Summary of information:
The gain of the walkie-talkie signal amplifier is the RF power amplification of the walkie-talkie signal amplifier, because it is a two-way amplifier, there is uplink gain and downlink gain, under normal circumstances is basically the same. shoot
The gain of the walkie-talkie signal amplifier is the RF power amplification of the walkie-talkie signal amplifier, because it is a two-way amplifier, there is uplink gain and downlink gain, under normal circumstances is basically the same. Rf power amplification is expressed in db, 10db means 10 times, 20db means 100 times, 30db means 1000 times... .. 100 dB means 10000000000=10 billion times

The db number represents the relative ratio of the signal strength of the input and output ports of a device (or system)

For example, +10db means that the output of the device amplifies the input signal by 10 times

-10Db indicates that the output of the device attenuates the input signal by a factor of 10

Today, let's ask Wang Gong of the walkie-talkie company to talk about the RF power amplification value of the LD series digital walkie-talkie:

1, dbm and dbuv

dbm and dbuv are both a measure of the absolute value of power and level, calculated as follows: dbm=10lgP (power value /1mw), dbuv=10lgP (level value /1uV). Converted dbm=dbuv-107(50 euros), dbm=dbuv-108.8(75 euros).

[Example] If the transmit power P is 1mw, it is 0dbm after converted to dbm.

[Example] The transmission power P of digital FM walkie-talkie LD608 is 1w/5w(high/low), and the value after conversion according to dbm unit should be:

10lg (1w/1mw)=10lg (1000)= 30dbm;

10lg (5w/1mw)=10lg (5000)= 10lg5 10lg1000=37dbm.

The receiving sensitivity of FM radio LD688 is ≤0.2uV(wide)/ 0.25uV (narrow), which can be expressed as the receiving sensitivity of BF-5111UV is ≤-7dBuv (wide)/ -6dBuv (narrow):

10lg (0.2uV /1uV) =-7 dbuv;

10lg (0.25uV /1uV) =-6 dbuv.

2. dbi and dbd

dbi and dbd are the values of the measured gain (power gain), both are a relative value, but the reference base is not the same. The reference for dbi is an all-directional antenna, and the reference for dbd is a dipole, so the two are slightly different. It is generally believed that the same gain is 2.15 larger in dbi than in dbd.

[Example] For an antenna with a gain of 16dbd, when its gain is converted into the unit of dbi, it is 18.15dbi (generally, decimal places are ignored, and it is 18dBi).

Example: The gain of the special antenna of Lingtong handheld digital intercom is 2.15dbi (0dbd).

3. db

db is a value that represents the relative value, when considering how many db more or less A power than B power, according to the following formula: 10lg (A power/B power)

The transmission power P of LD608 professional digital walkie-talkie is 1W/5W(high/low), and it can be said that the high power of LD608 is 7 dB larger than the low power.

[Example] The transmission loss of 100 m for 1/2 and 7/8 inch feeders at 400MHz is 4.6db and 2.9db respectively, then the power of a 400 MHZ with a power of 40W after passing 100 m 1/2 and 7/8 inch feeders is as follows:

10 lg (40 w / 1 mw) - 4.6 db 46 DBM = 4.6 db = 41.4 DBM material 13.8 w

10 lg (40 w / 1 mw) - 2.9 db 46 DBM = 2.9 db = 43.1 DBM material 20.5 w

It can be seen that the use of low-loss cables in the backbone of signal transmission can greatly reduce the loss of signals.

[Example] The gain of the outdoor dual-section omnidirectional antenna is 11dBi, and the gain of the UHF outdoor single-section omnidirectional antenna is 9dbi. It can be said that the gain of a single antenna is 2 db smaller than that of a dual-section.

4. dbc

Sometimes you will also see dbc, which is also a unit that represents the relative value of power and is calculated in exactly the same way as db. In general, dbc is relative to the Carrier power, in many cases, used to measure the relative value of the carrier power, such as to measure the interference (in-frequency interference, intermodulation interference, cross-modulation interference, out-of-band interference, etc.) and the relative value of coupling, stray, etc. Where dbc is used, db can in principle be used instead.