[BC] IP Radio(s) oddity

[Mark Croom]

Since I know there are a number of broadcast users running unlicensed links
to get LAN data back and forth between studio and transmitter sites, I
thought I'd toss this one out for some input.

I got to initiate a new transmitter site this week. STL and transmitter are
normal name-brand broadcast gear and working fine. So far anyway.

The real issue--I have a pair of those 5.8 gig Tranzeo FDD series radios
with dish antennas and radomes connecting  the sites. They have good signal
strength and I can ping anything on the local LAN at any time. There is very
little equipment on the radio link. I have a pair of those Linksys SPA VoIP
adapters set up as OPX on one of my phone lines at the studio. Pick it up at
the remote end and get dial tone from the studio. So far so good. FWIW, the
"router" features of the SPAs are all turned OFF, so they are just a dumb
bridge of their own. At the far end, when I access the Internet with my
laptop PC plugged into a hub out there, it will run fine for a while, then
for no apparent reason it not be able to get out. When this happens I cannot
get a reply from the local side of the gateway (a Linksys FVS318).

Here's where it gets interesting.

While I am unable to ping the gateway from the remote PC, I can ping any
machine on the local side of the LAN. I can VNC into any of those machines,
open a browser window, and get Internet. All the while a CMD window on the
laptop is running non-stop pings to 192.168.1.1 and getting "Request Timed
Out" back each and every time.

If I take my laptop and plug it into the network cable that the radio is
connected to at the studio, everything works normally.

I'm starting to wonder just what might be going on here. If everybody was
having trouble getting to the internet when I have trouble remotely I'd look
elsewhere, but somehow I think this problem is going to be in either the
radio pair's configuration, or the way it passes packets to the router.

I have learned there is a practical limit to how much data I can force
through the Linksys router--when we get a certain number of clients they
start to get overloaded and act oddly. Typically this problem messes up the
DHCP server, that uses up most of the processor and nobody gets internet.
This is NOT the same problem, since the only person with no internet is on
the far side of the radio bridge.

Any ideas or experience to share?

Thanks.

Mark
MN