Recently a question was raised by someone who was trying to figure out the descrambling feature of some Wouxun GMRS radios. He wanted to know how setting both of his radios to the same setting in the descrambler affected reception. If the descrambler was enabled and on the same setting for both radios, why were the incoming transmissions to either radio garbled?
To answer the question, we first need to understand what a descrambler is and how it works.
What is a Descrambler?
Many commercial, business and other types of radios have a scrambler feature to provide a layer of privacy and security for two way communications. The scrambler takes an outgoing transmission and encrypts or inverts it before sending it over the air so that only the intended recipient can receive, decode or decrypt, and hear the transmission as intended.
Digital radios have the capability to encrypt and decrypt the signals using sophisticated 128-bit or 256-bit encryption algorithms. Analog radios may use one of several methods to scramble and descramble signals. One of the oldest methods still used in some radios is called voice inversion scrambling, which "inverts" the audio so that it is somewhat unintelligible to anyone except those are able to descramble it with the same supported protocol used by the transmitter. While not reliably effective in this age of privacy concerns, it can offer a very low level of security for some who may need it.
Why a Descrambler on a GMRS Radio?
The FCC does not allow scrambling on the General Mobile Radio Service. Yet some of the higher end Wouxun GMRS radios have a feature called Descrambler. Why?
While not found on models that only transmit and receive on the GMRS, it is often included as a premium feature on models that can also receive on other bands. The Descrambler is included with these models so you can hear those receive-only frequencies that are scrambled. Although The act of scrambling transmissions is not allowed on the GMRS, it is sometimes used on certain other bands and services that can and do sometimes use it. The descrambler allows anyone who is listening in to scrambled transmissions on those bands to hear such incoming signals clearly.
How to use the Descrambler
The descrambler feature is applied individually to each channel. For example, if you program channels 31 and 32 to receive on different frequencies and the incoming transmissions on channel 31 are scrambled, you would need to enable the descrambler on that channel to hear it clearly. This can be done either from the menu of the radio or through programming software.
To enable the descrambler on a channel directly from the radio itself, first go to that channel, then enter the menu on the radio and choose the Descrambler option. Wouxun radios typically support 8 descramble protocols. At this point it's a matter of either knowing which protocol the sender is using, or go through the process of trying each one until you can hear the transmission clearly. Once you've found the protocol that descrambles the signal, choose it and press the MENU button to set it for the current channel.
There are a lot of scrambler protocols, and some may be proprietary to a specific make or model radio. If none of the 8 supported protocols listed in the menu of your Wouxun radio can decramble the signal, you may not be able to do so. However, the scramble protocols on Wouxun radios are standard across most, if not all of the analog models. If you are attempting to descramble a signal sent from another analog Wouxun radio, chances are one of those protocols should be compatible.
It is important to note that the inversion method works both ways. If an incoming voice transmission is scrambled using this method, the descrambler should convert it back to normal speech. Likewise, if the signal being received is not scrambled, it will come out inverted if it passes through the descrambler on its way to your ear.
Which brings us to the question, If GMRS radios cannot transmit a scrambled signal, what do you do if a Wouxun GMRS radio receives garbled transmissions from another GMRS radio?
Before tossing your radio or calling for a replacement, check the descrambler. It's probably enabled.
Including encryption capabilities ie. Scramblers, there will always be those with less scruples, that will abuse those capabilities!
As the FCC has had a, " Paper Tiger " reputation for decades, people believe they can do nearly everything, without worry !
And with a new sheriff in town, who knows what enforcement policies might be coming ?