Yea. While I will admit I have good signal levels there I failed to provide my previous signal levels before doing a COMPLETE overhaul of the wiring situation. While the firmware upgrade issue and subsequent noise related issues may be solved with new firmware, I have done some research and have found that my firmware is quite outdated compared to many others using the SB5120. While this is RCN's responsibility to monitor and upgrade users of the SB5120, I doubt they have kept on top of it. My firmwares' version is as follows:
Software Version: SB5120-2.19.0.8-SCM02-NOSH
Hardware Version: 4
MIB Version: II
GUI Version: 1.0
VxWorks Version: 5.4
Now my cable signal seems quite stable at those numbers stated above. In essence, to correct the UDP packet loss and restore my speeds to the FULL Mach20 specifications I did the following: ran a separate RG-6 Quad Shield line (using high-quality F-type compression connectors and an expensive COAX cable stripper) to my modem, installed a 1-way passive tap (one port of a 1-way tap has -1dB of loss while the other port takes on a full -6dB insertion loss), and finally I installed a 4-way Scientific Atlanta tap MODEL SAT4G-11.
Link to SAT4G-11 here:
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www.cisco.com/application/pdf/en···7ab0.pdfLink to 1-way tap description, use of, and more here:
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Cable Modems and Wiring IssuesMy NEW setup configuration to my modem is as follows (where ---> indicates a RG-6 COAX cable run):
cable plant--->1-way 'lossless' tap--->Motorola SB5120
Connected to the 2nd port of the 1-way 'lossless' tap is the SAT4G-11 and off of the SAT4G-11 is one more 2-way splitter to accommodate for the extra cable run now used by my modem.
I have to say I have been working all night on the internet and monitoring signal levels, UDP packet loss (mainly the intermittent dropouts when my SNR began to fluctuate), and the temperature... and I believe I have really solved all my problems.
Prior to solving such problems, My "Forward Signal to Noise" levels were between 32-33.6dBmv, the "Modem TX Power" was at 52dBmv, and my "Forward Power Level" read at 8.2dBmv.
My OLD setup to my cable modem was as follows (where ---> indicates a cable run using RG-6 COAX):
cable plant--->2-way splitter -3.5dB/port & -130EMI--->ANOTHER 2-way splitter--->Motorola SB5120
Off of the FIRST 2-way split I had one port running to the SECOND splitter and the OTHER port off of the FIRST splitter ran to a 4-way -3.5dB/port passive splitter connecting 4 televisions. So then off of the SECOND 2-way splitter, I had my modem connected to one port while the OTHER port of the SECOND splitter was connected to a HD-DVR.
It seems complicated, and this took me more than an hour to complete, but is quite easy if you have the resources.
Feel free to PM me and I can hopefully answer any questions any of you have.
-Bill
HERE is another link that is a good step-by-step discovery into RCN, speed drops during the winter, and the associated temperature:
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forums.speedguide.net/archive/in···679.html------------------------------
SPEED TEST RESULTS WITH RECONFIGURATION
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Download #1
------------------------------------------------------------------
File size transferred : 29.5 MB (30937448 bytes)
Total time taken : 11.56 seconds (11563 milliseconds)
Throughput : 2675.0 KB/sec [Kilobyte-per-second]
= 2.67 MB/sec [Megabyte-per-second]
= 21400.0 Kbps [Kilobit-per-second]
= 21.4 Mbps [Megabit-per-second]
Upload #1
------------------------------------------------------------------
File size transferred : 29.5 MB (30937448 bytes)
Total time taken : 117.69 seconds (117687 milliseconds)
Throughput : 262.0 KB/sec [Kilobyte-per-second]
= 0.26 MB/sec [Megabyte-per-second]
= 2096.0 Kbps [Kilobit-per-second]
= 2.1 Mbps [Megabit-per-second]
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