Batboard

Some time ago, we all discussed the feasibility of hooking up two Astro Spectras together to form a repeater by double vocoding the signal- and probably using a RICK type interface.

Well, today I found out what double vocoding Astro IMBE digital sounds like thanks to some antics the PD pulled this afternoon- where the dispatcher was transmitting at the Centracom while the centracom was receiving an officer and repeating the audio (which can be done and happens a lot- apparently a Centracom can work full-duplex.

At any rate, and to my surprise, double vocoding sounds exactly like Nextel- like $hit, but really- exactly like a Nextel phone does.

So, would an Astro Spectra repeater work? Yes, could you understand the other person? Probably. But, would it sound half-decent? Not a chance.

Guess you should just invest in a Quantar

-Josh

Josh wrote:Some time ago, we all discussed the feasibility of hooking up two Astro Spectras together to form a repeater by double vocoding the signal- and probably using a RICK type interface.

Well, today I found out what double vocoding Astro IMBE digital sounds like thanks to some antics the PD pulled this afternoon- where the dispatcher was transmitting at the Centracom while the centracom was receiving an officer and repeating the audio (which can be done and happens a lot- apparently a Centracom can work full-duplex.

At any rate, and to my surprise, double vocoding sounds exactly like Nextel- like $hit, but really- exactly like a Nextel phone does.

So, would an Astro Spectra repeater work? Yes, could you understand the other person? Probably. But, would it sound half-decent? Not a chance.

Guess you should just invest in a Quantar

-Josh

I hardly think that a CIE receiving audio in it's unselect speaker, and having it retransmit through the gooseneck boom microphone is a valid test of how doublevocoding would sound. Regular analog in that scenario sounds like $hit to. According to a post from XMO several months ago, it doesn't sound bad at all, when the vocoding is being done properly, within the Centracom CEB.

Todd

We are currently working with DVSI using their Net2000 Internet vocoder box (http://www.dvsinc.com/products/Net-2000.htm) to tie together two Quantar repeaters over the Internet (a Quantar in Seattle and a Quantar in Chicago).

We are doing this via a DIU3000 on each end, which utilizes the RJ-45 Patch Port jack on the rear of each DIU3000 connected to the TX and RX Audio ports of a Net2000. The Net2000 is connected to a cable router on each end, and we have it set up as a VPN Tunnel connection. We are running full rate AMBE+ @ 9.6 kb/s. DVSI is coming out with an IMBE Net2000 box very soon, but there is no reason to use this since AMBE is so much better, especially at full rate 9.6 kb/s!

The end-to-end audio sounds pretty darn good, so far, albeit when you vocode yet a third time with the MRTI2000, the degredation starts getting a little noticable, but it is still very acceptable.

Larry

Wow, 9.6k with AMBE, you've got to send me a sample! The DVSI web site only goes as fast as 4k or so- which sounds great as-is.

-Josh