[WriteLog] Networks and RFI Issues

[Dale Jackaman]

(This is for anyone doing contesting with a PC on a LAN with other 
computers and networking devices.)

Just a note to say I've tracked down some Writelog stability issues caused 
by RFI getting into various commonly used LAN devices, notably routers and 
switches.   Most of these devices are poorly shielded and I've measured 
high levels of time-outs and packet loss within a strong RFI environment, 
notably my radio shack.  This has caused stability problems not only with 
Writelog but with other networked logging programs I use as well. 

You can test for these problems by opening up command window on a 
convenient PC on your LAN and running a continuos ping to your various 
other computers and devices. including the upstream gateway of your 
router.   You should have no more than a few milliseconds delay (ms) to 
any of these devices, and less than 100ms to your upstream gateway on the 
WAN (internet) side of your router. 

ping -t [ip address]

If you want a graphical display, with a nice graphical timeline and packet 
loss percentage measurements, download the following software.

http://www.pingplotter.com/

Once you have set up these ping windows or Ping Plotter, crank up your 
radios, turn your antennas towards your shack, and bombard your LAN with 
RF from all frequencies at the power levels you normally operate at.  If 
you start to see lengthy time-outs in any of the ping windows then you 
know you've got a problem. 

I've tested a number of Linksys and D-link Devices, the most commonly used 
brands in North America, and most of them fail.   I've found a combination 
of an old D-Link switch and a new LinkSys WRT54GS router to be fairly 
immune at my location.   Wireless devices faired the best for RFI immunity 
but do create some minor birdies on the HF bands.  Network cable that's 
plugged into a router or switch and not terminated into a device are the 
worst offenders for causing havoc.  I've not tried RFI filters on the 
power cables and that might help.  However, I do have RFI filters on the 
UPS power bars that the network and PC hardware all plug in to. 

I started to have this problem a couple of months ago when we installed a 
new 4el Quad 30' away from the shack for use by the spotting station. When 
beaming toward the shack we had Writelog doing some funny things, notably 
the workstations not seeing each other along with subsequent crashes in 
extreme cases.   Timeouts were in the order of 4-5 seconds, or the length 
of a QSO or CQ. 

I tested this out in the last WPX contest and am pleased to say that once 
the tested hardware was installed the computers and Writelog worked just 
fine and no crashes. 

Dale  VE7GL
http://ve7gl.reboot.bc.ca