Re: Analog Bridge

Steve N4IRS

Both YSF and DMR are AMBE. The only difference is the wrapper. Let me try to explain it this way.
You write a letter and put it in a envelope addressed to me. You mail it off trough the post office. When the post office receives it, they take you letter out of the envelope. They put your letter, unaltered, into a a new envelop and deliver it to me. The only thing taht changed it the envelop. The letter is unchanged.

MB receives the YSF. It extracts the raw AMBE. It builds a new DMR transmission containing the raw AMBE wrapped in such a way that a DRM radio can understand it.

DMR, YSF (narrow) and NXDN are all AMBE.
P25 and YSF (wide) are IMBE
D-Star is AMBE (more or less) at a different rate.

A transcoder is 2 vocoders back to back (AB <-> AB)
AMBE to AMBE does not need a transcoder (Analog_Bridge)
AMBE to IMBE needs a transcoder.
AMBE to D-Star needs a transcoder.
IMBE to D-Star needs a transcoder.
Anything to analog needs a vocoder. (Digital <-> Analog) Analog_Bridge

Hope this helps, Steve N4IRS

On 11/23/20 7:42 PM, Aaron Groover wrote:

I just gotta know. How in the world is analog bridge not used for YSF to DMR?


How does this communicate?

Where is the PTT going? As in transmission.

I see nothing on MMDVM when I key it up.

The point of analog bridge is to bridge the analog OVER to the DMR/Fusion/Dstar or whatever flavor suits your side right?

Where is the audio exactly coming and going to and from?


15 years in radio development, and I still cant understand how or why this is…. NEVER have I seen just a MMDVM bridge running.


Because we use the same method to cross over any trunked county radio system to analog aka Berks County, City of Allentown, With an analog bridged system. MMDVM “Bridge” to me is simply just only logging into the networks.


I think this a good topic I guess, lets all the curious minds know 😉


Thanks for what you do Steve.











Thank You,


Aaron Groover

(610) 379 6148




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