ROUNDTABLE The Denver Radio Club Newsletter January 2013 Since 1917 PRESIDENT’S MESSAGE By Bryan Steinberg – KB0A Happy New Year! I hope everyone had a great holi- So we’re going to give our annual holiday party an- day and that Santa brought you whatever you need- other try on January 16th. This will be in place of our ed to make your shack a little better. Now we’re all regular January meeting. As originally planned we looking forward to some great DX during the rest of will meet at the Golden Corral, 3677 S. Santa Fe Dr., the cold winter months here in Colorado. With the Sheridan, CO 80110 (Phone: 303-643-5898) which is new year we have some changes going on. Becky the same location we used in 2011. We will be us- Campbell, KD0AOE, has stepped down from her po- ing one of the rooms at the left end of the restaurant. sition of managing the weekly “Learning Net”. She Our presentation this year will be the “K4T DXpedi- started the net over 5 ½ years ago and has done a tion to the Dry Tortugas” by Pete Fountain, great job since then keeping it active. We thank her WD4IXD. Pete will discuss the planning and imple- for the effort she put into this project. Larry Irons, mentation procedures involved in coordinating a K0LAI, has stepped up and will keep the Learning DXpedition. He will also talk about the issues that net active. At this time Larry is looking to move the had to be overcome to bring this event to fruition. night of the weekly net in order to increase the avail- Don’t miss this great presentation. Our holiday meet- ability of elmers. So keep your ears open and we will ing will be held in place of our normal January meet- make announcements on the weekly club net. ing on the 16th. People usually start showing up around 5 PM and we expect to start the presentation The club is still in need of an Emergency Communi- at 6:30 PM. Also, don’t forget the door prizes and cations Coordinator. We’ve been limping along for member grand prize. Hopefully I will get a chance to most of last year without one and the vacancy is ob- see many of you at the holiday dinner. vious. We need a person who can oversee our rela- tionship with organizations we support: The Salvation Till next time… Army; City of Lakewood; and West Metro Fire Dis- Bryan, KBØA trict. We have individuals who manage each of these relationships but the job of the ECC is to over- see the total effort and bring it all together in a con- sistent manor. If you are interested, or know some- one in the club that could fulfill this position please contact me or any board member. As everyone is aware we had to reschedule our holi- day meeting, which was planned for December 19th, until this month due to some severe weather. INSIDE THE ROUND TABLE December Meeting - Cancelled Pg 2 The Good Book was Right Pg 5 No Tech Committee Report Pg 2 Up Coming Events & Propagation Charts Pg 6 January Presentation – DXpedition Pg 3 Holiday Dinner Meeting Info & Calendar Pg 7 Build a PVC J-Pole Pg 3 DRC Information Pg 8 © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information W0TX http://www.w0tx.org Denver Radio Club January 2013 DECEMBER MEETING - WHAT’D I MISS December Dinner Meeting was canceled due to inclem- NO TECH COMMITTEE REPORT FOR DECEMBER ent weather. The Holiday Dinner Meeting has been rescheduled for the Wednesday 16th of January in place of our Who’s New In The DRC regular January meeting See you there! The DRC is a very active club in the Denver metro area and we’d like to have all of our members listen for these JANUARY MEETING ANNOUNCEMENT new calls and personally to make them feel welcome. Welcome to our newest members. We have a number Our holiday meeting presentation will be given by Pete of activities throughout the year and we’d like very Fountain, WD4IXD, documenting the trip he and seven much for you to participate in serving your community. others made in March 2010 to Fort Jefferson in the Dry If you have questions please feel free to ask on any of Tortugas. the repeaters or see the contact information on the last page of this publication. Also please join us once a month at the regular club meeting on the 3rd Wednes- day at 7pm. For new hams we have the Elmer session which starts at 6:30pm before the regular meeting. More information can be found on the Denver Radio Club website at http://www.w0tx.org. Rick Ogden N3RO J. Mike Needham KD0JXP John Burrell K0IKN Rick Budinger WA9IPK Bill Niles KJ4CLO Connie Krajcirik W0SNO Jim Krajcirik W0JEK This location is steeped in history and made for an ex- cellent location for HF, VHF, UHF, and satellite opera- IItt’’ss TTiimmee OOnnccee AAggaaiinn tions. It is a very rare entity on the IOTA (Islands On The Air) program and an extremely rare grid square for FFoorr VHF and amateur satellite operators. Hear the details of TThhee AAnnnnuuaall HHoolliiddaayy all that was involved in making this 4 day operation such a success and how they overcame obstacles such MMeeeettiinngg && DDiinnnneerr as the basic preparation, permitting requirements to When: January 16th camp and operate from there, power requirements, and Where: Golden Corral Buffet Restaurant transportation of the equipment. This will be an interest- 3677 South Santa Fe Drive ing and entertaining program that could benefit the club Sheridan, CO with ideas for future Field Day operations as well. Time: 5pm Dinner / 6:30pm Presentation and Drawing Pete has been licensed since 1977 and his interests For map & directions check www.w0tx.org are DXing, contesting and VHF/ UHF/Microwave weak signal work (including EME). Pete is an RF Engineer for ViaSat and in his spare time enjoys helping the club as a VE. © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Page 2 W0TX http://www.w0tx.org Denver Radio Club January 2013 BUILD A PVC J POLE ANTENNA Most hams prefer J Poles over Ground Planes be- cause they have the following advantages: By Bill – W6OAV • Easier to build, especially as portable an- Building a twin lead or a ladder line J Pole antenna tennas. is pretty straight forward. However, due to de- • Easier to tune. tuning issues, inserting the J Pole into a PVC pipe • Have some gain over Ground Planes. for portability isn’t as straight forward. The purpose • Produce a stronger signal at the horizon of this article is to detail how to build a portable having a azimuth radiation angle of 3.5 de- PVC twin lead/ladder line J Pole antenna. grees as opposed to the Ground Plane’s azimuth radiation angle of 20 degrees, • Greater bandwidth. WHY A J POLE? • Good "stealth" antenna. VHF /UHF Ground Plane • DC grounded so can be easily mounted to antennas and J Pole an- metal supports. tennas have been favor- • Low receive noise due to DC ground. ites among hams for • Safer antennas for providing temporary many years. Figure 1 communications at various events as there shows a typical J Pole. A are no dangerous radials sticking out. J Pole is a ½ wave radi- ator end fed by a ¼ I’ve built many twin lead J Poles over the years. wave matching section. The twin lead J Pole is inexpensive and very easy Figure 2 shows a 2 me- to build. The first time I installed a twin lead J Pole ter twin lead J Pole and in a length of PVC pipe for portability, I ran into the formulas for calculat- tuning problems. The dielectric constant of the ing lengths. Note, the PVC detuned the J Pole when I inserted it into the references to twin lead PVC pipe. I needed a process to “pre-tune” the J below also apply to Pole so that it would be resonant where desired “window” ladder line. when inserted into the PVC pipe. The following describes the process. BUILDING A TWIN LEAD PVC J POLE The following describes the necessary steps to build a twin lead J Pole and to properly “pre-tune” it for insertion into a PVC pipe. Obtain materials The following items will be required for this project: • Six and a half feet of 300 ohm twin lead or ladder line. • Six foot minimum length of 1” in diameter white Sked 40 PVC pipe. • Two PVC pipe end caps. • 2” minimum length of ¼” in diameter wood dowel. • Short length of string or fish line. • Desired length of coax feed line and a PL259 connector. • Eye bolt. (Continued on page 4) © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Page 3 W0TX http://www.w0tx.org Denver Radio Club January 2013 (Continued from page 3) 3. Solder the coax feed line to the twin lead Test PVC feed point as shown. The first step in this project is to find PVC pipe that 4. Cut a small hole in the top of the twin lead is suitable for the antenna. Most white Sked 40 and tie a small string or fish line loop PVC pipe is suitable. To verify suitability, place a through the hole. This loop will be used to short piece of the PVC pipe in a microwave oven. support the twin lead from a wood dowel Turn the oven on for one minute. If, after the mi- inside the PVC pipe. nute, the PVC pipe is hot, it is not suitable as it will 5. Cut the PVC pipe to a length of eight inch- adversely affect the J Pole’s radiation efficiency. es, or more, than the length of the J Pole. This extra length is for mounting the PVC Cut twin lead to proper length pipe to a mast or a tripod, if desired. When the twin lead J Pole is inserted into the PVC 6. Mark the top end of the PVC pipe approxi- pipe, the PVC’s dialectic constant will cause the J mately ½” from the end. Drill small opposing Pole’s resonant holes just large enough to accommodate frequency to de- the wood dowel. Insert the dowel trough the crease. There- holes with the far end just flush with the out- fore, the J Pole er edge of the PVC pipe. Cut the long end must be con- of the dowel so that it is flush with the out- structed to be side of the PVC pipe. 7. Remove the dowel, insert the twin lead into resonant at a the pipe and reinsert the dowel through the higher frequency loop. Place the top end cap over the pipe than desired so covering the dowel. This will hold the dowel that it will in place. “detune” down to 8. Drill a hole just slightly larger in diameter the desired fre- than the coax in the base PVC end cap. quency when in- 9. Push the coax serted into the through the PVC pipe. Figure hole in the 3 shows the for- base end cap. mulas which will Slide the end produce a twin cap on to the lead J Pole which base of the will be close to the desired frequency when placed PVC pipe. in a PVC pipe. When cut as shown for 2 meters, 10. Solder a the J Pole will resonate outside of the PVC at ap- PL259 onto the proximately 151.5 MHz. When inserted into the coax. PVC pipe it should resonate close to 146 MHz. It 11. Seal the end may be necessary to slightly trim the J Pole for cap hole resonance when it is in the PVC pipe. around the co- ax. Build the PVC J Pole 12. Mount or sus- Refer to Figure 4 for the following procedures: pend the J Pole 1. If the antenna is to be configured to hang in an open area from an over head support, cut a hole in the and measure top PVC end cap and mount the eye bolt. the SWR. Trim 2. Cut the twin lead as shown in Figure 4 us- the long side of the J Pole if necessary. ing the dimensions calculated from the for- mulas. (Continued on page 5) © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Page 4 W0TX http://www.w0tx.org Denver Radio Club January 2013 (Continued from page 4) THE GOOD BOOK WAS RIGHT By Bill – W6OAV My PVC J Pole measured as shown in the chart: You might be interested in a not too scientific ex- MHz SWR periment that AI, W6WSH and I performed. It 144 1.8:1 seemed to prove that, like the good book says, an antenna works best in the center of the car roof. 146 1.1:1 148 1.7:1 In the experiment, my car was pointed towards AI's base station with 30 miles separating us. With Final comments a 5/8 wave Larson on the center of the roof, Al Some designers prefer to install a choke as close copied me with about 75% quieting. With the an- as possible to the feed point to keep RF off the tenna on the trunk lid, Al could hear me in the coax shield. If desired, for 2 meters create a choke noise, but could not copy the words. This was in- by winding the coax into teresting, as theoretically, with most of the car a coil as close as possi- body between the antenna and AI, I should have ble to the feed point. had a major lobe towards AI, whereas the antenna The coil should consist on the roof should not have had any lobes. To ver- of 5 taped side by side ify the lobe, the antenna was placed on the hood. turns about 3 inches in Al could not hear us at all, indicating the lobe had diameter. These dimen- now shifted to the rear of the car. sions are not critical. For UHF, reduce the We also tried a 1/2 wave Gam in the center of the dimensions by about a car roof. Al could not tell the difference between third. the 5/8 and 1/2 wave antennas. Figure 5 shows my So, when the XYL isn't home, get out the drill and PVC J Pole mounted on move the antenna up to the center of the roof! By a tripod. This is a handy the way, thanks to Irv, K6DUX, who not only sup- arrangement for provid- plied the antennas, but did all the leg work moving ing temporary commu- them while I just stay there and pushed the mike nications at various button. events. Should I not have a tripod, I can The Denver Radio Club throw a rope over a high support and, using Is an ARRL the eye bolt on the top Special Service Club of the J Pole, hoist it high into the air. Support your hobby Don’t forget to join in Wednesday Join the ARRL TODAY nights at 7:30pm for the DRC Learning Net ! Note to DRC Members: Due to the fact that many ISP’s reject documents which 145.49/448.625 machines contain active hyperlinks, the URLs in the RoundTable are Watch the RoundTable for Upcoming not active. However, you can copy and paste the link into you browser and view the web content. Sorry for the incon- changes to Learning Net Schedule venience. Editor © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Page 5 W0TX http://www.w0tx.org Denver Radio Club January 2013 UP COMING EVENTS HAMFESTS & CONVENTIONS The following are the HAMfests & Conventions which have been registered with the ARRL so far. More infor- mation can be found on www.arrl.org/hamfests. 2013 January 19 – NCARC Winter Hamfest Larimer County Fairgrounds http://www.ncarc.net February 10 – ARA Swapfest Adams County Fairgrounds http://www.n0ara.org THE ROUNDTABLE ARCHIVE April 6 – LARCfest Have you been looking for a back issue of the Boulder County Fairgrounds Roundtable? Many are available on the DRC web site. http://w0eno.org Access http:/www.w0tx.org. On the left side of the page, click on “Roundtable”. June 28 – Rocky Mountain Division Convention Rocky Mountain Park Inn, Estes Park, WHAT IF THE WEATHER CHANGES? Colorado http://www.hamconcolorado.org As every Coloradoan knows our winter weather can take a sudden change for the worse. If we should expe- More to come later... rience a turn in the weather on the day of our monthly DRC meeting it may be necessary to cancel the meet- ing. If this should happen listen for meeting status re- ports on 145.49 or 448.625 MHz repeaters during the afternoon before the meeting day. PAST & FUTURE PROPAGATION CONDITIONS By Bill – W6OAV The charts below show the Solar Flux and “A” indexes for last month and the forecast for this month’s Solar Flux index. Refer to the September 2010 Roundtable for more complete information on interpreting these charts. Issues of the Roundtable are available at www.w0tx.org. © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Page 6 W0TX http://www.w0tx.org Denver Radio Club January 2013 IItt’’ss TTiimmee OOnnccee AAggaaiinn FFoorr TThhee AAnnnnuuaall HHoolliiddaayy MMeeeettiinngg && DDiinnnneerr When: January 16th Where: Golden Corral Buffet Restaurant 3677 South Santa Fe Drive Sheridan, CO Time: 5pm Dinner / 6:30pm Presentation and Drawing For map & directions check www.w0tx.org JANUARY 2013 DRC Net Sunday’s at 8:30pm Local on 145.490 & 448.625 (No PL) Sunday Monday Tuesday Wednesday Thursday Friday Saturday 1 2 3 4 5 ARRL Learning Net ARRL Straight 7:30pm RTTY Round-Up Key Begins 1800U Night 6 7 8 9 10 11 12 ARRL Learning Net Save Amelia Kid’s Day 7:30pm The Earhart 1800U to 2359U Eagles Day ARRL Day RTTY Round-Up Ends 2400U 13 14 15 16 17 18 19 Club Holiday ARRL Dinner & January VHF Meeting 5pm Sweeps Begins 1900U 20 21 22 23 24 25 26 ARRL Martin Learning Net January VHF Luther 7:30pm Sweeps King Ends 0359U Jan 21 Day 27 28 29 30 31 © 2007 - 2013 Denver Radio Club; All Rights Reserved; See Editor’s Note for Additional Information Check www.ARRL.org for Contests and Rules! Page 7 W0TX http://www.w0tx.org Denver Radio Club January 2013 DRC BOARD OF DIRECTORS President KB0A Bryan Steinberg 303-987-9596 [email protected] Vice-President W0GV Gerry Villhauer 303-467-0223 [email protected] Secretary WW0LF Orlen Wolf 303-279-6264 [email protected] Treasurer K0TOR Jim Beall 303-798-2351 [email protected] Board Member N4ATA Doug Parker 303-922-3305 [email protected] Board Member K0HTX Dave Gillespie 303-880-1938 [email protected] Board Member KD0CXX Paul Meenach 720-746-1488 TBD Board Member N3PQ Frank Ortega 303-452-0283 [email protected] DRC STAFF AND VOLUNTEERS Trustee WW0LF Orlen Wolf 303-279-6264 [email protected] Net Control K0TOR Jim Beall 303-798-2351 [email protected] TSA/EmComm Coordinator OPEN Membership KC0CZ Bob Willson 303-659-0517 [email protected] Club Librarian WG0N Dave Baysinger 303-987-0246 [email protected] VE Team KC2CAG Tom Kocialski 720-493-1426 [email protected] Swapfest Mgr KB0A Bryan Steinberg 303-987-9596 [email protected] Field Day OPEN for 2013 Tech. Committee Chair W6OAV Bill Rinker Check Roster Benevolent Carolyn Wolf 303-330-0721 RT Editor AG0S George McCray 303-751-7246 [email protected] RT Assoc. Editor W6OAV Bill Rinker Check Roster Education KD0CXX Paul Meenach 720-746-1488 [email protected] Web Master N0LAJ Bill Hester Check Roster DRC REPEATERS BAND Freq / Shift / PL Tone Additional Information 6m 53.090mHz (-1mHz) Packet 145.05mHz<>14.105mHz 2m 145.490mHz (-) 100Hz PL Linked to the 70cm - 448.625mHz machine. 2m 147.330mHz (+) 100Hz PL Local Area, Members Auto-Patch Does Not TX a PL! 2m 147.330mHz (+) 131.8Hz PL Not in service at this time! 1.25m 224.380mHz (-) 100Hz PL 70cm 447.825mHz (-) 100Hz PL Saint Anthony’s 70cm 448.625mHz (-) 100Hz PL Linked to the 2m - 145.490mHz machine. 70cm 449.350mHz (-) 100Hz PL Wide area coverage with Echolink Node # 4140. 70cm 446.7875mHz (-) MotoTRBO Repeater | Slot 1 – DMR-MARC WW, Slot 2 – Local EDITOR’S NOTE © 2007 - 2013 Denver Radio Club; All Rights Reserved; Articles in the RT may be reprinted with permission for non-commercial or educational use. DRC members - this is your newsletter. If there is something which is club or amateur radio related that you’d like to see as a regular feature, email suggestions to the editor. Members are the heart and sole of The Denver Radio Club, if you have an expertise or an interest in a particular segment of ham radio that you’d like to write about, you may email your submissions to [email protected]. Submission deadline is the 25th of the Month. Editor Page 8 W0TX http://www.w0tx.org