Fast Light Digital modem application FLDigi is a free and open-source program which allows an ordinary computer's sound card to be used as a simple two-way data modem.
You should also load FLMsg. T-Hunting aka Fox Hunting has a long amateur radio history. Hunt participants use radio direction finding techniques to locate one or more radio transmitters hidden in a designated search area.
There is an active local ham community that participates in T-Hunting. First class radio telephone license First transmitter hunt about Retired Pacific Bell communication engineer. Registered Professional Engineer with the state of California. Amateur radio operator KN6FW.
Upgraded to extra when the code requirement went to 5 wpm. Hobby: Designing and using radio direction finding equipment. Do you have a computer in your shack storing your valuable logs and carefully configured software? The internet can be a dangerous place. Computer security is the protection of computer systems and the data stored on them. This presentation will introduce good computer security practices and how to incorporate them into your everyday routine. Computer Security in the Shack.
RTL-SDRs are ultra cheap software defined radios that runs on most platforms with a wealth of free software. If you have one bring it in with a laptop to try some software. The instructors are encouraging their students to optionally become licensed hams, so they can test what they build in class. She'll describe what it took to get and keep these "Mega-Sessions" going.
All the participants are delighted to be helping in Science, Technology, Engineering, and Math STEM education, in addition to furthering the amateur radio hobby.
Organizining a Mega VE Session. We flew another HAB - Photos. We will have a presentation on the Moxon Rectangle antenna. It's a great Saturday antenna project, especially for new hams seeking their first gain antenna. The Moxon is especially attractive to hams who want to avoid purchasing more expensive towers and rotators and who desire a directional antenna.
For their size, Moxons are high performance antennas that lend themselves well to the spirit of experimentation and easily be scaled for any band, HF to UHF. DXers thrill at a contact with an exotic and distant location like Heard Island or Turkmenistan, but you can hardly get more distant and exotic than the moon.When you subscribe, you receive only messages for the product you have subscribed to.
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Toggle navigation. Forgot Password. Reviews Home. I There are three ways to view the far field antenna pattern upon creating a model and running it. This enables rotating through user specified slices around degrees and pulling detailed gain data as a function of angle and azimuth angle. In this view one can show the antenna, and, its full 3D, color coded in terms of dBi gain, visual view. This view enables detailed 3D analysis of antenna pattern, in the context of the antenna placement, for understanding peaks, nulls, and all aspects of complex far field propagation.
I used this view to understand my 80m OCF on 40m, 20m, 17m, 12m, and 10m. Very complex patterns appear at all bands c 3D wire view that is selectable on the antenna view that shows as default.
You have to select View, then, select far field pattern. A 3D wire view sliced at the angle decrement specified in the simulation setup shows. IF you toggle over to the 2D view, then, rotate through the 2D view, a colored traced on the slice of the 2D view follows the 3D view.
This enables the designer to specify, say, for an OCF, both of the lengths of the segments as variables. In complex antenna models, the variable name can be re-used in multiple locations.
Then, if that variable length for example needs changing, it can be changed in one place in the model much like a software program.The large maple tree in the backyard served as a good support for a vertical wire, which I could only throw high enough to be resonant at about 4.
Ground radials were out of the question, so a counterpoise was installed along the property line and fence. The wire was sensitive to wind, often becoming wrapped in leafy branches and driving the SWR crazy. It worked better than the 40m dipole on 80m and 20m, but was never wonderful, particularly on receive.
The vertical was very sensitive to noise, but not much else. It was clear that there had to be a better way, and then I modelled the vertical on the computer and saw the problem.
The pattern that was produced sent the power everywhere except in the direction needed, and probably warmed up plenty of earthworms as well. It served me for a log full of DX contacts and contests despite the poor performance, but it was time to try modeling something better. Computer modeling provides some advantages. The design was based on trap coils of high-Q with inductance chosen to produce 80m sections that would fit in the available space.
The middle section was simply a 40m dipole, which was expected to provide little improvement over my old dipole. Insulators were made from sections of PVC pipe, with holes drilled in the ends to secure the wires. An important consideration in the design was multi-band use.
Even with a tuner, SWR losses from using coax would prohibit the use of m, and reduce performance on the higher frequencies. Using ohm twin-lead would raise the resonant SWR to aboutbut provided much wider bandwidth, and the SWR on all bands could be handled by the tuner. The penalty was completely offset by the advantages, particularly when loss calculations showed dramatic losses with even the best coax when the antenna was operated off-resonance with high SWR at the feed point. Using balanced feedline meant that each side of the dipole had to be kept symmetrical to avoid feedline radiation.
Space constrictions prevented the 80m extensions from being longer than 3m. By adding capacity hats on the ends, less inductance was required in the trap coils, with better current distribution in the shortened wires.
There is more than one combination of inductance and capacitance that will resonate, but only one inductance value will work with a specific wire length — in this case, 3 meters end-loaded.
With satisfactory gain patterns and SWR graphs plotted on the computer, it was time to start cutting wire and building traps. The trap coils needed to be 15uH, which were constructed by winding 13 turns of insulated 12 household copper wire around an 85mm cylinder, secured with duct tape. The trap capacitors had to be homebrew as well. The value of 33pF would have to withstand some high voltages at some frequencies, so I decided to try using lengths of scrap 75 ohm coax as capacitors.
Once connected to the coils, this turned out to be a good choice that easily facilitated tuning the traps. It might even be possible to use the same piece of coax for the coil and capacitor, with greater difficulty tuning it to resonance, and less flexibility balancing the coil inductance with the wire length. However, variations in coax capacitance between different kinds might yield a combination that works, and could be used where the luxury of changing the outer dipole wire length can assist tuning such a system to resonance.
That was easy to fix, at the expense of scale accuracy, but coupling an oscilloscope and frequency counter handily displayed the resonant frequency of the traps.
It was amazing how the signal started jumping out of the flat line on the scope as the GDO approached trap resonance. Trimming the coax bit by bit reduced the capacitance and allowed resonance to be set perfectly at 7. The excess coax was coiled and taped, and the trap was attached to the outside of a 20cm piece of PVC conduit. All the required wire was unrolled and measured using chalk marks on the driveway.Manual Ref. Among them are modelcontrolsystemuser defined and card functions. Additionally, NC provides a set of extended functions that are not directly translated into NEC cards.
These include terminations, coax and twin lead models, insulated wire models, etc. A model function is the shortest way in NC to describe antenna geometries and define environmental parameters such as frequency and grounds. The simplest NC program consists of a single model function.
When the Run button in the NC window is clicked, cocoaNEC compiles the contents of the model function into an internal representation called a directed acyclic graph where each DAG node is a Cocoa object. If no errors are found, cocoaNEC then interprets "execute" the graph "code" from the model function once to generate an NEC-2 card deck file. If a control function is present, cocoaNEC will not directly execute the code from the model function after the compilation phase.
Instead, cocoaNEC compiles the model and control functions, and proceed to execute the code that is created by the control function instead of the model function. Code in the model function is executed when the model function is explicitly execute by the use of a runModel function call from the control function.
By including more than one runModel function call in the control function or a runModel inside a repeat loop inside the control functionthe model function can be run multiple times, each time with a different set of global parameters. This is a mechanism to automatically "optimize" an antenna.
Both the model and control functions can call system and user defined functions. Indeed, if you have a control function, you can generate a card deck by calling user defined functions instead of using runModel. The rest of this section describes the NC system calls. For information on user defined functions, see here. There is also a set of functions that can directly generate a NEC-2 card, see here. As mentioned above, extensions can be found here.
Geometry Functions wire x0, y0, z0, x1, y1, z1, radius, segments generates a wire element from coordinate x0, y0, z0 to x1, y1, z1. With wire radius and number of segments. The result is a reference of type "element. NC will generate a wire made up of segment lengths that matches the two ends and follows a geometric progression note: not arithmetic progression. If there is an excitation, load or network card on the wire, a segment for the excitation etc will be placed at the middle segment of the wire.
In addition to the geometry functions above that use scalar numbers to specify coordinates, you can describe wire geometries using vector variables see Vectors and Transforms. These are please note that their names end with a "v" : wirev t, v0, v1, radius, segments linev t, v0, v1, radius, segments taperedWirev t, v0, v1, radius, segmentLength0, segmentLength1 v0 and v1 are vectors that represent coordinates in 3-space.
In addition to the vectors v0 and v1the vector functions include a transform variable t. The transformation represented by the transform variable t is applied to v0 and v1 before the results are used to generate the actual coordinates for the wires. This allows you to rotate or move the wire element by just modifying the transform variable t. The other variables in the vector version of the geometry functions are the same as their counterparts in the scalar versions of the functions.
The keyword nil can be used in place of the transform variable for the case where a transformation is not used. In this context, nil is equivalent to using identityTransform. You can think of this as analogous to "in-line assembly language.
The arcRadiusstartAngleendAngle and wireRadius are real valued variables and the segments argument is an integer. The transformation arguments are as defined in the wireCard function above.
The angles are in degrees, and the orientation of the arc and the angles are referenced as in the NEC-2 documentation. The plane of the arc can be rotated and the arc can be translated per the last 6 arguments.Mine is a staple of my Field Day excursions. Works great, but the gel cell is kinda heavy and bulky. So, in a moment of boredom I had the itch to build something, I guessI ordered the KBT1 internal battery option and installed it.
Hardy seemed to recognized the adapter just fine out of the box, and even detected my wireless network, but I was never able to connect to anything over the web using my browser. My suspicion is that WPA encryption is still not supported for my adapter using the native drivers.
Being an occasional backpacker, I use topographic maps both for planning hikes and camping trips, and for navigating on the trail. My map of choice, just like practically everyone else, is the 7. I think I ended up ordering it from someplace, and it came in the mail rolled up in a cardboard tube. I think I just about wet my pants when I first unrolled it.
It was soooo cool! I decided to give the Ubuntu 8. I figured that I could simply follow the instructions that I wrote for doing so with Gutsy Gibbonbut alas, there was no joy. When I tried to manually configure the network settings, I found that I could not select the wireless network settings to modify them. Perhaps this will be fixed before it goes final, or someone else will solve this problem….
In the mean time, my experiment with the Hardy Heron beta has ended. I made the switch a few months ago. I made the switch more for philosophical reasons than anything.
I was having a big problem envisioning myself running Windows Vista in the future. Vista contains nothing that I find compels me to want to upgrade, and seems to have been created mainly as a vehicle to generate sales for Microsoft. Was I running an operating system or a marketing tool? So I decided to make the switch to Ubuntu. Here is the 4Nec2 input file for my shortened antenna model :.
Short vertical NEC input file. Note that I make no claims that this is a super antenna. It works. It appears to suit my needs, given the constraints under which I designed it. This is good—and cool.This is a 3 rd party book and is not connected to Arie in any way.
If you find mistakes in this book, they are all mine. The sample version of the book is complete but the full version is in progress. As chapters or appendices are completed, they will be released as updates. The full version of the book starts with chapter 4 that covers the different 4NEC2 editors. Other chapters will include using the optimizer and matching tools, using gnuplot for high resolution graphs, using ItsHF and VOACAP with the remaining chapters on design and analysis of various kinds of antennas such as verticals, multi-element, loops, satellite, and a grab bag of antennas the author finds interesting.
There is a Groups. IO mailing list dedicated to this book. Both menus and their options matches what is shown in the program. Program specific text IE: menu text and screen output, etc will look like this Program Specific Text a fixed monospaced font. Just about all computers of recent vintage can run 4NEC2 without issues. Obviously the more memory and CPU speed you have the faster the analysis will go and the more complex of an antenna that can be analyzed. Mark Schoonover has been licensed since when he got his Novice license on a wager with his dad.
Upon his return from Navy active duty in he got his Advanced license. Around he got his Extra. He enjoys homebrewing and contesting from his pip-squeak station in southern California. Professionally, he has a degree in Computer Science and Software Engineering.
He switched from Electrical Engineering when the internet became publicly available. Downloading and installing 4NEC2 will be covered in this chapter. Installation is straight forward and the default settings will be used throughout this book for all screen captures. The author is using Windows 8 64bit for this book. Screens in other operating systems may look slightly different but otherwise 4NEC2 will function identically.Moxon Antenna. RCHacker #49
This book will cover version 5. There are several different files available to download.The original nec2c is a non-interactive command-line application that reads standard NEC2 input files and produces an output file with data requested by "commands" in the input file. In contrast xnec2c is a GUI interactive application that in its current form reads NEC2 input files but presents output data in graphical form, e.
These results are only calculated and drawn on user demand via menu items or buttons, e. Printing of results to an output file has been removed starting from version 1.
If printing to file is needed then it is better to use the original NEC2 program, to avoid bugs that may still be lurking in the C translation. Xnec2c now has a built-in editor for NEC2 input files which can be used to edit geometry or command "card" data.
This basic editor displays comment, geometry and command cards in tree views where individual rows, each representing a card, can have their cells edited directly for "raw" entry of data.
More useful are pop-up "editor" windows that open when appropriate buttons are clicked or when a selected row is right-clicked with the mouse. These editors allow easier, more convenient entry and editing of individual rows, with no need for detailed knowledge of "card" formats. When editing is completed, the contents of the nec2 editor can be saved in a NEC2-compatible input file which can then be re-loaded by xnec2c for execution. Interactive Operation: Xnec2c is interactive in its operation, e.
Once a valid input file is opened, all the normal widgets in the Main window appear so as to allow proper operation. The NEC2 "commands" in the input file are read in but not executed, until a request is issued by the user via buttons or menus in the appropriate windows. No Output File: Printing of results to an output file has been removed starting from version 1. Color coding is also used to clarify the Graphs of Frequency-related data. A color code strip is shown in the Main and Radiation Pattern windows.
On-demand Calculation: Since xnec2c collects data to be displayed in buffers directly from the functions that produce them, there is no need to produce and parse an output file and no need to re-run the program when certain input data currently the frequency is changed or when different output data gain, near-fields, input impedance etc is required.
The frequency can be changed either from spin buttons in the Main and Radiation Pattern windows or by clicking on the Frequency Data window's graph drawing area. The frequency corresponding to the pointer position will then be used to re-calculate whatever data is on display. Multi-threading operation on SMP machines: Since version 1. Thus data related to n frequency steps will be calculated concurrently and passed on the the parent process by pipes, to be further processed for graphical display.
Child processes are spawned before GTK is initialized and started so that only the parent process is tied to the GUI interface. Please note that its pointless and counter-productive to specify a value of n greater than the number of steps in the frequency loop. Data in NEC2 "cards" can be entered or edited either directly in the main editor window tree view or in more convenient dedicated editors for each type of card. Edited data can be saved to a NEC2 input file and reloaded for execution so that the edit-execute-display cycle is quicker and more convenient.
Since xnec2c is interactive, it cannot operate in the same way as NEC2 or nec2c.
Also, some options of certain commands e. There are advantages deriving from the interactive operation: it is possible, for example, to specify both the NE and NH commands in combination with a multiple-frequency FR card, although only the relevant data of the last command will be used.
To compile the package, it may be preferable to first run the included "autogen. Then the "configure" script can be run with optional parameters to override the default settings and compiler flags, e. It will also install the default configuration file into the user's home directory. This will have to be edited by the user as required. There is also this hypertext documentation file which you can copy to a location of your choice.
Command Line Options: Xnec2c has the following command line options:. If the -i option is omitted, xnec2c will take the last argument to be the input file path name, but will only open it if it has the. The Main Window:. Note: As of version 3. Once an input file is opened, the structure display can be rotated around the Z axis and tilted about a horizontal axis through the origin.