Re: Topband: New TX antenna for 80 and 160?
I recently built a dipole for 40/20/15 using 300 ohm twinlead, which worked out very well, so I'm thinking of using a similar approach for this antenna, using the full length for 160, and trimming one wire to be resonant on 80. I'd like to do whatever I can to maximize bandwidth. If I could cover both 80 and 75, for example, that would be great. Why not use a dipole and feed it like a T on 160 or maybe 160 and 80?? Are they really going to inspect what is buried or laying on the ground, so far as a counterpoise?? For what it is worth, a friend of mine lived on a city lot in a densly populated area with only about ten feet of back yard depth, and about 130 feet of length. He was surrounded by parking lots and buildings. I had about 100 radials with a 1/4 wave tower, and I lived in an area with rich wet black sandy loam. From that back yard, he was consistantly within a few dB of my signal. You never have known his end-fed 80 meter Zepp antenna was there. Harold did so well from a tiny lot it actually caused him social problems. Another nasty bitter old cranky man (the type we seem to tolerate up here) named Joe was so upset Harold was significantly louder then him, that grumpy old Joe would actually curse poor old Harold. It was always quite a show. Questions: -- Is a low dipole for 80 and 160 on a sloping site like mine worth the effort? I'm interested in DX, not NVIS. Anything works. Anyone can work DX with a low horizontal antenna. It doesn't exclude DX like a some sort of filter would. -- Given my constraints, are there other types of TX antennas I should consider? I'd consider a T antenna out of a dipole, or a bent wire. -- What's the best wire to use to minimize stretching and to maximize bandwidth and efficiency, and that can handle full legal power? Any wire can handle full power, but you want **real** copperweld or solid hard drawn copper. You can hard draw your own solid copper wire. Watch out for Ham wires that use very thin copper coating or cladding. There is a lot of that, and the stranded copper clad steel sold for Ham use is absolute junk. The copper is so thin the RF is down in the steel on low bands, and the stuff rusts if scratched or rubbed. A good copperweld has a pretty thick copper overlay, and that generally means it should be at least a 16 gauge strand. If you see fine strands or wire the size of a thick needle, it will behave like steel on low bands and be subject to rust. That doesn't mean it is useless, just not the best. I have copperweld here on beverages and other antennas, and I can scratch it with a knife to clean it and it won't rust. If I even try to solder the Ham grade junk, it rusts. Copperweld is (or was) used in long life outdoor support cables like for bridges, so there may be local suppliers to you. 73 Tom ___ Topband reflector - topband@contesting.com
Re: Topband: New TX antenna for 80 and 160?
Hello, Your location sounds similar to mine. I'm on a hill about 200 ft up and about 100-150 yards from ocean. I figured I'd throw yet another dipole over the tallest tree behind me. It's only about 30ft off the ground at the center - right next to the 40 and 80M... The 160M ends are about 8 ft and 15 ft I wasn't sure how the TX would work? Concerned at first. My 80M works well.. so I figured - give it a try. Dipole is cheap. Sling-Shot.. Wire.. done... Turns out - with about 600W it works with grey line or without. Reached East Coast, Russia, Chile, Caribbean etc.. on 160M. 5000-8000 miles so far. The problem for me was RX. I put up a 600ft beverage a few feet off the ground going east and it picks up signals I can't hear on other Radio... Probably S5 improvement? You don't NEED the beverage - but it helps big time. For me, it appears my signal was traveling further than my RX before.. call that barking dog or something... I use my TS-570 for TX with Dipole and Yaesu 897 with Beverage and use the Array Solutions RF Limiter to protect - keeps it around +40-60db max - not burying the needle. The beverage is also right next to low dipole for 160ft of the run. Doesn't seem to matter. I like have the two radios working the same time and playing with the volume etc.. :-) I would certainly try the Dipole first. Your location might be the equivalent of a 150ft tower on flat land not near the ocean. I figured, if my dipole didn't work.. I'd try the Cushcraft MA160V - good reviews.. low height - not that visible compared to tower - (I can't build a tower). I don't think I need it though. Last night I had a quick QSO with N7DD on LSB and he was 59 and I was 57 (3000 miles). I could hear his contact in Mexico but he couldn't hear me. We were both using beverages.. very clear. That was my first real 160M on phone (Told Larry that.. thank you!!). 160 is pretty much all CW... and my Beverage is only a month old if that. Have fun.. I'd start cheap and go from there. Maybe look into chicken wire to help with the ground. Throw it around the base and just throw a bunch of long wire around where you can. Water it! :-)) I posted this on Low Dipole 160M. Great article. http://lists.contesting.com/pipermail/topband/2012-November/039732.html Bryan WH7DX [CONFIDENTIALITY AND PRIVACY NOTICE] Information transmitted by this email is proprietary to Mr. Mrs. B and is intended for use only by the individual or entity to which it is addressed, or where ever the hell it ends up, and will almost certainly contain information that will offend a large portion of the population, which isn't our concern. If you are not the intended lucky recipient, or it appears that this mail has been forwarded to you without the proper authority of the Wizard of Email or Al Gore, you are notified that any thought, use, or consumption of this email is entirely your choice. In such case, Bon AppetitNote: A $.02 Internet Tax was charged for receiving this email and all funds were given to some family somewhere in America or the U.N Have a nice day. ___ Topband reflector - topband@contesting.com
Re: Topband: New TX antenna for 80 and 160?
Hi Rick, I've been down this same road as you - starting with a low (18 metre) dipole, and after 1+ year of using it, I was only able to copy work just (1) DX station from here in the Northeast US - that being DF2PY. I couldn't even work to the west coast of the US with the low dipole. Later, I replaced this dipole and installed an Inverted L with just (3) radials and worked lots of DX straight away - including VK / ZL. The difference between antennas was immeasurable - it was really that good. If you can manage just (1) bent radial with your Inverted L, it will still beat the low dipole if your interest is DX - especially at your QTH near the ocean. It won't be optimum, but it will work for you - and with just one radial you'll probably have 150-200 Khz of 2:1 bandwidth on 160m. Your questions: 1) Yes 2) I use a single 10 gauge copper clad wire for my L. Even heavily loaded with ice every winter, I've never noticed this wire stretching in 4 years of use. Takes full power easily. 3) I have no experience with a Spiderbeam. 4) My Inverted L is fed direct from 50-ohm 7/8 hardline - no matching network whatsoever. 1:3 minimum SWR at resonance. 73, Dan KK3AN Rick Kiessig wrote: Until recently, I was planning to put up an inverted-L as a TX antenna for 80 and 160. However, things have changed, and it no longer looks like I'll be able to run the radials I would need to have an effective vertical. Now I'm leaning toward a low dipole. My site is highly constrained: it's near the top of a ridge, on a slope, facing the ocean (100m above sea level, 300m from the water). The highest spot above sea level is the top of my tower: it's only 8.5m above immediate ground level (next to the house), although the ground 10m away is 7m lower. I can't run more than a wire or two and a coax feed on (not above) the ground - an FCP, for example, would be much too large. Due to limitations imposed by the city, I can't go higher than 10.5m above ground level. If I run a wire around three sides of my property in a U shape, hung from the tower near (but not at) the feedpoint, I can just hit 80m total length, with a 46m long center section and two 17m long end sections. The wire would attach to 10m high fiberglass poles near each of the four corners of the property. I recently built a dipole for 40/20/15 using 300 ohm twinlead, which worked out very well, so I'm thinking of using a similar approach for this antenna, using the full length for 160, and trimming one wire to be resonant on 80. I'd like to do whatever I can to maximize bandwidth. If I could cover both 80 and 75, for example, that would be great. Questions: -- Is a low dipole for 80 and 160 on a sloping site like mine worth the effort? I'm interested in DX, not NVIS. -- Given my constraints, are there other types of TX antennas I should consider? -- What's the best wire to use to minimize stretching and to maximize bandwidth and efficiency, and that can handle full legal power? I will need at least two (maybe three?) wires to cover both bands. Copperweld is strong, but I've heard it can be lossy, too. Twinlead has two wires, but it's stranded and doesn't feel very strong. -- I'm thinking about using Spiderbeam black fiberglass telescopic poles at the corners. However, I'm concerned about durability in high winds and having enough strength to be able to tension the wires so they don't droop terribly. Is there a better choice? -- I'm planning to put a common mode choke at the feedpoint and run coax from there, as I've done with the other dipole. Any reason to do it differently? 73, Rick ZL2HAM ___ Topband reflector - topband@contesting.com ___ Topband reflector - topband@contesting.com
Re: Topband: New TX antenna for 80 and 160?
Hi Rick- In regards to copperweld near the ocean, here in California wire near the coast, my copperweld has not held up too well as the steel rusts then fails due to intrusion through any damage to the copper surface. solid copper will last much better. BTW I understand the utilities use solid copper wire instead of copperweld or aluminum for same corrosion reasons. Someone else may be able to verify this info. I'd feed the dipoles with open wire and use a good matching unit.. possibly a remote unit and real open wire feed is also less noticeable. ( old Johnson Matchbox works for me everywhere except 160, I'm building one for 160. the 2 small holes coming into the shack easy to insulate and easy to fix laterit does take some ingenuity to route though) another possibility is a loop corner fed w/open wire, open at opposing corner for 160. makes a low visibility antenna, try modeling and see, my 235m square loop at 10m high does ok for a stealth antenna on 75/80/30/40. sometimes all you can do is try some things and see what works for u at a particular location. 73, Renée K6FSB Rick Kiessig wrote: Until recently, I was planning to put up an inverted-L as a TX antenna for 80 and 160. However, things have changed, and it no longer looks like I'll be able to run the radials I would need to have an effective vertical. Now I'm leaning toward a low dipole. My site is highly constrained: it's near the top of a ridge, on a slope, facing the ocean (100m above sea level, 300m from the water). The highest spot above sea level is the top of my tower: it's only 8.5m above immediate ground level (next to the house), although the ground 10m away is 7m lower. I can't run more than a wire or two and a coax feed on (not above) the ground - an FCP, for example, would be much too large. Due to limitations imposed by the city, I can't go higher than 10.5m above ground level. If I run a wire around three sides of my property in a U shape, hung from the tower near (but not at) the feedpoint, I can just hit 80m total length, with a 46m long center section and two 17m long end sections. The wire would attach to 10m high fiberglass poles near each of the four corners of the property. I recently built a dipole for 40/20/15 using 300 ohm twinlead, which worked out very well, so I'm thinking of using a similar approach for this antenna, using the full length for 160, and trimming one wire to be resonant on 80. I'd like to do whatever I can to maximize bandwidth. If I could cover both 80 and 75, for example, that would be great. Questions: -- Is a low dipole for 80 and 160 on a sloping site like mine worth the effort? I'm interested in DX, not NVIS. -- Given my constraints, are there other types of TX antennas I should consider? -- What's the best wire to use to minimize stretching and to maximize bandwidth and efficiency, and that can handle full legal power? I will need at least two (maybe three?) wires to cover both bands. Copperweld is strong, but I've heard it can be lossy, too. Twinlead has two wires, but it's stranded and doesn't feel very strong. -- I'm thinking about using Spiderbeam black fiberglass telescopic poles at the corners. However, I'm concerned about durability in high winds and having enough strength to be able to tension the wires so they don't droop terribly. Is there a better choice? -- I'm planning to put a common mode choke at the feedpoint and run coax from there, as I've done with the other dipole. Any reason to do it differently? 73, Rick ZL2HAM ___ Topband reflector - topband@contesting.com ___ Topband reflector - topband@contesting.com
