A solution to solve all the problems
Walkie talkie Two-way Repeater Box
Two-way of the radios can both transmit and receive in VHF/UHF/Digital/Analog band.
Relay box at both ends of the walkie-talkie as a signal source, the middle through the wired connection. Two signal sources can be arranged in different locations, expand the signal coverage area, reduce dead ends.
The antenna of the walkie-talkie is replaced by a high-gain antenna with a gain value of 6.0dB.
The gain antenna and the walker use feeder links, and the feeder can pass through the weak wells through the ground and the ground. Send the underground signal to the ground.
Installation of underground garage and ground communication equipment
A and B two walkie-talkie as a transit signal source, for the C and D from the transit bridging role.
A and B two sources are located in the ground and ground. So that the ground and underground in the A, B under the coverage of two signal sources.
C and D can not be communicated directly through. With the transfer of A and B, C and D can be communicated.