what is first-class radiotelephone?
95259
It is a license in the Electronic field. You get it by taking a test administered by the FCC. Take you ALL day (8 hours). It is required to work on many Electronics such as a Radio Station. When you have one of these, you most likely know your stuff.;-)
902185
the radio/stereo, television, phone, cameras, electricity
1098183
The first part of the sound is the destination number that is being dialled.\n\nThis follows the DTMF which is Dual Tone Multi-Frequency. The signal generated by a DTMF encoder is a direct algebraic summation, in real time, of the amplitudes of two sine (cosine) waves of different frequencies. i.e. pressing '1' will send a tone made by adding 1209 Hz and 697 Hz to the other end of the line.\n\nThe subsequent sound is the protocol for handshaking, acknowledgement, and authentication to establish the link. Once a valid connection had been made, the sound will stop.
174605
The first one! The sound is more clear!
1077755
buy two wireless VOIP handsets and mail one to the place you wish to send to.\ninitiate an internet phone call.\nboth pick up handsets and walk away from the wired connection point.\n\nbingo!\n(also works with cellphones, particularly if you buy two pairs of duplexing walkie-talkies and duct tape one of each pair to a cellphone mid-call & walk away with the other)\n\nalternatively, negotiate with your local pirate radio station to borrow one of theirs in exchange for you not turning them over to the feds. the range will only be about ten miles tops, but 1/ that's more than pretty much anything you can buy in the store, 2/ you didn't specify exactly what you meant by "long range", 3/ you could probably reverse-engineer it pretty simply and plug in a higher power amp.\n\nremember that lower frequencies carry further but have progressively worse bandwidths. if a fair bit of noise can be tolerated, AM is also detectable over a longer distance. also remember that this sort of thing tends to require a license, particularly if you're messing with frequencies that may disrupt the business of other licensed users (commercial / national stations, emergency services, taxis, air traffic, maritime, HAM radio) and you could get a serious legal buttspanking if you cause any trouble and/or are discovered.\n\nPS - 1750 metres? isnt that like 171, maybe 172khz? slap in the lower third of the (inter-)national / commercial (only just, nowadays, but still hanging in) long-wave AM band? potentially dodgy that, doesnt the bbc world service, US overseas forces radio, some station like that already use 172khz? bbc radio 4 long-range is certainly on 198khz...
432286
http://sound.westhost.com/class-a.htm
992673
I think called as bag phones or Mobile phone....\n\nwant to see Histroy of Mobile phone...\nsee this link\n\nhttp://en.wikipedia.org/wiki/History_of_mobile_phones
635484
The first one. Atleast you could have a desent conversation with him/her.
625015
Wow.. you do not want much.. Try starting with thie URL and click on the various links it has: (oh yes.. keep in mind that this FA-312 replaced the EE8)\n\nhttp://olive-drab.com/od_electronics_ta312.php\n\nhttp://www.19bdetxsg.org/activities/field_phones/milphones1.html\n\nhttp://www.peryphon.co.il/312kit.htm\n\nI know there are a number of army/navy surplus stores around but I am Quite certain that you will not find what you are looking for in those places
40129
That's a big subject.  Analog or digital? U.S., Europe, Japan, Germany, Scandanavia, Germany, UK?  All use different systems.  Most use some form of spread spectrum technology, which makes them resistant to jamming.  A good reference is Peterson, Ziemer, and Borth, "Introduction to Spread Spectrum Communications", ISBN 0-02-431623-7.\n\nAlso, see http://en.wikipedia.org/wiki/Cell_phone_jammer\n\n\nFor U.S., "The FCC has fielded enough queries about the legality of cell phone jammers that it issued a notice last year. In it, the agency warns that jammers violate federal laws that broadly prohibit interfering with licensed radio spectrum. Owning, manufacturing, marketing, offering for sale or operating a cell phone jammer is punishable by an $11,000 fine and up to a year in prison for each offense, the notice states."\n\nFrom http://www.newhousenews.com/archive/story1a092200.html
197101
A simple radio system is the superhetrodyne receiver system.\nHetrodyning is the process of shifting in the frequency domiain.\nThe elements for transmission are signal source (microphone), Amplifier, Modulator, RF oscillator, RF Mixer, RF amplifier, Antenna.  \nThe elements for receiving are Antenna, RF Amplifier, Local Oscillator, RF Mixer, Filter, IF Amplifier, Demodulator, Amplifier, Speaker.
749091
The RT-1694D is an advanced HF manpack radio that provides long-range, tactical communications.  The extended transceiver frequency range of 1.6 to 60 MHz provides plain-text interoperability with VHF radios.  The radio incorporates a high-speed data rate of up to 9600 bps, reducing transmission time.  It is equipped with the MIL-STD-188-110B Serial Tone and NATO STANAG 4285 waveforms that utilize patented data and filtering to overcome the effects of interference and jamming.  The AN/PRC-150C provides embedded digital voice and data encryption. \nThe antenna is type dipole. If you consider the frequency of 50 MHz, the wavelength is 6m, so the antenna will be around this length.\nhttp://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=7536
766228
Hi! The below web-site gives you full details about the concept of Internet Radio. Hope this helps you. \n\nhttp://computer.howstuffworks.com/internet-radio1.htm
1121100
I say First Response.
29417
General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that is the only kind of network where GPRS is in use. GPRS is integrated into GSM standards releases starting with Release 97 and onwards. First it was standardised by ETSI but now that effort has been handed onto the 3GPP.
1086582
Radio was inventi by Marconi\n\nTelevision by John Logie Bierd
733106
I presume that you mean a Handheld Radio or Walkie Talkie?  If my assumption is correct then the normal industry system for talking is what we call the 10-code system.  You hear in movies all the time :10-4 good buddy"  it means hear you clear and acknowledge your message.  Here are the rest of the 10-codes.  \n\nThere are other codes.  And some companies and State Departments create their own.\n\nHere is the basic list of codes:\n\n10-1    Receiving poorly\n10-2    Receiving well\n10-3    Stop transmitting\n10-4    OK, message received\n10-5    Relay message\n10-6    Busy, stand by\n10-7    Out of service, leaving the air\n10-8    In service, subject to call\n10-9    Repeat message\n10-10  Transmission completed, standing by\n10-11  Talking too quickly\n10-12  Visitors present\n10-13  Advise weather/road conditions\n10-16  Make pickup at ......\n10-17  Urgent business\n10-18  Anything for us?\n10-19  Nothing for you, return to base\n10-20  My location is.....\n10-21  Call by telephone\n10-22  Report in person to.....\n10-23  Stand by\n10-24  Completed last assignment\n10-25  Can you contact......?\n10-26  Disregard last information\n10-27  I am moving to channel.....\n10-28  Identify your station\n10-29  Time is up for contact \n10-30  Does not conform to FCC rules\n10-32  I will give you a radio check\n10-33  Emergency traffic at this station\n10-34  Trouble at this station, help needed\n10-35  Confidential information\n10-36  Correct time is....\n10-37  Wrecker needed at......\n10-38  Ambulance needed at......\n10-39  Your message delivered\n10-40  Please tune to channel......\n10-42  Traffic accident at.......\n10-43  Traffic tie-up at.....\n10-44  I have a message for you \n10-45  All units within range please report\n10-50  Emergency traffic at this station (accident)\n10-60  What is next message number?\n10-62  Unable to copy, use phone\n10-63  Net directed to.......\n10-64  Net clear\n10-65  Awaiting your next message, assignment\n10-67  All units comply\n10-70  Fire at.......\n10-71  Proceed with transmission in sequence\n10-73  Speed trap at.......\n10-75  You are causing interference\n10-77  Negative contact\n10-81  Reserve hotel room for......\n10-100  Rest stop \n\nGood luck and 10-4 !