grohgreg
Dunno. Ask The Chief
join:2001-07-05
Dawson Springs, KY
3 edits | reply to horse7
Re: Slowly dropping signal
said by horse7  :My original intent with the cabling was to rule out the possibility that the cables were the issue-- Yeah, but in swapping out only part of the cable path, you could have introduced a whole new problem that can skew the results. I can't personally approve of what you've done so far, simply because the CCS cable segments represent a red herring. Your perception of "problems" with BC don't hold water, unless the guy pulling the cable is a total incompetent.
T&B make a wide range of connectors. Just because they're Snap&Seal doesn't mean they're frequency/impedance compatible with your cable path.
RG11/heliax are overkill - money wasted - unless your dish is more than 276 cable feet from the modem. And neither will have ANY impact on latency whatsoever.
//greg//
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HN7000S/98cm Prodelin/2w Osiris/ProPlus - G16/1250H/Germantown - NAT 66.82.187.152/Gateway 66.82.25.10/DNS 66.82.4.12 and 66.82.4.8 - Firefox 3 - AV/Firewalled by NIS2009 |
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horse7
join:2008-09-10
Staatsburg, NY
| reply to DaveL
CCS vs. copper...
CCS, 18AWG (CommScope) at 0.0163 ohm/ft,
Copper, 18AWG, at 0.0075 ohm/ft.
For 100', at 2A draw, the drop is
CCS 3.3v drop
Cu 1.5v drop
This ignores non-linear effects and presumes that only the center conductor is used for current carrying (not the shield). In my case there is 50' of cable to and from the TRIA for a total of 100', with perhaps another 60-70' indoors (round trip 120-140) of original copper.
I don't remember the brick voltage output since I am not colocated with the satellite modem at the moment (I called Hughesnet Level 1 support, with the net result after an hour that now I have dropped from 40% availability to 1% availability.... really, they need to train level1 support better, there is only so much that can be done from a script)-- anyway, I sort of recall the voltage is 30-40v, which implies that 100' (round trip) of CCS adds 4-8% additional drop.
This probably affects transmit much more than receive, receive maybe more in noise margin reduction. I don't see this as being sufficient to make or break the link quality if the signal were adequate though-- partly this is because the original installer would go up to 200' outdoors with the cable he was using, 4x my length, and that apparently was functional (with copper).
If I ever get the blasted thing working again it would be interesting to experiment with swapping cable sections and observe the results. At the moment further experimentation is pointless.
Yes, I know, the latency is mostly geosync and unless Einstein was wrong that isn't going to change.... |
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grohgreg
Dunno. Ask The Chief
join:2001-07-05
Dawson Springs, KY
3 edits | reply to DaveL
Horse7: You're correct that Cu is more important on the TX than on the RX. But it's important that both runs present identical potential to the modem. Plus, you never know when it may be come necessary to swap Tx and Rx cables around.
Do you understand skin-effect? It's a problem with CCS. With CU, there's no "skin".
//greg// |
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