Greg - you've posted loads of things about your problems in lots of topics, and everyone asks for details to help you, and all you do is ask the same question again.
First thing - are you sure the signal you are receiving is the correct 'brand' of digital? There are lots of different types, but like betamax and VHS, they do not all work on every radio. You have a DMR radio, but as Metro Radio said - not every digital noise you hear can be decoded, Many people run a cheap SDR system on their computer which will identify what kind of signal it is, and also importantly NOT identify some things you hear, saving you wasting time trying to get voices to pop out. Even when you do determine what a signal is, and although they sound similar, you can after a while listen to a signal and make a pretty good prediction. None of the proper radios, unlike scanners, tell you why they are silent - so many things can cause this - colour codes, groups, encryption etc - so you have a lottery number thing on guessing the right paramaters.
Maybe if you tell us what the frequency is you are listening to, and where in the country you are - somebody will be able to indemnify it for you, but to be honest, I have numerous digital radios of all sorts of makes - and in my local area, I have only successfully got one of them identified and listenable to. That was because SDR and the digital decoder plug in identified it to be nexedge and I have some of those, and got the right thing programmed in on perhaps the 10th guess or so. This is a killer - changing one parameter, then waiting 30 seconds to try it, then after a failed decode, trying the next one, time and time again.
We genuinely want to help you, but you have to give us something to use.
As to the little 'd' - doesn't this just display on a channel that is programmed for digital, rather than FM?