[SBE] stereo audio RPU

[Vic Jester]

Henry - I'd look at 5.6 or 2.4 Gig unlicensed microwave radios with either T1 channels or an Ethernet interface.  Both are bidirectional by definition.  Once you have the link up you can use it for audio and/or LAN/WAN or any sort of data transport you want.  Yeah, there's lots of stuff out there in the unlicensed band, but if you engineer it right it won't bother your shot.  

I've had 6 systems on the air here for over 5 years with very few problems.  They are my main STL's (four commercial FM's).  I use two 5.6 Gig radios with 8 channels of T1 each to a repeat site.  From there I go to each of four different FM transmitter sites via 2.4 Gig radios.  Those have four T1 channels.  The shots range from 6 to 21 miles.  I have Proxim (nee Western Multiplex) radios, but there are many different manufacturers.  

The T1 channels will allow you to use Intraplex shelves natively, or with Ethernet you can use an audio-to-IP converter such as the Barix instreamer/exstreamer or Apt or other brands of CODECs.  The Intraplex units offer linear or compressed audio transport.  Most of the others have some sort of compressioin (data reduction).  Depending on your audio quality needs you can go expensive or do the job for a lot less.

If you're only going two miles you can use small antennas.  I'm going about 4 miles with my 5.6 Gig radios with 2.5' dishes on each end.  I have about 100-150' of 1/2 Heliax (foam) on each end and still have almost 30 dB fade margin.  Some of the newer super-cool radios allow you to configure them through a web interface.  They give you the option of more data or more robustness - your choice.  Think of the old gain-bandwidth model and you get the idea...

LOS, with not-too-long runs of coax at each end, modern Ethernet radios, and 2.5' dish antennas will probably give you something like 20-50 Mb/s (or more) Ethernet speeds with a good fade margin.  With that, you can plug in a Comrex Access, TieLine, Barix, Intraplex, or APT CODEC and get what you need.  It becomes a price vs. quality excercise at that point.

Regards,
Vic Jester
Atlanta



-----Original Message-----

>From: A9xw at cs.com

>Sent: Jul 28, 2008 6:04 PM

>To: sbe at sbe.org

>Subject: [SBE] stereo audio RPU

>

>I am in need of an audio only short haul link, 15 Khz stereo, about 2 miles, 

>bi-directional.  Anyone have suggestions?  This is a 24/7 link for four months 

>for simulcasting with backhaul. No control signals or other data load.  Telco 

>Comrex, Tieline, radio RPU,  23 Gig microwave?  LOS tower to tower. Good 

>stuff, not elcheapo K-tel radio on a chip part 15 RCA connector stuff. Quality and 

>reliability is the issue, not price. 

>

>Henry

>WYIN   </HTML>

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