Interference

[BobR]

Yesterday I took down the extended USB connectors from the RB box in the loft and replaced it with a run of Cat 5 cable which attaches to the Cat 5 USB extenders on each end.

I noticed a slight drop in how often the 'tracked' column updates. It went from updating by the second to only updating every 4 or 5 seconds which I can live with given the extended range the cat 5 cable gives me.

However what I have noticed is a considerable amount of noise breaking through on my scanner which was not there before. Both the Coax and the Cat 5 run together into the attic and the RB and antenna are about 8 metres apart. The scanner is in the same place in relation to the computer and has never really suffered from noise generated via that.

My very limited knowledge of this seems to indicate a shielding problem with the Cat5 as this (and the usb extenders ) are the only change in the whole setup.

Has anybody got any thoughts or experienced the same and managed to resolve it?

Thanks,

Bob

[tarbat]

Yes, this has been mentioned before, with standard Cat5 twisted pair.  From my previous post on this:
I'm no expert, but maybe you can try using cat5e STP (shielded twisted pair).
http://www.universal-cables.co.uk/shielded-cat5e-patch-cables.htm?gclid=COrKi7uyppcCFRpUEAodcx4m9Q

[jgomberg]

What do you mean by "extended" USB connectors, and how extended is "extended"?

Which Cat 5 USB extenders did you use?

The problem could be impedance mismatch, transmission loss through the connectors, and/or adverse changes to the cable shielding if any.

Some Cat 5 is shielded, others are not and rely solely on pair twisting to mitigate noise issues. If you are using shielded cable, are you grounding the shield?

Depending on your cable length requirements you may want to upgrade to Cat-6 which has better bandwidth and transmission properties. But that only assumes that the problem is strictly cable related and not something else.

---------------------------------

Don't forget to wear a foil hat whenever doing RF work.
It serves no useful purpose but your friends and neighbors will have a good laugh at your expense.

[BobR]

I used Maplins USB Cat5 booster (http://www.maplin.co.uk/Module.aspx?ModuleNo=221290) with 20 metres of Cat5 attached.

I have since found out the Cat5 cable I used was not shielded in anyway which I think may be the problem. I think an updgrade as you suggest to Cat6 is going to be a better solution.

Cheers,

Bob

[jgomberg]

Let me know how it works out