BBS: SWEDX Conference: Ham_Tech Imported: 5/18/1993 To: ALL Num: 7243 Date: 5/14/1993 From: WAYNE SAROSI Re: Time: 10:14 pm SUBJECT: Field Day Antennas & Equipment. Part one This is an eight part series and will conclude in April so that anyone building these antennas or preparing for Field Day will have enough time. FIELD DAY OVERVIEW: There are many stories from field day events that new amateurs hear from rain, wind, and rotten luck to the day the team made the top 10% in the class. Field day is not a contest but it is hard to tell with some clubs or groups. For point chasers, total HF QRP CW will bring in the big points. Of course, excellent antennas are a must to make the QRP CW work in a sea of Amateurs. There so many combos of point gathering that it could make your head spin. One year I made a full size 40m 2ele beam and under poor conditions we racked up over 800 points on SSB alone at 100w. CW pulled in another 600 which was over 40% of our total score. We had the E.F.Hutton station on 40m. When our station talked everyone listened. BTW, it took two people to move the beam to a new bearing. :) Field Day is actually an event to see just how well amateurs can put together an emergency communications field station and make as many contacts as possible in a twenty-four hour period. Huricane Andrew taught us the value of Field Day here in Florida. So when you get out to participate in Field Day, think of what it would be like to have no commercial power, little or no water, food, cover, and help. It's just you and your ham friends providing the only local communications link to the rest of the USA. When disaster happens know one knows the date in advance. So keep these designs and ideas and prepare now. Keep them in a kit that you can grab in a moments notice. When disaster strikes, you're ready! As for the Field Day event, all you'll have to do is show up with your kit. ========================================= NOTE: All of the following in this series is based on no commercial power or facilities. If these are available to you, treat them as a plus. ========================================= EQUIPMENT Transceivers o 2m (144-148){All mode & FM} [Mobiles, HTs] o PACKET with laptop & software o Simplex operation o HTs for local comm at the site o Satellite work o HF (80/75m, 40m, 20m, 15m, 10m) [DC powered rigs] *CB mobiles for the real McCoy-Not everyone is a ham when disaster happens. o Hi VHF and UHF for SAT work or simplex Receivers o Scanners for local emergency reception o AM/FM Commercial band (540-1610 kHz,88-108 MHz) o DC powered Television. Gen HF o Tuners o SWR bridge Power o Batteries - deep cycle 12vdc (trolling motor type or the type used in golf carts) o Solar Cells for recharging batteries o Small generators ( don't forget the fuel ) o Battery chargers to operator off the generators o Power supplies to operate off the generators o Wind generators (pray for a good wind which usually comes with the rain) o Large generator (if possible) Supports o Crank-up towers o Push-up masts o Sling shot and/or bow and arrow, fishing line (There maybe a tree or pole handy) o Tower sections (Like Rohn 20/25) Coax (stick with coax for this event unless you have a clear shot to the rig) o Jumpers o RF runs (that actually reach the antenna without moving the rig. Misc o Safety Belt o Rain coat o First Aid kit o Water o Packaged, ready-to-eat food o Gum o A hat and bandana (sun and sweat) or prepare for cold weather for the real McCoy. o Toilet paper (sometimes lots of it because no one else remembers) o Pencil, notebook, and a calculator(solar powered, when does a battery go bad?) o Extention cords o Soldering iron and solder o Toolbag with the right tools this time :) o Extra connectors (PL259 males, bullets, barrels, elbows, BNCs etc, etc.) o Mosquito repellent (SLAP!! "Oh!, sorry Bob." A must!) o Asprin or equal (For the five a.m. headache) o Imodium D for the green-apple two step from too much coffee by 10 a.m. Sunday o Coffee (I forgot) and accompanying equipment. o Plop plop fizz fizz if you have a headache and upset stomach from the rain, wind, and rotten propagation, not to mention the two day old pizza you're still nawing on. uhhhhhh. "Field Day, Field Day from ... from ... What the hell is the call we're using this year? And someone check Bob. He hasn't made a contact since I slapped that mosquito on his forehead!" Quick set-up modifications for antennas. One of biggest problems during an emergency or field day operations is the assembly and tuning of an antenna. Granted, a whip does not require much in the line of tuning or assembly, however a yagi would. As I recommended before, use antennas that are prepared prior to an emergency or a field day and for emergency use; the simpler the better. Things to keep in mind are that stations outside the emergency area are running at full potential with large directional antennas and full power. Trying to match them while operating in a mud & debris enviroment, out of the back of a car, may be a large undertaking and not practical under the situation. You may have walk in serveral miles carrying 80-lbs of equipment and supplies to reach the emergency site. As for field day, it's much easier. Preps can be made months in advance and it's this one factor that can make or break a field day. Lets look at the Yagi, Cubical Quad, Inverted Vee, and Wire Dipole. These antennas seem to appear at most field days stations I've been to and I've been to several. Keep in mind that a sloper will have similar solutions, which is another antenna I've seen at field day sites. YAGI: (3 Element mono band, HF, armstrong rotor, gamma match) {Use the Cushcraft as a model} Assemble at home per directions. Assemble coax to be used at field day and be sure to provide enough (ie 70-100 ft). Test the coax via a dummy load with 100 watts of power CW. Check the SWR and loss at the desired band for the coax. When complete, save for antenna testing. Place the assembled antenna on a mast or tower for tuning. This height should be the height the antenna is to be used at during field day. I would recommend here that, if possible, test the antenna at the site with the support that is to be used during field day. Adjust the element lengths and gamma match, with the coax tested before, until all the 'kinks' are worked out. The SWR should be less than 1.5:1 across the band area you desire to operate in. Remove the antenna intact and mark the joint fittings of the tapered elements. Mark the dogbone on both the DE and the gamma match element. Disassemble the antenna and store in a PVC 4-in pipe with caps or a wooden box or canvas bag. Coil the coax and cap the PL-259s. Disassemble the mast or tower. Bag the hardware and attach to the support. When Field day or an emergency comes up, you are ready with premarked and pretested equipment. I have done this for six years and have found that it saves a bunch of grief. Use the coax you tested, not some hoser's botch job. And do you own assembly. If it fails, there is no one but you to blame. This concept can take a 2000 point total to a 4000 point level if done right. In an emergency situation, it's the difference between a poor signal and a clear signal. Make it so the tuner is not required. ============================================================ Cubical Quads: (Mono band, armstrong rotor, etc) This antenna can be a real hoser if not constructed correctly the first time. Preps on this antenna are a must. Spreaders must be checked and elements also. There is nothing worse than getting to the field day site and having difficulty with a Cubical quad. A strong antenna but a real pain in the butt raising and lowering to adjust, especially in the rain. Like a box kite, this antenna does lend itself to the wind. Whether you use the D/DE or DE/R configuration, it makes no difference. This is a homebrew antenna for the most part. There is very little in the commercial source market for these antennas. So, get your sh** together early if you want to use a Cubical quad on field day. Assemble per your design and test per the yagi directions. Cumbersome as it is, this must be done. Mark all connection points and if possible, use expanding spreaders and wire clamps on the ends. IF you use a tuning arm, be sure it's protected in the correct position and can be easily re-adjusted if required. A cubical quad can fold down into a very neat package, but that will take some forethought on your part. ============================================================== Inverted Vees: (fixed, mast support or improvise) An Inverted Vee *may* tune fine at home and then be out to lunch at the Field day site. Using the tuning extentions I posted for Inverted Vees will solve any problems relating to this. Why this happens is that at home the IVee is interacting with Guy wires or other wire antennas or something in the imediate area of the antenna. At my home, the roof flashing does not require a tuner when used as an antenna on 40m. I found this out by accident. Thus, my 40m inverted vee was very difficult to tune. So was a 15m yagi I had once. Solution: I grounded the roof flashing. Select a clear open area to cut, assemble and test the antenna. Once this is accomplished, the IVee should work just fine. Hints: Raise and lower the antenna using a rope and pulley. You can attach a rope & pulley to the mast prior to raising and securing the support. Use rope as guys rather than cable. A wheel & tire from a car make an excellent mast base when combined with a clamp & flange assembly. This appeared in QST I believe about a couple of years ago. Any good mast base will work and I have used plywood and a hinged base support many times. If you can, use a 1:1 BALUN. Hook ups are easier and so is raising. ================================================================= Wire Dipoles: (fixed, mast or rope support) Pretty much like the Inverted Vee, prepare ahead. Similar problems may happen so test in an open area. At the site, determine where the antenna needs to face and then pick out the best supports. If using masts, set up similar to a large volley ball net (very large). The farther apart the supports, the more the rope will sag if no center support is used. On 10m and 15m this is not too much of a problem. By the time you get to 40m and below, the sagging is a big problem. I will suggest the wire dipole be supported in the middle and the ends held out with rope. Set up similar to the Inverted Vee. Use a 1:1 BALUN. ================================================================== Setup at a site can be easy or a nightmare. I'm sure even a simple wire dipole has had it's day in the sun beating the amateurs 14 to 0. Scope out your site first and note structures, cover, water, toilets, etc. Take a friend and make extensive notes. Draw a layout of the site and if possible, measure the distances where you plan to put your antennas and equipment. Here's an example: This site is at a park by a river. 1X tree 1[pavillion] 1T picnic table [toilets] 2X tree 3X tree 4X tree 2[pavillion] 5X tree 6X tree 2T picnic table <- North ========================================================== ========================================================== river Location state: New York Looking at this site it can be seen that most of the contacts are going to be west and south although some contacts will be east and north. Your geographic location plays a big factor in you antenna placement. This same site in Central Florida will have a different lay-out. And the same site in Washington State will be different again. Look at the setup and make some notes on how you would setup the following antennas and equipment: 10m two element yagi 15m two element yagi 20m aluminum dipole 40m Inverted Vee 80m Wire dipole SAT setup PACKET setup Generators (2) Food area Public greeting area You have three push-up masts and each coax is 70 feet for HF and 30 feet for VHF/SAT. The distance between the pavillions is 75 feet. Here's another site: 1X tree [building] W water tower L street light 2X tree [building] 3X tree North ---> Location: Kansas Use the same antennas as above except 40m is a wire dipole. 2X and 3X are 120 feet apart. Rotor use on field day: Somehow, rotors have been deemed off-limits in some unsaid word by amateurs during field day operations. This is nothing more than pure BS. If you have a beam antenna then get that rotor under the beam and use it, especially if you are running 'A' for field day. If you believe an amp or two draw on a generator for 30 secs is going to ruin your power source, well ... what can I say. Even in an emergency condition, it is not necessary to run a wire antenna and have a car battery as a source of power every time. But ... and a big but here, in an emergency, that may be all you have. Rotors work and they work well. Pre-preps include quick disconnects on control cables, lubrication of the bearings, U-bolt de-corrosion and lubrication, pre-testing as a MUST before using a rotor on field day or in emergency use. Rotors can be stored in storage boxes made of wood or old luggage. SOME NOTES: o Do not over rate your rotor. - Light duty means light duty. Don't stack a 10m and 20m beam on a rotor built for a TV antenna. o Do tin the wires before attaching them to rotor and/or controller. - Frayed wires are shorts waiting to happen. o Do not attach the control wires with the control box powered. o Do disconnect via the QD connector when lightning storms are in the area. - Power down the rotor and use the QD. It's the one item we seem to forget in a lightning storm. Kits: (Weather boxes for rigs) Keeping in mind the kit boxes of a previous posting, a box can be made to house your rig, P/S, tuner, and speaker. For example, an old machinary crate box can be used for this purpose. The box should be about 2' X 1.5' ant the top and at least 1.5' deep with a lid. The box can be cleaned out, sanded, and stained or for that rustic look, Placing handles on the sides makes for an easy lift. The lid can be hinged and a clasp placed on the front for locking. Feed through RF connectors can be installed on the back side for antenna attachment. A fan or pair of fans on eith side can be added for cooling. External power connectors round off the field day / emergency kit. The radio kit could look something like this: _________________________________________________________ | | | | | SPEAKER PAIR VHF rig | | | | | | |<--Fan | | Flow | MIC HOLDER | | | | HF Rig | | | | FAN SWITCH | |_______________________________________________________| leg leg Screw on legs can be added to the box if a table is not available. Also the lid can be removed and legs attached for a seat. More times than not we end up running our field day operations from places that are not quite the greatest locations for antennas. With this in mind the field day team must plan ahead by using the good ole push-up mast. They are easy to tote to the site and set- up. Another item is the Rohn tower section. Mounted to a piece of plywood with a mounting plate and guy lines to support the tower sections. A three section tower is easy to assemble and tilt up with just a few amateurs. Add a mast and an antenna and up it goes. Looking at the emergency aspect of operation, a tower maybe a bit tough to cart into a disaster area where the push-up mast would prove a better choice. The mast can be secured at the bottom using a spare tire and clamp/flange. Guying the mast is a must. The mast can be stored in a 4-in PVC pipe with screw on caps as discussed earlier. Handles can be attached for ease of carry. Another concept is the crank-up tower mounted to the bumper of a pick-up or van. The tower is slid back to the half way point and then tilted up. A step ladder allows the attachment of an antenna or used for tuning. Also this set-up allows the amateurs to attach the antenna before the tower is raised when using a whip, wire antenna, or aluminum dipole antenna. ********************************************************* * Origin: Ham_Tech Moderator - KB4YLY/AFA2GN (Quick 1:374/73.2)