![]() January, 2002 |
MEETING SITE CHANGED
The school is closed January 21 so the meeting has been moved to the conference room at 610 State Street, Hudson and tours of the Columbia County E911 communications center will be available after the meeting. As usual the meeting is at 7 PM and talking will be on the 147.21 repeater. ![]() W1AW REVISES SCHEDULE
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Time to gather up all those treasures and near treasures and dust them off for the annual auction. March 18 isn’t that far away and it may take that long to get the dust off some of those, er, gems so others will see their real value. Remember that your “excess” whatcha may call it may be just what some one else is looking for to finish their dream station. This is our only fund raiser and a lot of fun so plan on being there, selling your treasure and hauling home the find of the night.
CW frequencies include code practices, Qualifying Runs and CW bulletins.
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Instant Messaging, Ham Radio, Computers, and Recruiting Teens to Amateur Radio It has been said in the Amateur publications, magazines and club newsletters, that young people are not attracted to our beloved hobby of Ham radio because they are more attracted to computers, the internet, the cute blonde next door, etc. Well, we’re no competition for young blondes, but we do have something to offer that can compete with computers and the internet. The best way to compete with computers is to use them in conjunction with Amateur Radio. The digital modes that have become so popular in the past few years require a computer, a transceiver, a few cables from Radio Shack, and little else! Most of the young folk today are using the internet for instant communication with their friends. And, most of them are located locally. If there’s one thing we hams are good at, it’s communication, right? What we have with our VHF repeaters and HF digital modes is wireless instant messaging! The kids (and a lot of adults) have made AOL’s Instant Messenger and ICQ into a replacement for the telephone and post card. Heck, we can do that without the internet! The amazing thing about the new digital modes is that all of the esoteric (and even messy) equipment we used in “the Good Old Days,” has been replaced by a computer and it’s sound card. Using that, along with free software, we can then enjoy radio teletype (RTTY), PSK31, AMTOR, PACTOR, and even slow-scan television (SSTV). So, you say, many will have a computer, but ham rigs cost over a thousand bucks! Yes, that’s true, but good used rigs are available for quite a bit less money. But also, there are some new exciting kits available now, which will work very well. One of the is the “WARBLER” 80 meter transceiver kit available from the New Jersey QRP Club at their web site: http://www.njqrp.org/warbler/ The kit includes a printed circuit board, all parts and building instructions. An “Elmer” and a new Ham can easily construct this little rig in a few evenings. The amazing part is that the kit costs only $45! Add an 80 meter antenna and a computer and you’re “Instant Messaging” with your friends! There are kits available for other bands as well. 20 and 10 meters are also popular with the PSK crowd. While these little rigs put out only a few watts, the wonderful nature of the digital modes makes them work extremely well at low power. No “Big Guns” needed here for solid contacts!
So, what are you waiting for? Get on these modes. Listen to 3.580 MHz or 14.070 MHz. Hear the “warbling?” Download the free software, DigiPan, from http://members.home.com/hteller/digipan/ install it and hook your computer up to your rig. The web site has simple instructions on how to do it. Once you’ve got it working, give me a call. And, if you can get his attention away from that cute blonde, call that kid over to show him what he can do with Amateur Radio.
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WHERE IT ALL BEGINS
Carl Luetzelschwab K9LA has written another piece explaining basic shortwave propagation principles, titled The Sun, the Earth, the Ionosphere, What the Numbers Mean, and Propagation Predictions – a brief introduction to propagation and the major factors affecting it. The Sun emits electromagnetic radiation and matter as a consequence of the nuclear fusion process. Electromagnetic radiation at wavelengths of 100-1000 Angstroms (ultraviolet) ionizes the F region, radiation at 10-100 Angstroms (soft X-rays) ionizes the E region, and radiation at 1-10 Angstroms (hard X- rays) ionizes the D region. Solar matter (which includes charged particles – electrons and protons) is ejected from the Sun on a regular basis, and this comprises the solar wind. On a 'quiet' solar day the speed of this solar wind heading toward Earth averages about 400km per second. The Sun's solar wind significantly impacts the Earth's magnetic field. Instead of being a simple bar magnet, the Earth's magnetic field is compressed by the solar wind on the side facing the Sun andis stretched out on the side away from the Sun (the magnetotail, which extends tens of earth radii downwind). While the Sun's electromagnetic radiation can impact the entire ionosphere that is in daylight, charged particles ejected by the Sun are guided into the ionosphere along magnetic field lines and thus can only impact high latitudes where the magnetic field lines go into the Earth. Additionally, when electromagnetic radiation from the Sun strips an electron off a neutral constituent in the atmosphere, the resulting electron can spiral along a magnetic field line (it spirals around the magnetic field line at the electron gyrofrequency). Thus the Earth's magnetic field plays an important and critical role in propagation. Variations in the Earth's magnetic field are measured by magnetometers.
There are two measurements readily available – the daily A index and the 3-hour K index. The A index uses a linear scale and goes from 0 (quiet) to 400 (severe storm). The K index uses a quasi-logarithmic scale (which essentially is a compressed version of the A index) and goes from 0 to 9 (with 0 being quiet and 9 being severe storm). Generally an A index at or below 15 or a K index at or below 3 is best for propagation.
Sunspots are areas on the Sun associated with ultraviolet radiation. Thus they are tied to ionization of the F region. The daily sunspot number, when plotted over a month time frame, is very spiky. Averaging the daily sunspot numbers over a month results in the monthly average sunspot number, but it is also rather spiky when plotted. Thus a more averaged, or smoothed, measurement is needed to measure solar cycles. This is the smoothed sunspot number (SSN). The SSN is calculated using 6 months of data before and 6 months of data after the desired
month, plus the data for the desired month. Because of this amount of smoothing, the official SSN is one half year behind the current month. |
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(Continued from Page 2)
Sunspots come and go in an approximate 11-year cycle. The rise to maximum (4 to 5 years) is usually faster than the descent to minimum (6 to 7 years). At and near the maximum of a solar cycle, the increased number of sunspots causes more ultraviolet radiation to impinge on the atmosphere. This results in significantly more F region ionization, allowing the ionosphere tofract higher frequencies (15, 12, 10, and even 6 meters) back to Earth for DX contacts. At and near the minimum between solar cycles, the number of sunspots is so low that higher frequencies go through the ionosphere into space. Commensurate with solar minimum, though, is less absorption and a more stable ionosphere, resulting in the best propagation on the lower frequencies (160 and 80 meters). Thus in general high SSNs are best for high frequency propagation, and low SSNs are best for low frequency propagation. Most of the disturbances to propagation come from solar flares and coronal mass ejections (CMEs). The solar flares that affect propagation are called X-ray flares due to their wavelength being in the 1-8 Angstrom range. X-ray flares are classified as C (the smallest), M (medium size), and X (the biggest). Class C flares usually have minimal impact to propagation. Class M and X flares can have a progressively adverse impact to propagation. The electromagnetic radiation from a class X flare in the 1-8 Angstrom range can cause the loss of all propagation on the sunlit side of the Earth due to increased D region absorption. Additionally, big class X flares can emit very energetic protons that are guided into the polar cap by the Earth's magnetic field. This can result in a polar cap absorption event (PCA), with high D region absorption on paths passing through the polar areas of the Earth. A CME is an explosive ejection of a large amount of solar matter, and can cause the average solar wind speed to take a dramatic jump upward - kind of like a shock wave heading toward Earth. If the polarity of the Sun's magnetic field is southward when the shock wave hits the Earth's magnetic field, the shock wave couples into the Earth's magnetic field and can cause large variations in the Earth's magnetic field. This is seen as an increase in the A and K indices. In addition to auroral activity, these variations to the magnetic field can cause those electrons spiraling around magnetic field lines to be lost into the magnetotail. With electrons gone, maximum usable frequencies (MUFs) decrease, and return only after the magnetic field returns to normal and the process of ionization replenishes lost electrons. Most of the time elevated A and K indices reduce MUFs, but occasionally MUFs at low latitudes may increase (due to a complicated process) when the A and K indices are elevated. Solar flares and CMEs are related, but they can happen together or separately. Scientists are still trying to understand the relationship between them.
One thing is certain, though – the electromagnetic radiation from a big flare, traveling at the speed of light, can cause short-term radio blackouts on the sunlit side of the Earth within about 10 minutes of the eruption. Unfortunately we detect the flare visually at the
same time as the radio blackout since both the visible light from the flare and the electromagnetic radiation in the 1-10 Angstrom range from the flare travel at the speed of light - in other words, we have no warning. On the other hand, the energetic particles ejected from a flare can take up to several hours to reach Earth, and the shock wave from a CME can take up to several days to reach Earth, thus giving us some warning of their impending disruptions.
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Panel Recommends Eliminating Novice Bands The ARRL Novice Spectrum Study Committee has recommended that the ARRL petition the FCC to eliminate the CW novice subbands and allow Novice and Technician with element 1 credit licensees to operate CW on the general 80, 40, 15 and 10 meter cw allocations at up to 200 W output. The panel suggested recognizing portions of those bands for ''slow CW operation'' to aid new CW operators in enhancing their skills. The committee recommended refarming the current Novice/Tech Plus subbands in part to allow expansion of the phone allocations on 80, 40 and 15 meters. The committee's complete report will be presented to the ARRL Board of Directors for consideration during its annual meeting in January. The committee's determinations were based on opinions expressed by 4744 respondents to an ARRL Novice Spectrum Study survey launched in June. Those expressing their opinions included ARRL members and nonmembers. Nearly 61% of those responding were Extra class licensees. The committee, chaired by ARRL International Affairs Vice President Rod Stafford, W6ROD, has been studying the status and usage of the Novice/Technician Plus HF bands with an eye toward determining appropriate changes in usage of that spectrum now that the FCC no longer issues new Novice licenses. A guiding principle was that no class of licensees would lose any privileges as a result of refarming. The committee recommended expanding the phone bands in accordance with the most popular of the survey choices offered--three for 80, 40 and 15 meters and two for 10 meters. Here's a summary: * On 80 meters, nearly 40% of those responding opted for a plan that would extend the US phone allocation to 3700 kHz, with Extras permitted on the entire subband, and with Advanced and General class subbands starting at 3725 and 3800 kHz respectively. * On 40 meters, nearly half of the respondents picked the plan to extend the primary US phone allocation to 7125 kHz, with Extra and Advanced licensees allowed on the entire segment and Generals from 7175 kHz and up. (The committee's report suggested no changes to the special allocations for amateurs on certain Pacific or Caribbean islands and in Alaska.) * On 15 meters, nearly half of those responding wanted the US phone allocation extended to 21175 kHz, with Extras permitted on the entire allocation, and Advanced and General subbands beginning at 21200 and 21250 kHz respectively. * On 10 meters--where Novice and Tech Plus licensees already may operate CW, RTTY and data from 28100 to 28300 kHz, nearly 55% of the respondents favored a plan to retain the US phone allocation from 28300 to 29700 kHz and to extend CW access to Novice/Tech Plus operators to 28000 kHz--an additional 100 kHz. The current Tech Plus 28300 to 28500 kHz phone segment would be retained. ARRL Bulletin 55 |
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