++++++++++++++++++ From: jeff.h.burns at delphiauto.com To: elecraft at mailman.qth.net Date: Fri, 15 Mar 2002 10:25:42 -0500 Subject: [Elecraft] Antennas for Field Day I am planning new antennas for Field Day and could use some advice on w= hat configuration will give the best-cost performance ratio. Last year my club was 4A with stations for 20, 40 SSB and 20, 40 CW. My= K2 was used for 20 CW only because the QRO rig was not there in time. The K2 d= id well so I hope to use it this year. I am located in central Indiana. The field day site is the local fair g= round. There are two rows of wood light polls running north and south. They ar= e spaced conveniently to string up dipoles that point east and west. These poles= are about 30 ft tall. The club has used dipoles for several years. I am looking for a simple antenna system that will be an improvement ov= er the dipoles. Twenty-meter performance is a must, but a multi-band solution = would be nice. Option 1 ? Two Dipoles The simplest option I can think of is to just add a second dipole at a = right angle to the first. Because of the spacing of the supports the second d= ipole will be in an inverted-V configuration. With the K2 dual antenna ports = it will be easy to switch between the two. The tuner will make multi-band opera= tion possible. Option 2 ? Manually turned wire beam A beam like the one described by VE7CA in the November QST would work w= ell at our site. Cebik describes a 3-Band Hybrid Maxon-Yagi on his web side th= at could be used in the same manner. Ether of these antennas would be inexpensiv= e and provide significant gain. My main concern is the need to manually point= them. How does this work out in practice? It seams that valuble time can be w= asted moving the antenna. Option 3 ? Two beam antennas With two beams antennas, like the ones above, one can be mounted pointi= ng east and the other one pointing west. With the K2 antenna switch east/west d= irection changes would be instant, but the antennas could not be pointed north o= r south. Is it better to have the quick choice in two directions, or the slow ch= oice of all directions provided by option two? Any thoughts or comments are appreciated. ----------------------------------------------------------------- Jeff Burns AD9T +++++++++++++++++ Date: Fri, 15 Mar 2002 09:49:02 -0600 From: "George, W5YR" To: jeff.h.burns at delphiauto.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] Antennas for Field Day Jeff, I use your Option 1 here with two 88 ft 20-meter Extended Double Zepps at right angles each fed with ladderline. With the same feedline lengths, the tuning remains the same for either. This antenna gives 3 dB gain on 20 meters and works great on 40 as well. I don't know if you keep up with the QRO-L Fox Hunts, but these antennas have been real "Fox Gitters" for a couple of years now. My Field Day experiences over many years have shown that the simpler the antenna, more time is devoted to operating instead of turning beams, putting up beams, repairing beams, and general fiddling around with antennas. Put em up and forget em! 73/72/oo, George W5YR - the Yellow Rose of Texas Fairview, TX 30 mi NE of Dallas in Collin county EM13qe Amateur Radio W5YR, in the 56th year and it just keeps getting better! QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735 Icom IC-756PRO #02121 Kachina 505 DSP #91900556 Icom IC-765 #02437 ++++++++++++++++++ Date: Fri, 15 Mar 2002 10:54:57 -0500 To: jeff.h.burns at delphiauto.com, elecraft at mailman.qth.net From: Hank Kohl K8DD Subject: Re: [Elecraft] Antennas for Field Day Horizontal antenna - Option 1 - Double Extended Zepp on 20M .... In an Inverted Vee configuration so it is not too directional. Or two of them - 1 east west and one north south, although from MI we rarely turn the TA-33 away from SouthWest! Make them as close to duplicate as possible so you can switch the balanced feedline from one to the other without retuning ..... or have two tuners. Option 2 - a ZL-beam. 2 elements and a phasing line of 300 ohm line between the two elements. If you slope it, you can run out and move the lower end of it to change direction. Or put up a couple of them! Vertical antenna - 1/2 wave vertical End fed - with a few radials - don't need many. or Center fed with coax. 73 Hank K8DD +++++++++++++++++ Date: Fri, 15 Mar 2002 08:51:52 -0800 From: Tree N6TR To: elecraft at mailman.qth.net, jeff.h.burns at delphiauto.com Subject: Re: [Elecraft] Antennas for Field Day > I am planning new antennas for Field Day and could use some advice on what > configuration will give the best-cost performance ratio. I think you should carefully look at full wave loop antennas - that are "squished". These are very effective antennas that fall into the easy to erect and low cost category. For a full web page of information, http://www.cebik.com/scv1.html. I built one for 80 meters that was about 45 feet high on the sides - fed in the middle of one side and it was a very effective antenna. They are great antennas for the higher bands as well - and their bidirectional pattern is perfect for those in the middle of the country. 73 Tree N6TR tree at kkn.ne +++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: , Subject: RE: [Elecraft] Antennas for Field Day Date: Fri, 15 Mar 2002 09:08:55 -0800 > I am planning new antennas for Field Day and could use some advice on what > configuration will give the best-cost performance ratio.... > Jeff Burns > AD9T At 30 feet up, the 20 meter dipole is showing about 10 dB of directivity. That is, signal off the 'ends' is about 10 dB below the main lobe off of the sides. "Crossed dipoles" on that band might be an advantage. You can do away with the pattern altogether by using something vertically polarized, but that would reduce your signal in all directions by 6 dB - the 'ground reflection' gain you are enjoying by having a horizontal antenna up at 30 feet on 14 MHz. I'd stay horizontal at that height and keep the gain. On 40 and 80 the situation is a lot different. At 30 feet up, the horizontal is no better than a vertical at elevations of 20 to 30 degrees above the horizon. You are too low to get any advantage from the ground reflection except virtually straight up. The near-vertical radiation will help with close in contacts (out to a few hundred miles), but won't be much help beyond that. On 40 and 80, I'd take a hard look at something vertically polarized - probably a loop to avoid the issues of radials, counterpoises, etc., - and possibly something that is somewhat directional such as a phased array. A lot of that depends upon how many bands you want to cover. Arrays can get tricky as you try to hop from band to band. It's not just a matter of being able to 'load up' but also what happens to their patterns as you change bands. Field day is about the only contest that I've been very active with. In the club efforts I have seen, there is always a lively discussion between going for 'high gain and high directivity' to kill QRM and 'reach out' and going for low directivity that doesn't require twiddling with the beam all the time. Personally, I like something that is not too directive. Ron AC7AC +++++++++++++++++ Date: Fri, 15 Mar 2002 11:48:37 -0800 (PST) From: Jessie Oberreuter To: Elecraft mail list , "Ron D' Eau Claire" Cc: "James A. Doty" Subject: RE: [Elecraft] Antennas for Field Day Ron wrote: > Field day is about the only contest that I've been very active with. We used to only do Field Day as well, but after having a lot of success on 2m and 6m at last year's, I talked the gang into trying a VHF contest. They'd tried once before, and failed miserably, but they were willing to try again, so we tried the Sept. contest. We didn't make a huge number of contacts, but we more than demonstrated that the contest was a lot of fun and there were plenty of contacts to be made. We added 220 fm and 440 fm/cw/ssb to the list for the January contest and actually made more contacts than we did last field day! We haven't decided what we are going to do for the June contest, but we're planning on running a convoy in a loop through OR, ID, and WA in Sept. I bring this up especially in light of the recent "crazy idea" posts. It doesn't take much to have fun at these contests. We were running 12w on 6m (MFJ) into an M2 loop, 20w on 2m (706) into a 3 element quad, 25w on 220 (ancient Kenwood mobile) into a mag-mount, and 5w on 440 (DX-70 and junk box transverter) into a vertical. It's also pretty easy to start simple and progressively improve. Location is the #1 factor, then bands, then antennas, then power. You could honestly have a lot of fun w/ 10w on 2 and 6 cw/ssb, and 5w fm HT's for 220 and 440. My first 220 contact was over 30 miles to a 5w HT on its rubber resistor. -- Jessie Oberreuter joberreu at moselle.com "He's a bit on edge, Mr. Johnston -- he hasn't slept since 1945." +++++++++++++++ From: "Stuart Rohre" To: , , Subject: Re: [Elecraft] Antennas for Field Day Date: Fri, 15 Mar 2002 14:22:07 -0600 The best all around Field Day antenna our club has found after some years of research, is not a dipole at all, but giant, greater than one wave around horizontal loop set on a hill and only 20 feet high. It models with both lower angle modes and high angles, just what you need for in state and cross country work on Field Day. We started with 1.25 waves on 160M and last year used 849 foot circumference. We have used east west rectangular and NSEW Square. Square was the best at the larger size of course. Next best were IDEZ antennas, Inverted Double Extended Zepps. Up 30 feet to 40 feet. For bi directional, we have used low 10 waves at 10m horizontal VEE beams. But, they were too long to keep up easily in storms. Need to drain static on any large wires, 150k ohms from each side of balanced feedline to ground. Three of them would pretty much cover the compass, since they were bi directional. 73, Stuart K5KVH +++++++++++++++++ From: K4IA at aol.com Date: Fri, 15 Mar 2002 18:41:16 EST Subject: Re: [Elecraft] Antennas for Field Day To: jeff.h.burns at delphiauto.com Cc: elecraft at mailman.qth.net Jeff Check out the top fed inverted L. It has a nice omni-directional pattern that will serve you well and get the benefit of both a horizontal and vertical antenna. You can feed it with ladder line to be multi band or cut one for each band. I use one that is 52 feet on a leg and 60 feet high. It works well on 160-10 meters. I modeled one for single band use on 40 and it looks great. Our club may try it this year. Cebik has an article at http://www.cebik.com/gup25.html and http://www.cebik.com/ltv.html. Your 30 foot poles would support one for 40 meters if you bend the end a bit. Probably won't hurt it at all. Radio K4IA Craig "Buck" Fredericksburg, Virginia USA QRP ARCI #2550 FISTS #6702 CC 788 Diamond #64 K1 #470 K2 #2460 ++++++++++++++++ Date: Mon, 25 Mar 2002 20:04:44 -0600 From: "Stuart Rohre" To: "Karl F. Larsen" Cc: Subject: [123204] Antennas for Field Days Well Karl, it is probably not a good thing to over generalize! Field Day up until June 2002, was primarily a North American contest. What covers that well, (6th place last year in class-W5KA) was a 849 foot around loop 20 feet up, and running 5 watts SSB, yes SSB. Now, beams are good for DX, and will be useful for FD to South America, a new participant this year. But, horizontal vee beams 10 waves long at 10M also make a huge signal stateside, if low enough, ie not over 15 feet high! Otherwise they skipped out over USA coast on first bounce! Great DX antenna at 25 feet! Inverted Double Extended Zepps, (5/8 wave leg inverted vee dipoles up 30 feet) are good all band antennas for Field Day high scores. They, and the others were all fed with window line to conventional Tee net transmatches. For Field Day, you have to be careful to have some antennas that do not skip out too far, and miss many sections. The giant 1.25 wave or larger horizontal loops for 80M or 160M will give you great powerful signals on higher bands at a combination of low and higher take off angles making possible the working of nearby towns, states as well as both coasts from a central location. Yes, a beam on east coast for Field Day might make sense, but not if you are in the middle of the country; you get more general results with antennas such as the above tailored for the places your signal must reach on Field Day. And they do not require as large a crew for assembly and no tune up, except to make a quick cheat sheet of transmatch settings. The big advantage of big loops is you can put them up one leg at a time, and then pigtail the legs together and to the feed line at a corner by the use of Wire Nuts! We use wire nuts for the Zepps feeders attachment as well, making short work of raising antennas by having all wire on reels to be rolled out in place then raised. 72, Stuart K5KVH also 45 years of Field Days +++++++++++++++++++ Date: Mon, 25 Mar 2002 20:15:11 -0600 From: "George, W5YR" To: rohre at arlut.utexas.edu Cc: Low Power Amateur Radio Discussion Subject: [123205] Re: Antennas for Field Days Back many years ago, the Richardson Wireless Klub - K5RWK - departed from tradition by putting up an array of four vertical all-band antennas fed by a phasing controller that Electrospace Systems had just put into production. The system was designed by Dick Fenwick. It worked fine when and IF you could find the desired station and point the array at him. It was altogether too sharp for FD use and for the first time in years we really got snockered. First and last time for directional arrays other than rotatable yagis for 20-10 and even there the directivity cost points on average. Stuart has the right idea: broad azimuthal coverage with mostly high vertical angle capability and some low-angle coverage. A modest signal "everywhere" earns more points overall than a super signal in just a few places. 73/72/oo, George W5YR - the Yellow Rose of Texas ++++++++++++++++++ Date: Mon, 25 Mar 2002 18:34:23 -0800 (PST) From: Jeff To: qrp qrp Subject: [123211] Re: Antennas for Field Days --- "George, W5YR" wrote: > Stuart has the right idea: broad azimuthal coverage > with mostly high > vertical angle capability and some low-angle > coverage. A modest signal > "everywhere" earns more points overall than a super > signal in just a few places. Looks like the 88 and 44 foot doublets would be a good choice for Field Day. They both have nice wide broadside lobes on 10 through 20 meters that would be great for hearing and working stations coming from the various directions. Jeff ===== AB6MB NorCal QRP Club #65, QRP-L #1780, ARCI 10071 Radical FIST Member 6798 +++++++++++++++++++ Date: Mon, 25 Mar 2002 21:52:09 -0500 From: "ss lyon" To: , "Low Power Amateur Radio Discussion" Subject: [123212] Re: Antennas for Field Days An antenna that has served 'wonder fully' for us at W1QI / W1QK Field Days is a 600' loop up 60'. It has placed us in the top ten QRP for a few years, and beats everything else we put up in terms of reach, except in the preferred direction of the much more directional 44' "Lazy H". If we were restricted to only one antenna, it would be the loop, absolutely. Doc seems to be suffering along with his ok, too. I'll have one up as soon as it gets safe to climb trees around our new QTH. 72 AA1MY Seabury & Sharon Lyon 99 Sparrowhawk Mtn Rd Bethel ME, 04217 U.S.A. 207-836-2576 +++++++++++++++++++ Date: Mon, 25 Mar 2002 22:40:08 -0500 From: "ss lyon" To: "Bob W7AVK" , "chat qrp" Subject: [123217] 600' Field Day Loop... The loop is four sided, (put up by sling shot) and suspended by pulleys all around. The reason for that is that we thought we could steer the lobes to advantage. That does indeed happen on the hi freqs, but not to huge advantage. We do seem to get some benefit on 40m and lower freq. by rotating it back and forth between corner fed and center fed on a side. That means having a gofer out there running back and forth pulling on the ladder line, and that gets old fast... no matter how much libation is supplied. The pulleys will stay, tho, as it allows for stress distribution all around the loop as the trees move in the wind. It works like a champ on 160m, but that's not a good time of year for it since every thunderstorm in the hemisphere is heard. 72 AA1MY ++++++++++++++++++++ Date: Tue, 26 Mar 2002 01:45:00 -0500 From: Pete Burbank To: qrp-l at lehigh.edu Subject: [123226] Re. field day antennas The best one I remember was a few years ago. A friend and I bought a mile of aluminum electric fence wire and bright and early on FD headed out to is his father in laws farm. We picked a nice shady tree on the top of a hill and ran five 1000 foot wires to five points of our compass out to other trees...it was a real workout. We fed 2 legs at a time with an SPC transmatch clipping on to the wires hanging down from our shade tree. It was a dynamite antenna! During the night we were hearing so many DX signals, many from over the North Pole that we thought about dropping out of FD and doing some serious DXing but we persisted in FD and racked up a tremendous score.Of course, being slovenly and not into wallpaper we never turned in the log. At the same location we had 2 phased 14AVQ verticals with lots of radials but there was no comparison. Whoever on here who said lots of wire up high has got it right! 73 Pete NV4V +++++++++++++++++++++++ Date: Tue, 26 Mar 2002 09:18:47 -0500 From: "ss lyon" To: , "Low Power Amateur Radio Discussion" Subject: [123239] Re: F.D. Loop: Getting it up... Well, we've been doing it for several years now so the process is really slick. Two or three guys/gals make it go very smoothly. We have the Red PVC coated #14 all wound up on a large spool, with heavy duty lugs on each end. Similarly, the lines with pulleys are all rolled up and laid out at each tree. * We first sling shot pull lines over the tops of the four support trees, * then pull the 3/8" support lines over and tie on the pulleys. * Thread the wire thru the pulleys, starting where the feed point insulator will be. * Attach the wire lugs to the feed point insulator, with the feed line. * Hoist the whole thing up, making adjustments to clear obstacles. ( an additional "tag line" over the wire will help pull the wire clear branches, etc.) * Secure the support lines.... and I do mean SECURE! * Tune 'er up and Rock 'n Roll! Try pulling the configuration from corner feed to center or off-center feed when you get some time to play with it. I'd like to hear what you find. 72 AA1MY Seabury & Sharon Lyon 99 Sparrowhawk Mtn Rd Bethel ME, 04217 U.S.A. 207-836-2576 +++++++++++++++++++ Date: Tue, 26 Mar 2002 08:48:35 -0700 From: "Walter AG5P" To: Subject: [123250] Re: coax as an antenna element re velocity factor Hi Dave and all, wow, it is refreshing to read your posting on the variations of lengths from the standard formulas. My findings are very close, for horizontal loops under 30 feet usually 984/fMHz gets within inches of resonance. With a tuner and twin-wire feed it is not an issue. With coax and No tuner and a 75 ohm 1/4 w.coax attached directly to the swr bridge and rig then maybe take off 1 to 2 inches from the wire loop. For horizontal loops over 30 feet, it seems that 995/fMHz is best and it gives the same 1 to 2 inches still need to be trimmed for resonance. Guess it needs saying that these measurements are used in conjunction with non-metallic supports, ie, pvc pipe or trees. Another thing that has proven the horizontal loop for a 'keeper' antenna is make it for one band lower than your normal operating use. That is if you work 40 and up, then put up an 80 meter horiz. loop. Sure they are real estate intensive, but at field day or operating portable there is normally space to put up a loop. One last note, using insulated wire, put another loop under your 'in the air' loop which is about 3% longer than the transmitting loop. Just lay it out on the ground, directly under your transmitting loop.You have to use a tuner with your loop because the counterpoise loop will detune it but oh my, what a difference a little wire makes. 72 / 73 Walter, AG5P +++++++++++++++++++ Date: Tue, 26 Mar 2002 13:21:26 -0500 From: "ss lyon" To: , "Low Power Amateur Radio Discussion" Subject: [123263] Re: FD Ants: Kites/wind problems... I got lots of inquiries on kites / antennas. For the one I use most regularly, check out the Scott Sled kite featured on the NJQRP web site. I modified the original design for the NJQRP Home Brewer mag. article, to accommodate a standard 9' roll of TYVEK. Don't fly it with less than 200lb line, and ALWAYS WEAR LEATHER WORK GLOVES -if you want to maintain a full compliment of digits. Lift is in excess of 30 lb even in light breezes and that's plenty to hoist the 250' 160 dipole and ladderline NE2Q and I used in the QST article. Wind at 16 -18 mph can challenge your ability to stay on the ground. Don't try to fly it much above that. Follow precautions provided on the NJQRP site. I do own several commercial kites and have used a big parafoil successfully, but the one that will do the job costs $100 or more. The HB Sled costs about $25 to make and it can be decorated to your liking. Keep two or three ready to go. 72 AA1MY +++++++++++++++++++ Date: Tue, 26 Mar 2002 21:20:37 +0000 From: Larry Cahoon To: fantbb at yahoo.com, "Low Power Amateur Radio Discussion" Subject: [123271] Re: Antennas for Field Days Message-ID: <5.1.0.14.0.20020326211923.00b89e28 at pop.erols.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed At 06:34 PM 3/25/2002 -0800, Jeff wrote: >Looks like the 88 and 44 foot doublets would be a good >choice for Field Day. They both have nice wide >broadside lobes on 10 through 20 meters that would be >great for hearing and working stations coming from the >various directions. That is what I used last year. Set them up perpendicular to each other, worked great. 73 de Larry..........WD3P in MD http://www.qsl.net/wd3p/ ++++++++++++++++ Date: Wed, 27 Mar 2002 08:04:19 -0500 From: Bill Coleman To: , "Low Power Amateur Radio Discussion" Subject: [123312] Re: Dipoles, Windoms, Loops, oh my! On 3/7/02 9:03 AM, Jason Hissong at jhisson1 at columbus.rr.com wrote: >The candidates are a Carolina Windom 40 (yea, the one the >broke the record), the Super Loop 40, or building a Skyloop. Question is, >which is better? What's a Super Loop 40? What's a Skyloop? (Perhaps you're thinking of a Loop Skywire?) > I have heard that the Superloop (or loops in general) are >less noisy than dipoles. That's true for certain types of noise. You'll get less precipitation static on a loop over a dipole or monopole. > I have also heard that the Windom does great as a >DX antenna. Comments? Windom, Dipole, Horizontal loop. Frankly, once you have them matched, you'll notice little, if any difference between a Windom or a Dipole at the same height and roughly the same dimensions. Horizontal loops have different patterns than dipoles, especially above 1/2 wavelength over ground. Low Horizontal loops make good NVIS antennas. Not so great for DX. The single most important dimension for any of these antennas is the height above ground in wavelengths. That dimension defines the pattern and the elevation response of the antenna. > I cannot put a tower up (not because of CCR's, my >town is very nice about towers, but because of $$$$$). Cost me less than $600 to put up my modest 44 foot, house bracketed tower. I already owned the A3S that sits on top of it, on 5.5 feet of mast. A beam will make a bigger difference than any single-element wire antenna you could put up. >Will I notice any >difference between the dipole I have now, and one of the antennas mentioned >above? I have about 70' between two trees to play with and about 55' >between a mast that I installed (about 6 feet) and one of the trees. The >antenna will be installed about 40 feet. The DXLB+ is a trapped dipole. Height will make more difference in horizontal, single-element antennas than any other single dimension. I've favored dipoles over horizontal loops since I figured out that a dipole only needs two supports, but a horizontal loop needs at least three, more likely four supports. Another antenna to consider is a delta loop installed vertically. Makes a good DX antenna to the broad side, particularly if you feed it part way up one leg (eg not at the bottom or top), so it is vertically polarised. (LB Cebik had a 5-part series in the National Contest Journal about short vertically polarised antennas, and the vertical loops were one of the favorites) Bill Coleman, AA4LR, PP-ASEL Mail: aa4lr at arrl.net Quote: "Not within a thousand years will man ever fly!" -- Wilbur Wright, 1901 ++++++++++++++++ Date: Wed, 27 Mar 2002 22:46:09 -0500 From: "DIANNE M WISE" To: "Low Power Amateur Radio Discussion" Subject: [123365] FD Antenna Ideas/ Kite, Balloon The Jayhawk Amateur Radio Society of Kansas City Kansas tried using a helium weather/carnival balloon to hold a long vertical wire aloft for Field Day a few years ago. We used a balloon that was about four feet in diameter and suspended a 160 meter half wave wire from it. We used a separate tether for the balloon. The idea worked wonderfully until a breeze started up in the afternoon. The balloon generated static electricity and started causing curiously large arcs across the internal parts of the antenna tuner. The antenna wire was tied about six feet under the balloon, directly to the nylon tether cord. We probably should have separated it by using a long, ribbed antenna insulator. Roy KE0UQ/8 +++++++++++++++++++ Date: Wed, 27 Mar 2002 21:54:38 -0600 From: "David H. Hatch - N9ZRT" To: "Low Power Amateur Radio Discussion" Subject: [123366] Re: FD Antenna Ideas/ Kite, Balloon Dianne wrote... The balloon generated static electricity and started causing curiously large arcs across the internal parts of the antenna tuner. Dave replies... With our kites, we use a "Static Bleeder Gadget", sometimes two at once. Read about it here... http://www.wireservices.com/n9zrt/live-wire/events/marconi/staticbleed.html See one here... http://www.wireservices.com/n9zrt/live-wire/events/marconi/bleeder.JPG Dave David H. Hatch - N9ZRT, "Zesty Red Tomatoes" http://www.wireservices.com/n9zrt/kite.html http://www.wireservices.com/n9zrt oslc at netnet.net - Green Bay, Wisconsin ++++++++++++++ Date: Thu, 28 Mar 2002 01:19:30 -0500 From: Pete Burbank To: "Low Power Amateur Radio Discussion" Subject: [123370] Re: FD Antenna Ideas/ Kite, Balloon FWIW I was reading the Fair Radio catalog today and they list a box kite and the wire. Pete NV4V 73 ++++++++++++++++++ Date: Thu, 28 Mar 2002 07:44:07 -0500 From: "AI2Q Alex" To: "QRP-L (E-mail)" Cc: Subject: [123375] RE: FD Antenna Ideas/ Kite, Balloon Hi Roy, and group: I know I've described this here before. Abt fifteen years ago we encountered the same HV arcing when using a Gibson Girl balloon inflated with helium, carrying an end-fed wire. This was during QRP F.D. at N2RI with ops KQ2G, KA2CAQ, and me. Anyway, we simply put a 2.5-mHy pi-wound RF choke from the feedpoint to ground, and that was that---no more sparks and jolts. Prior to the choke, we were drawing 1/2-in. to 1-in. sparks (yoiks). Balloon lofted antennas seem more prone to generating really high static charges, perhaps more so than those held aloft by kites. Anyone care to conjecture if this might this be due to their shape? Vy 73, AI2Q, Alex in Kennebunk, Maine QRP-L 687 .-.-. ++++++++++++++++++ Date: Thu, 28 Mar 2002 09:58:41 -0500 From: "ss lyon" To: , "chat qrp" Subject: [123384] STATIC: Kite vs Balloon You're correct... a balloon does generate more charge, generally. Has to do with the nature of the balloon material, (usually latex, mylar, poly...) surface area, (usually huge compared to a kite) and the fact that air molecules roaring over the surface rip electrons loose from the balloon material atoms, leaving a reservoir of positive charge on the balloon. That gets transferred thru the charge field around the balloon and/or bled thru the high resistance tether material, to the wire. The rf choke or resistor "bleeder" to ground disposes of all that without effecting the signal. Don't us a spark gap type arrestor. We didn't have a bleeder at Atlanticon two years ago and got up close and personal with charges from an approaching storm miles away on the 40m c.f. vertical hung from the Scott Sled. REALLY scary and only a person in serious denial or absolutely clueless will ignore safety in this regard. 72 AA1MY ++++++++++++++++ Date: Thu, 28 Mar 2002 10:47:21 -0500 From: Jake Brodsky To: "Low Power Amateur Radio Discussion" Subject: [123389] Re: STATIC: Kite vs Balloon I will second those remarks and add that wire insulation may also play a part. =20 Tony, N3JLI, and I once flew such an antenna suspended by kite. We were mostly interested in reception and we were trying to keep the weight down, so we used wire wrapping wire with kynar insulation. =20 We were flying it from his boat on the Chesapeake Bay. It was a bright sunny day, with no storms anywhere near us. The static charge on that wire was almost deadly. Tony touched it by accident and he jumped across the deck of his boat. We learned this lesson the hard way.=20 Don't repeat this mistake. It isn't worth it. 73, Jake Brodsky, mailto:frussle at erols.com "Nearly fifty percent of all graduates came from=20 the bottom half of the class." +++++++++++++++ Date: Fri, 29 Mar 2002 20:22:05 GMT From: jakidz at pullman.com To: "Fancher, Mark (GEAE)" , "'jakidz at pullman.com'" , Subject: [123522] RE: 20m W7EL Field Day Special dimensions? Mark: > Here is the FDSP program written by W7EL. If it doesn't come through, you can > download it from his site. Thanks. The attachment was stripped off but I found the program on his site at . The dimensions for his home 20m version are in the program data file "20_home.fd". 40 and 80m files are also there. > Please let me know how it turns out. Looks like I'm going to need some more RS twinlead first. John, KD7OIU ++++++++++++++++++++ Date: Fri, 29 Mar 2002 17:33:49 -0600 From: "Stuart Rohre" To: Cc: Subject: [123534] balloon lofted antennas and static build up The higher you raise a wire, the higher the voltage gradient to earth. Static is also induced by wind action over the wire. Large (long element) high antennas then, suffer static buildup both from wind action, and altitude, and of course if nearby storms approach the field gradient is raised even more. They are very dangerous antennas to your rigs, unless you provide a resistive or RF choke bleeder for the wire. Remember also, in Field Day, the objective is mainly to work the Continental states and Canada, and US possessions. This year South America and Central America are included for first time, but TOO high an antenna can skip right over the coastal locations of so many hams in the East Coast or West Coast corridors. 73, Stuart K5KVH ++++++++++++++++++++ Date: Tue, 25 Jun 2002 20:01:59 -0500 From: "Stuart Rohre" To: Cc: Subject: [128555] Re: So tell me about the field day antennas? Message-ID: <015001c21cad$132e8150$4e100a0a at rohredt2000> Hi Alan, W5KA, went 5A battery, this year; after studying entry classes and scores re our possible ability to mount an effort. Got 5000 points so far, and expect to find some more scratch paper logged QSOs not transferred to formal log page! We tried to teach everyone to log things neatly, immediately, but some do not because they are used to own methods. Well we put up the same 849 foot around loop 20 foot high on 20m as last year. In packing it, however, someone must have swapped a couple of legs labels, for we had too much wire in last leg! To avoid cutting it we loosely dressed it over tree limbs and made that side pooch out bigger, like the side of a box that is swelled out. This was a quad loop, as you may remember. One guy had one of those poles with hook on end for running network cables and it really helped get wires over trees etc. Gotta make one of pvc and put coat hanger on end, folded double in inverted U shape so you can hook over a wire and pull it down to grab it. Use TV mast for feed corner on SW,and 450 ohm line to tent. As you may remember the NW corner is on a coaching stand on a mast, the NE corner is on wood lamp pole, as is SE corner. Feed corner is on push up pole, and 450 ohm line fed. The wire over tree was enameled and no effect since we had dry wx. My flip over A frame or extension Aluminum ladder that is light is essential to hanging these loops up 20 feet and two guys did the 849 foot loop with one helper part way thru. One guy was W5LUQ, Mike who gave us the loop idea, and the other main man is from last year, too, Jim Rudd W5SIO, 80 plus years young! He ran 20 CW with a 1943 bug he used to fly with in a DC 3 over Europe in WW2! Rig on 20m was Ten Tec Scout at 5w, with Dentron Super Tuner. Jim put rig on top of tuner sideways with speaker forward to better hear it, and when I went to SSB, I did not unplug his bug. It was on back with coiled cord, (inductive). I used coiled cord hand mike, (inductive) and ALC locked up meaning I had RF feedback. Well, I caught the bug cable right off but still had funny TR and ALC, and I finally realized that the radio atop the tuner had magnetic coupling to the tuner's big coil! Took the rig to side of Dentron and all OK, and turned down the mike gain to only 2 notches, rather than half way up, which also overdrives the radio. Lesson learned, watch out for magnetic coupling of radio and tuner if both are non steel cased. Watch out for coiled cords, their shield can become an inductor. We had perfect wx btw, so not even wind static developed on big wires. Loop worked great again, cleaning up when 20 opened up at night, Sat. Sat. afternoon had disappointing signals as we had D layer summer absorption, but we were still working anyone we called. The noise level kept folks from hearing other stations well, until sun set, then the band was several layers deep in signals. Again we observed definitely two major take off angle lobes of the loop in any direction. That meant we could hear many stations with good signals, especially if they were short skip, on one of their MINOR lobes. Thus, they might not come back to our first call. If you persisted you could work them. But, we usually tuned on for easier pickings. I tried to CQ once, but finding a clear spot was hard, so it was just easier and more efficient to hunt and pounce in the first few hours with so many strong signals. We worked folks on one call, and got many more unsolicited reports of "Nice strong signal". One NEngland station when asked, said we were very Q5 and S8. I also had several times, a call to a CQ station and when I turned it over, a third station would call me for my loud signal! Worked double that way! We used the Scout on 20m, at 5 watts, SSB. Also took a listen later to 160m but no hams on there down here. Besides the two lobe effect of hearing better and more sigs, we also saw it in hearing both short skip like El Paso Tx, 500 plus miles and longer skip on 20m SSB at same time! The long skip would be Cuba, or Central America, or Maritime province of Canada. Worked TI and Cuba among other DX. Worked every ham in PR I think! The North field loop was used on 10m and 80m. The idea was to work 10m Sat. daytime, and keep checking 80m for any activity in day, but then use 80 if it opened at night. Indeed, no one is on 80m FD here in afternoon, contrary to practice of 20 plus years ago! We had never had enough stations to check that, but this year with five, we could. We put that 849 foot loop on South 50 yards and end zone of football practice field at Anderson Hi. Then, we put on North 50 yards plus, a delta horizontal loop roughly 600 plus feet around, again 20 feet up. At 50 yard line there is a coaching stand, and we radiator hose clamped masts to upper legs of this stand to raise loops above it. On other corners, we tied off with nylon line to upright of goal post on NE and went west to tie nylon line in a tree. Corner of loop out from tree to clear canopy. Went N to S then with final leg back to coaches stand to feed point. Used 300 ohm slotted line for this one. About 111 feet of feeder used to the 10/80 station. Rig for 10m was first my Atlas 110, but it does not do 10m with full 5 watts, so switched Sun. Am to Kenwood TS 120 set to 5 watts SSB, much better. 10 was mostly closed Sat. daytime. Worked the few that were there. Later Sat. I put up a trap dipole tri band type Mosley on 10 foot pole. You could not hear ANY signals on it, when it was up on hill, and down on field loop we were getting maybe a dozen signals. Later it had some signals Sun. and was used on 15 m SSB with good result. Used a B&W transmatch of the 300 watt low profile type with built in SWR meter. Coax fed the dipole without balun and no problems. Fed the ladderline to built in balun for loop tuning. The 80m band yielded a few contacts early Sat. evening, and then on Sun. AM low in phone band. The next station was at west end of complex, whereas the first two were East end of hill above field. The west station set up outside a Tennis Ct. backboard, under shelter half tarp. They had another large loop, about 385 feet around. This one fed on NE corner,and was delta pointing West, with a NS leg, other legs angled about equally to west. Again on poles fastened to fence of tennis courts (high fence), with hose clamps and slip up masts to 20 plus feet. On west corner, pole was on basketball goal. Worked 40m with a Kenwood TS 140. SSB of course, as we were short several CW folks out of town. Sat. afternoon, 40 was working mostly around TX, but then the band lengthened out, as expected, and the second low angle of the loop looking clear shot across a parking lot came to play. They worked until the sun started setting on them, heating up the tuner by projecting under their tarp. Another lesson learned, a black transmatch will heat up in the sun and detune! They had trouble getting out, and I retuned them from SWR 1.5 to 1 to 1:1 and QSO rate picked up. They could have used a DSP, but we forgot to tell the ops there it was over at the VHF tent! The DSP Timewave model has a carrier notch that is awesome on 40m at night to clear out around shortwave BC so you can work hams in between the BC stations.. However, at night that loop attenuates the European BC stations compared to the Double Zepps. We got so tired putting up five plus antennas plus tower and VHF beams and a triband beam, that I only put one Zepp, on tower at 25 feet. It went east and west for use of either the 15 M band station who ran either phone or PSK 31, and RTTY for ARRL bulletin, or we used it for the GOTA station who worked 80m, 40m and 20m SSB, and maybe some on 15m. The Zepp was tuned with a Johnson Match box balanced tuner. The beam is good match across each band and coax fed. We had Ringo for 6m, and worked a few on it. We had beams for 2m traffic link, also 440 and other VHF and packet. Set up two packet stations, one a portable node but only worked about four packet contacts. 2m and 440 was disappointing as well, and no serious effort made on SSB 2m. Man and woman power was the cause. We did get 10 messages and sent the SCM message for bonus points. Got ALL bonuses available save GOTA, since they did not do 400 QSOs, and the guy to do Satellite did not show up, due to business trip late return. We had 300 points for 3 bonus modes, ATV on a model car, APRS, and portable packet node in a transit case. We found PSK 31 to again be a waste in Sat. daytime, on 15m, with only 11 contacts. After midnite, another op came with PSK 31 and did 33 contacts all nite. The PSK stations were in tent alongside the GOTA, and each got into the others receiver. PSK especially tore up nearby HF stations, with its high duty cycle on time. They ended up alternating getting on the air. We had about 4 GOTA operators, maybe 5. They did no where near 400 contacts needed for bonus. 40 and 20 were workhorse bands, with 15 behind, and 10 a shadow of past 6 years. 80 was used for first time for a few contacts. 160m had only BC harmonics and AC line noise harmonics. The Zepp worked good, as always, and the triband 3 element beam was underutilized. They had a rope to rotate it, but left it pointed North until midnite, when I pointed it west to decouple it from the Zepp. The tri bander had been left behind last year for it was weaker receiver than the Zepp. But, this Spring we found it had a bad balun at the Beta Match to coax point, and replaced the core balun with a coax coil balun and it worked great. The rotary dipole did not get a good check out on 10m due to poor band condition, as I said it did not have any signals when the band was bad. But, that proves capture area is good, as the big 600 foot loop did have sigs. Well, with CO-QRP out of the 4A running we should have dropped to 4A, maybe, as we only had 4 overnite. The only time we were fully manned was I think Sat. at start and Sun. at end. In the night, some bands would close for awhile and the lone operator would move to another tent and try there. One guy went from 80m, 10m to 40m, and back and then 15m. I stayed on 20m all nite. A TV station with a morning show WX man who does remotes, showed up at 6AM with microwave truck, and from 7 to 9 did 6 interviews with hams. We got lots of good exposure on this station, and I was surprised how many channel surfers at my work have told me they caught it. We even got some visitors before 1 PM due to the TV remote! That was a first for us, usually they come by for 5 minutes or so, and we get 30 seconds on 10 o'clock news. This was set up not by our PR guy, but by a ham that worked at the TV station. Well, we will see where we end up in 5A battery. Surely heard a lot of 5A stations this field day! 72, Stuart K5KVH +++++++++++++++++