On Tue, 12 Jun 2012 04:49:35 -0400, "Michael A. Terrell"
wrote:


Name CISCO DPC2100R2
Modem Serial Number 224656807
Cable Modem MAC Address xx:xx:xx:xx:xx:xx
Hardware Version 2.1
Software Version dpc2100rx-v202r1256-110513Uas-TWC
Receive Power Level -4.9 dBmV
Signal to Noise Ratio 37.7 dBmV
Transmit Power Level 41.5 dBmV
Cable Modem Status Operational

I only edited the MAC Address, for security reasons.

Veddy strange. SNR usually isn't expressed to 3 significant figures
and should be in dBm, not in dBmV. The firmware scribblers seemed to
have goofed. Oh well.

Directional couplers provide better isolation from the garbage sent
upline by crappy TV tuners.

Huh? The FCC demands that anything connected to an antenna have very
low LO radiation. That transfers to the cable TV connection when the
F connector is attached to the cable instead of an OTA antenna.

This is kinda old, but covers the topic:
New Measurements and Predictions of UHF Television
Receiver Local Oscillator Radiation Interference
http://h-e.com/sites/h-e.com/files/tech_docs/rw_bts03.pdf
With 40dBmV (or about -9dBm @75 ohms) transmitted on the return path,
even a lousy LO radiation of maybe -40 to -60dBm in the return channel
isn't going to do much damage.

I'm used to using a Fireberd to measure the BER on digital
communication systems.

The Acterna (JDSU) Fireberd is a nifty gadget. I had an Acterna
HST-3000 but didn't have the CATV plug in or software. I did have a
BERT but it maxed out at T1 rates.

FPQSK was real fun when we first added it to our
telemetry products. The units are those selected by SA, long before
Cisco bought that divison. At one time we built the SA Telemetry
receiver that they had cloned from our 1200 series.

I think you mean FQPSK.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS