[cma-l] Streaming audio problem

[Phil Edmonds]

Hi Gordon,

I've took the liberty of including the "Hospital Radio Onelist" into 
this reply as there will probably be some technically knowledgeable 
people who subscribe to that list that aren't on the CMA mailing list.

See below for my comments

On 31/10/2011 20:19, Gordon Sharpe, TMCR 95.3 FM wrote:
> Guys, I have an issue with hospital radio, rather than community, but
> hope someone can help as it may solve another issue for me.
> */Trust AM/* serves the Bassetlaw (Worksop in N Notts, if you need to
> ask) and Doncaster hospitals. It's main base is Bassetlaw and from there
> there has been a Band 1 FM link for the last 6 years to feed audio to
> the remote hospital in Doncaster, a tad over 13 miles as the crow flies.
> Except it broke last week, the antenna fell apart. Thats been fixed but
> now Ofcom want to check the link transmitter and it could be a while
> before service can be restored.

That's interesting - in my experience of JFMG licenced "Programme Making 
and Special Event" links Ofcom have not been interested in checking the 
equipment - though they do often specify use of directional tx aerials 
(I assume that any new kit would have to be CE type approved - but that 
would only apply to the transmitter not the antenna?)
It would be interesting to know on what grounds they want to check the 
link system before you can put it on-air - after all I assume you've 
already paid the £800+ annual licence fee for the privilege.


> So, to try and make sure the patients could still listen I set up a PC
> to use Winamp to listen to streaming audio feed sent out from Bassetlaw
> using Shoutcast. It works fine for me at home, I could listen all day -
> and have done. Not so at the Doncaster studio though. It's been breaking
> up very badly, stop/start and sometimes showing [Buffer: 0%]
> I've read up about adjusting this that and the other settings and have
> tried just about everything I could find on the topic, it still does it.
> Except, when I connect via VNC to have a look at the log files or
> whatever. As long as there's a connection the stream remains stable. The
> stream is 'private' and had a password, which I took off to allow it to
> reconnect during these troubles. I often listen from home, to check that
> everything is up and running as I live in Doncaster too and can't hear
> the AM signal.

I'd try a different playback client - such as VLC.

Maybe TalkTalk do have some sort of traffic management in place which is 
not seeing any upload traffic from your remote site - seems unlikely, 
perhaps something on your local machine or router is dropping the 
connection?

Try opening a Command Prompt Window (Start ->Run -> cmd) on the remote 
end machine and running the following command:

ping -t google.com

this will run a continuous string of ping commands - which will keep the 
connection live. This is a trick I use when using mobile broadband to 
keep the connection open - as I find my provider often seems to 'drop' 
my connection if I don't do anything for a few minutes.


> The router has already been set to a 'nailed up' connection, it's on
> TalkTalk Business. Checking the speed via ThinkBroadband.com says
> they're getting roughly 4.6 down and 0.7 up . I'm on a Virgin Cable 10Mb
> connection at home (9.6/1.0).
> I have a silence detector module running on the PC itself, it triggers
> after 16 seconds of silence. It kills Winamp and restarts it, taking it
> that the program itself has got stuck. Any blip in the meantime resets
> the counter, so the stop/start issue isn't always being detected. The
> resets are being logged at 4-5 per hour, except between 11pm and 7am
> when it seems to run smoothly ?
> I have had an active connection via VNC for the last hour and a half and
> the stream has remained up and stable during that time. Having noted the
> 11pm to 7am window when all runs with no problem I had suspected some
> sort of blocking by TalkTalk, but by having something else connected it
> sorts itself out...?
> Ideally I want to use the stream to feed the audio to the Doncaster
> studio 24/7, rather than have the FM link. OK, so the audio would be 40
> seconds behind real time but who's bothered about that when you're laid
> up in a hospital bed?

If you go down the replacing the FM link route I'd recommend not using 
PC's and get a pair of Barix codecs (you'll recoup the cost in 1 year of 
no JFMG licences) - though in my experiences it will drop occasionally 
over ADSL links. Fine for non 24/7 purposes such as I have it in use 
for. However cue Ian Hickling who I believe has had success doing this 
on a 24/7 basis in Wales.


If both hospitals are the same NHS Trust you may be able to negotiate a 
link over their LAN/WAN - I know of Chorley Hospital Radio and Roch 
Valley Radio who do this - the former with Barix units the later with 
more expensive Comrex codecs - but the principle is the same. I believe 
Nick Beer at Westcountry Broadcast is your man who set-up Roch Valleys 
system so give him a shout for some advice.


> I had planned to have a haircut later this week, I just hope I've got
> some left by then as this one has me puzzled.
> Any ideas?
> Gordon Sharpe, TMCR FM
>


Regards,
Phil Edmonds.