Дождались! Новые радиосистемы Shure SLX-D.

[Дискоград]

Select an RF power setting:
High = 10 mW
Low = 1 mW

так то есть там переключение в меню передатчика. 1мВт действительно мало

Setting the AA Battery Type
To ensure accurate display of transmitter runtime, set the battery type in the transmitter menu to match the installed AA battery
type (the default setting is Alkaline). If a Shure rechargeable battery is installed, selecting a battery type is not necessary and
the battery type menu will not be displayed.
Press the menu button to navigate to the Battery screen.
Press enter, then use the menu button to select the installed battery type:
Alkaline = Alkaline
NiMH (nickel metal hydride)
Lithium (non-rechargeable, 1.5V max)
Press enter to save

проверьте тип батарей, какой выбран у вас?