Astro Repeater

[batwing4ever]

An analog repeater goes like this:

Analog Rx Radio >----audio out----->Controller>-----audio out------>Analog Tx Radio

An Astro repeater should work the same:

Astro Rx Radio >----audio out----->Controller>-----audio out------>Astro Tx Radio


Some guy is trying to tell me that it is not possible to do this with Astro radios. The audio in and out of an Astro radio is just audio like any other radio and should work like any other radio used to build a repeater.

Am I missing some important detail?

[escomm]

I am pretty sure Quantars and the like do their own DSP. Someone with more knowledge will come along and elaborate, I'm sure (and hopefully correct me if I am wrong )

[n7maq]

Just by itself the Quantar will not do D/A conversion on a P25 signal, you need a DIU for that. If you open the local speaker on a Quantar when it is RXing a P25 signal all you hear is noise.

Jim

[xmo]

In a digital repeater the receiver feeds the digital data directly to the "controller" which recovers and conditions the data [error correction] and forwards that clean data to the repeater transmitter.

As previously posted, the data is never downconverted to analog audio. To do so results in what is called "double VOCODING" - which creates artifacts in the second generation audio that result in reduced intelligibility. That's why you can't make a "real" digital repeater with a couple of back-to-back mobiles.

There have been some digital "repeaters" made with back-to-back analog radios configured to have wide frequency response that allows the data to be repeated. Without the error correction of a real repeater these systems will not produce the same operating range [reduced coverage area]

[wavetar]

A search uncovers some fairly in-depth threads on the subject:

http://batboard.batlabs.com/viewtopic.p ... al#p217166

http://batboard.batlabs.com/viewtopic.p ... al#p247473

Not to mention the first link is a sticky in the Astro forum.

Todd