THE SPARK GAP A monthly publication of the Meridian Amateur Radio Club September 2004    Bible Verse Psalms 107:25-29 For he commanded, and raised the stormy wind, which lifted up the waves of the sea. They mounted up to heaven, they went down to the depths; their courage melted away in their evil plight; they reeled and staggered like drunken men, and were at their wits' end. Then they cried to the LORD in their trouble, and he delivered them from their distress; he made the storm be still, and the waves of the sea were hushed.     Emergency Frequencies With Hurricane Ivan bearing down upon us, here are a list of frequencies that will come in handy during the landfall for any and all emergency, or health and welfare traffic. The Red Cross Net will be located at 7.6985 upper side band. This frequency will be used for Red Cross officials only. The Red Cross Watch will be on 3862 starting Wednesday after the Mississippi Section Net. This is not a net, just a watch frequency that will be used at the top and bottom of each hour for the Red Cross Agencies. The West Gulf Coast Emergency Net is located at 3873 at night and 7285 during the day. The Alabama Net is located at 3965. If and when Ivan makes landfall, Skywarn will activate on 3862. Please remember to have your station in tip top shape. Have all batteries charged and ready to go if needed. Please let me know if I am not accurate on these frequencies, or if I need to add anything to this frequency list. Tim Ferguson, KC5IJP Pontotoc County EC W5FQ Repeater Update At the September business meeting it was voted upon to add a 100 Hz Tone. Please program your radios to allow access to W5FQ repeater. S E P T E M B E R - WX - S E P T E M B E R The weather is starting to change again and we are likely to experience an increase in thunderstorms. With that change also comes the likelihood of increased severe weather; even tornadoes. The following storm spotter tips are from the National Weather Service (NWS). + Most tornadoes in the southeastern part of the US move from southwest to northeast. The best viewing angles are southeast of the storm. It is important to report the direction of movement. If a tornado appears to be standing still it may be moving directly toward you. + The largest hail generally falls just preceding the tornado. Report the size of the largest hailstones. Use a ruler for reference and report using the scale below. 1/4 inch is pea size. 1/2 inch is marble size. 3/4 inch is dime size. 1 inch is quarter size. 1 3/4 inch is golf ball size. 2 3/4 inch is baseball size. + When reporting wind speeds or gusts, tell whether they are measured or estimated. The modified Beaufort Scale below will help you estimate speeds. 25 - 30 mph. Large branches moving; whistling heard in wires. 30 - 40 mph. Whole trees moving; inconvenience walking against the wind. 40 - 45 mph. Breaks twigs and small branches; impedes walking. 45 - 55 mph. Larger branches and weak limbs may break; slight structural damage occurs. 55 - 65 mph. Moderate structural and tree damage. 65 mph. Heavy to severe structural and tree damage. + Tornadoes and rainshafts can look alike. Look for rotation and upward motion. Also, look for other visual clues, such as the wall cloud, overshooting tops, storm rotation, etc. If you aren't certain of what you see, contact your NWS office. Spotters in the field might get another spotter to take a look to get a better overall idea of what is being observed. + Report accurately: a tornado is a violently rotating column of air in contact with the ground; a funnel cloud is a violently rotating column of air not reaching the ground. Be observant -- sometimes there is no visible connection between the cloud and the ground, but the tornado is causing debris to be blown about at the surface. A wall cloud is a lowering of the cloud base below the storm tower. Most of us do not have WX systems that give us wind speed or direction so the above info may be of great help to you when the local WX net cranks up. If you are new to the area check into the net. You will most likely spend most of the time just waiting and watching but we need all the spotters we can get. The more spread out we are the better. W5ED   M A I N T E N A N C E - T I P Fall is one of the best times of the year to work on your tower, antenna, feed lines, or control cables. You make inspections and repairs that should see you system through the winter. One of the most common problems that you can encounter with the wires, cables, and connections exposed to the weather being damaged by water intrusion. You may also find chaffing where something has rubbed on a cable or wire insulation damage that could cause a short or intermittent condition. Malfunctions with the W5FQ repeater recently were due to water getting into the barrel connector used between the coax hard-line and the antenna pigtail. The water caused corrosion and as the corrosion progressed the connection between the center receptacle in the barrel and the pin of the pigtail failed. This caused high VSWR problems and loss of ability to communicate. This malfunction could have been prevented if the connection had been properly protected. How is that done you ask? There are several ways you can protect your connections. The first is electrical tape. It is messy looking at best and as the bonding agent ages it often fails causing the tape to unravel. This can cause some serious trouble. When the sticky stuff deteriorates it also leaves a nasty, hard to clean up mess on the surface of the material it was covering. I do not recommend electrical tape for any use in the electronic field. It may be OK in electrical work so leave it there. The second method is the putty like self bonding material some of you may have used that is supposed to seal antenna and other connections. After installing it is supposed to set up and form a tough coating. It may have worked for some but others have just not seen its benefits. It is messy to use and if not applied uniformly to a clean surface it is worthless. The third method is caulk or silicone sealers that come in a tube. They are OK for some things but can make a real mess and are hard to remove. They are sort of like the putty above. The fourth and last method is the best. It is a tape that is easy to use and does a great job. The USAF uses this type material protect connections on its high speed jets and in a zillion other places. It was known as F - 4 tape. It is a soft silicon tape that only sticks to itself (self bonding). Once it molds to itself it is pretty much impervious to the elements and fuel. You can use the stuff and come back in years and find it just as you left it. Yet, with just a sharp knife you can easily cut through it. Almost like a knife through cool butter if you would. It came in two colors. The orange type had a green or black stripe down the middle. The black variety came with a stripe of green or orange down the middle. Please forgive me not knowing the color of the stripes. It has been fourteen years since I worked with the stuff and just can't remember. The orange was for use in hi-temp areas so it was used around jet engines. The black was the general purpose variety and was used everywhere. It also cost a little bit less. If you are not in the military you might have trouble getting the stuff they use; however, there is now a source available that us civilians can use. The Duluth Trading Company, 1-800-505-8888, www.DuluthTrading.com, 170 Countryside Drive, P.O. Box 409, Belleville, WI 53508 has a tape that is much like that used by the USAF except that it is black with a blue stripe. They call the stuff X-TREME TAPE; product #96825 and sells for $5.99 per 1" wide by 10' long roll. You can get three rolls for $14.97. Its rated good to 500 degrees F. and 8KV. It is sold as self bonding and it may be, but in the USAF we were required to tie the end wrap with lace cord. That insured that it did not unwrap under any circumstance. Dirty hands, sand, or other contaminants can cause the end not to bond properly so the tie can't hurt. It can be used anywhere you would have used the plastic or cloth electrical tape. Below are a couple of pictures. Hope this will help those of you that need this type of tape. You will note that there is a clear plastic layer between layers of the tape. This is to keep it from doing the self bonding thing. I purchased three rolls of the stuff and tried it out. It works just like its mil-spec cousin did so I can recommend it with out hesitation. If you have a question or comment about this tape you can contact me at w5ed@arrl.net. One last note. The mil-spec stuff had a shelf life and after a while it would lose its desire to stick to itself. I do not know about this stuff. I plan to keep mine in an air tight container which should cause it to retain its self bonding properties. W5ED       Have a great month    Last Month Next Month Back to The Spark Gap