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#1
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Ham op writes:
My installation is as follows: 1) 600 ohm open wire line [tuned of course!] from the antenna to a protected [from WX] area under the sun porch. There I simply connected 450 ohm ladder line to the 600 ohm line for the run into the house. [450 ohm line has increased losses in bad WX]. As mentioned in another response, I run the 450 ohm line at right angles over metal structures. I keep the line a least 6 inches from pipes, heating vents etc and twist the line one twist every three [+/-] feet. I run 1 KW 80 through 20 meters with NO interference or RFI in the shack. This computer is located 3 feet from the amplifier and has no adverse effects from the amplifier. BTW, my station is grounded [earthed] IAW electrical code. Are there any lengths for the xmission line one should avoid when feeding different types of wire antenna? -- R*Horse rwinner.blogspot.com |
#2
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On Mon, 26 Sep 2005 00:29:55 GMT, Rockinghorse Winner
wrote: Ham op writes: My installation is as follows: 1) 600 ohm open wire line [tuned of course!] from the antenna to a protected [from WX] area under the sun porch. There I simply connected 450 ohm ladder line to the 600 ohm line for the run into the house. [450 ohm line has increased losses in bad WX]. As mentioned in another response, I run the 450 ohm line at right angles over metal structures. I keep the line a least 6 inches from pipes, heating vents etc and twist the line one twist every three [+/-] feet. I run 1 KW 80 through 20 meters with NO interference or RFI in the shack. This computer is located 3 feet from the amplifier and has no adverse effects from the amplifier. BTW, my station is grounded [earthed] IAW electrical code. Are there any lengths for the xmission line one should avoid when feeding different types of wire antenna? Some lengths work better than others, depending on band. See the web site, http://www.qsl.net/w5dxp and look at the "tunerless" all band antenna fed w/ladderline. bob k5qwg |
#3
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Bob Miller writes:
Some lengths work better than others, depending on band. See the web site, http://www.qsl.net/w5dxp and look at the "tunerless" all band antenna fed w/ladderline. bob k5qwg Thanks fer info. I'll check it out-- R*Horse rwinner.blogspot.com |
#4
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The reference to Cecil's web site is VG if you do not want to use a
tuner. Cecil does a great job with tuning stubs. I use a tuner. Some have stated that multiples of 1/2 wavelength can produce RF in the shack. In 50+ years I have not experienced this. I may be JUST LUCKY! Do you plan on using a tuner? Rockinghorse Winner wrote: Ham op writes: My installation is as follows: 1) 600 ohm open wire line [tuned of course!] from the antenna to a protected [from WX] area under the sun porch. There I simply connected 450 ohm ladder line to the 600 ohm line for the run into the house. [450 ohm line has increased losses in bad WX]. As mentioned in another response, I run the 450 ohm line at right angles over metal structures. I keep the line a least 6 inches from pipes, heating vents etc and twist the line one twist every three [+/-] feet. I run 1 KW 80 through 20 meters with NO interference or RFI in the shack. This computer is located 3 feet from the amplifier and has no adverse effects from the amplifier. BTW, my station is grounded [earthed] IAW electrical code. Are there any lengths for the xmission line one should avoid when feeding different types of wire antenna? |
#5
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Ham op writes:
The reference to Cecil's web site is VG if you do not want to use a tuner. Cecil does a great job with tuning stubs. I use a tuner. Some have stated that multiples of 1/2 wavelength can produce RF in the shack. In 50+ years I have not experienced this. I may be JUST LUCKY! Do you plan on using a tuner? Yes, I think I'll buy the MFJ QRP tuner. -- R*Horse rwinner.blogspot.com |
#6
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On Wed, 28 Sep 2005 01:11:20 GMT, Rockinghorse Winner
wrote: Ham op writes: The reference to Cecil's web site is VG if you do not want to use a tuner. Cecil does a great job with tuning stubs. I use a tuner. Some have stated that multiples of 1/2 wavelength can produce RF in the shack. In 50+ years I have not experienced this. I may be JUST LUCKY! Do you plan on using a tuner? Yes, I think I'll buy the MFJ QRP tuner. The instruction book I got with my mfj 989c tuner has a section on ladder line lengths to gravitate to, or avoid, depending on band. It can be downloaded free from the mfj web site. bob k5qwg |
#7
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Bob Miller wrote:
The instruction book I got with my mfj 989c tuner has a section on ladder line lengths to gravitate to, or avoid, depending on band. It can be downloaded free from the mfj web site. Hopefully, the lengths to avoid are associated with specific loads. Avoiding 1/4WL of ladder-line when feeding a 1/2WL dipole may be good advice but 1/4WL of ladder-line is ideal for feeding a one wavelength dipole. -- 73, Cecil http://www.qsl.net/w5dxp |
#8
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On Wed, 28 Sep 2005 14:14:51 GMT, Cecil Moore wrote:
Bob Miller wrote: The instruction book I got with my mfj 989c tuner has a section on ladder line lengths to gravitate to, or avoid, depending on band. It can be downloaded free from the mfj web site. Hopefully, the lengths to avoid are associated with specific loads. Avoiding 1/4WL of ladder-line when feeding a 1/2WL dipole may be good advice but 1/4WL of ladder-line is ideal for feeding a one wavelength dipole. They're fairly specific about loads -- their manual is at http://www.mfjenterprises.com/produc...rodid=MFJ-989C with pages 7 and 8 talking about feedline lengths. bob k5qwg |
#9
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Bob Miller writes:
On Wed, 28 Sep 2005 14:14:51 GMT, Cecil Moore wrote: Bob Miller wrote: The instruction book I got with my mfj 989c tuner has a section on ladder line lengths to gravitate to, or avoid, depending on band. It can be downloaded free from the mfj web site. Hopefully, the lengths to avoid are associated with specific loads. Avoiding 1/4WL of ladder-line when feeding a 1/2WL dipole may be good advice but 1/4WL of ladder-line is ideal for feeding a one wavelength dipole. They're fairly specific about loads -- their manual is at http://www.mfjenterprises.com/produc...rodid=MFJ-989C with pages 7 and 8 talking about feedline lengths. bob k5qwg Wow! I'll have a look a this ASAP. -- R*Horse rwinner.blogspot.com |
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