The Yaesu

Yaesu (brand)

Yaesu is an international brand of commercial and amateur radio equipment.It was founded as in 1959 by a Japanese radio amateur Sako Hasegawa with callsign JA1MP in the Tokyo neighborhood of Yaesu...

 VX-7R is a handheld transceiver

Walkie-talkie

A walkie-talkie is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald L. Hings, radio engineer Alfred J. Gross, and engineering teams at Motorola...

 for use on the amateur radio

Amateur radio

Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...

 bands. It is a "quad band" transceiver, capable of transmitting and receiving on the 50 MHz (6 meters

6 meters

The 6-meter band is a portion of the VHF radio spectrum allocated to amateur radio use. Although located in the lower portion of the VHF band, it nonetheless occasionally displays propagation mechanisms characteristic of the HF bands. This normally occurs close to sunspot maximum, when solar...

), 220 MHz (1.25 meters

1.25 meters

The 1.25 meter, 220 MHz or 222 MHz band is a portion of the VHF radio spectrum internationally allocated for amateur radio use on a primary basis in ITU Region 2, and it comprises frequencies from 220 MHz to 225 MHz...

), 144 MHz (2 meters

2 meters

The 2-meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144.000 MHz to 148.000 MHz in International Telecommunication Union region Regions 2 and 3 and from 144.000 MHz to 146.000 MHz in ITU Region 1...

) & 440 MHz (70 centimeters

70 centimeters

The 70-centimeter amateur radio band is a portion of the UHF radio spectrum. This band is used by amateurs engaged in emergency communications where portable and mobile radios are frequently used. Many such radios have dual-band capabilities, operating on both the 70-centimeter and 2-meter bands.-...

) bands. It also features a general-coverage receiver, meaning it can operate as a receiver on many additional bands. The radio's magnesium alloy case is available in black anodized or silver (clear anodized). The model number suffix "B" or "S" denotes which color, black or silver respectively.

The radio is designed to operate in extreme conditions. It is designed to be shock-proof, and is sealed against water and chemicals, making it well-suited for emergency-services duty. Available accessories include remote microphones, earphones, barometric pressure sensor module, and adapters for digital communications modes.

The VX-7R can be programmed directly from the integral keyboard, or using a computer, linked by a cable which connects to the speaker/microphone connector. There are several free and inexpensive programs available with which to modify settings.

Like other multiband handheld transceivers, the VX-7R can be used for amateur satellite communications, which typically use uplink and downlink frequencies on separate amateur bands. The VX-7R is not capable of Full-duplex satellite operation like some amateur transceivers, but instead operates as a dual-simplex

Simplex communication

Simplex communication refers to communication that occurs in one direction only. Two definitions have arisen over time: a common definition, which is used in ANSI standard and elsewhere, and an ITU-T definition...

 transceiver, meaning each band carries information in one direction only. In other words, one cannot hear one's own voice returning from the satellite during a transmission.

A unique feature of the VX-7R is its ability to transmit in AM

Amplitude modulation

Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

 at a 1 watt carrier power on the six meter band. This mode of operation allows the VX-7R to be used to drive a Transverter

Transverter

A transverter is a radio frequency device that consists of an upconverter and a downconverter in one unit. Transverters are used in conjunction with transceivers to change the range of frequencies over which the transceiver can communicate....

 or for QRP

QRP operation

In amateur radio, QRP operation means transmitting at reduced power levels while aiming to maximize one's effective range while doing so. The term QRP derives from the standard Q code used in radio communications, where "QRP" and "QRP?" are used to request, "Reduce power," and ask "Should I reduce...

 DXing

DXing

DXing is the hobby of tuning in and identifying distant radio or television signals, or making two way radio contact with distant stations in amateur radio, citizens' band radio or other two way radio communications. Many DXers also attempt to receive written verifications of reception from the...

, where a weak FM signal would not be able to overpower natural or man-made interference.

The DTMF memories allow strings of DTMF tones to be stored, allowing it to be conveniently used in a "remote-base" system with a radio such as the TS-2000

Kenwood TS-2000

The Kenwood TS-2000 is an amateur radio transceiver manufactured by the Kenwood Corporation. Introduced in the year 2000, the radio has come to be very popular among hams for its "all-in-one" functionality...

.

Feature overview

• 900 Memories
• Wideband receiver, 500 kHz - 999 MHz (the US version has cellular telephone frequencies blocked)
• CTCSS/DCS tone squelch
• European Tone Burst
• True user-selectable Dual Receive
• ARTS-Automatic In-Range Transponder
• Backlit Keypad & LCD
• Internet Key for Access to WIRES
  Wide-Coverage Internet Repeater Enhancement System
  Wide-coverage Internet Repeater Enhancement System is a standard created by Yaesu designed to link compatible amateur radio repeaters over Voice over IP, allowing any home stations using those repeaters to communicate with each other over VoIP....
  
  
• DTMF encoder for control of remote systems and telephone dialing
• Sensors for temperature, voltage (internal battery or external power source), real-time clock, and barometric pressure (optional module)
• User-definable icon images for bands, S-Meter glyphs and font characters
• Waterproof (3 foot depth for 30 minutes)
• 132 x 64 pixel back-lit dot matrix display

Selected specifications

Receive:

Specified	Actual (U.S. Version)	VFO Availability
0.5 - 1.8 MHz (BC Band)	0.510 - 1.795 MHz	Main
1.8 - 30 MHz (Shortwave band)	1.800 - 29.995 MHz	Main
30 - 59 MHz (6-meter band 6-meter band The 6-meter band is a portion of the VHF radio spectrum allocated to amateur radio use. Although located in the lower portion of the VHF band, it nonetheless occasionally displays propagation mechanisms characteristic of the HF bands. This normally occurs close to sunspot maximum, when solar...  Amateur)	30.000 - 58.995 MHz	Main, Sub 50.000-53.995 MHz
59 - 108 MHz (FM/TV-VHF Lo)	59.000 - 107.900 MHz	Main
108 - 137 MHz (Airband Airband Airband or Aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as VHF, or phonetically as "Victor"... )	108.000 - 136.975 MHz	Main
137 - 174 MHz (2-meter band Amateur)	137.000 - 173.995 MHz	Main and Sub
174 - 222 MHz (TV-VHF Hi)	174.000 - 221.995 MHz	Main
222 - 225 MHz (1.25-meter band Amateur)	222.000-224.995 MHz	Main
225 - 420 MHz (ACT1: Action Band 1)	225.000 - 419.995 MHz	Main
420 - 470 MHz (70-centimeter band Amateur)	420.000 - 469.995 MHz	Main and Sub
470 - 729 MHz (TV-UHF)	470.000 - 728.995, 758.000-773.995 MHz	Main
800 - 999 MHz (cell-blocked)	803.000 - 823.995, 849.000 - 868.995, 894.000 - 914.995, 944.000 - 959.995, 989.000 - 998.995 MHz	Main

Frequency Range Transmit:

• 50 - 54 MHz – 5 Watts FM / 1 Watt AM
• 144 - 148 MHz – 5 Watts
• 222 - 225 MHz – 300 mW (US version)
• 430 - 450 MHz – 5 Watts

Output power on each band (except 222 MHz) can be reduced from 5 watts to 2.5 watts, 1 watt, or 50 milliwatts (on 222 MHz can be reduced from 300 milliwatts to 50 milliwatts). Reducing output power allows the transceiver to be used over shorter communication distances for longer battery life.

Characteristics

The VX-7R can transmit in AM

Amplitude modulation

Amplitude modulation is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength of the transmitted signal in relation to the information being sent...

 at a 1 watt carrier power on the six meter band. This mode of operation allows the VX-7R to be used to drive a combination of bands functions reasonably well. The "Sub" VFO is limited to frequencies around the 50, 144, and 440 amateur bands, while the "Main" VFO has a much broader frequency coverage.

Modifications

The VX-7R can be modified to transmit on MARS and CAP frequencies through both hardware and software techniques, however this radio does not meet NTIA standards for either MARS or CAP. The hardware modification requires the removal of small solder contacts located under the battery pack. The software modification can be made with the VX Commander software through a data interface cable. Both modifications obtain the same result, except that the software modification will be disabled if the radio is hard-reset.

Soon after the release of the VX-7R a design flaw was discovered related to the radio's waterproof housing. Not only was the radio water-tight, but it was also air-tight. This would result in a pressure differential between the inside of the radio and the atmosphere, caused by changes in barometric pressure or altitude. This pressure differential would prevent proper oscillation of the speaker diaphragm, resulting in reduced and muffled audio output. Yaesu remedied the problem by adding a small valve under the bottom left rubber armor, which allows equalization of the interior pressure with the atmosphere. The design change was reflected in all new radios produced from that point on, and any older radios sent in for repair are retrofitted with this modification.

Some VX-7R owners complained of poor microphone sensitivity, which resulted in low audio levels on transmit. A crude modification was developed by end-users to solve the problem, at the expense of sacrificing the radio's water-proof capability. If small holes are pierced in the rubber seal covering the microphone diaphragm, then sound waves can better reach the microphone diaphragm, resulting in better audio sensitivity.