RADIO ACTIVE Newsletter of the Las Vegas Radio Amateur Club July 2004 Serving Las Vegas since April 1961 President's Corner By Charlie Kunz, AA5QJ What a great Field Day! Due to an administrative mix-up, we ended up in a substitute location, but boy, did we come out ok! I'll leave the details to our Field Day Coordinator, Jamie N3TOY. But let me say Thanks to all the hams, their friends and family from the LVRAC, Nellis Radio Amateur Club and the Frontier Amateur Radio Society (FARS) for their participation and support to pull off this fine event. We'd like to get our Elmer program off the ground, so if you feel you know enough to help another person in one or more areas of ham radio, please sign up for the Elmer's section of our website presently under development. Just email me at aa5qj@arrl.net and let me know the areas you would like to be listed in: antennas, HF, repeaters, packet, whatever... And don't be bashful; share your knowledge. 73 --------------------------------------------------- Special Recognition – Field Day Assistance By Bill Cornelius, K8XC and Carolyn Cornelius, K9XC "The Las Vegas Radio Amateur Club is always pleased to welcome and thank new organizations that provide monetary and material support to our activities. This month, we are especially grateful to Reddy Ice, Inc, and specifically Mr. Kevin Phenix, Sales Manager, for providing many, many bags of ice in support of our annual nationwide communications drill, Field Day - 2004, at Sunset Park. The temperature was 105 degrees, our volunteers were on a 24 hours operating schedule and cold drinks and safe food were an absolute necessity. Reddy Ice is the primary supplier of ice to the Las Vegas Valley and we wish them continued success." Thanks, Bill --------------------------------------------------- Secretary's Report By Sandy Nelson, KD7WYD Minutes of the General Meeting of the Las Vegas Radio Amateur Club Tuesday, June 8, 2004 Call to order 7:00pm Bob Nelson, KD7UHG, conducting Welcome and Introductions 49 Hams were in attendance. 0 new licensees. 3 visitors. Secretary: Sandy, KD7WYD - The members attending approved May's Minutes from the Newsletter. Dennis, N7HRO, moved and Lou, WA0EPD, 2nd. Treasurer: Jamie, N3TOY - The Treasurer's Report was posted on the Website and printed in the May Newsletter. Jamie read the report to the membership and with Dennis, N7HRO, moving and Lou, WA0EPD, 2nding, the members approved the report. Trustee: Pat, N7QE - Pat – Brought up that there are reports that the Tropicana may be going to remodel their towers. A discussion followed that included ideas of other buildings along the strip. Pat and Bob shared with the membership that the board has formed a committee to consider this and other issues with the repeaters. The issues include deciding whether or not the club should rebuild or replace our equipment. The membership was asked to email Bob @ bobnelsoncan@aol.com and let him know if they have interest in joining the committee or have connections in the community that may be able to assist us with alternate repeater sites. At this time the committee consists of Bob KD7UHG (Chairman), Bill WB0KSW, Jim Mellon KA3IDN, Bill K8XC, Pat N7QE, Jack N8RRL, Tom KE4ULL, Jamie N3TOY, and Art K7ZE. Newsletter Editor: Gary, KK7LV – absent. Librarian: Shelly, KD7HZK – A few books were returned and she acknowledged the Donation from Bill K8XC and Carolyn K9XC of the Ham Radio for Dummies book. Comm Trailer Manager: Vern, K0EGA – Nothing new to report at this time. Public Information Officer: Frank, KL7IPV – absent. Old Business: Silver State Gold Rush Challenge, July 18th: Silver State Classic Challenge, Sept 19th: There was no one in attendance from these events. Field Day, June 26th and 27th: Jamie N3TOY, requests as many people as possible show up early on Saturday morning to assist with the set up and let morning on Sunday to help with the teardown and clean up. Tom KE4ULL will be cooking again! FARS and Nellis will be joining us. Our event call is N7V. All types of antennas and all bands will be in use. Jamie is still in need of someone to set up the GOTA station. The Saturday night dinner is Potluck with the club providing the hamburgers, hot dogs, and drinks. Palo Verde High School, Zack N2ZS and Colin N0VSJ: Neither were present. Arnie WA2SOE, volunteered to contact Zack and get an update. Towers, Hal Waite, K3AB: absent. New Business: Repeater Committee, Bob KD7UHG: This was covered during the Trustee's report. Silent Key Program, Bob KD7UHG: The board has approved a Silent Key Program. Bob reviewed the concept and guidelines. There was some discussion on the outlined proposal. Bob will champion this program. Please contact him if you are interested in helping. An announcement covering the program will be included in the next newsletter. Announcements: Radio Donation, Bob KD7UHG: Mike M1KE is taking the donated Kenwood radio to test it and report to the club on it's condition. ARES/RACES, Vern K0EGA: There were several meetings in the last month and the ARES/RACES website will be updated with the information. Thank you, Butch WA0VJR: Butch thanked the club for the flowers that were sent when we heard of his hospital stay. Vests, Sandy KD7WYD: The vests have arrived, they are $35.00. If you ordered one, please see Sandy during the break to pick it up. Field Day T-shirts & Pins, Sandy KD7WYD: These are also available for pick-up during the break. Raffle Prizes, Byon N6BG: AES has donated several Test Books and Cassettes as part of the raffle tonight. Some expire on July 1, but as we all know the information is still extremely useful when studying. There were also solar panels, volt meter, power pole supplies, Black & White TV, earphones, $20.00 AES gift certificate, 2m Hershey Kiss antenna, and Radio Shack Handheld Dual Band radio. Refreshments/Break Program: Portable Antenna Show and Tell, Dan AA7I and Bill WB0KSW: Dan presented his portable equipment including his ICOM 706 Mark 2 radio and the Outbacker multi-band antenna that can be adjusted by moving the jumpers. Bill then led an impromptu discussion on portable antennas, how they work and what works best. It was informational and entertaining! Raffle: Solar Panel, volt meter, and power pole connectors: Bob, KD7UHG Red & Black Zipcord, Power pole connectors and cigarette adapter: Dennis, N7HRO Black & White TV, earphones and power pole supplies: Bill, WB0KSW $20.00 AES Gift Certificate and power pole supplies: Fred, KB2CT 2m Hershey Kiss Antenna and power pole connectors: Bill, K8XC Radio Shack Dual Band H/T: Fred, K9GAJ Meeting adjourned at 9:15PM. --------------------------------------------------- Treasurer's Report By Jamie Gorr, N3TOY Beginning Balance 12,064.06 Deposits Dues 60.00 Raffle 180.00 FD Shirts 104.00 Vests 175.00 Total Deposits 519.00 Expenses Sprint 30.11 Vests 126.00 Sec of State 15.00 Refreshment 64.65 LVRA (Knwd HF400.00 Field Day 353.69 Total Expenses 989.45 Ending Balance 11,593.61 --------------------------------------------------- Wanted: Graphics person to clean up the LVRAC logo and font for expanded use. Contact Byon N6BG at byon@byon.com. --------------------------------------------------- ARES / RACES By Charlie Kunz, AA5QJ Clark County ARES Emergency Coordinator/RACES Officer - Charlie Kunz AA5QJ EC attended a presentation on Jun 23 to Clark County first responder organizations on wireless interoperability. - Charlie Kunz AA5QJ EC and Vern Garman K0EGA AEC Operations/Training met with the UNLV Emergency Planning Coordinator on Jun 24 to discuss ARES/RACES support of UNLV disaster operations. - ARES/RACES members throughout the county participated in annual ARRL Field Day events on Jun 26-27. - Upcoming events: General membership meeting at the Clark County Government Center on Jul 24 at 9am. --------------------------------------------------- Field Day Report 2004 By Jamie Gorr, N3TOY The Las Vegas Valley Field Day 2004 celebration was a huge success! Field Day tests an Amateur's ability to set up and operate in less than optimal environment. Sometimes we get comfortable in our yearly routine, but not this year! With less than 10 days to go, Sunset Park informed us that due to a booking error, we would not be able to meet at Area F as usual. After some negotiating, we were offered a very nice area in the park that does not get rented out. Sunset Park went above all expectations to see that this new area met all our needs, including a 20' by 40' tent! They also provided 2 porta-potties, a huge gas grill, and plenty of table and chairs. If you missed Field Day this year, you really missed out! Field Day is a time when FARS, Nellis, and the LVRAC work together to provide a wonderful HAM radio experience for the Amateurs of Southern Nevada. And with the combined talents of these three clubs, it is no wonder Field Day is such a success year after year. I don't have the final numbers tabulated yet, but if you check back on http://n3toy.net/fd_2004, I will post the results of our logs and photos there for you to see. If you happen to have any photos from Field Day, please email them to me for posting. (field_day@lvrac.org) Many thanks are in order to a number of helpful HAMs that work together to make Field Day happen. First, it wouldn't much of anything without all the HAMs who came out and operated. I bet a few of you were driving around Area F confused. But you all made it, thanks to Bill's signs. Thanks to Fred and Butch who provided me with guidance in organizing Field Day this year. There was much more to do than I expected and Fred and Butch made sure I had all I needed to cover all the bases. Thanks to FARS who provides the core of the equipment for Field Day year after year. Thanks to NellisRAC/Larry Jr. for the swamp cooler in the tent. Thanks to Luke and AES for bringing out two very nice Icom HF radios for us to use. Thanks to Tom, KE4ULL, who took ownership of the food committee. Tom is well known for cooking at Field Day, especially Sunday morning breakfast. This year he took on an even bigger role in feeding all the troops. He cooked Saturday lunch, Saturday dinner, and Sunday breakfast! His wife has him well trained! And this is in addition to planning out the food, purchasing the food, and delivering the food to Sunset Park. Thanks Tom for your help and support! Thanks to Bill and Carolyn Cornelius who stepped up when Sunset Park pulled Area F. They made several trips to the park looking at other areas for our use. It is always a pleasure working with Bill and Carolyn. Bill was also very busy during Field Day manning the generators and setting up lights. Bill was also responsible for securing the very generous ice donation. No matter what the event, Bill is usually in the thick of things and stands out as a major contributor. Field Day 2004 was no different. Thanks to Byon for the Fox Hunt, packet demo, and APRS demo. I got much positive feedback from many people who really enjoyed the Fox Hunt. Thanks to Charlie and Byon for the Wi-Fi / HSMM demo in the LVRAC trailer. And, of course thanks to Sandy, KD7WYD for allowing Bob to tow the trailer with her Navigator. The club has benefited greatly the last couple years since they joined. Keep up the good work Sandy! Oh, and Bob too… Also, I want to recognize Reddy Ice for their generous donation of all the ice we had at Field Day. Also, Sunset Park went well above all expectations in providing us such a great place to have Field Day. We really couldn't have asked for anything better. Remember to check back to the Field Day web site for all the results and photos from Field Day 2004. --------------------------------------------------- Technical Tips Tech Talk by Bob, AF6C Attenuators: Often, on one band or another, you'll hear: "Larry, you're two S-units stronger than Bob at this QTH." Or "Bob, you're lighting two more bars than Larry, here." Or perhaps, "Ken you're 40 over nine here, Bob's an S-7." While these sound like good signal comparisons, their accuracy leaves much to the imagination. Most receiver S- meters are notoriously inaccurate and their sensitivity varies tremendously from band to band. How can you give a good comparative report? It's simple if you have a reasonably accurate step attenuator. Reasonably accurate step attenuators are inexpensive and easy to build for the HF and VHF bands. They can also be purchased in all sizes and flavors from companies like MFJ and Hewlett Packard. Probably, if your rig has one, you've used the built-in attenuator to reduce strong signals or help remove interfering QRM. The step attenuator differs from a built-in attenuator in that it has 4 to 8 or more switched attenuator sections, each of which can switch in a fixed attenuation. Steps are often binary, such as 1 dB, 2 dB, 4 dB, 8 dB, 16 dB, etc. On less expensive attenuators the largest step is usually 20 dB since attenuation larger than that requires extra careful shielding. Since attenuators are usually low power devices, it is best to use one only with a radio that has a separate receive antenna line. Transmitting through most attenuators will result in smoke! After you've installed an attenuator in the receiver antenna line, you can set all the switches to the out position and receive normally. To compare two signals, as in the first example above, wait until Larry is transmitting and then start switching in some attenuation until the s-meter reading is peaking at some convenient point; say S-6. Note the setting of the attenuator switches. Now, when Bob starts to transmit, remove (or add) attenuation until the S-meter again peaks to the same convenient point. Note the new attenuator setting. The difference between readings is an accurate report of the difference in signal strength of the two stations. The station with more attenuation is the stronger. To read the attenuator, just add the dB reading of the sections switched in. For example, if Larry is an S-6 with the 20 dB and 4 dB sections switched in (24 dB total), and Bob is S-6 with the 8 dB, 2 dB and 1 dB sections switched in (11 dB total) then Larry is 9 dB stronger than Bob. If you have the chart handy from last month's Tech Talk, you can report: "Larry is eight-times stronger than Bob at this QTH!" When finished be sure to switch all sections of the attenuator out or you'll think your receiver has gone hard-of-hearing! If your rig has a bar-type S-meter you're at a slight disadvantage. However, with practice, the level can be adjusted so a given bar segment is just flickering at a reference point. Bar type S-meters are more rugged and cheaper than real meters, but that is where the advantage ends. The reason they are becoming so popular is the latter reason! With an attenuator you can do a relative calibration of your S-meter. What you need is a steady signal source for each band. A signal generator or grid-dip meter will work. With a minimum of 3 dB set on the attenuator; adjust the signal source for full S-meter deflection. Now add attenuation until the S-meter drops to the next mark and note the change in attenuation. Continue for all desired calibration points. When you run out of attenuation, reset the attenuator back to 3 dB and readjust the signal source level until the S-meter is at the last calibrated point and continue. Always start with a minimum of at least 3 dB; the reason for this is explained later. If you are lucky to have access to a signal generator that has a calibrated output, you can even calibrate your S-meter directly in microvolts. In either case, you'll notice that the calibrations vary significantly from band to band and possibly even from one end of a band to the other. Attenuators are commonly resistive devices that operate over a large frequency range and down to DC. They come in numerous types. Besides their attenuation value, other specifications are input and output impedance (attenuators with the same input and output impedance are called symmetrical), power capability, and balanced or unbalanced. Unbalanced attenuators are used with signals that have one side grounded (RF in coax for example). Balanced attenuators are used with balanced lines such as many audio lines and ladder-line. Figure one shows four common types of unbalanced attenuator circuits. Circuits 1a and 1b are commonly used to match two different impedances over a wide frequency range. They are often called "minimum loss pads". For any given impedance change this attenuator gives the minimum loss that can be achieved with resistive matching. Note that the circuits are bidirectional. The first circuit increases the impedance and the second lowers it. Circuit 1c, called the "tee", and circuit 1d, called the "pi", allow you to select the input and output impedance and attenuation independently. Often, as in the case of the step attenuator discussed earlier, the input and output impedances are symmetrical, commonly 50 or 75 ohms. The "tee" and "pi "circuits can be used interchangeably. The circuit using the most standard value of resistors for the given attenuation is usually selected. Figure two shows five common balanced attenuator circuits. Circuits 2a through 2d correspond to their unbalanced cousins. The series resistors are just divided equally between legs. Circuit 2e is a favorite in audio circuits; it's called the symmetrical lattice attenuator. The values for R1 and R2 can be interchanged without affecting the attenuation on this circuit only. Calculating resistor values for attenuators is beyond the scope of this series. There are numerous books that have programs for handheld calculators and computers for calculating the resistor values for given parameters. See the side bar on Nepers. Table one shows some common 50 and 75-ohm attenuator resistor values. What is the input and output impedance of an attenuator? Since attenuators commonly work to DC you can use an ohmmeter to check them. The input impedance is just the impedance (resistance at DC) that you measure looking into the input when the output is terminated at its impedance. For a 50-ohm attenuator connect a 50-ohm resistor across the output and measure the resistance of the input. It should read close to 50 ohms too. The output impedance is just the reverse; terminate the input with its specified impedance and measure across the output terminals. Another feature of an attenuator is that it corrects circuit impedance errors. A small attenuator, or "pad", is often used between a signal generator and circuit under test. This helps insure that the signal generator is seeing the impedance it's designed to work into. Thus it's a good idea to have a minimum of 3 dB of attenuation on when making measurements with your attenuator. That assures that the antenna looks close to 50 ohms to the receiver and that the receiver input looks close to 50 ohms to the transmission line. If you decide to build your own attenuator here are some suggestions that will help make it a top-notch unit up into the VHF region. First, attenuator sections should be shielded from each other. Printed circuit board or brass stock (available at hobby and hardware stores) can be used for shielding. Second, use the proper type switch. Cheap slide switches actually work very well due to their wiping action. If you use miniature toggle switches, use the ones that are designed for "dry switching". These usually have gold contacts and don't rely on a bit of current to keep the contacts clean. Third, keep sections that have large attenuation separated when possible. If you have two 20 dB sections, don't put them directly next to each other; put a lower value attenuator section between them to reduce unwanted coupling. Finally, keep the sections at or below 20 dB; above that leakage will limit the section's accuracy. Here are some references on attenuators where you can get more information, construction ideas, etc.: Jules Gilder, Basic Computer Programs in Science and Engineering, Hayden Book Company, 1980, Chapter 12 "Attenuator Pads" Pete Ostapchuk, N9SFX, A Rugged, Compact Attenuator, QST - May 1998, pp. 41-43, (See errata) Reference Data for Radio Engineers - fourth edition, IT&T Corp., 1956 The 1989 ARRL Handbook, "Low Power Step Attenuators", pp. 25-36 to 25-38 SIDEBAR FOLLOWS: Nepers: If you decide to calculate attenuator resistor values you will likely come across the term nepers. The neper is similar to the decibel, except it is based on the natural logarithm (loge): Nepers = (1/2) * loge (P2 / P1) dB = [loge (10) / 20] * Nepers = 8.686 * Nepers Nepers = [20 / loge(10)] * dB = 0.1151 * dB 50 Ohm "PI" and "O" Symmetrical Attenuators Atten. R1 & R3 R2 dB Ohms Ohms 1.0 869.7 5.77 2.0 436.3 11.6 3.0 292.5 17.6 4.0 221.0 23.8 6.0 150.5 37.3 8.0 116.1 52.8 10.0 96.2 71.1 16.0 68.8 153.7 20.0 61.1 247.3 50 Ohm "Tee" and "H" Symmetrical Attenuators Atten. R1 & R3 R2 dB Ohms Ohms 1.0 2.87 433.4 2.0 5.73 215.3 3.0 8.55 142.0 4.0 11.3 104.9 6.0 16.6 67.0 8.0 21.5 47.3 10.0 26.0 35.1 16.0 36.3 16.3 20.0 40.9 10.1 600 Ohm Balanced Symmetrical Lattice Attenuators Atten. R1 R2 dB Ohms Ohms 3.0 3508.8 102.6 6.0 1805.7 199.4 10.0 1155.0 311.7 12.0 1002.5 359.1 20.0 733.3 490.9 Minimum Loss Pads (Reversible) Atten. Z Ohms R1 R2 dB Zin Zout Ohms Ohms 5.72 75 50 43.3 86.6 13.42 300 50 273.9 54.8 11.44 300 75 259.8 86.6 7.66 600 300 424.3 424.3 14.77 600 75 561.2 80.2 16.63 600 50 574.5 52.2 --------------------------------------------------- Coming Events July Meeting July 13, 2004 at Nevada Power on Sahara just west of Jones. Get ready for thunderstorm season with a refresher on weather and weather-spotting from the National Weather Service. July Raffle The July raffle will have a Yaesu FT-1500 VHF Mobile Radio as the grand prize. There will be other prizes equal to the past raffles we have had. ARES/RACES Meeting July 24, 2004, There will be a membership meeting for ARES/RACES at the Clark County Government Center on this Saturday morning beginning at 9:00 AM. --------------------------------------------------- FCC News The FCC has announced that the new Amateur Radio vanity call sign regulatory fee of $20.80 for the 10-year license term will go into effect August 6. Applicants for amateur vanity call signs will continue to pay the $16.30 fee per vanity call sign application received by FCC until the new fee goes into effect. The FCC says it expects to collect close to $162,000 from 7800 Amateur Radio vanity call sign applicants during Fiscal Year 2004. See the FCC's annual Report and Order (Docket MD 04-73) on the Web at http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-04-146A1.doc for details on their assessment and collection of regulatory fees for FY2004. --------------------------------------------------- 2004 Exam Schedule License examinations are given on the second Saturday of each month. There are a couple of evening sessions at a different location. July 10th 12:30 PM (PST) August 14th 12:30 PM (PST) September 11th 12:30 PM (PST) October 9th 12:30 PM (PST) October 22nd 6:30 PM (PST) evening November 13th 12:30 PM (PST) December 11th 12:30 PM (PST) Day Time Test Sessions at: All Saints Episcopal Church 4201 W. Washington Ave. Between Decatur and Valley View Evening Test Sessions at: Clark County Government Center, Training Rm 3 500 S. Grand Central Pkwy. Southeast of the spaghetti bowl (I-15 & 95) Please visit www.lvhamtest.com for updates, maps and further information. $12.00 Exam Fee Proper Identification, prefer a picture ID with your signature. Normally applicants provide a drivers license or student ID. Social Security Number (SSN) or Taxpayer ID number (TIN) if you are not eligible for an SSN. If you presently have an Amateur Radio License, we will need the original plus a photocopy. If you have a CSCE, we must see the original plus a photocopy. Pen and a pencil. You may bring a calculator as long as the memory can be "flushed" before you take the exam. Las Vegas Radio Amateur Club P.O. Box 27342 Las Vegas, NV 89126 Internet: http://www.lvrac.org/ Radio: 146.940 MHZ (K7UGE repeater) 448.500 MHz (K7UGE repeater) 146.730 MHz (QST machine) Las Vegas Radio Amateur Club July 2004 Issue