Long-Distance Wireless Sound Pick-up, Audio Transmitter, Distance 3km-7km. Ism/UHF Band (GM980)

Audio transmitter

Long-distance wireless sound pick-up, audio transmitter, distance 3km-7km. ISM/UHF band

GM980 Long-distance wireless sound pick-up

The 980 professional wireless audio frequency transport of GM series is a wireless hearing-aid tool that can help you to hear distant sounds. It has characteristics as clear sound, far distance, small size and perfect functions, which using sophisticated high-tech devices, innovative circuit design, US ASIC and STD installation process. It is applicable to scene monitor and wireless audio transmission, such as security monitoring system, hidden interview, audio-visual education, tourism, amusement, filed expedition, the industrial and mining enterprises, and so on.

Technique parameter

Frequency band: ISM/UHF band. GM980 use fixed frequency point and GM980DJ use broadband to transmit signal. Audio transmitter

Transmission distance: 2800(max 7km) in widen area, which is according to its using conditions
Power supply: The monitor head uses a high energy lithium battery which can be used for 16hours in total. The receiver uses two 7th batteries of 1.5V which can be used for 24 hours in total.
Sensitivity: (all directions) of sound picking up is better than 12dB, differentiate rate is high within 200 square meters. Impedance of audio input circuitry is low.

Use instructions:

Swith ON the monitor head JT980 to enter work state and place it at the position away from the main sound source of 1-5 m with the antenna extended previously. Plug earphone into the hole marked with EAR of the receiver, and turn on the power switch(V0L/OFF) to fit volume for hearing the scene sounds.
A compatible cable can be used to connect the sound pickup with the secondary equipments such as recorders, amplifiers, stealth headphones, wire or wireless relays, etc. Through inserting one end of the cable to the hole (3.5mm) marked with A-our of audio output regulating V0L can control the electrical level output. It can realize the second relay transmission to use withGM910B.
The jack (3.5mm) of the monitor head can be input all kinds of audio signals wireless, which can be regulated for a loud and distortion less sound.
The monitor head will be auto power off when the electric energy has been used up. Please charge in time with the charger of 5V DC and 300mA. When charging, the power switch should be turned off. The charger can be used as an external power under the state that the electric energy has been charged enough( the green light die out). There may be light AC noise that would be reduced or disappear when expanding the receiving distance. Audio transmitter

When the monitoring distance is longer, please carefully adjust the direction and position of the receiver to keep its best receiving state. There will be blind spots(some closer points have weaker signals) in dense buildings area because of signal have been greatly changed by being obstructed and multiple reflections. It is particularly important how to choose a suitable receiving point and position for the monitor-head, and the receiver should be as high as possible or in an open space. The monitor-head should be near the window when used in a room. The fewer the building obstructs are between the receiver and the monitor-head, the farther the transmission distance is.

Index test explanation:
The product has been tested with special instruments before leaving factory, and all indexes have met the requirements.

Pickup sensitivity: Normal human ear can hear the voices of 5dB-25dB(decibels). Pickup sensitivity of this product is equivalent to hearing whispers and breathing two meters away in a quiet room. For the high pickup sensitivity and whole direction pickup, as well as that the seemingly quiet environment often has more than 20dB noise of natural, therefore, it was recommended to use the products in quiet locations to increase its signal-to-noise ration and differentiate rate.