| An Inexpensive External GPS Antenna (Part 1) | | 2008-06-09 15:46:55 | | If you operate APRS or just need an external antenna for your GPS receiver, here’s one that is easy to build yet offers surprisingly good performance in a compact size. Best of all, it uses commonly available components and materials.This antenna design is based on a classic turnstile configuration (for circular polarization)—two dipoles are placed on the same plane but rotated 90° from each other. These dipoles are then spaced ¼ wavelength above a ground plane. A ¼ wavelength “parallelplate” transmission line (printed circuitboard material) serves as the connection method and mounting post for the dipoles.ConstructionStart with the base plate. Cut a 4-inch diameter circle out of thin hobby tin or brass. (It happens that the inside diameter of the container lid is 4 inches, approximately the same width as the hobby tin/brass sheet.) Mark the exact center of the base plate. This is where the parallelplate transmission line assembly is attached (see Figure 1). Cut two 4-inch l | | By: Gps News update and Gps Review. | | |
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| Homemade 802.11(b or g) Wireless Antenna | | 2008-05-15 03:51:33 | | As we know that commercials 802.11b/g (2.4 Ghz) Wireless Antenna offered by many computers store are really expensive today. Some creative people write articles about making homemade 802.11b/g wireless antenna for either a client or an access point. Those articles are intended to reduce our cost by make us more creative and productive with make a homemade antennas our self. Bellow are some of | | By: Computers & Networking | | |
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| Real 10$ Wi-Fi antenna (Video) | | 2008-05-01 03:24:34 | | Why spend $100 or more on a Wi-Fi antenna when you can create your own one for $10? The following components are needed:
35-mm foam (like the kind desktop and laptop PCs usually come with)
Solid-core copper wire
Small brass plate
Multiple BNC connectors
Follow the instructions in the video:
Related PostsDownload and convert YouTube video online and offlineVideo conference between [...] | | By: Linux Screw | | |
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| Certification for Log Antenna periodic and Mini Repeater "Andrew products" by Suryajaya Teknotama | | 2008-03-14 00:05:13 | | Incorporated in 2001, PT. Suryajaya Teknotama [SJA Technologies], is an Indonesian based company focused to support mobile equipment vendors and mobile operators in providing a high availability and reliable source of supply of Antenna Line System & Components.. I Just want to inform you about Certification for Log Antenna periodic and Mini repeater of Andrew Corporation Products by PT. Suryajaya Teknotama.* Equipment : 1. Log Antenna Periodic & 2. Mini Repeater* Product of : Andrew* Model/Type : 1. STA3 and 2. MR 403 B/D* Country of Origin : Latvia* Certificate Holder : Suryajaya Teknotama, PT., Jl. Benda Raya 11 , Jakarta 12560 Indonesia.NOTE:Operating Frequency : Log Antenna Periodic = 1710 MHz - 2500 MHzOperating Frequency : Mini repeater Uplink = 1710 MHz - 1785 MHz Downlink = 1805 MHz - 1880 MHzTesting Fee for Log Antenna Periodic is : Rp 6.000.000Testing Fee for Mini Repeater is : Rp 6.000.000Both of devices for th | | By: Indonesia Type Approval/homologation/Compliance ce | | |
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| Super Cantenna WiFi Antenna Booster | | 2008-01-04 13:16:00 | | Extend the range of your wireless network, or connect to other wireless networks in your neighborhood.
Just connect the antenna to your wireless router, access point or network card, then point and shoot.
(See below for list of compatible wireless devices.) Package includes: 12 dBi Super Cantenna Booster AntennaIntegrated 36-inch RF cable with RPSMA connectorRPTNC adapterDual tripod/ | | By: Millennium Lifestyles | | |
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| The Food Antenna | | 2007-07-25 21:42:47 | | On the lighter side of Geekdom, we all have our ability to sort out, hunt, and scavenge for food on a regular basis. So when there is a big training session underway anywhere in the company, usually there is food that is left over and dumped in the local community area for everyone to use once the trainees have moved on.
What special skills do true Geeks have in that they can usually hunt down and gather this sustenance even if they do not know something is going on?
The Geek Food Antenna is the answer.
This highly sought after skill and ability is only found in true geeks, sometimes in geek wannabe’s because some major geek found the food first. Consider this almost a training session in its own right. The food antenna is a skill that is learned, and passed down amongst generations of geeks much like the hunter gatherer skills of African Bushmen.
It takes years to fully develop the “Geek Food Antenna” hunter gathering skill set. Not for the weak, or the otherwise non commit | | By: techwag | | |
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| Antenna Control Unit | | 2007-06-17 18:40:00 | | Antenna Control Unit's front panel consists of :Vacuum fluorescent (VF) displayKeypadLED enunciatorsFront Panel Layout & DisplaysPower-Up Display = On power-up the 4 line blue plasma display initially displays the Sea Tel controller model and software version, then “Remote Initializing” if the antenna is in the process of power-up cycle also, and finally the remote PCU model and software version will be displayed.AUX1 & AUX2 = Sequential pressing of the AUX1 key toggles tracking ON/OFF. As a shortcut to “Save New Parameters” (bypassing the password) press & hold the AUX2 key and press the “C” key on the numeric keypad.Ship Displays = Initial display of all present settings of the information listed below. Sequentially pressing the Ship key will access entry mode for each of these displays to enter, or correct, the desired setting :LAT (Ships Latitude) = Manual entry of the present position of the ship or position as automatically updated by GPS input.LON ( Ships Longitude) = Manual entry of the present position of the ship or position as automatically updated by GPS input.HDG (Ships Heading) = Manual entry of the heading of the ship and present heading as automatically updated by Ships’ Gyro Compass input. When input is from a 1:1 Synchro or an NMEAH heading input sources this display will be the value of that input. When the input is coming from a multi-ratio (36:, 90:1 or 360:1 Synchro, or is Step-By-Step at 6 steps per degree) the operator will have to set HDG to the present value of the ships heading for it to increment/decrement from that value.Satellite Displays consists of :SAT = Satellite longitudeTHRS = Signal level thresholdRCVR = Receiver selection & tuning frequencyAGC = Signal AGC levelAntenna Displays :AZ = True azimuth positionEL = Elevation positionREL = Antenna position relative to the ships BOWPOL = PolAng (Polarity Angle) Position or modeConscan Signaling = Commands from the conscan controller to the main boa | | By: VSAT for Marine | | |
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| Antenna Tracking | | 2007-06-10 21:25:00 | | Antenna Tracking (Tracking of the satellite) - Fine adjustments to the pointing of the antenna to optimize the received signal level (AGC is monitored by the ACU). Tracking is controlled by the ACU.AGCThe internal tuner provides a DC voltage output that is directly proportional to the level of the satellite signal input. The receiver output will be positive going (voltage increases as satellite signal level increases) between 0.00-5.00 VDC. This output is converted from the analog voltage to a digital value be a 4096 bit A/D converter on the DAC-97 Main PCB. 30-40 digital counts of AGC is approximately 1dB of satellite signal. Satellite IF signal is provided into the internal tuner of the DAC-97 using the BNC or “F” connectors mounted in the rear panel.Receiver selection and tuning is set by pressing SAT key 4 times to the RCVR menu. The input is selected by pressing the NSEW key until the appropriate input is selected. Selections are Ext AGC (external connection to the Terminal Mounting Strip), INA (TVRO receiver F connector input “A”), INB (TVRO receiver F connector input “B”) or IF (70/140 MHz SCPC BNC connector input).Tuning frequency is then entered by using the numeric keys to input the frequency you want the receiver to be tuned to. AGC value will be displayed to assist in setting selection and frequency that provides the best (highest) AGC value.Ext AGC selection does not allow any frequency to be entered.INA can be tuned to an IF, channel 1-24 (C-Band ONLY), C-Band downlink frequency or Ku-Band downlink frequency. Tuning of Ku-Band downlink frequencies is based on a wideband LNB having Local Oscillator frequencies of 9.75 & 10.75 GHz. Tuning of C-Band downlink frequencies is based on an LNB having a Local Oscillator frequency of 5.15 GHz. If your LNB(s) local oscillator frequency(ies) are not the same as the DAC-97 frequency plan is based on you should tune by entering the IF frequency you wish to use. Calculate the IF frequency b | | By: VSAT for Marine | | |
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| Antenna Stabilization | | 2007-06-06 20:45:00 | | Pointing and Targeting the antenna is accurately pointing the antenna to an angular position in 3-dimensional free space. Controlled by the ACU :Antenna DriveSatellite targetingPositional Display Antenna Drive consists of :AZ stepping, slewing and targetingEL stepping, slewing and targetingPositionnal Display consists of :Azimuth DisplayRelative DisplayElevation DisplayACU & PCU Functions associated with Pointing and targeting the antenna :Antenna Control Unit - Master, controls the antenna through the PCUPedestal Control Unit (PCU)Antenna Control Unit - Master, controls the antenna through the PCU consists of :Interface with Ships Gyro CompassInterface for GPS inputControls Pointing and Targeting of the antennaPedestal Control Unit (PCU) takes pointing and tracking direction from the ACU.3-Axis Stabilization :Antenna Initialization - Every time the antenna is energized (or commanded to re-initialize) the PCU initializes the antenna in the following phases. Each phase must complete properly for the antenna to operate properly (post-initialization).Level Cage is driven CW, issuing extra steps to assure that the cage is all the way to the mechanical stop. Then the Level cage will be driven exactly 45.0 degrees CCW.Elevation axis activates - Input from the LV axis of the tilt sensor is used to drive the Elevation of the antenna to 45.0 degrees (brings the tilt sensor LV axis to level)Cross-Level axis activates - Input from the CL axis of the tilt sensor is used to drive the Cross-Level (tilt) of the antenna to level (brings the Cross-Level Beam, and the tilt sensor CL axis to level).Azimuth axis activates - Antenna drives in azimuth until the “Home Flag” signal is produced. (This signal is produced by a Home Switch hitting a cam or by a Hall Effect sensor in close proximity to a Magnet).This completes the phases of initialization. At this time the antenna elevation should 45.0 degrees and Relative azimuth should be at be at home flag (home switch engaged on t | | By: VSAT for Marine | | |
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| Antenna Pointing / Stabilization / Tracking | | 2007-06-06 02:24:00 | | There are 4 primary componenet in antenna section where they make it stable in tracking the satellite signal :1. Antenna Control Unit - Master, controls the antenna through the PCUInterface with Ships Gyro CompassInterface for GPS inputInterface with computer to Monitor and Control the ACUControls Pointing and Targeting of the antennaControls Tracking2. Pedestal Control Unit (PCU)Reads sensorsControls MotorsControls Stabilization of the antennaTakes pointing and tracking direction from the ACU3. ACU-PCU Control Signals - Pedestal M&CACU RS422 input/output via the Base MUXPCU RS422 input/output via the Pedestal MUXBase and Pedestal MUXes are mirror tuned4. Software versionsAre matched to hardware and functional capabilitiesACU and PCU software versions are reported by the ACU | | By: VSAT for Marine | | |
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| Antenna ConScan | | 2007-05-28 04:12:00 | | Antenna ConScan section consists of :ConScan (Conical Scanning) - Uses a bore-sight shift of the signal entry into the throat of the OMT. Provides 75-150 RPM sampling of signal level on the four quadrants of the dish to provide intelligent tracking. Provides Timing marks of boresight location relative to the four quadrants of the dish (up, down, left & right).Conscan controller.Feed Modifications on ConScan :Ku-Band Feed - Eccentric scalar plate, motor drive and timing mark sensor. C-Band Feed - Eccentric throat, motor drive and timing mark sensor.Dual Band Feed. - Eccentric C-Band throat, Ku-Band teflon wedge, motor drive and timing mark sensor.The ConScan controller function is for :Timing Marks from feed (dish quadrant location of the feed eccentricity).AGC from IF signal.Compares Timing marks to AGC in near real time.Timing Marks from feed (dish quadrant location of the feed eccentricity) AGC from IF signal.Compares Timing marks to AGC in near real time. | | By: VSAT for Marine | | |
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| Antenna Reflector | | 2007-05-25 08:45:00 | | The Gain & Efficiency of the dish is directly related to:Size of reflector (in square centimeters).Type of reflecting surface.Parabolic curve accuracy.Focal type of the reflector.Struts.Type of reflecting surface consists of Mesh and Solid. Mesh is Framed sections of screen material form a light weight reflector, but is not as efficient as solid surface dishes and has higher level side-lobes.The solid type of reflecting surface consists of :Spun - Least efficient of the solid dishes because the surface is not smooth and the ridges cause some energy to be lost as stray reflections.Hydro-formed - Good surface accuracy, efficiency and low side-lobes.Precision - Very high surface accuracy, efficiency and low side-lobes .Parabolic curve accuracy is how accurately formed the reflector surface curvature is determines how accurately the energy captured by the dish is focused to the focal point.Focal type of the reflector consists of :Direct Focus - Feed and Scalar block receive signal from t | | By: VSAT for Marine | | |
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| Autotrack VSAT Antenna Introduction | | 2007-05-22 07:55:00 | | The antenna will be used onboard a ship and it will have to be able to provide uninterrupted satellite usage while under a variety of motion - we are a leading manufacturer of Marine Stabilized Antenna Pedestals.What are the key points :Pointing/Targeting - Accurately driving the antenna to a precise Azimuth and Elevation angles in three dimensional free space to be consistent with where the satellite signal is emanating from. Stabilization - Maintaining the Azimuth and Elevation pointing angles while the ship is rolling, pitching and turning.Tracking - Use of the received satellite signal level to continuously evaluate and optimize the pointing angles of the antenna for maximum signal level reception.Definitions of other relevant terms :Relative (REL)Mechanical azimuth rotational position of the antenna relative to the Bow of the ship. When the antenna is pointed inline with the Bow of the ship the REL display should be 360.0/000.0. Range of display is 000.0-359.9.Azimuth (AZ)True A | | By: VSAT for Marine | | |
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| Pointing the VSAT Antenna | | 2007-05-22 07:31:00 | | Pointing the VSAT Antenna – Beam vs Mechanical Axis as used for Physical, or Course Elevation Adjustment :Pointing the VSAT Antenna – Setting the Antenna Course Elevation Adjustment : | | By: VSAT for Marine | | |
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