Date and time: Tuesday, May 1, 2007 at 7:30 p.m.
Location: Salvation Army Building, 1033 Big Bethel Road.
Subject:  Computer Spam & Security

This month we continue supporting many Public Service Events, see the list else where. Operators are always needed. You can help part time or full time at each event. Most events also need folks that don't have to be out in the field. Please try to help whenever possible. If you don't know who to contact, contact me and I'll get you to the right person.

There are also 2 training classes this month. NIMS training will be given as part of CERT Classes on Thursday May 10th at 6:30 pm at Hampton Fire Station 9 on Briarfield Road between the main Post Office and Briarfield Park. NIMS training may be needed to support an emergency, contact your EC.

SKYWARN Training will be held May 17 at 6:30 pm in Hampton Council Chambers, 8th floor of City Hall. This class gets you certified as a NOAA NWS Spotter for 3 years. Email me ASAP for enrollment in either or both classes as there is limited room.

Articles and comments on the articles are needed. Thanks to Chris, KC4CMR and Don, N4DJ we have some interesting stories this month. Feel free to share SPARKGAP with all your friends. Non-SPARK members can get on the mailing list by dropping me a note.

73,

Stu, N4STU
[Note: click on the BLUE callsign to send email to the editor]

The next edition will be mailed about May 30th.  Articles and comments due by May 26th.

May

• Wednesdays, 7:00 pm CW Class and antenna discussion, VA Air & Space Center
• 1st, Tue., 7:30 pm SPARK meeting
• 2nd, Wed., 7:30 pm PARC business meeting
• 4th - 5th, Fri. and Sat., Children's Festival, downtown Newport News
• 9th, Wed., 6:30 pm NIMS Training, Hampton Fire Sta. 9
• 11th, Fri., 2:00 pm Relay for Life, Todd Stadium
• 14th - 18th, 7:15 pm HPT BoD meeting this week, day tbd
• 12th, Sat., 10:00 am PEARS meeting
• 16th, Wed., 7:30 pm PARC program meeting
• 17th, Thu., 6:30 pm SKYWARN Class, Hampton Council Chambers
• 19th, Sat., all day Tour de Chesapeake, Mathews County
• 19th, Sat., Community Safety Fair, Northampton Church of Christ
• 25th, Fri., Flag Planting @ National Cemetery
• 26th, Sat., 8:30 am HPT breakfast meeting

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The Daffodil Festival was held April 7th in the blowing snow. The roads were slick and there was a good 4 in. of snow at Gloucester Courthouse. Lots of fun, I'm sure!

These are the events I am aware of that are coming, so reserve some dates to help out.
May 4th & 5th, The Childrens Festival in downtown Newport News
May 11th, Relay for Life, Todd Stadium
May 19th, Tour de Chesapeake, Mathews County
May 19th, Safety Fair at Northampton Church of Christ
June 2nd, The Running Crab 15 K race in downtown Hampton
June 23rd and 24th, Field Day
July 14th, Disaster Volunteer Day, Liberty Baptist Church
September 8th and 9th, Bay Days, downtown Hampton
October ??, Fall Festival, Newport News Park
October ??, NN City Employees Picnic, Newport News Park
And of course the holiday events in Newport News and Hampton.

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QSL Card Program
We have added a new Power Point program to the ARRL multi media library. www.arrl.org/multimedia  The QSL card has traditionally been called the final courtesy of the contact. "QSL Cards -- Sending and Receiving Paper Gems" shows the operator the ins and outs of exchanging QSL cards.  Some of the topics covered in this program include using the outgoing and incoming QSL bureaus, working with QSL managers and basic information required for a valid QSL card. We have even included some tips from the experts for QSLing those elusive DX cards. The program also includes handout material that will serve as a handy reference.  All of the programs in the multi media library are free to download and make excellent meeting programs. 

reprinted from ARRL Club Newsletter dated April 6, 2007

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Bogus e-mails that claim to be from the "arrl.net user support = team."
Do not follow instructions in bogus e-mails: The ARRL is alerting members -- and especially users of the ARRL E-Mail Forwarding Service <http://www.arrl.org/members-only/emailfwd.html> -- about bogus e-mails that claim to be from the "arrl.net user support team." There is no such entity, and the messages do not originate with ARRL but appear to be coming from outside the US. Recipients should not follow the instructions in the e-mail, which reads, "We have received reports that your e-mail account has been used to send a large amount of unsolicited commercial email messages during this week. We suspect that your computer had been infected by a recent virus and now contains a hidden proxy server. We recommend you to follow our instructions in order to keep your computer safe." Following the instructions will have the opposite effect, however, infecting your computer with the MyDoom Trojan worm and making it part of a spamming network. The League urges all members to invest in and use anti-virus software.

reprinted from ARRL Letter dated March 30, 2007

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This is the last of two parts, submitted by Don, N4DJ
Antenna Basics Part 2

Antenna patterns

Most of the time we think of antenna patterns or directivity in terms of directions of the compass, like North or 0 degrees, North East or 45 degrees and so on.  We sometimes tend to forget that an antenna has vertical directivity also.  For example a quarter wave vertical, like a 2 meter mobile antenna, radiates very little energy straight up.  That's usually a good thing good unless you want to work someone up on the International Space Station! All of the energy that would have been radiated straight up (where there is usually no one to talk to) is re directed to a lower angle where it is more = useful.

Suppose we have a dipole in free space.  If you look into the end of that dipole the radiation from that dipole will be the same all the way around the wire.  There will be radiation straight up as well as straight down.  Now let us bring that dipole down from space and put it near the ground.   The radiation that goes down and hits the earth is reflected right back up.  Depending on the distance the antenna is above ground, this reflected wave may be in phase with the wave that is being radiated straight up and add to it so the signal above the antenna is twice as strong as it would be with out the reflection. However, at other heights, the reflected signal could almost completely cancel the upward radiation and the result would be almost no signal above the antenna.  At this point we have only considered the radiation straight up and straight down. A similar situation exists for any angle.  For example, the part of the wave that strikes the earth at a 45 degree angle, will be reflected back up at a 45 degree angle.  At some point far away from the antenna, 45 degrees above the horizon, this reflected wave will interact with the direct wave and there could be almost complete cancellation of the wave, there could be addition of the two waves (the signal could almost double) or the signal strength could be anywhere from almost zero to almost double!  It all depends on the height above ground in terms of wavelength.  The effect is the same for a 10 meter dipole at 33 feet as it is for an 80 meter dipole at 253 feet.  Maybe this is at least part of the reason some people can work DX on 10 meters with a dipole only 33 feet high while finding it almost impossible on 80 meters with a dipole 33 feet high.  The dipole at 33 feet on 10 meters has the reflected wave adding to the direct wave at low angles necessary to long distance communications, where as the 80 meter dipole is very low in terms of wavelength at only 33 feet and there is almost complete cancellation of the wave radiated at the low angles. Go to http://www.eznec.com and download the free demo version to EZNEC and try it out using the backyard dipole example at various heights above ground.