[cma-l] Preparation

[Two Lochs Radio]

Livewire certainly has negligible latency over a LAN, but when it comes to 
studio-transmitter links you aren't usually in a situation where a single 
LAN will cover it - uslaly it's a point-to-point or WAN link. It's still 
perfectly possible of course, but real-time protocols such as Livewire and 
the others don't have the error-correction that comes with TCP-IP and of 
course have no significant amount of buffering, so you need a really solid 
IP link of high-speed, which can significantly raise the cost of wireless 
links, especially over longer distances, and they don't work across typical 
public networks.

On the other hand, good quality analogue links, such as SHF/microwave, tend 
to be very pricey compared with reasonably good IP wireless links - I can't 
see any inherent reason for this, it's just market economics of scale.

One aspect easily overlooked when considering the analogue/digital options 
is that it can dictate where you put the ancillary gear - processor, 
multiplexer, RDS encoder. With an analogue link it's usually most 
cost-effective and convenient to have all these at the station end with a 
single composite analogue signal sent over the link straight to the TX, but 
with digital it's usually more practical to send a stereo audio feed on the 
link and have the multiplexing and encoding etc at the TX end.

It's possible to use an ordinary PC to do stereo and RDS encoding and a 
high-quality 192kHz PC sound card to regenerate a composite feed, but I 
haven't seen anyone offerring this cheaply as two halves mediated by an IP 
link, only and all-in-one PC based encoder.

Alex


----- Original Message ----- 
From: "Peter" <peter at engineeringradio.co.uk>
To: "Ian Hickling" <transplanfm at hotmail.com>
Cc: "The Community Media Association Discussion List" 
<cma-l at mailman.commedia.org.uk>
Sent: Friday, December 19, 2014 3:35 PM
Subject: Re: [cma-l] Preparation


> Depends what you mean by latency. Products that use Livewire, Wheatnet, 
> Ravenna, MADI and AES67 have very low latency that is barely noticeable if 
> at all over LANs.
>
> PeteOn 19 Dec 2014 15:24, Ian Hickling <transplanfm at hotmail.com> wrote:
>>
>> I agree wholeheartedly with Alan's point about the STL situation, and 
>> also JC's about the visual image of the station as seem by visitors and 
>> potential Clients.