The YS Main Screen
This screen contains the main menus. The safe wind speed for the elements and boom are displayed as along with the system of units (Imperial or Metric) that is active. Top and side views of the antenna are displayed to the correct scale. The highlited numbers and letters are the single keystrokes used to access each of the menu options. The check marks next to many of the options indicate that the particular feature has been installed on the antenna, or that the analyses are current.
Most antennas are not naturally balanced for forward/aft weight distribution. Antenna balance is achieved when the antennas Center of Gravity is located at the mast connection point. With YS, you can select a piece of material to place in the end of the boom, to balance the antenna. This piece is automatically adjusted, during your antenna design changes, to maintain the antenna's balance.
This antenna is not properly balanced. The front end of the antenna is heavier than the back end. This results in a 506 In-Lb moment on the antenna attach point to the mast. The antenna's Center of Gravity (C.G.) location is shown, along with the mast location to show you how they compare.
Using a Counterweight to Balance the Antenna
This shows a different antenna that has been balanced with a counterweight mounted at the forward end. You can see the variety of different sections and materials that you may select to use for your counterweight. You may be wondering why someone would want to use a counterweight on a yagi, when it would appear that simply moving the mast connection to the location of the C.G. would solve the problem and eliminate the need to figure out how to balance it with a counterweight. It is often far better to use a counterweight than to attach the mast at the C.G., which can cause terrible antenna torque imbalance and damage rotators. This can be seen in the examples below.
Antenna Area & Weight
This option displays the Antenna area and weight. Additionl options allow access to the detailed breakdown of the boom, elements, and antenna components.
The projected areas and weights for the elements, boom, and boom components (like the mast plate, coax, and balun) are shown. The total antenna weight is displayed, and the max. area and its azimuth are indicated. The first option "A" at the bottom toggles the areas between projected and effective areas. Options "E", "B", & "C" call up separate screens showing detailed information about each of the major antenna member groups. Option "U" toggles the display between small and large units of measurement (Feet & Inches or Meters & Millimeters). Option "P" prints the "Area/Weight" information displayed to the printer.
YS lets you select from several common alloys to use in your antenna. If you need to use a different alloy, you can chose the "user defined" option to define a new alloy with properties of your choice.
This option displays the boom details and allow you to change the entire boom configuration.
All of the details for the boom are displayed, including the stress in each section. Option "V" activates the YS antenna viewer where you can zoom in/out and pan around to see all the boom details. "E" activates the boom editor which allows you to access every section parameter to change it. You can Add or Remove sections. The "W" option sets the wind speed at a fixed value so you can design the boom for that value. Pressing F1 resets the automatic peak safe wind speed calculations. Select the "J"oints option from this screen to define the boom joints. "U" toggles the display between large and small units like the other screens. "T"ubing brings up a tubing database display for reference. "P" prints the displayed screen.
Here the type of connection between the boom sections can be defined.
The deflections option calculates the amount of boom sag (deflection) due to the gravitational forces on the antenna. It also calculates the guy tensions required to make the guy attachment points on the boom to be level with the boom to mast connection. You have the option to increase the segment density for this analysis to increase its accuracy.
You can add up-guys to your boom or element (if you made a single element model as a YS boom), to see how the guys lower the stress or improve the sag.
This option displays the safe speed for all elements and allows the user to select any element to examine the details and make changes. Here, using the cursor key, you can select an element for viewing its details. An element can be added to the antenna by copying another one or an element can be removed.
After selecting an element, the element details can be viewed and changed.
The element display shows all of the element section dimensions and the stress in each one. The location on the boom, element area, weight, sag, and safe wind speed are also displayed. Option "V" activates the YS viewer that provides for detailed viewing of the element, with zoom and pan capabilities. "E"dit is the way to access all of the section dimensions for changing them. "A"dd/"R"em is used to add or remove sections from the element. "M"ove is where you can change the element location on the boom. "W"ind allows you to set the wind speed at a fixed value to work on an an element design for that wind speed, F1 unlocks the wind speed and puts YS back into the normal mode of finding the max safe wind speed. The Ne"X"t function let's you access any of the other elements from this screen, without having to go back to the main screen. "N"ame is used to define or change the name of the element. The remaining functions are the same as described above. One important feature, is the resonant frequency displayed in the lower left corner. This is used to maintain the electrical design while improving the element strength.
This option is used to cover the antenna with Solid or Rime ice. If you live in this type of area, you'll need this feature to avoid aluminum loss! YS analyzes the antenna with the additional wind load and weight created by ice buildup.
A balun can be added to the antenna to evaluate the effects of its weight and exposed area on the antenna balance and torque.
The mast connection dialogue box is used to define how the antenna is connected to the mast.
Here, the mast/boom plate dimensions and the mast location are edited. The mast diameter and the clamp offsets are used by YS to determine antenna torque that is caused by this connection.
This is where you can find out what the antenna is going to do to your rotator!
YS calculates two antenna torque values. One is the torque caused by the placement of the mast on the boom and/or the placement of the balun and coax on the boom. The second torque value is caused by the offset from the center of the mast to the center of the boom, where the antenna is connected to the mast. All of the YS features that relate to antenna torque are available for modifying the antenna to correct the problem.
This is used to assign the antenna a unique name. This option will help you identify different models, and is displayed while selecting a model to load into YS.
This brings up a text editor that is used to append the antenna file with notes. You can add lots of comments and details to describe your models.
YS calculates the antenna turning radius. This is valuable for determining clearance for antennas stacked under guy wires.
This option is available for designers who want to include a Safety Factor in their designs.
YS can model a torque compensator! This is a plate attached to the boom that corrects the imbalances in antenna torque caused by asymetric placement of the mast connection, or the affects of the coax and balun on the symetry of the antenna.
YS comes with a database of standard tubing sizes available in the U.S. This database is available from several screens for reference.
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