Dynamic, threshold and other noise suppressors are designed to prevent background hiss from entering the signal during pauses. But when listening to weak signals, they themselves can impair hearing. In this case, such devices must be turned off or bypassed.
If the squelch is a threshold, find on the body of the device, inside of which it is built-in, a button or switch to turn it off. Sometimes there is no separate noise canceling control, but instead there is a corresponding item in the menu. Both can be called Dolby NR, dbx, "Mayak", and if the noise suppression device is implemented without compliance with one or another standard - UWB (noise reduction system), ShP (noise reduction), NR (noise reduction), etc.
Please note that not everything that is called Dolby is a noise canceling system. This company has developed standards for other devices, designed, for example, to expand the stereo base or to encode signals of more than two channels. Find out what the system is for before shutting it down. Also note that some noise reduction systems will only work properly if the signal is pre-processed before recording or transmitting. If the signal is not processed, it is advisable to disable them.
Threshold squelchs, in contrast to dynamic ones, disconnect the amplifier from the signal source abruptly. This happens when the amplitude drops to a predetermined value. To change the response threshold of such a device, a regulator designated as Squelch serves. When receiving strong signals, set it in such a position that the appearance of a carrier on the channel is guaranteed to turn on the signal transmission from the detector to the amplifier, and its loss leads to a shutdown. Then your hearing will not get tired when working with the radio station. If the received signal is weak, set the turn-on threshold to a minimum. Then you can listen to what is happening on the channel all the time, which is equivalent to disabling noise cancellation.
Finally, if the noise reducer is a separate unit, to bypass it, de-energize the equipment, disconnect the cable from the output of the node, and connect to the input cable. The equipment can then be turned on again.