GMRS (General Mobile Radio Service) is a licensed radio service. GMRS consists of 16 UHF channels on FM, plus 7 channels that are shared with FRS. The maximum allowable power for a GMRS radio is 50 watts. The GMRS channels which are shared with FRS are limited to 5 watts of power. The use of repeaters is allowed on GMRS. Most GMRS repeaters use CTCS (Control Tone Coded Squelch). GMRS Frequencies The frequencies assigned solely to GMRS are: Designator Simplex or Repeater Output Repeater Input 550 462.550 MHz 467.550 MHz Read More

An oscilloscope is a tool that allows the user to do two things. The first is measure time-varying signals. The way it does this is it shows details of the wave shape. The faster the wave shape, the faster the signal over a period of time. This leads to the second thing it does which is measure different aspects of time-varying signals such as the frequency of the signal and the peak value of the signal. Whenever there is an instance when the signal varies as time goes on, you’ll Read More

A potentiometer, called pot for short, is an electrical component that acts as a variable voltage divider. They usually have three terminals, one of which is connected to a moving center contact. A potentiometer with two terminals is a variable resistor, called a rheostat. Potentiometers come in many forms including rotaries, trimmers, sliders. Potentiometer is also the term for an old instrument that measured an unknown voltage after being calibrated with a known voltage. These have been replaced by multimeters today. Potentiometer Types Rotary potentiometers have a semi-circular contact made Read More

Fixed Radio Scanners My recommendations for general purpose radios for scanning are the PC controlled models. PC controllers scanning radios give you many more options for playing and are a great bang for your scanning buck. The only downside is that you can't carry these radios around on your belt! Icom PCR-1000 WinRadio Mobile Radio Scanners To scan while walking around, I recommend either the Uniden BC250D Trunked Radio Scanner, which will enable you to listen to trunked radio, or the Yaesu VX-7R tranciever, which will allow you to both Read More

Declination is a coordinate system that uses Latitude that is then projected on large arbitrary radius measurements around the Earth that rotate on the same axis. Declination’s main purpose is to locate a specific object or point in the sky. It is measured in a value of degrees north and south of the celestial equator. These values are positive if north of the celestial equator, zeroed if equal to the celestial equator, and negative in the south. For example, the following values are true for declination positions from the celestial Read More

A Ham radio antenna tower is usually a metal tower that hams use to support their antennas. There's also an interesting story behind birth of the terms Ham or amateur radio. The actual signification of the term 'ham' was lost but there are several theories that explain its provenience. For example some say it was an insult at first, others say it's just the simplified version of the term amateur and so on. In order to understand what a Antenna Tower is, you must understand what it's used for, and Read More

A police scanner is basically a radio scanner that is also a receiver that receives wireless radio signals. A scanner identifies these wireless radio waves. A scanner can identify numerous radio signals and bands concurrently making it easy to keep track of many channels simultaneously. The phrase “police scanner” derives from the fact that the majority of scanner users take pleasure in listening to police radio broadcast. Police scanner codes vary from department to department. Most codes are reasonably standard, but a few of the codes are specific to the Read More

S band is a frequency range from approximately 2 to 4 GHz. S band is used for Digital Audio Radio Satellite (DARS) satellite radio systems such as Sirius XM Satellite Radio.  Sirius XM uses frequencies between 2,320.00 and 2,332.50 MHz, and also between 2,332.50 and 2,345.00 MHz. S band is also used by many weather, communications, and intelligence satellites.  Most of these satellites transmit using CW, usually with sidebands.  PSK with a sub-carrier is a less popular option. A portion of the S band from 2.4 to 2.4835 Ghz is Read More

A breadboard is a thin rectangular piece of insulating material used to hold electronic components when making circuit prototypes. They have many rows and columns of conductive points for inserting component terminals and jumper wires. The original breadboards were just wooden boards, presumably used to cut bread on, but the modern versions have plastic cases containing many spring-metal strips. Breadboards come in many sizes, from less than one hundred connection points to several thousand points. Some breadboards even come with larger components already connected, like displays and speakers. Breadboards are Read More

Uplink refers to a transmission of data in which data flows from a ground-based transmitter to an orbital satellite receiver. Uplink is used to send data to a satellite in Earth’s orbit in order to make changes to the way the satellite functions or simply redirect data to another ground-based receiver. Uplink is used in every application that involves the use of an orbital satellite and is a necessary component of all satellite-based telecommunications systems. Like downlink, uplink depends on the use of C Band, Ku Band, and Ka Band Read More