Re: Topband: Ladder line vs coax loss epiphany
Tim wrote: > I made some initial plastic spacers using drill press and saw but > for me, the real timesaving breakthrough in making the spacers, was > figuring out that snips cut the polycarbonate sheet just fine, and > the Roper Whitney #5 does the holes like magic. I love that thing. > > http://www.roperwhitney.com/store/shop/no-5-jr-hand-punch/ YES!! Good, no...SUPER, punch! I purchased mine over 20 years ago and it still works great! Hard to wear out. It came with a fitted metal case (then!!)I see now it's a plastic case which, I hope, is "un-breakable". Charlie, N0TT _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
On Wed, Apr 30, 2014 at 10:46 AM, Tom W8JI wrote: > Lines I measured here with heavy conductors were about 370 ohms, > Others have gotten 370 as well. I got 360 and 370 off different rolls. That's less than 3% variation. The one up now is 360. The next roll, who knows. I was always surprised at how often 50 and 75 ohm coax weren't actually those values. I always measure the coax now, and construct series matching transformers based on the measured Z0. Get much better results. and loss, velocity factor, and surge impedance changed with water. They > also changed substantially when the line was laid against things, or a line > enclosed in PVC pipe was buried. > As would any parallel line laid against things or inserted in PVC. It is illogical to have a change in Vf without an accompanying change in > loss or impedance. > Certainly. There was measured change in impedance, but proportionally not nearly so much as the VF. This was also noted on VK1OD's site (no longer available), who carried dry and wet table entries for Wireman window lines in his tables. So taking the trouble to get to 360 ohms did actually minimize SWR change in the rain. I am certain the loss increased, from RBN, but that was hard to separate from loss from wet trees in close proximity to the L. Standing in a heavy rain down by the creek with electronics was not really an option with my equipment. Unfortunately, the box at the antenna feed wasn't constructed with a relay to terminate the feedline to make that kind of measurement easy. Next version of box will have that operation in mind. > The odd impedance of "450 ohm" lines aggravates the issue of broadband use > in matched systems. > It certainly does. > I would stay away from ladder lines for low loss impedance matched > systems, and stick with real open wire line of a modest planned impedance > such as 450 ohms. > I certainly considered it. However much "cleaner" that solution, the downside was the need to fabricate *everything*, supports, the spacers for the line itself, and in my case having to run it through the woods. The Wireman #554 actually stands up to smaller trees falling on it (happens a couple times a year) and instead tears up the supports. Out across the open field I might have tried the homebrew bare wire stuff. Acres and acres of open farmland certainly does have its advantages. Surplus hardline is a much better option, IMO. > For all the physical reasons, yes. At the point it was going up, the main energy was being spent developing the FCP. Have to say though, for all the maintenance irritations, the 554 line performance is never an issue. An Alpha 8410 with its tetrodes in AB1 and effectively no grid current, rides the changes in the rain well enough. 73, Guy > 73 Tom > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
I use strips of 1/16" polycarbonate, about 5/16" wide by 4" long, with 1/16" holes punched near the ends and a slit cut for wire insertion, as spacers for my #14 solid wires. Has held up to the weather and UV just fine over past 5 years. I made some initial plastic spacers using drill press and saw but for me, the real timesaving breakthrough in making the spacers, was figuring out that snips cut the polycarbonate sheet just fine, and the Roper Whitney #5 does the holes like magic. I love that thing. http://www.roperwhitney.com/store/shop/no-5-jr-hand-punch/ Tim N3QE -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Eric NO3M Sent: Wednesday, April 30, 2014 3:42 PM To: topband@contesting.com Subject: Re: Topband: Ladder line vs coax loss epiphany OWL using #14 THHN and 1/2 in. irrigation "drip" tube. If drilled with the right sized hole, the spacers pinch the wire enough to stay in place w/o any additional hardware: http://no3m.net/index.php?page=open-wire-transmission-line 73 Eric NO3M On 04/30/2014 11:16 AM, Rik van Riel wrote: > On 04/30/2014 11:08 AM, Shoppa, Tim wrote: >> I briefly used the "window line" you all are discussing, before I >> built my own parallel line from scratch. > > It is surprisingly easy to make one's own ladder line, on a budget, > from materials that are locally available. > > I have made ladder line from 12ga THHN wire, 1/4 tubing, UV resistant > zip ties, and super glue. > > First, I cut the 1/4 inch tubing in many pieces of equal length, > representing the distance between the wires. > > Then, I string up two lines of copper wire near each other, at a > convenient to work with height. This can be done between two trees, > between a tree and the deck, etc... > > To assemble the ladder line, I run a zip tie through the tubing, > around one wire, back through the tubing, around the second wire, and > then I ratchet it close. > > I put spacers on about every foot and a half. Afterwards, I run by and > snip off the zip tie ends, followed by another run to put a drop of > superglue where each zip tie touches the wire. > > Ladder line like this has been up both at my house, and at a friend's > place, for a few years now. > > It is a lot easier to make it this way, than to run hundreds of feet > of copper wire through ready-bought spreaders. > > I did take pictures at one point. If someone wants the illustrated > version of the above description, I'll type up a blog post with > pictures. > > If someone has ideas on how to do it better, I am all ears :) > _ _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
OWL using #14 THHN and 1/2 in. irrigation "drip" tube. If drilled with the right sized hole, the spacers pinch the wire enough to stay in place w/o any additional hardware: http://no3m.net/index.php?page=open-wire-transmission-line 73 Eric NO3M On 04/30/2014 11:16 AM, Rik van Riel wrote: On 04/30/2014 11:08 AM, Shoppa, Tim wrote: I briefly used the "window line" you all are discussing, before I built my own parallel line from scratch. It is surprisingly easy to make one's own ladder line, on a budget, from materials that are locally available. I have made ladder line from 12ga THHN wire, 1/4 tubing, UV resistant zip ties, and super glue. First, I cut the 1/4 inch tubing in many pieces of equal length, representing the distance between the wires. Then, I string up two lines of copper wire near each other, at a convenient to work with height. This can be done between two trees, between a tree and the deck, etc... To assemble the ladder line, I run a zip tie through the tubing, around one wire, back through the tubing, around the second wire, and then I ratchet it close. I put spacers on about every foot and a half. Afterwards, I run by and snip off the zip tie ends, followed by another run to put a drop of superglue where each zip tie touches the wire. Ladder line like this has been up both at my house, and at a friend's place, for a few years now. It is a lot easier to make it this way, than to run hundreds of feet of copper wire through ready-bought spreaders. I did take pictures at one point. If someone wants the illustrated version of the above description, I'll type up a blog post with pictures. If someone has ideas on how to do it better, I am all ears :) _ _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
On 04/30/2014 11:08 AM, Shoppa, Tim wrote: I briefly used the "window line" you all are discussing, before I built my own parallel line from scratch. It is surprisingly easy to make one's own ladder line, on a budget, from materials that are locally available. I have made ladder line from 12ga THHN wire, 1/4 tubing, UV resistant zip ties, and super glue. First, I cut the 1/4 inch tubing in many pieces of equal length, representing the distance between the wires. Then, I string up two lines of copper wire near each other, at a convenient to work with height. This can be done between two trees, between a tree and the deck, etc... To assemble the ladder line, I run a zip tie through the tubing, around one wire, back through the tubing, around the second wire, and then I ratchet it close. I put spacers on about every foot and a half. Afterwards, I run by and snip off the zip tie ends, followed by another run to put a drop of superglue where each zip tie touches the wire. Ladder line like this has been up both at my house, and at a friend's place, for a few years now. It is a lot easier to make it this way, than to run hundreds of feet of copper wire through ready-bought spreaders. I did take pictures at one point. If someone wants the illustrated version of the above description, I'll type up a blog post with pictures. If someone has ideas on how to do it better, I am all ears :) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
- Original Message - From: "Tom W8JI" To: Sent: Wednesday, April 30, 2014 10:46 AM Subject: Re: Topband: Ladder line vs coax loss epiphany That tenuous advantage disappears if one popular 360 ohm heavy duty window line variant of "450" line is operated at a mismatch. At that point the stranded copperweld conductors (used for physical strength) start to lose a lot of power at the current maximums of the standing waves. I confirmed the 360 ohms on my particular piece of the window line. In my case, almost 500 feet of that running through the woods needed a surprising amount of finagling the system to present 360 ohms to the feedline. That SWR change people see in the rain apparently is a velocity factor change, making the degree of change in the rain proportional to the mismatch to the window line Z0. The 450 ohm baluns are not all that good a match, and most of the baluns are poor at 160.. The ARRL has had some goofy measurements. They had one article that showed almost no change in loss with a line laying right on wet dirt! Lines I measured here with heavy conductors were about 370 ohms, and loss, velocity factor, and surge impedance changed with water. They also changed substantially when the line was laid against things, or a line enclosed in PVC pipe was buried. It is illogical to have a change in Vf without an accompanying change in loss or impedance. The odd impedance of "450 ohm" lines aggravates the issue of broadband use in matched systems. I would stay away from ladder lines for low loss impedance matched systems, and stick with real open wire line of a modest planned impedance such as 450 ohms. Surplus hardline is a much better option, IMO. 73 Tom These days even surplus 50 Ohm hardline (Andrew Heliax and other brands) in 1/2" and 7/8" is often available at low scrap cost as 2 way shops and sites are going out of business and towers dismantled.. Many come with connectors and price can be free if you do the climbing. Let your fingers do the walking and call around. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
I briefly used the "window line" you all are discussing, before I built my own parallel line from scratch. I think all the window line that's available today from Wireman, RF Connection, etc is made by JSC. My experience was with JSC 1318. Yes, the window line had some issues. Change in properties when wet and the way it turns into a "sail" in any wind were my biggest problems. I think the window line is probably useful under some circumstances. It rolls up kinda nicely (being copper plated steel it will always coil back up!) and is rather lightweight. I know for sure my home-made parallel lines doesn't roll back up nicely! So maybe it would be useful to backpackers etc. especially in dry weather. Tim N3QE -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Tom W8JI Sent: Wednesday, April 30, 2014 10:46 AM To: topband@contesting.com Subject: Re: Topband: Ladder line vs coax loss epiphany > That tenuous advantage disappears if one popular 360 ohm heavy duty > window line variant of "450" line is operated at a mismatch. At that > point the stranded copperweld conductors (used for physical strength) > start to lose a lot of power at the current maximums of the standing > waves. I confirmed the > 360 ohms on my particular piece of the window line. > > In my case, almost 500 feet of that running through the woods needed a > surprising amount of finagling the system to present 360 ohms to the > feedline. That SWR change people see in the rain apparently is a > velocity factor change, making the degree of change in the rain > proportional to the mismatch to the window line Z0. The 450 ohm baluns > are not all that good a match, and most of the baluns are poor at 160.. The ARRL has had some goofy measurements. They had one article that showed almost no change in loss with a line laying right on wet dirt! Lines I measured here with heavy conductors were about 370 ohms, and loss, velocity factor, and surge impedance changed with water. They also changed substantially when the line was laid against things, or a line enclosed in PVC pipe was buried. It is illogical to have a change in Vf without an accompanying change in loss or impedance. The odd impedance of "450 ohm" lines aggravates the issue of broadband use in matched systems. I would stay away from ladder lines for low loss impedance matched systems, and stick with real open wire line of a modest planned impedance such as 450 ohms. Surplus hardline is a much better option, IMO. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
That tenuous advantage disappears if one popular 360 ohm heavy duty window line variant of "450" line is operated at a mismatch. At that point the stranded copperweld conductors (used for physical strength) start to lose a lot of power at the current maximums of the standing waves. I confirmed the 360 ohms on my particular piece of the window line. In my case, almost 500 feet of that running through the woods needed a surprising amount of finagling the system to present 360 ohms to the feedline. That SWR change people see in the rain apparently is a velocity factor change, making the degree of change in the rain proportional to the mismatch to the window line Z0. The 450 ohm baluns are not all that good a match, and most of the baluns are poor at 160.. The ARRL has had some goofy measurements. They had one article that showed almost no change in loss with a line laying right on wet dirt! Lines I measured here with heavy conductors were about 370 ohms, and loss, velocity factor, and surge impedance changed with water. They also changed substantially when the line was laid against things, or a line enclosed in PVC pipe was buried. It is illogical to have a change in Vf without an accompanying change in loss or impedance. The odd impedance of "450 ohm" lines aggravates the issue of broadband use in matched systems. I would stay away from ladder lines for low loss impedance matched systems, and stick with real open wire line of a modest planned impedance such as 450 ohms. Surplus hardline is a much better option, IMO. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ladder line vs coax loss epiphany
On Tue, Apr 29, 2014 at 11:32 AM, Shoppa, Tim wrote: > It took me literally decades to realize this, but the low ladder line > losses that show up in the ARRL graphs are not because ladder line is > magical..snip... > > It's because ladder line is used at 450 or 600 ohm impedance, so it of > course has one tenth the resistive losses of 50 ohm coax built with similar > amount of copper. > That tenuous advantage disappears if one popular 360 ohm heavy duty window line variant of "450" line is operated at a mismatch. At that point the stranded copperweld conductors (used for physical strength) start to lose a lot of power at the current maximums of the standing waves. I confirmed the 360 ohms on my particular piece of the window line. In my case, almost 500 feet of that running through the woods needed a surprising amount of finagling the system to present 360 ohms to the feedline. That SWR change people see in the rain apparently is a velocity factor change, making the degree of change in the rain proportional to the mismatch to the window line Z0. The 450 ohm baluns are not all that good a match, and most of the baluns are poor at 160.. In my case trimming the big L and adjusting the series cap allowed me to present 360 ohms resistive on the window line side of the 4:1 FCP isolation transformer. But none of that helps with branches and whole trees falling across the window line. This of course pops the support points, and I've had to partly redo the supports a half a dozen times after storms. Also, squirrels eat the window line PE, which seems really weird. Buried Hardline or balanced feed parallel coax increases in allure. 73, Guy _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Ladder line vs coax loss epiphany
It took me literally decades to realize this, but the low ladder line losses that show up in the ARRL graphs are not because ladder line is magical. I had been reading many articles in QST, and on the web, that made it seem like ladder line was magical this way. Really, for decades I did not understand why ladder line had so much less loss than comparable-copper coax. It's because ladder line is used at 450 or 600 ohm impedance, so it of course has one tenth the resistive losses of 50 ohm coax built with similar amount of copper. There a similar (but smaller) advantage to 75 ohm coax vs 52 ohm coax. Tim N3QE -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Kenneth Silverman Sent: Tuesday, April 29, 2014 11:00 AM To: topband@contesting.com Subject: Re: Topband: 1000 feet 5/8" hardline or 600ohm True Ladder lin Rune, Back in 1997 N6BV and I did some testing using "ladder line" (not the real 600 ohm stuff) and some 9:1 baluns on each end. We were looking at a site in YV where the beach was about 1000' from the hotel room. We tested the following: - loss in back to back baluns - loss in 100' of ladder line and baluns on each end We tested 160 to 10m. We lost the data but I seem to remember the total loss on 80/160 with 1000' of line was negligible. Maybe in the 2 dB range on 10m with 1000' of ladder line. A few of us went to the YV location to run the IARU contest with the 1000' run of ladder line, using a single vertical on the beach. The system worked well, except when there was rain (varying SWR), or coconuts and palm fronds fell and broke the line. I just talked to N6BV and he said the ARRL Labratory recently did some careful measurements on matched-line losses for open-wire line for input to Dean's TLW program. There is a new executable that contains the algorithms for loss computation. Good luck, Kenny K2KW _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
