OSCAR News - August, 2ØØ9
The next OSCAR meeting is 08-Aug @ 9:00 AM, the second Saturday of the month. Meetings are held in the meeting room at the Owatonna Hy-Vee, 1620 Cedar Ave S. Note new meeting location. The Happy Chef closed its doors on 26-Jul. We appreciated their hospitality while we met there.
The next SKYWARN meeting is 18-Aug @ 7:00 PM, the third Tuesday of the month. Meetings are held at the Owatonna Fire Station.
Dale WB0PKG, Jeff KC0UOW, and Tom N0UW spent a pleasant evening pulling four additional runs of coax into the basement of the EOC. This will allow additional equipment for voice and digital modes. The City provided a run of 1-1/2" conduit for the coax run and an additional ground rod for lightning protection.
Simulated Emergency Test
The July issue of QST included the results of the 2008 SET. It caught the editors eye for two reasons. There was a nice story about Obion County, TN, which is where the editor moved to Owatonna from. The Reelfoot ARC serves the far western counties of KY and TN along the state line.
The second item of interest was the state-by-state summary. Steele County was the only entry for Minnesota. The 2008 SET was a demonstration of transferring messages using PSK. The 2008 SET was part of the annual Steele County drill.
Lightship & Lighthouse Weekend
From AR Newsline
A total of 135 registrations have been received from 18 countries have already been received by the organizers of International Lightship & Lighthouse Weekend. Many more are expected before the event takes
place on the weekend of August 15th and 16th. For an online entry form and a list of entrants, visit the
International Lightship & Lighthouse Weekend website.
Austin ARC Fox Hunt
The Austin Amateur Radio Club is planning on having another Fox Hunt. It is tentatively set for September 12, 2009 at Victory Park in Brownsville, MN. The plan is to kick off the day with a 10am Swap Meet followed by the fox hunt at 1pm then finishing the day off with a grill out in the park at 4pm.
Updated Information - 02-Aug - The event will be held in Blooming Prairie, the fox hunt will begin around noon.
W1AW Digital Modes
W1AW will begin using twodifferent modes on 17-Aug-2009. AMTOR and ASCII transmissions will be replaced with PSK31 and MFSK16, respectively. RTTY (Baudot) will continue to be the first digital mode used in the transmission schedule. The W1AW operating schedule -- complete with times and frequencies-- can be found on the at
MN ARES SEC
Dan Anderson KDØASX has been named as the new MN SEC. Dan has been DEC for MN District 5 DEC and is also the Nobles County Emergency Management Director. He has worked on behalf of the region's hospitals, health clinics, long-term care facilities and public health agencies to create an amateur radio emergency communications system between these entities. He is also active in regional and statewide public safety interoperable communications planning, serving as a subcommittee chair charged with developing and funding a strategic technology reserve of equipment in case of catastrophic failure of public safety interoperable communications within the state.
At every OSCAR license class, the questions is always raised about what type of radio to buy. The Elmers of the class are usually happy to extoll the virtues of the equipment in their shack and mobile installation. In an attempt to help newcomers to Amateur Radio answer that very question, the ARRL is adding a suplement to the ARRL Ham Radio License Manual. The guide covers VHF, UHF, and antennas. ARRL members who are logged on to the ARRL Web site can view Choosing a Ham Radio: Your Guide to Selecting the Right Equipment online.
From AR Newsline
The FCC of the United States has finally issued new proposed regulation for Broadband over Powerline Internet access. It is seeking comment on the power levels that should be permitted for BPL systems so they don't cause interference with other services. The new proposal is the result of litigation won by the ARRL last year regarding new requirements and measurement guidelines for Access Broadband over Power Line Systems. So far the ARRL is yet to make
known its response to the new proposal. (Southgate)
From Fast Company
In 1890, Tesla based his wireless electricity idea on a concept known as electromagnetic induction. We know that electric current flowing through one wire can induce current to flow in another nearby wire. This is the basic process of any simple transformer. After more than 100 years of dashed hopes, several companies are coming to market with technologies that can safely transmit power through the air. In addition to inductive coupling, potential technologies include Radio-Frequency harvesting and magnetically coupled resonance.
In Radio-Frequency harvesting, electricity is transformed into RF and is transmitted across a room. Power harvesters receive the RF and convert it back into low-voltage direct current. Magnetically coupled resonance uses two coils. Energy is transferred bwteen the coils when the magnetic resonance matches.
World's Smallest Incandescent
From Live Science
Incandescent bulbs have used carbon filaments since Thomas Edison. Researchers created a filament from a single carbon nanotube. At jus t100 atoms wide, it is invisable unless illuminated. It really does not have any practicle use. the goal is to help scientists better understand how the physics of large things and the physics of invisible things are possibly related.
60MHz CMOS Chips
From Science Daily
Researchers have produced a CMOS chip capable of transmitting 60 GHz digital RF signals. The design could speed up commercialization of high-speed, short-range wireless applications, such as wireless home DVD systems by moving gigabytes of video almost instantly. The chip unites 60GHz CMOS digital radio capability and multi-gigabit signal processing, achieving 15 Gbps data transfer rates at a distance of 1 meter, 10 Gbps at 2 meters and 5 Gbps at 5 meters.
From National Science Foundation
Scientists created the first-ever comprehensive computer model of sunspots. The new simulations can help scientists decipher the subsurface forces in the sun that cause sunspots. The research team designed a virtual, three- dimensional domain measuring about 31,000 miles by 62,000 miles, and about 3,700 miles in depth - an expanse as deep as Earth's radius. Each grid point was spaced 0 to 20 miles apart, creating 1.8 billion grid points. Dynamics are simulated using a series of equations involving fundamental physical laws of energy transfer, fluid dynamics, magnetic induction and feedback, and other phenomena.
Radiation and Pain
The effect of radiation from cell phones has long been under discussion. Aside from the cancer issue, they are also accused by some of causing pain. A growing number of people around the world claim to be physically responsive to the electromagnetic fields that surround phones and the other electronic devices. Sweden recognises such sensitivity as a disability. Studies of those claiming to be electrosensitive, however, show their ability to determine whether they are being exposed to a real electric field or a sham one is no better than chance.
Researchers used a body scanner to see how people’s brains react to two different kinds of stimulus. Participants were put in the imager and told that they would undergo a series of trials in which they would be exposed either to an active mobile phone or to a heating device called a thermode. The thermode was real. The mobile phone, however, was a dummy. The type of stimulus, be it the authentic heat source or the sham electromagnetic radiation, was announced before each exposure and the volunteers were asked to rate its unpleasantness on a five-point scale. In the case of heat, the two groups’ descriptions of their experiences were comparable. So, too, was their brain activity. However, when it came to the sham-phone exposure, only the electrosensitives described any sensations and showed neural activity to match. This suggests that electrosensitivity is akin to other well-known psychosomatic disorders.
From New Scientist
While we are still getting throuhg the transition to DTV, a lengthy battle between competing 3DTV formats is brewing. Today,
anyone interested in a 3D system for the home must pick between three or more very different and incompatible technologies. Polarised views involves a home theatre projector running at high frequency to deliver left and right images in rapid succession. Viewer wears LCD spectacles that alternately block the left and right eye view to ensure that each eye only sees the correct viewpoint. Panasonic's 3D offering uses a plasma screen to flash the alternate left and right images. Hyundai uses an LCD screen to display left and right images simultaneously with a filter over the screen to polarise the two images differently. The closest the industry standard is Panasonic's campaign to add 3D playback to the Blu-ray. This could lead to a single format for discs or broadcasts that any 3D or even 2D TV set can play.
Line of Sight
From Multiple Sources
When we talk about VHF/UHF communications, we often refer to the range as being dependent on the line of sight. What does “RF line of sight” really mean? We like to think of everything in perfectly straight lines, but radio waves don’t necessarily act that way. Some waves will travel the straight line, while others will effectively spawn new waves at each wave front (i.e. wave length) which interfere both constructively and destructively. Enter the Fresnel Zone. Fresnel showed the waves create ring shaped zones between two points.
The size of the cirlce is dependent on the distance between two points and the wave length. Imagine two antennas placed 2km apart. At 150 MHz, the diameter of the circle midway between the two antennas would be over 200 feet. A WiFi connection at 2400 MHz produces a 10-inch circle. The Fresnel Zone needs to be considered with any obstructions, the size of the obstruction, and type of obstruction. If the onstruction is tree, WiFi sees foliage as a significant obstruction. VHF doesn’t really see foliage as too much of an obstruction at all. A
calculator is available to experiment
A grass fire caused the collapse of a 600-foot radio tower in the Sacramento, CA area. Heat from the fire caused structural damage to an adjacent tower. The second tower was intentioanlly brought down and captured with as part of a
video news story.
From AR Newsline
Back in February, the DTV conversion was delayed because over 1.7 million households were not prepared. Over a month after the 12-Jun switchover, 1.5 million United States households with television receivers in them remain unready for DTV.
DTV and TVI
From ARRL Contest Update
Digital TV may be less susceptible to the usual types of TVI, but as more people add antennas and preamps to receive the signals in fringe areas, overload from nearby ham transmitters may be a problem. Since most DTV signals are now in the high-VHF or UHF channels above 2 meters, a high-pass filter with a cutoff frequency below channel 7 (174 MHz) would work well. Microwave Filter Company series 3378 head-end filters are an example. They can be installed between an antenna and DTV receiver or preamp. Adding some common-mode ferrite chokes on the feed line can also reduce pickup of strong HF and VHF signals that could cause overload problems, as well. Even local paging and FM broadcast stations can cause overload problems - notch filters, such as those made by Winegard, help in these situations. (Thanks, Paul W9AC and Jim K9YC)
From Broadcasting Cable
There was a lot of hype about the improved picture quality the public would enjoy with DTV. Now that it is here, broadcasters are working to reshape the bandwidth of signals. Local broadcasters are degrading HD picture quality to allow them to transmit digital subchannels alongside the primary HD stream. The subchannels are at the expense of the high-definition images that were the primary impetus for the DTV standard. Stations will need to balance HD picture quality, existing SD subchannels, and new services.
Older 440MHZ radio for control link. Single channel needed for receive only with PLL decode.
Tom NØUW: email@example.com