Increase Your Odds in Model RetrievalBy:
Much has been voiced and written about easier and faster ways to find your model. Most involve using an electronic retrieval system: transmitter in the model, receiver and Yagi antenna that operate as an optimum matched system. Most ideas that complement this system can help or give you insight into other ideas. Retrieval falls into two categories: short and long.
A) Short retrieval
This scenario is where you see your model DT and you have a fairly accurate visual line on it. You are on your chase bike, moving toward that point on the horizon where you saw the model touch down. You're relaxed and feel good because you maxed and you think you know where your model is located. You throttle back a bit and euphoria begins to settle in. You are going to float right up to the model, pick it up and motor right on back to the flight line. Right? Wrong! Why so? Most of the time, your model is not where you think it is. If it lands in crops or foliage you may not spot it, even from a few feet away. Unless you can actually see your model, stop your bike well before you reach the general area where you believe your model is located. Break out your receiver and point the antenna at the model's theoretical location on the horizon. You will get a signal that becomes louder and stronger as you approach the model.
Begin operating your system before you arrive on the scene. It will save you time and energy, as this is the way the system was intended to be used.
(B) Long retrieval
This scenario is when your model did not DT, it is in a boomer or, for any other reason, is still in the air but is passing out of sight (OOS). You are moving along on your bike, looking at your model, which is on its way off the field. Or, you may have already lost sight of it. At this point, stop your bike. Quickly assemble your receiver/antenna and point the antenna to the point where you last saw the model. You should pick up a loud signal. Don't get on your bike and attempt to follow the signal. With fences, crossroads, traffic, woods and other obstacles likely ahead of you, it's better to stay put and continue to track the signal. Listen to the beep and note the elapsed time. Even after 10 or 20 minutes the signal should remain strong and you will hear a steady beep. Take a compass reading along the main shaft of the antenna at the point when you hear the loudest beep. This reading will become your search line.
Keep an accurate line on the signal with your antenna. If the signal suddenly stops, you'll feel your heart did too, and you'll suspect the transmitter quit working. Not likely. What has happened is you model has descended to the ground and is beyond the ground range of the transmitter. If your transmitter has a ground range of three miles and 30 miles line of sight (LOS), the model is likely 3-8 miles away. However, if you continue to get a strong, consistent signal for a long time—say, 45 minutes-1 hour, your model is down, but high in a tree or on top of a hill or building. This signal is coming to you LOS and will continue. The model is likely 3-15 miles away Remember! Continue to take compass readings along the main shaft of the antenna. Another situation: You continue to get a signal that slowly fades in and out. That indicates the model is still in the air, is circling and is drifting away. If the signal stops after perhaps 45 minutes, the model is down, some 25 miles out. But if the signal keeps on until finally fading away, the model is probably 30 or more miles away. Keep the antenna locked on the signal, without making side swings. To fine tune your search line it is important to confirm the compass heading.
It is vital to accumulate county maps of every flying site you visit. County maps of the area help determine your best driving route since they show all roads (even dirt and gravel). Draw a line on the map from your location and along the compass heading (your search line). Return to the flight line and head out in your vehicle. Zigzag through the countryside to remain near your search line. Stop at intervals on the line and listen for a signal as you slowly sweep your antenna along the line. Use your judgment where to search, depending on which of the above scenarios best fits your situation. The long retrieval is your toughest test. Bring out your "true grit" and never give up!
Here is a great retrieval tool used by Bob Johannes (St. Charles, MO) and some others: A Magellan GPS Model 315 navigational aid (available at Wal-Mart for about $150). The unit will display the search line once you enter three factors: (1) Landmark 1 (point of origin—where you are standing); (2) compass heading; and (3) Landmark 2 (the maximum distance the model is likely to have traveled (i.e., 20 miles). Magellan's screen will display the search line and where you are as you traverse the line. Johannes checks for the signal each time he crosses or nears the search line. He knows how far he is from the point of origin and his arbitrary Landmark 2 location. He can reset the search line if he thinks the model is further out. This easy-to-use navigational tool can save you a lot of time and effort in your search.
Raise your sights.
Increasing the range of your receiver involves overcoming the influence of the earth's curvature.
You can rent a plane, which maximizes your LOS range but is not always practical. Moreover, it is expensive. Or you can rent a
"cherry picker" and have someone drive it while you stand high in the bucket. But this may not be for you.
Here is a simple,
inexpensive and practical solution that will give you an advantage. A rule-of-thumb formula tells you how much you must increase
the elevation of your receiver antenna to gain more LOS range. Ancient mariners used the crow's nest to spot a buoy, enemy ship
or land, from a greater distance than possible if they were merely standing on the deck. The simplified algebraic formula for
determining the effect of earth curvature is: Each foot you elevate your antenna will increase ground range about 1/4
mile. Example: If your signal is 3 miles when you hold your directional antenna 4 ft above the ground, you can double the range
to 6 miles by elevating the antenna to 16 ft above the ground. Here's an easy way to do it
You can make a sectioned pole from aluminum shower rods and wooden dowel joiners. Use duct tape to hold the rig in place. Devise a bracket to secure your antenna to the upper end, positioning the elements horizontally when you hold the pole upright. It would be good if you could somehow pivot the mounting bracket so the elements can position vertically. Remember: You get maximum signal when elements of the directional antenna and the transmitter antenna are in the same plane. You will need a 12-ft coaxial cable with BNC connectors (Radio Shack RG-58). Connect one end of the cable to the antenna and the other end to the receiver. Hold the pole upright with one end on the ground and the antenna above. Hang the receiver around your neck and use an earphone or headset, as you want to hear even the faintest signal. Slowly sweep the antenna by rotating the pole back and forth, just as if you were holding the antenna directly.
Caution: Do not use this setup near power lines! Static will interfere with the signal and high voltage could put you at risk.
Retrieving from a cornfield doesn't need to be as tough as you may think. Keep a few basics in mind: Corn is usually planted in rows 30-in. apart (a small percent age is in 20-in. rows). It grows vertically. This means if your model lands in a cornfield, it will likely be in a nose-down attitude. Hold your antenna with the elements vertical. You'll get a stronger signal and you'll also be able to walk between the rows with less effort. [The editor finds retrieving in corn to be somewhat more strenuous than a stroll in the park. For one, a long-sleeved shirt is always appreciated, as corn becomes increasingly abrasive and nettlesome to your arms as it matures. Needless to say, take water along on your retrieval. Also, never begin a search into any surroundings like crops or woods without establishing prior means of regular contact with someone back at the flight line, via cell phone or two-way radio. Keep in mind that most of us are no longer spring chickens.]
Final advice. Check your batteries. Check your system. Always have your receiver and antenna with you. Never give up!
This article was originally published in the February 2002 issue of the Free Flight Digest is and being republished here with the permission of the NFFS and author. Any questions or comments should be directed to the author. For information on the NFFS and how to join, click here.
More information on the Walston Retrieval System is available from their web site. You may contact Jim Walston by email.