[TowerTalk] help with interference problems

[James Wolf]

At 09:48 PM 7/17/2007, Roger (K8RI) wrote:

> > My Internet link is a 5.6GHz radio at the 100' level on the tower with
an
> > 11
> > mile shot to the ISP. I come down the tower with shielded CAT5 to the
> > router
> > in a trailer at the base of the tower; this is run with about 8 turns
thru
> > a
> > FT240-43 toroid . Then a 250' run of regular CAT5 to the house and a 8
> > port
>
>Lordy...I'm running a gigabit network through 130' of CAT5e parallel to and
>within about 5 to 10 feet of all the coax runs to the tower. (75 to 90
feet)
>It then runs under the 75 half wave sloper to the shop. I found that even a
>metal staple used to loosely hold the cable created enough inductance to
>screw up the network.  It won't work in metal conduit either.

I would be surprised if you ever get this running right at 1Gb speeds.
Gigabit speeds on Ethernet are really fussy and very susceptible to
interference.  The only thing you have going for you is that it is shielded
cable, which does help.
- Don't make sharp bends in the cable.
- Don't run the cable next to other cables.
- Don't crush the cable with tie wraps etc.
- GB Network cards that are on the MB are notoriously poor in performance.
A 'good' aftermarket card usually works better.
- Again, very susceptible to interference.
- This appears not to be a problem, but If your runs are more that 100
meters, then since the velocity factor of the twisted pair sets in the cable
are different, (to eliminate crossover issues) the signals arriving at the
far end are too far enough out of sync.

If you are still unsuccessful, look into using single mode fiber if you can.

James Wolf, KR9U