[BC] STL link...

[Burt I. Weiner]

For a STL I like to be in charge of my own destiny.  I've seen to 
many instances where the best of internet links has had it's problems 
with throughput.  When it goes down I can not do much more than 
reboot, scream, reboot, yell, reboot and cry.  With a properly 
engineered, coordinated and maintained RF STL that is in a licensed 
band I am more secure.  I feel that with the present State of The Art 
with regards to 24-7 reliability of the internet and its backbone I 
would not want that for a main STL.  Maybe backup.

I have seen some very successful WiFi links and I have seen some very 
bad ones.  It all depends on who and what else is on the band with 
you.  The frequencies used for WiFi are typically loaded with other 
devices and that situation will not get any better.  In major cities 
this can be a serious problem.   Spread Spectrum is not immune from 
interference.

On long paths a big dish can be both a good thing and a bad 
thing.  Good for higher gain but bad from the standpoint that higher 
gain equals narrower beamwidth which raises the chances for 
de-coupling between the dishes.  For best reliability it's best to 
use a lower gain (fatter beam) at the transmit end and higher gain 
(larger aperture) at the receive end.

Burt

At 06:27 PM 2/18/2006, you wrote:
>From: Robert Meuser <Robertm at broadcast.net>
>Subject: Re: [BC] IP STL
>To: "Broadcasters' Mailing List" <broadcast at radiolists.net>
>Message-ID: <43F7A584.8030306 at broadcast.net>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>I have had good experiences with the audio TX communicator. $700 per end
>for software that will run on a pretty modest computer, like a 600 mhz
>pentium. I has the ability to operate with linear as well as mpeg audio.
>The software adjusts its buffering automatically based on network
>condition and can also function via ISDN.
>
>We even ran it off a laptop in the middle of Manhattan via plain vanella
>WIFI and it worked quite well.
>
>If you could get DSL lines with enough uplink speed, you could run
>linear audio and the network traffic would not likely be an issue if
>both DSL were from the same telco provider.
>
>You can get a free slightly crippled demo version here:
>
>http://www.musicamusa.com/
>
>
>Good Luck
>
>
>
>Bill Spry wrote:
>
> > Thanks to everyone for their input on our STL need.  It seems like a
> > very expensive venture to mount 8 ft. dishes on each tower in order to
> > make it 28 miles.  Not to mention the cost of the equipment (even
> > though I am a distributor for Nicom).
> >
> > As an alternative, we are looking at IP equipment.  I checked out the
> > Comrex Access.  Does anyone have experience with them.  It's hard to
> > believe that you can achieve full quality at such a low bitrate.  But
> > because the bitrate is so low, I doubt there would be any 'hic-cuping'
> > on the audio due to bandwidth problems.  Plus the delay is only 1/4 of
> > a second.  Nice.
> >
> > I would love to hear more from anyone that has used or experimented
> > with the Comrex Access or any other IP STL hardware.
> >
> >
> > Thanks again,
> >
> > William J. Spry

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at earthlink.net
K6OQK