Re: Cross linking (Was: Codec2)

"David Lake (dlake)" <dlake@...>



Completely agree.


Where I’ve interworked FM to D-Star, I’ve found the results to be perfectly acceptable within the confines of Amateur Radio.


You wouldn’t want to listen to Bartok or One Direction over it, but it works and that’s what matters.


All the time we have the entrenched view of “this is my system and it won’t connect to your system” we risk siloing and isolating users.  The net effect is less usage on amateur bands and less amateurs – exactly the effect that is being seen in many countries.


On the callsign ID, that is an interesting point.  Rules do vary from country to country, but what I’ve found is that Amateurs naturally ID every few minutes anyway.  In the UK, rules were relaxed on D-Star so that no voice ID is required, but you will still typically here an over start with “G6TBA from G4ULF” and end with “from G4ULF.”  Old habits die hard, and I certainly ID on every over still.


So, again, like you, I think these are both non-issues.


To me, the benefits in terms of increase usage and more linking possibilities far outweigh these issues. 


BTW, EchoIRLP does NOT allow interworking IRLP and Echolink as the IRLP crowd insist on the end-point being a repeater.    EchoIRLP allows a repeater to act as an IRLP node and and Echolink node, but it does not bridge the audio together.





From: UniversalDigitalRadio@... [mailto:UniversalDigitalRadio@...] On Behalf Of John D. Hays
Sent: Wednesday, May 23, 2012 5:03 PM
To: UniversalDigitalRadio@...
Subject: [UniversalDigitalRadio] Cross linking (Was: Codec2)


The argument that analog should never be linked to digital because of white noise and other artifacts forgets that Vocoders (as opposed to Codecs) like AMBE and Codec-2 are specifically looking for speech and work hard to remove background noise.  All audio starts and ends as analog and transitioning from an analog FM to digital voice system using a vocoder applies the same filtering to the audio.  I think the folks the argument haven't tested their theory.   Some who have tested it, can probably show some issues like drop out, overdrive on CTCSS, etc. that will degrade the system, however, well conditioned audio from an analog FM source should encode much like analog voice from a microphone.


The second argument is often that the callsign information isn't there in an analog signal or incompatible digital voice signal.  Rules may vary around the world, but here in the US the ID is for the transmitter where the signal originates. It doesn't need to be passed through the network for identification purposes (other than courtesy or vanity) when it comes to the regulations.  In D-STAR, the callsign is also used as an address for directed transmissions.  In a linked system the only address needed is the one that identifies the repeater(s) and conference channels, so that the traffic is properly routed.


Any linking protocol that mixes systems should contain an ability to identify the type of traffic source (Analog, Digital) and encoding (AMBE, Codec-2, etc.) and allow the administrator of a repeater to determine which traffic to accept.


Given these two "non-issues", the rest is just politics. :)

John D. Hays

PO Box 1223, Edmonds, WA 98020-1223 


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