of the increased circulating current resulting from operating at elevated SWR. That increased current is an issue in some baluns and tuners as well. *All* of these components must be considered when evaluating an antenna "system." Considering only one part in isolation is fraught with danger. Try running that 102' long "G5RV" up 50' on 160 meters. Feed it with 100' of Wireman 553 "low loss" ladderline. The 0.1 dB matched loss turns into over 13 db at the input and that's without considering tuner loss. (Source: EZNEC and TLDetails) Wes N7WS On 1/6/2019 3:15 PM, K9MA wrote: The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Then there must be less signal too:-) Wes N7WS On 1/7/2019 6:48 AM, Bob McGraw K4TAX wrote: ... less noise on receive... 73 Bob, K4TAX __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
They are a voltage type, 4:1 designed to feed a folded dipole. There are
actually 4 windings, 2 on each coil.
If you want to see the best in balun usage and efficiency, a folded
dipole typically has some 200 to 300 ohms impedance when constructed
from open wire line or like materials. Thus the upper radiator and
lower radiator are equal diameters. Of course it basically a single
band antenna and when used with a 4:1 balun provides, a 50 to 75 ohm
load for the transmitter. For that reason, I believe hams {not me for
one}, have gotten away from the design. There is a lot of merit to the
folded dipole antenna, relatively broadband, less noise on receive, low
loss, high efficiency and etc. I use one for my 160M and another for
my 75M AM stations. Both of mine are constructed from heavy 300 ohm
transmitting feed line. One must pay special attention to end support
means {and not by the conductors with an insulator} and center support
where the feed line is attached.
73
Bob, K4TAX
On 1/6/2019 10:17 PM, Charlie T wrote:
I should probably know this, but what is the old dual air coil Heathkit B-1
balun, a current or voltage type?
If I remember correctly, they are 4:1 ratio.
Would this be a better choice for open-wire feed to a dipole intended for
use on several bands?
73, Charlie k3ICH
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Re: [Elecraft] KAT 500 and open wire
Don: 1) made a distinction between feedpoint and load impedance, which led me to believe the load was the antenna, and the feedpoint the transmitter end; 2) said that the feedpoint impedance depended on the length of the line and the frequency, which further supported that interpretation. However, considering your definition of feedpoint, and consider balanced twin feeder. Even with a perfect choke at the feedpoint, there will be unbalance at the transmitter end, when using designs, like the K series, that feed against chassis. In particular, consider a feeder length of a quarter wavelength. As well as the intended differential mode signal, you will also excite the feeder as a quarter wave vertical against the chassis and, presumably, ground, if you don't choke at the transmitter end. My gut feeling is that having a good match to the feeder is an oversimplification, but I need to think about that a bit more. Incidentally, is the 4:1 "current mode" balun configuration really purely current mode? It seems to me that it is behaving as a transformer as well as as a choke. On 07/01/2019 02:12, Jim Brown wrote: I think we're confused here about the meaning the words "feedpoint impedance." It is the impedance of THE ANTENNA at the point where the feedline is attached, and it is determined entirely by the antenna, INCLUDING the common mode circuit of the I don't know of a way to EFFECTIVELY choke a feedline that is not matched to the antenna. a very good choke must be AT THE FEEDPOINT __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I've been using an open-wire fed rotary dipole that is a halfwave on 20 meters on all bands from 40 through 10 meters for the past 4 years or so. The feeding/matching system has gone through various iterations, but now uses homemade open-wire line of no. 12 wire (2 mm) spaced 4.5 inches (11.4 cm), a very slightly modified Johnson kW Matchbox, and a pair of inductors for reactance cancellation on 30 meters. The line is about 34 feet long (10.4 m). The SWR on the worst band (7 MHz) approaches 100:1, but losses calculated by TLW are around 1 dB or less. 73, Victor, 4X6GP Rehovot, Israel Formerly K2VCO CWops no. 5 http://www.qsl.net/k2vco/ On 7 Jan 2019 00:15, K9MA wrote: The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
The B-1 is indeed 4:1. It would be useful only for matched balanced lines. Unless you have a folded dipole, you probably don't have a match balanced line. 73, Scott K9MA On 1/6/2019 22:17, Charlie T wrote: I should probably know this, but what is the old dual air coil Heathkit B-1 balun, a current or voltage type? If I remember correctly, they are 4:1 ratio. Would this be a better choice for open-wire feed to a dipole intended for use on several bands? 73, Charlie k3ICH -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of K9MA Sent: Sunday, January 06, 2019 10:24 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KAT 500 and open wire On 1/6/2019 20:12, Jim Brown wrote: We add one or more common mode chokes to minimize the effect if the common mode circuit, which is radiation and reception, and to do that, a very good choke must be AT THE FEEDPOINT. I don't know of a way to EFFECTIVELY choke a feedline that is not matched to the antenna. Yes, you can put something there, but if it did anything useful it would fry (unless yo only ran QRP to the antena), and a choke that wouldn't fry with TX power won't do anything useful! I have to respectfully disagree a little here. A choke specifically designed for the antenna impedance at the feed point could effectively eliminate the common mode current. The problem is, we often use balanced line with antennas which have a large range of impedances over frequency range at which they are used. (Think G5RV.) It may be impossible to design a single choke which can work over the whole range. However, feeding balanced line with a balanced tuner can work pretty well, even though the feedline may radiate a bit due to common mode current. I've only attempted this with link-coupled tuners. I'm not sure it works as well with the double T-network tuners with a choke at the input, like the MFJ-976, but it may. For years, I've used a warped, lop-sided, short, 80 meter "dipole" fed with window line and the balanced tuner. I never bothered to try to figure out the impedance at either the feedpoint or the tuner, but the tuner matches it on several bands. I don't use it much on 80, though, as it's so close to the roof of my house that the RF gets into everything. I'm sure the feedline radiates some, but that's not where the RFI is coming from. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to pin...@erols.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k...@sdellington.us -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I should probably know this, but what is the old dual air coil Heathkit B-1 balun, a current or voltage type? If I remember correctly, they are 4:1 ratio. Would this be a better choice for open-wire feed to a dipole intended for use on several bands? 73, Charlie k3ICH -Original Message- From: elecraft-boun...@mailman.qth.net On Behalf Of K9MA Sent: Sunday, January 06, 2019 10:24 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KAT 500 and open wire On 1/6/2019 20:12, Jim Brown wrote: > We add one or more common mode chokes to minimize the effect if the > common mode circuit, which is radiation and reception, and to do that, > a very good choke must be AT THE FEEDPOINT. I don't know of a way to > EFFECTIVELY choke a feedline that is not matched to the antenna. Yes, > you can put something there, but if it did anything useful it would > fry (unless yo only ran QRP to the antena), and a choke that wouldn't > fry with TX power won't do anything useful! I have to respectfully disagree a little here. A choke specifically designed for the antenna impedance at the feed point could effectively eliminate the common mode current. The problem is, we often use balanced line with antennas which have a large range of impedances over frequency range at which they are used. (Think G5RV.) It may be impossible to design a single choke which can work over the whole range. However, feeding balanced line with a balanced tuner can work pretty well, even though the feedline may radiate a bit due to common mode current. I've only attempted this with link-coupled tuners. I'm not sure it works as well with the double T-network tuners with a choke at the input, like the MFJ-976, but it may. For years, I've used a warped, lop-sided, short, 80 meter "dipole" fed with window line and the balanced tuner. I never bothered to try to figure out the impedance at either the feedpoint or the tuner, but the tuner matches it on several bands. I don't use it much on 80, though, as it's so close to the roof of my house that the RF gets into everything. I'm sure the feedline radiates some, but that's not where the RFI is coming from. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to pin...@erols.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
On 1/6/2019 20:12, Jim Brown wrote: We add one or more common mode chokes to minimize the effect if the common mode circuit, which is radiation and reception, and to do that, a very good choke must be AT THE FEEDPOINT. I don't know of a way to EFFECTIVELY choke a feedline that is not matched to the antenna. Yes, you can put something there, but if it did anything useful it would fry (unless yo only ran QRP to the antena), and a choke that wouldn't fry with TX power won't do anything useful! I have to respectfully disagree a little here. A choke specifically designed for the antenna impedance at the feed point could effectively eliminate the common mode current. The problem is, we often use balanced line with antennas which have a large range of impedances over frequency range at which they are used. (Think G5RV.) It may be impossible to design a single choke which can work over the whole range. However, feeding balanced line with a balanced tuner can work pretty well, even though the feedline may radiate a bit due to common mode current. I've only attempted this with link-coupled tuners. I'm not sure it works as well with the double T-network tuners with a choke at the input, like the MFJ-976, but it may. For years, I've used a warped, lop-sided, short, 80 meter "dipole" fed with window line and the balanced tuner. I never bothered to try to figure out the impedance at either the feedpoint or the tuner, but the tuner matches it on several bands. I don't use it much on 80, though, as it's so close to the roof of my house that the RF gets into everything. I'm sure the feedline radiates some, but that's not where the RFI is coming from. 73, Scott K9MA -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I agree with Jim on this point. I have means to measure current in each side of the balanced feed line. And I have means to measure the voltage on each leg and observe the phase difference in each leg. A dual trace scope with 2 current probes is the basic configuration. If the currents are equal in each leg, and the voltage is equal in each leg, and the phase is 180 degrees between the two legs, the system is well balanced. As I stated earlier, random installation of an antenna and feed line will likely lead to random and usually unfavorable results. Otherwise, careful installation and positioning of the antenna legs and feed line run produces wonderful results. It is not that difficult to do. It just takes a bit of planning and careful attention to detail. Otherwise, just hang some commercial version of a touted antenna in a tree and be done with it. 73 Bob, K4TAX On 1/6/2019 8:12 PM, Jim Brown wrote: A few other points: 1) the SWR on a feedline is established BY THE ANTENNA, not the transmitter or antenna tuner; 2) feeding an antenna with two-wire line does NOT make it balanced -- most practical antennas that we think of as balanced are often un-balanced by their surroundings -- ground slope, variations in the soil under them, trees, wiring in buildings, unequal height ; 3) off-center-fed antennas are inherently unbalanced. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I agree with Jim on this point. I have means to measure current in each side of the balanced feed line. And I have means to measure the voltage on each leg and observe the phase difference in each leg. A dual trace scope with 2 current probes is the basic configuration. If the currents are equal in each leg, and the voltage is equal in each leg, and the phase is 180 degrees between the two legs, the system is well balanced. As I stated earlier, random installation of an antenna and feed line will likely lead to random and usually unfavorable results. Otherwise, careful installation and positioning of the antenna legs and feed line run produces wonderful results. 73 Bob, K4TAX On 1/6/2019 8:12 PM, Jim Brown wrote: A few other points: 1) the SWR on a feedline is established BY THE ANTENNA, not the transmitter or antenna tuner; 2) feeding an antenna with two-wire line does NOT make it balanced -- most practical antennas that we think of as balanced are often un-balanced by their surroundings -- ground slope, variations in the soil under them, trees, wiring in buildings, unequal height ; 3) off-center-fed antennas are inherently unbalanced. 73, Jim K9YC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I think we're confused here about the meaning the words "feedpoint impedance." It is the impedance of THE ANTENNA at the point where the feedline is attached, and it is determined entirely by the antenna, INCLUDING the common mode circuit of the feedline. That common mode circuit consists of the feedline, any chokes and matching elements, and whatever it is connected to in the shack. The ONLY contribution of the feedline to this is as a common mode element, and in the common mode circuit it looks like a wire connected between the feedpoint and the shack. We add one or more common mode chokes to minimize the effect if the common mode circuit, which is radiation and reception, and to do that, a very good choke must be AT THE FEEDPOINT. I don't know of a way to EFFECTIVELY choke a feedline that is not matched to the antenna. Yes, you can put something there, but if it did anything useful it would fry (unless yo only ran QRP to the antena), and a choke that wouldn't fry with TX power won't do anything useful! A few other points: 1) the SWR on a feedline is established BY THE ANTENNA, not the transmitter or antenna tuner; 2) feeding an antenna with two-wire line does NOT make it balanced -- most practical antennas that we think of as balanced are often un-balanced by their surroundings -- ground slope, variations in the soil under them, trees, wiring in buildings, unequal height ; 3) off-center-fed antennas are inherently unbalanced. 73, Jim K9YC On 1/6/2019 3:51 PM, David Woolley wrote: he feedpoint impedance DOES depend on the characteristic impedance! __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
The feedpoint impedance DOES depend on the characteristic impedance! Taking pure resistive cases (real characteristic impedances aren't), and lossless lines, a 75 ohm load at the end of a 75 ohm transmission line will have a feed point impedance that is a constant 75 ohms, whereas a 75 ohm load on 300 ohm feeder will have a feed point impedance that swings from 75 to 1200 ohms. -- David Woolley Owner K2 06123 On 06/01/2019 21:40, Don Wilhelm wrote: The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Don, I guess I should have pointed out that I was assuming one of those wide-range, balanced tuners of days of yore. I have one of those plug-in coil tuners I built long ago, and it will match almost anything, so feedline length is seldom an issue. Alas, the commercial tuners available today have much smaller ranges, so one does have to ensure that the impedance is in range, both of the tuner and the balun. 73, Scott K9MA On 1/6/2019 16:44, Don Wilhelm wrote: Scott, As I indicated, that is NOT true of just any length of window line. Some will work while others will not. With the G5RV, the only thing we know for sure is that on 20 meters, the impedance at the end of 34 feet of 300 ohm feedline is approximately 75 ohms. The impedance at that point will not be the same for other bands, and that is why a tuner is required. Once you get RF onto the radiator, it will be radiated. One real question is just how much loss do you encounter in the feedline. The other real question is, how much trouble do you have matching the shack end impedance to the 50 ohm output requirement of the transceiver. In days of old when we used plug-in coils in the transmitter and tuned the output tank to resonance, we could tap off those PA tank coils to match most any impedance. That capability moved into the antenna tuner with the advent of 50 ohm only transceivers - the first antenna tuners used balanced plug-in coils which could handle both balanced and unbalanced feedline, as well as low to high impedance depending on where you placed the tap(s) on the coil. The problem with those tuners is that they were not conducive to rapid band changes - you had to plug in coils for a different band. The Johnson Matchbox was a great asset to band changing and the proper taps on the coils, but its matching range was much more limited than those old-fashioned plug-in coils which provided a very wide range of matching impedance. 73, Don W3FPR On 1/6/2019 5:15 PM, K9MA wrote: The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
I learned a lot about my low band antenna system by building a full model of it using EZNEC and SimSmith. It enabled me to learn where the losses were band by band and resulted in a few changes. On 80m SimSmith said the loss in the 450 ohm was high because of the specific type I was using. It needed replacing anyway so I home brewed a length of ladder line and picked up over a dB. YMMV. 73, Brian, K0DTJ __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Scott, As I indicated, that is NOT true of just any length of window line. Some will work while others will not. With the G5RV, the only thing we know for sure is that on 20 meters, the impedance at the end of 34 feet of 300 ohm feedline is approximately 75 ohms. The impedance at that point will not be the same for other bands, and that is why a tuner is required. Once you get RF onto the radiator, it will be radiated. One real question is just how much loss do you encounter in the feedline. The other real question is, how much trouble do you have matching the shack end impedance to the 50 ohm output requirement of the transceiver. In days of old when we used plug-in coils in the transmitter and tuned the output tank to resonance, we could tap off those PA tank coils to match most any impedance. That capability moved into the antenna tuner with the advent of 50 ohm only transceivers - the first antenna tuners used balanced plug-in coils which could handle both balanced and unbalanced feedline, as well as low to high impedance depending on where you placed the tap(s) on the coil. The problem with those tuners is that they were not conducive to rapid band changes - you had to plug in coils for a different band. The Johnson Matchbox was a great asset to band changing and the proper taps on the coils, but its matching range was much more limited than those old-fashioned plug-in coils which provided a very wide range of matching impedance. 73, Don W3FPR On 1/6/2019 5:15 PM, K9MA wrote: The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
In the case of SWBC the matching happens at the TX. Sent from my iPad > On Jan 6, 2019, at 5:15 PM, K9MA wrote: > > The really attractive thing about open line, and even window line, is that > its loss is so low you can use it at a very high SWR, and take care of the > matching at the station end. This is especially useful for multi-band > antennas. The famous G5RV, for example, will work just exactly the same fed > with window line and a tuner as it will with the usual matching section. > > 73, > Scott K9MA > >> On 1/6/2019 16:09, W2xj wrote: >> And those broadcast stations generally work within a 2:1 VSWR range. >> >> Sent from my iPad >> >>> On Jan 6, 2019, at 4:51 PM, Bob McGraw K4TAX wrote: >>> >>> Correct on all points. >>> >>> That is the reason I gave my feedline type, and length and antenna length >>> alone with specific balun type and common mode choke type. Any old ragged >>> combination of chunks of wire and feed line is not assured to work and is >>> largely the reason many hams shy away from balanced feed systems. They >>> tried it once, it didn't work well thus they deemed all balanced feed >>> systems as being "bad". While the facts are, a balanced system correctly >>> installed and with correct lengths, it is the lowest loss feed of any >>> system reasonably available. Which is one of the reasons most short wave >>> broadcast stations used balanced feed systems. >>> >>> 73 >>> >>> Bob, K4TAX >>> >>> On 1/6/2019 3:40 PM, Don Wilhelm wrote: All, I think a bit of extended study on transmission lines and their impedance transformation characteristics is in order - refer to any ARRL antenna book, even those from the 1950 an 1960 era, not much new has been added, other than baluns. The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. The ARRL TLW program can do a lot of computation for you. You may be able to adjust the length of the transmission line so there is a moderate shack end feedpoint impedance on all bands of interest and be able to use a good current balun which has either a 1:1 or 4:1 transformation ratio. You have to measure the transmission line at the point where you intend to install the balun to be sure which to use. Yes, just hanging any balun on any length of parallel feedline connected to any length of antenna and expecting it to work without problems is just not going to happen in all but exceptional cases. How many cases where you see "this antenna works great" do you see any mention of how long the parallel feedline may be. Most hams simply ignore that, but it is likely the most important part of how the antenna works and what type of balun of you need to use. Your experience may be very different with the "same" multiband antenna than your local ham or that in the artic >> __ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to k...@sdellington.us > > > -- > Scott K9MA > > k...@sdellington.us > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to w...@w2xj.net > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
The really attractive thing about open line, and even window line, is that its loss is so low you can use it at a very high SWR, and take care of the matching at the station end. This is especially useful for multi-band antennas. The famous G5RV, for example, will work just exactly the same fed with window line and a tuner as it will with the usual matching section. 73, Scott K9MA On 1/6/2019 16:09, W2xj wrote: And those broadcast stations generally work within a 2:1 VSWR range. Sent from my iPad On Jan 6, 2019, at 4:51 PM, Bob McGraw K4TAX wrote: Correct on all points. That is the reason I gave my feedline type, and length and antenna length alone with specific balun type and common mode choke type. Any old ragged combination of chunks of wire and feed line is not assured to work and is largely the reason many hams shy away from balanced feed systems. They tried it once, it didn't work well thus they deemed all balanced feed systems as being "bad". While the facts are, a balanced system correctly installed and with correct lengths, it is the lowest loss feed of any system reasonably available. Which is one of the reasons most short wave broadcast stations used balanced feed systems. 73 Bob, K4TAX On 1/6/2019 3:40 PM, Don Wilhelm wrote: All, I think a bit of extended study on transmission lines and their impedance transformation characteristics is in order - refer to any ARRL antenna book, even those from the 1950 an 1960 era, not much new has been added, other than baluns. The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. The ARRL TLW program can do a lot of computation for you. You may be able to adjust the length of the transmission line so there is a moderate shack end feedpoint impedance on all bands of interest and be able to use a good current balun which has either a 1:1 or 4:1 transformation ratio. You have to measure the transmission line at the point where you intend to install the balun to be sure which to use. Yes, just hanging any balun on any length of parallel feedline connected to any length of antenna and expecting it to work without problems is just not going to happen in all but exceptional cases. How many cases where you see "this antenna works great" do you see any mention of how long the parallel feedline may be. Most hams simply ignore that, but it is likely the most important part of how the antenna works and what type of balun of you need to use. Your experience may be very different with the "same" multiband antenna than your local ham or that in the artic __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k...@sdellington.us -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Well said, Don! 73, Scott K9MA On 1/6/2019 15:40, Don Wilhelm wrote: All, I think a bit of extended study on transmission lines and their impedance transformation characteristics is in order - refer to any ARRL antenna book, even those from the 1950 an 1960 era, not much new has been added, other than baluns. The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. The ARRL TLW program can do a lot of computation for you. You may be able to adjust the length of the transmission line so there is a moderate shack end feedpoint impedance on all bands of interest and be able to use a good current balun which has either a 1:1 or 4:1 transformation ratio. You have to measure the transmission line at the point where you intend to install the balun to be sure which to use. Yes, just hanging any balun on any length of parallel feedline connected to any length of antenna and expecting it to work without problems is just not going to happen in all but exceptional cases. How many cases where you see "this antenna works great" do you see any mention of how long the parallel feedline may be. Most hams simply ignore that, but it is likely the most important part of how the antenna works and what type of balun of you need to use. Your experience may be very different with the "same" multiband antenna than your local ham or that in the article you read unless the feedline length and type is know. I do not see many antenna articles where the feedline length is mentioned if it is parallel feedline. With resonant antennas, the feedline length does not matter as long as the feedpoint impedance of the radiator is the same as the characteristic impedance of the feedline. In those cases, the feedline length does not matter, but in all other cases, it matters a lot. 73, Don W3FPR On 1/6/2019 3:17 PM, K9MA wrote: Using a balun with balanced line is risky. Window line or open line can be used with reasonable losses up to at least a 10:1 SWR, but that means the impedance at the balun output could be anywhere from 30 to 3000 Ohms (for 300 Ohm line). The current balun should work if the impedance at the balun output is low, not much over 50 Ohms. This is hard to measure, but modeling should give a close enough value. On the other hand, the impedance could be thousands of Ohms, and that kind of balun will be ineffective. Transformer-type baluns have limitations at both high and low impedances. While a transformer type balun could overheat and/or generate harmonics, I suppose the worst thing a current balun could do is to upset the balance. I've you're not seeing a lot of "RF in the shack", you're probably good. The only really reliable way to feed unmatched balanced line is with a truly balanced tuner, a seriously endangered species. I'm still using the one I built almost 50 years ago. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k...@sdellington.us -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
And those broadcast stations generally work within a 2:1 VSWR range. Sent from my iPad > On Jan 6, 2019, at 4:51 PM, Bob McGraw K4TAX wrote: > > Correct on all points. > > That is the reason I gave my feedline type, and length and antenna length > alone with specific balun type and common mode choke type. Any old ragged > combination of chunks of wire and feed line is not assured to work and is > largely the reason many hams shy away from balanced feed systems. They > tried it once, it didn't work well thus they deemed all balanced feed > systems as being "bad". While the facts are, a balanced system correctly > installed and with correct lengths, it is the lowest loss feed of any system > reasonably available. Which is one of the reasons most short wave broadcast > stations used balanced feed systems. > > 73 > > Bob, K4TAX > > >> On 1/6/2019 3:40 PM, Don Wilhelm wrote: >> All, >> >> I think a bit of extended study on transmission lines and their impedance >> transformation characteristics is in order - refer to any ARRL antenna book, >> even those from the 1950 an 1960 era, not much new has been added, other >> than baluns. The feedpoint impedance to the transmission line can vary from >> quite low to quite high dependent on the frequency, the length of line, and >> the load at the far end. It does NOT depend on the characteristic impedance >> of the transmission line. The ARRL TLW program can do a lot of computation >> for you. >> >> You may be able to adjust the length of the transmission line so there is a >> moderate shack end feedpoint impedance on all bands of interest and be able >> to use a good current balun which has either a 1:1 or 4:1 transformation >> ratio. You have to measure the transmission line at the point where you >> intend to install the balun to be sure which to use. >> >> Yes, just hanging any balun on any length of parallel feedline connected to >> any length of antenna and expecting it to work without problems is just not >> going to happen in all but exceptional cases. >> How many cases where you see "this antenna works great" do you see any >> mention of how long the parallel feedline may be. Most hams simply ignore >> that, but it is likely the most important part of how the antenna works and >> what type of balun of you need to use. >> >> Your experience may be very different with the "same" multiband antenna than >> your local ham or that in the artic __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Correct on all points. That is the reason I gave my feedline type, and length and antenna length alone with specific balun type and common mode choke type. Any old ragged combination of chunks of wire and feed line is not assured to work and is largely the reason many hams shy away from balanced feed systems. They tried it once, it didn't work well thus they deemed all balanced feed systems as being "bad". While the facts are, a balanced system correctly installed and with correct lengths, it is the lowest loss feed of any system reasonably available. Which is one of the reasons most short wave broadcast stations used balanced feed systems. 73 Bob, K4TAX On 1/6/2019 3:40 PM, Don Wilhelm wrote: All, I think a bit of extended study on transmission lines and their impedance transformation characteristics is in order - refer to any ARRL antenna book, even those from the 1950 an 1960 era, not much new has been added, other than baluns. The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. The ARRL TLW program can do a lot of computation for you. You may be able to adjust the length of the transmission line so there is a moderate shack end feedpoint impedance on all bands of interest and be able to use a good current balun which has either a 1:1 or 4:1 transformation ratio. You have to measure the transmission line at the point where you intend to install the balun to be sure which to use. Yes, just hanging any balun on any length of parallel feedline connected to any length of antenna and expecting it to work without problems is just not going to happen in all but exceptional cases. How many cases where you see "this antenna works great" do you see any mention of how long the parallel feedline may be. Most hams simply ignore that, but it is likely the most important part of how the antenna works and what type of balun of you need to use. Your experience may be very different with the "same" multiband antenna than your local ham or that in the article you read unless the feedline length and type is know. I do not see many antenna articles where the feedline length is mentioned if it is parallel feedline. With resonant antennas, the feedline length does not matter as long as the feedpoint impedance of the radiator is the same as the characteristic impedance of the feedline. In those cases, the feedline length does not matter, but in all other cases, it matters a lot. 73, Don W3FPR On 1/6/2019 3:17 PM, K9MA wrote: Using a balun with balanced line is risky. Window line or open line can be used with reasonable losses up to at least a 10:1 SWR, but that means the impedance at the balun output could be anywhere from 30 to 3000 Ohms (for 300 Ohm line). The current balun should work if the impedance at the balun output is low, not much over 50 Ohms. This is hard to measure, but modeling should give a close enough value. On the other hand, the impedance could be thousands of Ohms, and that kind of balun will be ineffective. Transformer-type baluns have limitations at both high and low impedances. While a transformer type balun could overheat and/or generate harmonics, I suppose the worst thing a current balun could do is to upset the balance. I've you're not seeing a lot of "RF in the shack", you're probably good. The only really reliable way to feed unmatched balanced line is with a truly balanced tuner, a seriously endangered species. I'm still using the one I built almost 50 years ago. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
All, I think a bit of extended study on transmission lines and their impedance transformation characteristics is in order - refer to any ARRL antenna book, even those from the 1950 an 1960 era, not much new has been added, other than baluns. The feedpoint impedance to the transmission line can vary from quite low to quite high dependent on the frequency, the length of line, and the load at the far end. It does NOT depend on the characteristic impedance of the transmission line. The ARRL TLW program can do a lot of computation for you. You may be able to adjust the length of the transmission line so there is a moderate shack end feedpoint impedance on all bands of interest and be able to use a good current balun which has either a 1:1 or 4:1 transformation ratio. You have to measure the transmission line at the point where you intend to install the balun to be sure which to use. Yes, just hanging any balun on any length of parallel feedline connected to any length of antenna and expecting it to work without problems is just not going to happen in all but exceptional cases. How many cases where you see "this antenna works great" do you see any mention of how long the parallel feedline may be. Most hams simply ignore that, but it is likely the most important part of how the antenna works and what type of balun of you need to use. Your experience may be very different with the "same" multiband antenna than your local ham or that in the article you read unless the feedline length and type is know. I do not see many antenna articles where the feedline length is mentioned if it is parallel feedline. With resonant antennas, the feedline length does not matter as long as the feedpoint impedance of the radiator is the same as the characteristic impedance of the feedline. In those cases, the feedline length does not matter, but in all other cases, it matters a lot. 73, Don W3FPR On 1/6/2019 3:17 PM, K9MA wrote: Using a balun with balanced line is risky. Window line or open line can be used with reasonable losses up to at least a 10:1 SWR, but that means the impedance at the balun output could be anywhere from 30 to 3000 Ohms (for 300 Ohm line). The current balun should work if the impedance at the balun output is low, not much over 50 Ohms. This is hard to measure, but modeling should give a close enough value. On the other hand, the impedance could be thousands of Ohms, and that kind of balun will be ineffective. Transformer-type baluns have limitations at both high and low impedances. While a transformer type balun could overheat and/or generate harmonics, I suppose the worst thing a current balun could do is to upset the balance. I've you're not seeing a lot of "RF in the shack", you're probably good. The only really reliable way to feed unmatched balanced line is with a truly balanced tuner, a seriously endangered species. I'm still using the one I built almost 50 years ago. 73, Scott K9MA __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Using a balun with balanced line is risky. Window line or open line can be used with reasonable losses up to at least a 10:1 SWR, but that means the impedance at the balun output could be anywhere from 30 to 3000 Ohms (for 300 Ohm line). The current balun should work if the impedance at the balun output is low, not much over 50 Ohms. This is hard to measure, but modeling should give a close enough value. On the other hand, the impedance could be thousands of Ohms, and that kind of balun will be ineffective. Transformer-type baluns have limitations at both high and low impedances. While a transformer type balun could overheat and/or generate harmonics, I suppose the worst thing a current balun could do is to upset the balance. I've you're not seeing a lot of "RF in the shack", you're probably good. The only really reliable way to feed unmatched balanced line is with a truly balanced tuner, a seriously endangered species. I'm still using the one I built almost 50 years ago. 73, Scott K9MA On 1/6/2019 13:42, Bob McGraw K4TAX wrote: Yes I use a balanced feed line being the "window" type line. It feeds a 250 ft wire in the center at 50 feet. I have about 75 ft of feed line from the center of the antenna then, through the attic eve vent, supported on some wooden hangers I made and attached to the roof rafters. Then it drops through the ceiling to the balun which sits on the shelf above the KPA500 and the KAT500. The balun is a Balun Designs 1:1 ATU current balun rated at 5 kW being model 1171t. I use a common mode choke, being model 8232 purchased from The Wireman. It runs from the balun to one of the tuner 3 outputs. Works great from 160M through 10M. Of note, I am on the 2nd floor of a wood frame house more in the center. No windows or walls to the outside. I do not use any type of "station ground" to the outside. I do have lightning protection devices where the feed lines and rotor lines enter the house. As the antenna and feed line is quite well balanced, there is no RF radiation in the shack an thus no RF issues with computers, phones, TV's, surround sound systems, and such. Each piece of station equipment is bonded to the station power supply ground terminal using a dedicated ground jumper. The 3rd pin AC ground is maintained and the amp runs from a dedicated 240 VAC circuit. Works great! 73 Bob, K4TAX On 1/6/2019 10:59 AM, Viggo Magnus Nilsen Nilsen wrote: Hello Elecrafters, Do some of you using KAT500 with open wire,ladder line feed to ur wire antennas with balun (outside the tuner) ? working ok ? 73' LA9NEA Viggo M. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k...@sdellington.us -- Scott K9MA k...@sdellington.us __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Yes I use a balanced feed line being the "window" type line. It feeds a 250 ft wire in the center at 50 feet. I have about 75 ft of feed line from the center of the antenna then, through the attic eve vent, supported on some wooden hangers I made and attached to the roof rafters. Then it drops through the ceiling to the balun which sits on the shelf above the KPA500 and the KAT500. The balun is a Balun Designs 1:1 ATU current balun rated at 5 kW being model 1171t. I use a common mode choke, being model 8232 purchased from The Wireman. It runs from the balun to one of the tuner 3 outputs. Works great from 160M through 10M. Of note, I am on the 2nd floor of a wood frame house more in the center. No windows or walls to the outside. I do not use any type of "station ground" to the outside. I do have lightning protection devices where the feed lines and rotor lines enter the house. As the antenna and feed line is quite well balanced, there is no RF radiation in the shack an thus no RF issues with computers, phones, TV's, surround sound systems, and such. Each piece of station equipment is bonded to the station power supply ground terminal using a dedicated ground jumper. The 3rd pin AC ground is maintained and the amp runs from a dedicated 240 VAC circuit. Works great! 73 Bob, K4TAX On 1/6/2019 10:59 AM, Viggo Magnus Nilsen Nilsen wrote: Hello Elecrafters, Do some of you using KAT500 with open wire,ladder line feed to ur wire antennas with balun (outside the tuner) ? working ok ? 73' LA9NEA Viggo M. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KAT 500 and open wire
Yes Viggo I use an open wire CF Zepp via a 4:1 balun with my KAT500. It works great. (:-)) 73 K0PP On Sun, Jan 6, 2019, 10:01 Viggo Magnus Nilsen Nilsen Hello Elecrafters, > > Do some of you using KAT500 with open wire,ladder line feed to ur wire > antennas with balun (outside the tuner) ? working ok ? > > 73' LA9NEA Viggo M. > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to kengk...@gmail.com > __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
