Weird one this - I have DMR project coming up for a client, and he doesn;t need much in the way of cleverness, just a swap of his analogue system to a digital one, and just a few radios on the system in total. 8, I think.
I noticed the TYT-8500 DMR repeater, and then spotted this page http://www.gb3gr.co.uk/index_files/Page1193.htm.
Inside the 8500 appear to be two modified ANALOGUE radios! TYT-9000Ds, a custom control board and that is about it. If this is a tier II DMR system then how on earth does this work in terms of the two timeslots? Can it be so simple as a discriminator output from the first radio, straight into the second? Surely not. Fair enough, this would indeed pass the signal through intact(ish) but would this really allow two radios on the same frequency at the same time to be combined and retransmitted without issues? I thought DMR repeaters also retimed everything being passed through and two mobile analogue radios could not possibly do this, unless the clever stuff is done to the data stream before being passed to the analogue radio to retransmit? This would also allow analogue straight through operation, but how would CTCSS tones be managed? The receiver output would be checked by an external board and identified as analogue with CTCSS? This would be a function of the receiver, so how could it also be bypassed for digital input?
The GB3GR website page is scant with the information.
If DMR can be passed by discriminator output, then can I pursuade the existing repeater to simply pass it through, if I knock off the CTCSS? Has anyone tried this?
Loads of questions and I don't remember us talking about this before? The DMR repeaters with 'cleverness' are clearly very different, but are these repeaters just a fudge/bodge?