I think Redstone's security and fire are digital and to some degree encrypted. Work hasn't taken me out there in a couple of years now, so things may have changed.
One thing I do recall, is sitting in a hotel on Martin and the Parkway, I very seldom heard anything on the scanner, not even a CC lock on. Now if I were up on University, reception was better. Although PD and fire were never very clear. This was on their new system.
I don't think I ever heard anything on either of the older channels and I had them programmed in the scanner as well.
They definately were not encrypted, I heard police doing routine patrols, I heard security checks, then got the fire tacs when they did a comm check with each station. I don't recall anything being encrypted at all...
I programmed the frequencies and talk groups as I found them on this site and I live close to the Arsenal , but all I have received so far is some control channel tones. Can you Please give me the info you programmed when you heard them. Thanks !
It's been almost 5 years since I lived within range of the Arsenal but at that time they were using the freq's listed in the database & it was analog, usually in the clear. I think they were in the process of installing a UHF TRS. Try searching 413-417Mhz - a LOT of unidentified military traffic used to be in that range, sorry I can't remember the exact frequencies.
Most of the DOD's trunked systems are digital and nearly all the newer ones (in the 380 band) are being encrypted to boot.
I'm pretty sure the new system for the Arsenal is digital (the DB says 'and APCO 25'). As I had a digital scanner the last time I was there, I cannot attest to whether they were broadcasting both.
If you upgrade to a digital scanner, you'll have to set the table for the system to work. If you get a new GRE (500 or 600), you will also have to include the high and lo thresholds. Search through the GRE threads from Oct last year to find out how to do that. I know it was posted there and in a couple of other places.