netgear prosafe gs110t network switch emissions
The netgear prosafe
gs110t is a network switch with:
- 8 10/100/1000 Mbps autosensing copper Ethernet ports
- 2 dedicated gigabit sfp (fiber) ports. It can take 1000base
sx,lx, or zx modules.
- A power supply module.
Jorge is planning on using these
switches at the observatory/vsq's.
Luis checked this
device in the screen room on 16oct12.
- the netgear prosafe gs11tp is the same switch, but
includes power over Ethernet on the copper ports.
16oct12:netgear gs110t switch
emissions in the screen room:
Luis measured the emissions of the netgear
prosafe gs110t switch in the screen room on 16oct12.
Luis' setup and
The setup was:
- Agilent E4445A spectrum analyzer:
- average 20 sweeps
- 8192 points/spectra
- 6db attenuation , preamp on
- 100 MHz span, 12.5 Khz/rbw. covering 0 to 3000 MHz in 30
- 904 Efield probe with a 15 foot coax cable.
- copper port 8 was plugged into ao net
- linksys 1GbE SX Mini-GPIC SFP module installed, but no
fiber connected to the module.
- Luis measured the emissions with the 904 Efield probe
close to the connected copper Ethernet port 8.
- He also measured the emissions at the power supply module
(external to the device).
The plots show the emissions from the
- The first page shows plots of 0-1000 MHz, 1000-2000MHz and
- The 2nd page shows some blowups around some of our
- 300-500 MHz (327,430)
- 1350-1550 MHz (lbw)
- 2000-3000 MHz (lbw)
- Emissions at
switch port 8 output (.ps) (.pdf)
- The strongest birdie is around 800 MHz at -78dbm
- page 2 shows that there are 3 combs:
- 14.2854 MHz .
- You can see it from 200 MHz up to 2000 MHz
- The strongest birdie within our rcvr bands is:
428.55 MHz at -84dbm.
- 20.8358 MHz
- You can see this from 2000 to 3000 MHz.
- the strongest birdie within our rcvr bands is:
2812.83 at -89dbm
- 100.00 MHz comb
- this is seen 100 through 3000 MHz.
- I thought it might be coming from somewhere in the
screen room (our 100 MHz distribution), but it is not
seen in the power supply plots, so it must be coming
from the network switch.
- The strongest birdies is at 800 MHz at -78dbm.
- The strongest birdies in our receiver bands:
- 1600 MHz -87 dbm
- 2500 MHz -92 dbm
- Emissions from
the power supply (.ps) (.pdf)
- These emissions are similar but much weaker than the
port8 output. Nothing is seen about 800 MHz.
- The emissions from the switch are much stronger that the
- there are 3 combs
- 14.285 MHz
- 20.836 MHz
- 100.00 MHz
- The table below summarizes the strongest birdies
strongest element in 327 rcvr
strongest elements in 430 rcvr
|14.285 and 100 MHz
combs overlap here.
strongest birdie 0 to 3000 MHz
birdie lbw rcvr
|14.285 and 100 MHz
comb overlap. in lbw rcvr
strongest element in sbw rcvr
- This switch probably needs to be shielded.
- We also need to test this switch with a fiber optic cable
installed to check on the fiber transceiver.
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