Volume 00 Issue 04 April 2000
THE AMATEUR RADIO NEWSLETTER
Laurel Amateur Radio Club, Inc.
P.O. Box 3039, Laurel, Maryland 20709-3039
http://larcmd.org email: email@example.com
Meetings and Nets:
Þ 1st, 3rd, 5th Wednesdays:
On-the-air Net at 8:30pm on 147.225+ PL156.7 (no tone required during nets)
Þ 2nd Wednesday:
Informal/Social Gathering at 7:00pm – Tubby’s Restaurant; Rt. 198, 1 mile West of I-95
Þ 4th Wednesday:
Monthly Meeting at 7:30pm - The Woman’s Club of Laurel, 384 Main Street, Laurel
Informal Net/Rag-Chew from 9-11pm on 147.540
Laurel Amateur Radio Club, Inc.
c/o John Swann (W3BUY)
8729 Birkenhead Ct.
Laurel, MD 20723.
THE LAUREL AMATEUR RADIO CLUB
President: Pud Reaver W3YD 301-498-6293 firstname.lastname@example.org
Vice-President: Jim Cross WI3N 301-725-6829 email@example.com Secretary: Roger Davis W3LM 301-776-6961 firstname.lastname@example.org
Treasurer: John Menard N3GXA 301-725-1641 email@example.com
Other LARC Positions and Contacts:
Immediate Past President: John Menard N3GXA 301-725-1641 firstname.lastname@example.org
FAR Representatives: Dan Blasberg KA8YPY 202-667-5780 email@example.com
Laurel VEC: Bob Busch WB3KXJ 301-317-7819 firstname.lastname@example.org
LARC VE Testing: John Creel WB3GXW 301-572-5124 email@example.com
AutoCall Reporter: Roger Davis W3LM 301-776-6961 firstname.lastname@example.org
T-MARC/D-MARC Rep: Kevin Arber W3DAD 301-725-0038 email@example.com
Public Information Officer: Pud Reaver W3YD 301-498-6293 firstname.lastname@example.org
Youth Programs: Mark Doore K3RAM 301-572-2385 email@example.com
Education and Training: Pud Reaver W3YD 301-498-6293 firstname.lastname@example.org
Technical Specialist: Kevin Arber W3DAD 301-725-0038 email@example.com
ARES/RACES Coordinators: Jim Cross WI3N 301-725-6829 firstname.lastname@example.org
Official Emergency Station:
Official Bulletin Station: John Creel WB3GXW 301-572-5124 email@example.com
Official Bulletin Station: Pud Reaver W3YD 301-498-6293 firstname.lastname@example.org
Official Relay Station: Pat Gormley KK3F 301-864-4694
Official Relay Station: Pud Reaver W3YD 301-498-6293 email@example.com
LARC Special Interest Groups and Mentors:
Antennas Kevin Arber W3DAD 301-725-0038 firstname.lastname@example.org
Packet Radio/APRS Mark Doore K3RAM 301-572-2385 email@example.com
Repeaters John Creel WB3GXW 301-572-5124 firstname.lastname@example.org
ARRL Field Organization:
Atlantic Division Director: Kay Craigie WT3P 610-993-9623 email@example.com
Atlantic Division Vice Director: Bernie Fuller N3EFN 814-763-1529 firstname.lastname@example.org
MD/DC Section Manager: Bill Howard WB3V 410-551-6775 email@example.com
MD/DC Asst Section Manager: Jerry Gavin NU3D 410-761-1423 firstname.lastname@example.org
MD/DC Emergency Coord: Mike Carr WA1QAA 410-799-0403 email@example.com
Affiliated Club Coordinator: Tony Young WA3YLO 301-262-1917 firstname.lastname@example.org
MDC Section Bulletin Manager Al Brown KZ3AB 301-490-3188 email@example.com
The Feedback is published monthly as the newsletter of the Laurel Amateur Radio Club, Inc.
Permission is granted to reprint from this publication provided credit is given.
Editor: John Swann, W3BUY 301-490-1212 firstname.lastname@example.org
Publisher: John Creel, WB3GXW 301-572-5124 email@example.com
Here we are and it is already April, where is this year going? Welcome to the latest Feedback.
Well, my constant pleadings seem to be bearing fruit, and I am happy to report that I am now starting to get a number of articles for publication. But of course, like any Editor, I am not content with that – so put quill to paper, dust of the old typewriter or make use of that computer system that you assured the XYL would solve all of your problems. Use it to solve one of mine and let me have an article for the next issue. Hi. Also, thanks to those of you that provided photos from the VE Session on 15 April. I have managed to squeeze a couple in on one of the later pages. I also have a great article (with photos) on Jim WI3N’s new roof mounted dipole. Unfortunately that will have to wait until next month, as we have a slightly shorter Feedback this month so that we can attach the Membership Roster for 2000.
I must make one apology this month. I forgot to publish the minutes of the 23 Mar LARC meeting in the last issue, so this month you have two lots of minutes to keep you up to date.
I hope that many of you managed to get up to Timonium for the State Convention and Hamfest/Computerfest, and I also hope that you managed to find what you were looking for. I went up on the Sunday, and managed to get a good deal on the HT that I was looking for. The biggest problem with Hamfests is keeping track of what you came for, and not spending loads of cash on all of those nice to have items that you didn’t intend to buy but you just know that they will come in useful at some time in the future!!
The logo on the front page is from the Royal Naval Amateur Radio Society, of which I am a member. I had it lying around on the computer, so I though I’d use it to fill up that space this month.
That’s it for now. Take care of yourselves, and keep the airwaves humming.
vy 73 de John W3BUY.
The RESTRUCTURING program is in place, and LARC came through with flying colors. Thanks to Bob/WB3KXJ and his crew (I won’t attempt to list those who I have knowledge of, because there are probably more in the background) we processed about 200 applicants on the 15th, had our "after action" debrief, and were home around noon. Not bad, for a bunch of "amateurs".
We used the clubhouse to test, and we used the Laurel Community Swimming Pool for the "paper only" upgrades. The wx was semi-cooperative, and a fun time was had by all…sometimes, work can be fun! Thanks to all who were involved; and thanks this is not an annual event.
Also, a big "thank you" to Paul/N3YOY, who created a special section of our LARC webpage for the testing session. Paul reports there were 158 hits on the page that week, usually a monthly average …I’m sure many applicants looked there for last-minute directions. The URL for our page is on the front page of FEEDBACK. Also, he has added some pictures of that Saturday taken by W3LM and KB3EFS … check ‘em out.
Our meeting this month will be at the Prince George’s Office of Emergency Preparedness (OEP). After a short business meeting, Jim/WI3N will offer a tour and briefing of the overall program. Directions to the OEP are as follows, but we can meet at the clubhouse and caravan/carpool down there for folks interested. We’ll leave the clubhouse at 7PM Wednesday night.
Directions to PG OEP / EOC. Talk in/out
freq/operator is to be determined.
From Wash beltway take Rt 214 (Central Ave) west to Washington.
Go about 1 mile, turn right on Jonquil Ave.
Go 1 block and turn right on Anchor St.
When you get to parking lot turn right and park on right going up the hill, or park on right in front of building going down
the hill. The overflow parking area is on the north end of the building.
DO NOT PARK IN THE SMALL LOT PAST (SOUTH OF) THE FLAG POLE! THAT LOT IS RESERVED FOR THE 911 CENTER STAFF. TOWING ENFORCED!
Push buzzer on door and sign in, take elevator to second floor and proceed down the hall. Room is next to last on the left.
Upcoming events include the MONTPELIER arts and crafts fair on Sunday, May 7. Roger/W3LM may be looking for a "few good hams" to support this morning-only effort.
The following Saturday is the MAIN STREET FESTIVAL, probably our biggest affair of the year, and we can’t have enough help in the morning … we shadow key committee personnel; we do crowd and vendor control before the big parade; we control the parade, and the we operate the information booth until the festival is finished, around 4:30. All in all, we have a lot of fun, but are also an important part of the event. Please mark this date on your calendar…hope to see you there (May 13).
Personal note: I’ve cut a trip short, so I can witness the parade, which will feature a Presidential Honor Guard, Laurel’s Congressional-of-Honor Medal recipient, the American Legion Color Guard, and marching veterans of WWII.
Also, just remembered: The fund-raising adventure at the Bowie Baysox has not been forgotten ... the Rotary Club is scheduled for "training" on April 26, and may work their first game on the 28th. As soon as I know something, I will pass on the word.
And, CONGRATULATIONS to all club members who took advantage of the upgrade, or will in the future … hope to see you on the bands… 73/PUD
Minutes of the LARC meeting – 23 Feb 00
1. The meeting was called to order at 7:30p by Jim/WI3N, V/Pres., in the absence of the Pud/W3YD, Pres. There were 17 members present (and one dog). Introductions were completed. Six additional members entered after the meeting started. Visitors included, Nick/KC5KBO (from Houston, TX) and Mort/KA1IU (Columbia, MD).
2. The Treasurer reported a balance of approximately $1536.00. An insurance bill was due for $325.00. Members were reminded to pay their dues for the current year.
3. Bob/WB3KXJ provided a summary of the VEC activities and of the upcoming VE exams. An increasing number of individuals are being tested due to the new licensing structure.
4. Jim/WI3N conducted a summary of the upcoming activities to include the Main Street Festival (May 13th), Montpelier Festival, Field Day, Christmas In April, MD QSO Party, ARRL Nov Sweepstakes, Laurel 4th of July and the Pallotti 5K.
5. John/W3BUY, Feedback Editor, advised that he is seeking articles by members for publication in the Feedback. He encouraged members to submit any Amateur Radio related items.
6. George/W3PPB was celebrating his 89th birthday. We sang "Happy Birthday" to George.
7. Dick/N3MJA gave a brief presentation on the "Amateur Radio Service" magnetic signs available.
8. Jim/WI3N reported on the status of using the Red Cross facility. Plans are progressing. He also described the need for helping the Laurel Women's Club maintain their facility while we are co-users.
9. A critique of the support provided the Washington Birthday Marathon was conducted. No major problems were identified. HD/K3HDM indicated that he will have his truck antenna mask back in operation soon.
10. Jim/WI3N concluded the meeting by reporting on the PG County ARES/RACES program and his new appointment as the PG EC. A club visit to the EOC is being planned.
11. The meeting adjourned at 9:40p with a "50-50" won by Joe/N3TZA.
Respectfully Submitted, Roger/W3LM, Sec.
Minutes of the LARC meeting – 22 Mar 00
1. Pud/W3YD, President, called the meeting to order at 7:30pm. There were seventeen (17) members present, plus "Molly". Introductions were completed.
2. The Treasurer reported approximately $1710.00 available in the account. An outstanding bill for a post office box was due. Dues from members were still being collected for the current year.
3. The activities of the VEC and the Laurel VE team were discussed. Plans were made for conducting a test session at the BARC Ham Fest on 26 March 00. A brief discussion was held regarding the need for extra help on April 15th for the monthly test session.
4. Jim/WI3N, PG RO, summarized the activities and status of the PG ARES/RACES program. A club visit to the EOC is scheduled for the April meeting.
5. Pud and John/N3GXA reviewed the plans for helping Pat/KK3F put up a tower and antenna at his QTH. John/N3GXA will be coordinating the plans.
6. Pud conducted a general discussion of upcoming events, to include: the meeting with the Woman's Club President on 27 March, the proposed fund raising activity with the Bay Sox concessions (TBD), the "Christmas In April program (TBD), the Montpelier Festival, the Main Street Festival, the Pallotti 5K Run , Field Day and the 4th of July Celebration. Also discussed was having a table at the FAR Fest later this year.
7. Under old business, Pud discussed the theft of several items from the club facility, including the air conditioners and a copier. The Woman's Club intends to submit a claim to their insurance company. The need for our own club copier for use at the test sessions was discussed. Roger/W3LM made a motion to authorize the President to spend up to $300.00 toward the purchase of a new copier. After a brief discussion the motion passed.
8. Jim/WI3N provided an update on the use of the Red Cross facility. It should be available soon. He invited all to take a quick tour of the facility after the meeting.
9. The meeting adjourned at 8:30pm....with several going to the Red Cross facility at the Laurel Armory.
Respectfully Submitted, Roger/W3LM
By Jim Cross WI3N – Prince Georges County EC/RO
April 5, 2000
What do ARES/RACES volunteers actually do? What kinds of problems can enrollees in the ARES/RACES program be called on to solve?
Looking at the ARRL newsletter that gets emailed to me periodically, two recent disasters were detailed. In New Mexico, brush fires blew some power transformers starting a chain reaction that interrupted power to most of the state. In Ft Worth, TX, a twister roared through downtown, knocking out power and damaging property and killing cell phone access. In both cases the amateur community responded by supplying emergency communications to local EOC’s.
Some of the most likely scenarios that we may be called upon to provide emergency communications for are power outages, shelter situations, problems due to weather events such as flooding, and search and rescue. Prince George’s County is starting a chapter of the National Search and Rescue organization and I will probably be speaking with them in May to see what they require in terms of communications help and tell them what we can provide.
One of the ways we try to prepare ourselves is to help with public service events. This includes marathon races (we are scheduled to help with one through the Beltsville Agricultural Center in September), festivals, and an event coming up on April 29, Christmas in April. We have been asked to help by delivering T-shirts to the work sites for the volunteers. While on the surface this may seem like a waste of time and gas, I believe there are two benefits to helping out. One is the good PR we can get by volunteering for a worthy cause. The second is to turn our efforts into a mini-training session. As the plans finalize, I’ll send an email out to notify everyone as to what the plans are re: time, where to assemble, etc.
I would encourage you to listen in on the Commex Net from 7:30 – 8:30 pm on 147.105 on the second Tuesday of each month through June. This is the planned RACES exercise and it would be instructive to copy the messages for practice. While most of the traffic comes from MEMA (Maryland Emergency Management Agency) to the counties, this is a way to demonstrate to the state that we do have a working emergency communications system linking the counties with the state. I would also encourage those of you who are ARRL members to read the Public Service Department in QST and similar columns in other ham magazines you might subscribe to.
Our bi-monthly meeting will be held at the EOC on Anchor Street at 7:30 pm April 25. We’ll have a short business meeting and a training session. Hope to see lots of you there. Any questions or if you are interested in becoming enrolled in ARES/RACES my email is firstname.lastname@example.org. There are three forms to fill out for membership. Many of you have filled out two. The EOC is sending the additional form to be filled out and returned. The form is for either the EOC or for the ID tags. Please get them back ASAP. Thanks.
73 de Jim Cross/WI3N
By Kevin Arber, W3DAD
When power is delivered to a transmission line by a generator (transmitter) the power travels up the line until it reaches the load (antenna). If the load has a pure resistance value equal to that of the transmission line, then the load absorbs all the power. In the case of an antenna it would all be radiated. If, however, an impedance mismatch exists between the load and the line, some of the power will be reflected back down the line to the transmitter causing standing waves of voltage and current. VSWR is the ratio between the maximum and minimum voltage on a transmission line. Normally VSWR is simply referred to as SWR.
VSWR = SWR = Emax/Emin = Ef+Er/Ef-Er
Where: Ef = E forward and Er = E reflected
SWR is measured with a bridge circuit. The bridge circuit components are chosen to match the impedance of the transmission line used, making it an impedance sensitive device. Therefore, one can not use a standard 50-ohm SWR bridge to measure SWR on 75-ohm or other impedance value transmission line. Most modern HF transceivers have an SWR bridge built into the output circuit that is sufficient for the basic measurements needed between the transceiver and the input end of the line. A stand-alone SWR meter is normally required at VHF and above, as an SWR meter is less likely to be built into the transceiver. Inexpensive SWR meters for VHF and above may be quite frequency sensitive and may not work well above 450 MHz. For UHF and microwave a specifically designed and dedicated SWR meter may be required.
SWR readings can be taken anywhere on the line between the generator and load; the readings will be identical. The reason is that SWR is a ratio and is not dependent upon exact values of voltage, current or impedance, all of which are different at different points on the line. Therefore, there is no need to hang off a tower or ladder to make the measurement exactly at the antenna feed point when an SWR measurement made at the transmitter will do. This assumes that the transmission line is in good condition.
RF Test instruments are available to the amateur community that are affordable and provide quite good accuracy. Specifically, instruments made by Autek Research, MFJ and AEA, Division of Tempo Research Corp. work well and are capable of SWR measurements up to 500 MHz. The advantage of using an instrument of this type is that it contains its own oscillator, will provide impedance values, and can be swept across the band without causing interference to others. It won't be long before these types of instruments will provide a computer connection port.
Two other terms that come up in SWR measurement are reflection coefficient and return loss. Reflection coefficient, called by the Greek letter rho (p) in engineering texts, can be obtained from the equation SWR = 1+p/1-p or p = SWR-1/SWR+1. In simpler SWR meters where a switch was used to obtain a forward and reflected voltage reading, the forward value is set for 1.0 and then the bridge was reversed (usually by a switch) and the reflected voltage was read. The value of the reflected voltage was the reflection coefficient. Return loss is the ratio in dB of the incident and reflected power on a transmission line. Return loss is related to SWR and reflection coefficient by RL = 20 log p and is expressed as a negative number. Return loss is often used to characterize the input matching quality for low noise amplifiers at VHF and above. Higher return loss values are better; that is, higher return loss values translate to lower SWR values.
SWR meters and the RF instruments above can be used to determine the quality of a transmission line. When a transmission line is either open or shorted, all the incident power will be reflected back to the source. The difference between the forward and reflected power can be used to determine the line loss. The matched line loss value is given by loss = 10 log SWR+1/SWR-1. Some problems may be encountered using a transmitter and a SWR meter as the transmitter may not operate into a high SWR and the meter may not be accurate for values above 5. The RF instruments will not have these problems and can accurately measure SWR up to values of 15 or so.
Photo Corner 1
"When you lot have finished talking about radios, how about takin’ me for a walk !!"
(Photo of Molly K9DOG supplied by Dave KB3EFS)
Photo Corner 2 from the VE Session 15 April
A rainy line of people waiting outside the Swimming Pool (photo by Toby KB3BWR)
Dealing with the demand at the Woman’s Club (photo by Toby KB3BWR)
5 Wed 8:30pm LARC Net (also 19th) 147.225+
12 Wed 7:00pm LARC Social Tubby’s Restaurant
15 Sat 9:00am VE Test Session 384 Main Street
15-16 Michigan QSO Party
22-23 Florida QSO Party
26 7:30pm LARC Monthly Meeting 384 Main Street
3 Wed 8:30pm LARC Net (also 17th and 31st) 147.225+
10 Wed 7:00pm LARC Social Tubby’s Restaurant
13-14 CQ-M International DX Contest
20 Sat 9:00am VE Test Session 384 Main Street
15 Deadline for May Feedback
24 7:30pm LARC Monthly Meeting 384 Main Street
27-28 CQ WW WPX CW Contest