Peter takes note that it is Time for the world peashooting championships again!. This is what happens when junior high school kids get older but don’t grow up. Age does make a difference as the tools of youth tend to acquire a sophistication of accessories and enhancements. While some keep to the bare bones classic straw armament, others are using gyroscopic stabilization, optical scopes, and laser indicators. Check it out.
Archive for July, 2010
Peashooting tech
Sunday, July 11th, 2010Signal strength
Friday, July 2nd, 2010It looks like Apple has stimulated some renewed interest in signal reports. Their latest cell phone has an antenna that is placed to keep the brain cancer folks happy but it can be easily hampered depending upon how you hold the phone. One problem Apple has was the phone signal strength indicators. Most cell phones use a 5 bar weak to strong signal indicator. This is like the Ham’s S meter. They can be deceptive.
cnet FAQ: What does the 5-bar signal strength icon really mean? has a good rundown on the issue.
With old time radios, signal strength was based on what the radio could pull out of the background noise. These days, a common power level to get a readable signal may be -100 dBm which is about a tenth of a trillionth of a watt (1e-13). A billions of a watt, -60 dBm, would usually be considered an excellent signal. By IARU standards a radio S-9 (very good signal) is equivalent to a power of -73 dBm for frequencies below 30 MHz. Each S unit is 6 decibels
My cable modem is reporting -12 dBmV down and 54 dBmV up. To convert volts to watts, you need to use the 75 ohm impedance of the cable. See From dB to S-point : Learn to play with power units (ON4SKY) for more on calculating signal strength in various units.
HDBaseT
Friday, July 2nd, 2010The big story this week seems to be a new cable standard for high definition TV’s. “Valens, LG, Samsung and Sony teamed up to work on an entirely new cabling system named HDBaseT.Valens, LG, Samsung and Sony teamed up to work on an entirely new cabling system named HDBaseT.” (Tech.Blorge).
This is an ‘about time’ thing. The new standard uses existing and well proven Cat 5 network wiring. The interesting parts will be how they can run 100 watts over 24 gauge wires while still supporting extremely high data rates. EE Times indicates this may be a result of some DSP magic by Valens. A comment at Tech Reports illustrates the power feed problem, though.
Appliance Magazine says “The cornerstone of the technology is 5Play, a feature-set that converges uncompressed HD video, audio, 100BaseT Ethernet, high power over cable, and various control signals through a single 100-m/328-ft CAT5e/6 LAN cable.”
The comparison chart (PDF) indicates a data rate of nearly twice that of HDMI 1.4, cable lengths an order of magnitude longer, standard cable and connectors, power delivery sufficient for medium sized TV’s, and daisy chain, USB, and networking capabilities.
Engadget says this was introduced at CES 2009 so it’s taken a while to settle to the 1.0 specification.
The telephone company designed the twisted pair cable and the RJ connectors for low cost and reliability. Ethernet has used that technology successfully and enhanced data rates by improving cable quality. The key to this HDBaseT standard is in the interface chips that Valens is producing. If those chips can be provided at low cost and if clones can be developed, also at low cost, this new standard could indeed match its hype.