++++++++++++++++++++ From: "Stuart Rohre" To: "Ed Juge/NM" , , Subject: Re: [Elecraft] Re:Alligators and Bats Date: Fri, 11 Jan 2002 13:02:44 -0600 I can vouch for the good performance of elevated dipole verticals, and have heard good reports on the Sigma series from Force 12. But to perk up any vertical of the quarter wave type, look at Force 12's web site for the illustrations of the gull wing elevated radials, that increase the efficiency of the antenna system over radials on the ground, (or in the ground). Broadcast stations are replacing expensive in the ground radials that corrode away with elevated radials as a cost saving measure for their quarter wave or loaded monopole installations. There is an AM station north of the plaza in Santa Fe NM, that has its tower over a parking lot, and above the parking areas is a mesh of ground wires, all elevated radials. 72, Stuart K5KVH +++++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: Subject: RE: [Elecraft] Re:Alligators and Bats Date: Fri, 11 Jan 2002 11:46:11 -0800 Stuart Rohre wrote: >Broadcast stations are replacing expensive in the ground radials that >corrode away with elevated radials as a cost saving measure for their >quarter wave or loaded monopole installations. >There is an AM station north of the plaza in Santa Fe NM, that has its tower >over a parking lot, and above the parking areas is a mesh of ground wires, >all elevated radials. Elevated radials work better too. If memory serves right, it's been about 10 or 15 years since some serious engineering effort demonstrated that the old formula of 120 radials on the ground did not produce the best or the most cost-effective ground system for short vertical radiators. A much smaller number of elevated radials can out-perform the old systems. I've read of a number of commercial systems being built or retrofitted using the new data for both short wave and broadcast band antennas, but I've not seen one yet. How high off the ground are the radials? Ron AC7AC K2 # 1289 +++++++++++++++++++ From: "Stuart Rohre" To: , Subject: Re: [Elecraft] Re:elevated radials Date: Fri, 11 Jan 2002 18:24:49 -0600 In the case of the Force 12, it was a few, (2?) feet up. They attach at the base of the vertical, then come up at an angle and run horizontal (thus the name "gull wing"), over the sea side when they were first used in the DX contest with Force 12 antennas. The AM station in Santa Fe, of course, had to accommodate cars under theirs, thus they are about 10 feet off the surface of the parking lot, (ground level). Stuart K5KVH +++++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: "Stuart Rohre" Cc: "Elecraft List" Subject: RE: [Elecraft] Re:elevated radials Date: Fri, 11 Jan 2002 19:51:30 -0800 Thanks, Stuart! I'll look into that Force 12. It sounds interesting. I've been following the issue of elevated radials for years. I looked up the reference I mentioned earlier and it was an engineering paper by Christman in 1988 that I was thinking of. That paper was about the commercial use of large counterpoises raised above the earth as compared to the "standard" of 120 radials on the ground that dates back to the 1930's. Christman subsequently wrote an article that appeared in the August, 1988 issue of QST about his work for Hams comparing systems more on the scale of what most of us are likely to install. In that article Christman says that, at 3.8 MHz, only four radials such as most Hams put up elevated 5 feet above the ground are within 0.5 dB of being as effective as 120 radials on the ground. I thought, Wow! But I've seen very little about it ever since. When I read Moxon's "HF Antennas for all Locations" a few years ago, I wondered if the shortened, "tuned" counterpoises that he recommends were based on Christman's work, but I never took the time to write and ask. I've also been told by one person that Christman's work was never verified by experiment. That's an interesting point. I don't have any other references to indicate whether it was or not. The writer said that Christman used an early version of NEC that was available back then to "prove' his theory. As usual, what I don't know far exceeds what I do know. It is very interesting that the commercial installation is using an elevated radial system. You pointed out that it also avoids corrosion by the soil. That's certainly another consideration. Ron AC7AC +++++++++++++++ Date: Sat, 12 Jan 2002 16:53:38 -0500 To: From: Charles Greene Subject: RE: [Elecraft] Re:elevated radials Cc: "Stuart Rohre" , "Elecraft List" At 07:51 PM 1/11/2002 -0800, Ron D' Eau Claire wrote: Ron, There are some articles in the ARRL Antenna Compendium #5 "Elevated Vertical Antenna for the Low Bands: Varying the Height and Number of Radials," and in Antenna Compendium #6 "Dual Mode "Elevated Verticals." My own experience is that our club has a portable vertical which uses 1 section of tubing for 20 or 2 sections of tubing for 40, with two elevated radials. We use it for Field Day and special event stations. It is an effective antenna. I recently modelled a 160-30 vertical, top loaded with linear loading, using two elevated radials. Software says it probably would work. I want to go back and use a near 1/4 wave radial for each band and see how that changes things. ++++++++++++++++++++ From: w7qhd at webtv.net (Kurt Cramer) Date: Sat, 12 Jan 2002 14:59:58 -0700 (MST) To: Elecraft at mailman.qth.net Subject: [Elecraft] Vertical Antennas CQ January 02 has an interesting article by VK6APH on compact radial systems for use on 1/4 wavelength verticals. Check it out if you can. 73, Kurt W7QHD (since 1951) web page: http://W7QHD.tripod.com +++++++++++++++++++++ Subject: RE: [Elecraft] Re:Alligators and Bats Date: Thu, 17 Jan 2002 17:41:29 -0500 From: Bill Coleman To: , On 1/11/02 2:46 PM, Ron D' Eau Claire at rondec at easystreet.com wrote: >Elevated radials work better too. Actually, they don't. >If memory serves right, it's been about 10 >or 15 years since some serious engineering effort demonstrated that the old >formula of 120 radials on the ground did not produce the best or the most >cost-effective ground system for short vertical radiators. A much smaller >number of elevated radials can out-perform the old systems. Actually, what happened is that folks using antenna modelling programs discovered this. Their predictions of antenna performance were the same or better using a small number of elevated radials rather than a set of ground-mounted ones. However, the reality is somewhat different. The results predicted by the modelling programs were not borne out in actual measurement of installations. Turns out the anomaly was an inaccurate modeling of the effects of ground in the programs. >I've read of a number of commercial systems being built or retrofitted using >the new data for both short wave and broadcast band antennas, but I've not >seen one yet. There were a number of broadcast stations that tried this, but they found they don't produce the same results as a properly installed set of ground-mounted radials. Basically, if you can put down 30-60 1/4 wave radials (or 60-120 1/2 wave radials), their performance converges to virtually the same as having a solid sheet of conductive material. 30-60 1/4 radials on the ground will out-perform 4-8 elevated radials. However, if you can only have 4 radials, you may be better off elevating them. Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 +++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: "Bill Coleman" , "Stuart Rohre" Cc: "Elecraft List" Subject: RE: [Elecraft] Re:elevated radials Date: Thu, 17 Jan 2002 15:15:52 -0800 To say again, what I had been told was that no actual installation had been made and tested. Bill, Are you saying that real tests were run and they did not perform according to the model? That's entirely different! If so, do you know when and where? Ron AC7AC ++++++++++++++++++ Subject: RE: [Elecraft] Re:elevated radials Date: Fri, 18 Jan 2002 10:17:43 -0500 To: , "Bill Coleman" , "Stuart Rohre" From: Bill Coleman Cc: "Elecraft List" On 1/17/02 6:15 PM, Ron D' Eau Claire at rondec at easystreet.com wrote: >To say again, what I had been told was that no actual installation had been >made and tested. > >Bill, Are you saying that real tests were run and they did not perform >according to the model? That's entirely different! > >If so, do you know when and where? Actually, I was told this by W8JI. It's in the TowerTalk archives somewhere (See: ) I just spent some time in the archives. I can't find the article I remember reading, but I did find this excellent summary: Take note of the actual experiments W8JI (his call is listed as W8JIT for some reason) did with both elevated and ground-mounted radials. The field-strength measurements don't bare out the claims of NEC modeling for elevated radials. Bottom Line: if you can only afford 4 radials -- you should elevate them. If you can put down 30 or more -- you should put them on the ground. (Unless, of course, you can elevate radials 1/4 wavelength or more above ground, in which case the 4 elevated radials win) Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 +++++++++++++++++++ From: "Stuart Rohre" To: "Jason Hissong" Cc: "elecraft" Subject: Re: [Elecraft] Verticals Date: Mon, 11 Feb 2002 13:04:55 -0600 Jason, A much better vertical in my Experience is the Gap Titan, (or Eagle), but the Titan has more bands I believe. The other antenna you mention is VERY dependent on local earth conductivity, and if you do not have that, and most ham urban locations do not, you are wasting your money on only a monopole antenna without extensive radial system. The Titan can be elevated a bit, as mine is at six feet above the center of the back yard. It is about 10 foot from a Live Oak much taller than it, but I think it was your bad solder joint and not the Silver maple that was at fault with your vertical as you say it works fine for the new owner. Mine works lots of DX and stateside with good signal reports. The aluminum siding houses need to be a quarter wave or more from your vertical, or raise it about 15 feet to be above the siding, (if single story houses). The other antenna you mention needs radials to function well, and my friend who had one had a devil of a time tuning them correctly. The Titan-- I just put up, soldered the coax plug correctly, and it is playing well, years later. Never had to tune it; it met specs right out of the box. The difference in what I have and what you propose, is mine is a center fed vertical dipole, more forgiving of earth conditions, than the trap loaded bottom fed antenna you are considering. The Eagle and Titan are linearly decoupled, non trap Asymmetric Vertical Dipoles. The other is a Monopole, and was problematic when we had two for field day, and later my friend had one backyard mounted on a chain link fence. By the way, they do like to call it a trap, but since it has coil and capacitor, of fixed components, they are subject to losses. If you have resonant aluminum siding in the near region of any vertical it is not going to work as well, as a non conductive environment. That is, any siding which is exactly quarter wave or half wave long at one of the bands will affect that band. You might also look at Force 12 Antennas web site for more on vertical dipoles, which are ground independent. Also, the W4RNL Antenna web site at . Force 12 has a multi band vertical dipole for 20-15-10, and may have some others for other bands. Soldering is EVERYTHING to antennas and ham radio hookups in general. Practice on scrap before soldering connectors, do not overheat them. Use good solder like Multicore Solders, (Richardson, TX) which have multiple cores of non corrosive flux. Clean off the resin with alcohol after soldering connections used outdoors. Tape them up, and use sealing compounds like Dux Seal to prevent moisture getting to your connector. Use an iron, not a soldering gun, unless you are well practiced with the gun. Do not solder outdoors, if you can get the antenna element into a sheltered, out of the wind indoor or sheltered area. You do not want wind to dissipate your heat. When soldering some coax connectors, you must clean off the outer plating, to get solder to wet well. The silver plated connectors, are easier to solder, and bring that advantage to their use, and are often sold in quantity for $1 each at ham fests here, (Silver plated and teflon high temperature center insulation.) Look up soldering as a key word in a search engine, and you will find many hints. Good Luck and 73, Stuart K5KVH +++++++++++++++++++ From: "Stuart Rohre" To: "Ed Juge/NM" , "Jason Hissong" , Subject: Re: [Elecraft] Verticals Date: Mon, 11 Feb 2002 13:34:02 -0600 Ed and the group, You have your experience with the vertical, and I had just the opposite. I always have a better signal with the Gap Titan, and no parts coming off, than my friend, whose R5 had bad traps and hardware fell off because of the poor design of the base mounting kept coming loose in wind. My Titan has been better than previous Hy Gain, and Butternut HF 6. Try getting much help from C. the maker of the R5! They finally did replace some traps on R7's that were faulty, but had the problems recur in later models. They have been less than forthcoming until the owner of the R7 used electronic lab equipment to demo to them they had a bad trap. I have had trouble with Hy Gain verticals durability, with Cushcraft, and with Butternut parts breaking. They had a run of bad ceramic capacitors at one time, and the head of the company confirmed that to our ham club. Things happen to any company. If it happens well out of the normal warranty, it is pretty hard for the company to get the capacitor manufacturer to not say the unit was exposed to too high winds, moisture or other mitigating factor. Hams think antennas should weather hurricanes, but most of them would be unaffordable if they were built to do that year in and year out. Most antenna problems come from hams not following directions to the letter, or doing poor soldering, or defying the laws of physics as applied to antennas. Verticals are NOT designed to work short skip, like TX to NM. Mine does sometimes and I am thrilled when it does. But, on the whole, any vertical worth its design is going to give you the lower angles of long skip, or DX skip. Any antenna will sometime work at angles other than its angle of maximum take off, and give propagation at some distance that is not its strong point. A dipole or doublet would work next state over better than a vertical. Check out the angles of take off and the resulting distances that are covered. NO SINGLE ANTENNA is optimum for all conditions of operation. I usually have a multi band wire antenna as well as any others. When I ordered my Gap, UPS mishandled it, and lost out half of the hardware. I filed a claim with UPS as required, and notified Gap, and they sent the missing hardware by return mail. All they asked was for copies of the claim forms to UPS. I later found out, that since it was summer, UPS used student workers, who did not know that UPS conveyor sorting is not for all their packages and longer boxes were to be hand sorted. Luckily I knew someone at UPS who followed up on the claim and found out what happened. UPS had retaped the package, and did not admit to a problem at time of initial delivery. When they came out and inspected the damaged package, they admitted it had been resealed and it was their fault. The antenna went together without tuning and met all specs. It is elevated six feet off the ground in the middle of the yard, and has worked so well on DX there, I never moved it to a higher pole. Yes, my neighbor who had a sixty foot tower heard louder signals than I do, but at optimum times of the propagation day, I work the same DX he does. You just listen, listen, listen, and bide your time, and it can be done. I have placed our club in the top ten in class at Field Day with nothing more than wire Zepps and giant horizontal loops up only 20 feet for the loops and 30 feet for the Zepps. With antennas, of simple wires, size matters greatly, and loops of 1.25 waves on 160m really have gain on the high bands. Same for the Double Zepps. Inverting Vee style, their modeled lobes seem to fill in, and give omni directional good Field Day coverage. We worked more stations with the Zepps or Loops than with a tribander beam on Field Day, over several years at the same site, with antennas situated the same. Capture areas dominate in that particular competition. Putting antennas too high, causes long skip to dominate their performance which is fine for DX contests, poor for working the midwest. It is pretty clear from the description of the badly soldered coax and connector that it kept the vertical from working properly, and the solder job is the key to many antenna successes. 73, Stuart K5KVH ++++++++++++++++++ From: "Stuart Rohre" To: "Jason Hissong" , Subject: Re: [Elecraft] RE: verticals........... Date: Mon, 11 Feb 2002 14:01:00 -0600 A vertical dipole system is ground independent and does not benefit from a counterpoise on your lot. See L. B. Cebik's excellent antennas site, where he investigated this. A dipole is a complete antenna unto itself. What is often overlooked, is are you in a flat area, or a bottom of a valley. The ground 5 waves out the Fresnel Zone can be of more importance to the propagation from your antenna than local earth, if using a ground independent antenna such as loops, beams and vertical dipoles. Not all verticals require a counterpoise or radials, only those quarter wave or less and base fed. 73, Stuart K5KVH +++++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: Subject: RE: [Elecraft] RE: verticals........... Date: Mon, 11 Feb 2002 13:06:32 -0800 Stuart, K5KVH wrote: > A vertical dipole system is ground independent and does not benefit from a > counterpoise on your lot. See L. B. Cebik's excellent antennas site, > where he investigated this. A dipole is a complete > antenna unto > itself. Right on! I would add that there are times when a transmitter using a 'ground independent' halfwave antenna still needs some sort of r-f ground. That is when the half wave antenna is fed at the end, or any antenna is fed at a voltage loop (high impedance point) with unbalanced feed. The antenna does NOT need an r-f ground, but the rig does! "Voltage fed" antennas got a bad reputation somewhere in the 60's or 70's for "putting r-f in the shack instead of in the antenna". That is nonsense. The problem is only that the antenna system does not keep the transmitter at a low impedance point so the transmitter itself must be equipped with an r-f ground. That can be simple ground rod if you are close to it, or a 1/4 wavelength long wire attached to the case. This is NOT part of the antenna; it is only a way to hold the transmitter at r-f ground. So the "quality" of such a ground only need be good enough that the rig doesn't appear "hot" with r-f as evidenced by getting "bit" with r-f when putting the microphone to your lips or seeing the SWR jump around when you touch the knobs, etc. Ron AC7AC K2 # 1289 +++++++++++++++