[BC] STL recommendations in the year 2012

[Robert Meuser]

Fred

In 2012 T1s and 950 STLs just do not offer the bandwidth necessary to be
future proof.  Digital 950 links are sadly not properly designed as they
use a single QAM carrier and have been the subject of many horror
stories from noisy LOs to mysterious forms of interference that was hard
to track down. If someone built an OFDM link, I might have a different
opinion.

Earlier Mike McCarthy suggested a licensed 6 GHZ IP link, I concur to a
degree. A licensed 11 GHZ link is also an option. Available frequencies
and a path study would be necessary to make the best determine the kind
of link to employ. I would suggest designing for five nines during your
worst rainfall.

Unlicensed spread spectrum is possible for smaller stations where some
minor degree of failure is acceptable although at 5.8 GHz the links
pretty well have to be on top of each other before there is destructive
interference.

Budget plays a big role in the decisions made. Lets start at the top.
If this is a major market station where being off air is not an option,
the I would seek an MPLS, Metro E or similar as a landline based link
and I would license a 6 or 11 GHZ link. Then I would use a Worldcast APT
codec with sure stream technology which simultaneously  uses both links
for diversity while at the same time uses time diversity on either link
to provide multiple layers of diversity. The drawback is about 100 ms
delay so off air monitoring is not possible. I might throw a 5.8 GHz
unlicensed link in as a last resort. All those links will be active with
sure stream and tests to date show an exceptionally high degree of
reliability. If a landline is not possible the licensed and unlicensed
links will offer good diversity.

OK, the station does not have that kind of budget and accepts that
putting all their eggs in one basket is OK. Then compare ongoing MPLS
(or similar) costs to a licensed microwave links and use a decent linear
IP codec and set up the link for QOS. I would still try to do the
Worldcast sure stream approach if possible since there is still a time
diversity option with a single link.

So the station claims to have no budget - call them on that first but
try first to do an unlicensed link and DSL with sure stream. If they do
not have budget for the Worldcast gear, go unlicensed spread spectrum
and a decent codec that does linear over IP.

Bottom line - 950 links and T1s are last century technologies.

On 2/24/12 2:16 PM, Fred Morton wrote:
>  To the brain trust...
>
>  In 2012, what are folks using for new STL systems? In my case I would have a 15.6 mile shot, LOS with no trees or other obstructions in the way. On the assumption that the telephone company could put in a T1, is that the way to go? (The last one I put in was over ten years ago, T1 and Interplex gear from Harris). Or standard analog 950 STL? Or digital STL (there are a number of folks making them now). How about 2.4 or 5.8 gig wireless stuff?
>