Re: Topband: 2 wl loop, worth the effort?
Thanks for all the replies, guess the consensus is it is not worth the effort to put up a 2wl loop over a 1wl. I know several mentioned verticals but I really was interested in the loop option. This is for QSO's with stations 500-600 miles from me, currently they report that my signal is strong and very consistent with the 25' high dipole believe it or not. But the dipole is fed with coax and has a limited bandwidth. I am switching to ladder line and was thinking the loop may be the next evolution. I also could move the dipole back to get it up to about 50' and feed it with ladder line as an option. My height is limited to what I have for trees. No tower planned for the new QTH since we are in hurricane/coastal storm country. As far as a receive only antenna that is in the plans soon. Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 On 01-Dec-15 22:00, NC3Z Gary wrote: > I have been contemplating a sky loop to replace my coax 160/80M fan > dipole. The loop would be fed with ladder line so I could use it on 160-40M. > > It would take a bit more effort clearing an area to get up 2wl of wire > but it could be done. Is the effort worth it over a 1wl loop? An > additional issue is I can only get it up about 50'. > > Right now the dipole is at 25' and works very well with the hams I daily > keep in touch with in the 500-600 mile range, but is limited in it's > bandwidth. > > > Gary Mitchelson > NC3Z/4 Pamlico County, NC FM15 > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: 2 wl loop, worth the effort?
I have been contemplating a sky loop to replace my coax 160/80M fan dipole. The loop would be fed with ladder line so I could use it on 160-40M. It would take a bit more effort clearing an area to get up 2wl of wire but it could be done. Is the effort worth it over a 1wl loop? An additional issue is I can only get it up about 50'. Right now the dipole is at 25' and works very well with the hams I daily keep in touch with in the 500-600 mile range, but is limited in it's bandwidth. Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Low band antenna project questions
That is the highest I can get support for. I am in far eastern NC and right on the sound where we get hurricanes and nor'easters so I am not putting up the towers I had at the old QTH. Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 On 07-Mar-16 09:49, Robert Harmon wrote: > Gary, > Are you restricted to 50 feet high max ? > > Bob > K6UJ > > On 3/7/16 5:50 AM, NC3Z Gary wrote: >> OK, still working on my permanent low band antenna and what I can fit >> for an effective antenna. The space I have is a recently cleared forest >> area. I had originally considered a full size loop but the best I could >> do is 50' high, although that would be a bit higher than my temporary >> dipole it is not much in the scheme of things. And I keep getting talked >> out of it. >> _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Low band antenna project questions
OK, still working on my permanent low band antenna and what I can fit for an effective antenna. The space I have is a recently cleared forest area. I had originally considered a full size loop but the best I could do is 50' high, although that would be a bit higher than my temporary dipole it is not much in the scheme of things. And I keep getting talked out of it. I have walked the back many times with the tape measure and lines to see what I can fit, and what I can fit is a catenary line to support a T or L at 50' above ground. And after reading numerous articles the consensus was not to use radials much longer than the vertical height. I can easily fit 32 radials @ up to 75' each. Now I want to be able to use this antenna for 80M as well as the non-DX portion of 160M. I can house a autotuner at the base (or make my own network but that would require control lines). My thinking is to make the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without loosing anything on 160M. With the above limitations is this an effective solution? T or L ? Am I missing anything? Working on a RX antenna later. -- Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Low band antenna project questions
OK, this has me intrigued. So the T top would look like this if looking straight up (or straight down) with the vertical portion at the xx? x x x xx xx xx xx x x xx x x xx xx xx xx x x x My 160M dipole is actually a 160/80M fan and resonates well on both bands, I did not think I could do that with a T top. That would solve issues. Would a cage of vertical wires be better than if I could use 2.5 to 1.5" aluminum masting? Luckily in our rural local club we have 2 hams that sell some neat products, one is the Air-boss launcher and the other is the Antenna Tensioner. The tensioner has proven its self here in the eastern NC winds. And being a boating area I have several West Marine stores nearby. Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 On 07-Mar-16 12:48, Jim Brown wrote: > Hi Gary, > > The antenna you describe should work quite well on both bands, but I'll > suggest a couple of tweaks to make the matching easier. First, make it a > Tee -- if you have a catenary, you can support a Tee as easily as an L. > Second, make the top section a fan (like a fan dipole) with short > elements to resonate it on 80 and longer ones for 160. Third, don't > worry about remoting the tuner unless you feedline is very long. Unless > the match is really bad, feedline loss on 80 and 160 is pretty low, > especially if you use RG8. Also, you can make the tuning more broadband > (and electrically lengthen the vertical section by 1-2 percent) by using > two parallel runs spaced 12-18 inches, tied together top and bottom. Do > a simple NEC model to get dimensions. > > Finally, use as many radials as you can, don't worry a lot about length, > just think more is better. :) BTW -- 50 ft on the ground will be close > to a quarter wave on 80, 100 ft on 160. > > As to physical details -- get a good pulley at each end, tie one end > down, put a weight on the other end, and use some sort of "mechanical > fuse" at the feedpoint so that wind doesn't break it. I use a mating > pair of Pomona connectors -- when the wind blows, they simply un-mate. > For the fan spreaders, cut short lengths (12-18 inches is great) of > 1/2-in PVC conduit, drill holes about 3/4-in from each end to pass the > wires through. Make this antenna as physically robust as possible to > withstand the wind. At a minimum, #10 THHN for the long top sections > that carry the stress. #12 or #14 is fine for the shorter top sections. > Don't make any soldered connections -- they don't weather well, and wire > tends to break at a soldered joint. Instead, use split-bolt copper clamp > connectors sized to fit the wire you're using. For support rope, use > 5/16-in rope from http://www.synthetictextilesinc.com/supportham.html > It's resold by lots of ham vendors, but Synthetic Textiles is a bit > cheaper. Smaller rope is sufficient for strength, but you'll appreciate > the larger size when you're trying to pull on it to maximize tension, > which pulls it higher. :) Don't use hardware store pulleys -- instead, > use marine pulleys (good) or this excellent "rescue" pulley, which is > also easy to rig. > > http://www.ropescoursewarehouse.com/catalog1/advancedwebpage.aspx?cg=1851=4=202=SKU=1250=914=CKfCobGOr8sCFQWUfgod5DUOHQ > > > Out here in CA, the West Marine is the place to buy marine pulleys. > > 73, Jim K9YC > > On Mon,3/7/2016 5:50 AM, NC3Z Gary wrote: >> Now I want to be able to use this antenna for 80M as well as the non-DX >> portion of 160M. I can house a autotuner at the base (or make my own >> network but that would require control lines). My thinking is to make >> the 160M a 5/16 WL vs 1/4 to be more beneficial to 80M tuning without >> loosing anything on 160M. > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > . > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: inv. L
Art, I put one up this spring with the encouragement on this list. The L's are back to back, e.g. the 160M L points north while the 80M points south. The vertical sections are 45' and the spacing is about 18". Fed with a decoupling choke at the base over 32 65' radials. My amp tunes up with no need for a tuner or matching network and I have been very pleased with the performance, even for local stuff out 300-600 miles all during the summer. Did a lot of comparison using WSPR mode into EU and OC and the L on both bands trounced the resonate dipoles, on both TX and RX, so they have since come down. I am considering adding a 40M element. Gary Mitchelson NC3Z/4 Pamlico County, NC FM15 On 17-Oct-16 11:16, Art Snapper wrote: > I was considering adding a second vertical element to my 160 inverted L. > This one would be roughly a quarter wave tall for use on 80. > > I tried modelling in Eznec, but wasn't comfortable with the results. I may > have screwed it up. > > Has anyone tried it for real? Is it a big compromise on either band? Would > a switch at the feedpoint have any benefit? > > My inverted L has about 50 radials. > > 73 > Art NK8X > _ > Topband Reflector Archives - http://www.contesting.com/_topband > . > _ Topband Reflector Archives - http://www.contesting.com/_topband
