[TowerTalk] help with interference problems

[Roger (K8RI)]

>
> 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.

It's running close with 105 to 115 MBs being typical between any two 
computers. Running a KW on SSB doesn't seem to show up as affecting the 
speed on the network monitor.

> 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.

It's not. I'm using CAT5e which is really fussy to run.

> - Don't make sharp bends in the cable.

I use sweep Ls for all corners. Like one staple, I found one kink caused 
problems.

> - Don't run the cable next to other cables.

The CAT5e runs all by itself, but parallel to and about 5 to 10 feet from 
the cables going to the tower.
That is except for each end which ends up in a rats nest of cables but only 
for about 5 feet.

> - Don't crush the cable with tie wraps etc.

AMEN!

> - GB Network cards that are on the MB are notoriously poor in performance.

I have two that are using the native NICs on the MB. One is an ASUS M2N SLI 
Deluxe and the other is a Gigabyte  of which I have forgotten the model but 
it uses the 590 chipset. These seem to run as well as the others using PCI 
NICs, but the ASUS is only about 3 months old and the other is around 2 
IIRC. At any rate they are late models.  The first is running an Athlon 64 
FX62 and the other is an Athlon 64 X2 6000.

> 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

I'm only running a 130 feet.

> 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.
>
It's working great and I'm afraid to touch anything. <:-))

73

Roger (K8RI)

> James Wolf, KR9U
>
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