THE MANATEE AMATEUR RADIO CLUB, INC. November 2017 RADIOWAVES

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1 THE MANATEE AMATEUR RADIO CLUB, INC. November 2017 RADIOWAVES MARCI Newsletter FROM THE PRESIDENT: Plans are moving along for the annual MARCI Christmas party to be held again at the Ranch Grill, SR 70, in Lakewood Ranch on December 5th. Starting time will be at 6:30 PM. A dinner selection menu will be available at our November meeting.as in past gatherings, many interesting prizes will be raffled off to our members. Hope to see you all there, 73, George, K4AWA FROM THE EDITOR: Our President, George, K4AWA appears to be on the mend after his date with a cardiac surgeon and my hip replacement in late August is now thoroughly healed so we are back to business. I am sure George will have words about the Christmas Party meeting which as usual will replace our December Meeting. For the November meeting, Ed will be presenting a talk about low power digital modes. This one promises to be a really good presentation as the low power digital modes are really hot and provide a way to get the message through even when the operator cannot even hear the signal. An Off-Center Fed Sleeve Dipole Vertical For The Magic Band By Geoff Haines, N1GY It has always aggravated me a bit that I had an IC-706 Mk II G in my radio room that was perfectly capable of operation on 6 meters and I had no antenna for that band. I resolved for New Years that I would correct that Page 1

2 omission. I looked at a number of designs in the various antenna books from the ARRL that I had on hand and also scanned the Internet for workable designs. Many were found but few coordinated with the supply of raw materials I had at hand. Then it occurred to me that with a little scaling up, the design for my dual band (2m/440) antenna that appeared in the pages of QST (Aug. 2006) might do the job. I set to work to scale the antenna from its original size up to a length that would work for at least part of the 6 meter band. After much tapping on the calculator I decided to use 67" for the upper element and 46 1/2" for the lower element with a 1/2" space between them at the feed point. This would make the antenna 9'6'' tall overall not counting the mounting method at the base of the antenna. Since I had some lengths of 1" diameter aluminum tubing on hand as well as a length of 7/8" diameter as well, the antenna was fairly easy to construct. Slipping a piece of the 7/8" dia. tubing inside a 24" long piece of the 1" tubing, I adjusted the length to 67" and clamped the tubing in that position. A 46 1/2" piece of the 1" dia. tubing was cut for the lower element. Two pieces of fiberglass tubing 7/8" OD with about 1/2" ID were used to complete the antenna. One section was slipped into the bottom of the upper element and the top of the lower element and secured with short sheet metal screws so that the elements were about 1/2" apart. A hole was drilled into the fiberglass tube between the two elements to permit the passage of the RG-8x coax down through the inside of the lower element. The dressed end of the coax was secured to the elements using hose clamps. The center conductor of the coax was clamped to the upper element and the shield braid was clamped to the lower element. The second length of fiberglass tube was inserted around the coax and inside the lower element both for strength and to keep the coax roughly centered inside the lower element. By countersinking the hole in the bottom of the lower element I was able to secure the fiberglass tube to the aluminum element with small flat-headed screws that would not interfere with the next step. In order to mount this antenna on a metal mast, the antenna must be placed above the mast completely. This requires another length of nonconductive material to bridge the gap. I chose a 24" long piece of 1" ID PVC pipe because I had it on hand. The lower element was inserted about 6" into the PVC and secured with sheet metal screws. A hole was drilled in Page 2

3 the PVC just below the end of the antenna for the coax to exit. The PVC pipe was secured to the top of the mast with two stainless steel hose clamps. Once erected temporarily in my driveway on a tripod, testing commenced. I found that while using an HT to feed the antenna, the SWR was excellent from 50.1 MHz to almost 52 MHz. This covers the SSB and FM simplex portions of the band fairly well, so I was happy. Unfortunately, the results were not so good when I tried feeding the antenna with my 706. The SWR was between 1:2.5 and 1:3. Not Good. After checking with my friend and mentor, Allan, KJ9N (Now a SK) who is a Technical Specialist for Antennas and Feed Lines, we decided to try a common mode choke mounted just below the bottom of the lower element. 11 turns of RG8X coax were wrapped around a short section of 3"dia. PVC and secured with wire ties and tape. The coil form was screwed to the 1" PVC "stub mast" and testing resumed. Now the SWR was between 1:1.1 and 1:1.6 from 50.1 MHz to 51.9 MHz. Now I was happy, and so it appeared was the 706. As you can see from the pictures, the antenna presents a very slim profile, a virtue not unimportant when the lady of the house has veto power on new antennas. Not only that, it is mounted right in the middle of the side garden. It must look pretty good. I have no doubt that the dimensions could easily be adjusted to cover the 52 to 54 MHz portion of the band. It is even possible that they could be adjusted to cover more than a 2 MHz portion of the band. I got what I wanted in coverage with the antenna at its current size, however, so I will leave the experimentation to others. Here is a shot of the common mode choke that keeps the RF where it should be, going out of the antenna. Page 3

4 Above is a schematic diagram (not to scale) and to the left is a photo of the finished antenna. Page 4

5 Radio interference from LED light bulbs? September 21, :13 Radio interference from LED light bulbs? The German Amateur Radio Club (DARC) has issued a press release identifying domestic LED light bulbs as a source of electrical interference. The increasing popularity of these light sources has led to a significant increase in reports of radio traffic disturbance, interruption of radio services and even poor DAB reception. In their opinion, the electrically noisy LED lamps are a result of a bad government policy which simply ignores regulations applicable to EMC and the generation of EMI by electrical equipment. According to DARC, the recommendations outlined in the regulations governing electromagnetic compatibility have simply been ignored. The result is that LED lamps currently on sale and in use generate considerable wideband RF interference. The German station Bavaria Radio has also pointed out the problem on its web page. Mains LED lamps Page 5

6 employ an integrated switching controller to power the LEDs from the high-voltage mains supply. Poorly or cheaply designed controllers can emit wide-spectrum electromagnetic RF noise because of unsuppressed fast switching signal edges. There are also stand-alone "electronic transformers" for low-voltage halogen and LED lighting systems which use the same voltage transformation techniques and these are often wired to the lamps using long cables/antennae. Such poor-quality products should simply not be on sale. On top of that, in the urban environment we have also witnessed a growing use of large electronic advertizing hoardings and increasing use of LED traffic signals etc. The November Word Search Puzzle On The Air With HF Digital D R R R A D I O V M E N Y D Z K T T G J L M F T L S Y R Y N T M A N F S J S C O X A I K Y C N B K M T M Y F T C N L R M O R L R T N C T M D T A T O C M O E O L Y W V N E T T Z T P P I T B T A K U R I V M Q C T U I G U R S O F G N X L A A X T G D E P S A I P I T F G P T E I W I M C D N S K B V P K T R D T Z E U T P F I L T E R S L L T X A I V I L O C G L D L U F D H J V S W O D N I W M M L COMPUTER DIGITAL DUTYCYCLE FILTERS FLDIGI INTERFACE LINUX MFSK MULTIPSK OLIVIA PACTOR PORTS RADIO RTTY SOFTWARE SOUNDCARD STATION TABLET Page 6

7 SWAP / TRADE / SELL If anyone has gear they wish to sell or donate, please send the particulars to the editor for inclusion in the next issue. VHF and UHF Antennas: Made with 3/32 welding rod and SO-239 connector easy to assemble and mount on ¾ PVC pipe. $10.00 each Call Geoff at PowerPole Power Distribution Blocks in 4+1, 6+1, and 8+1 sizes $15, $20, $25 each respectively Can custom build to suit. Call Geoff at Foot operated PTT switches brand new from MPJA wired with 3.5mm mono plug on 6 cable. $10 Call Geoff at AH sealed lead acid batteries (2) in commercial battery boxes with float charger. Each battery box has two pairs of Powerpole terminals and a switch controlled digital voltmeter. They also have a heavy duty webbing strap for carrying. Cost: $70 each Call Geoff, N1GY at TYT 440 MHz 45 watt transceiver, $ Contact George, K4AWA FOR SALE: Fitbit Flex wireless wristband. New in box, never used. $ Contact George, K4AWA or E Mail K4AWA@aol.com From Burch K4QXX Dentron 2k antenna tuner. $150 Ameritron AL-811H 800 watt amp. The tubes are a little soft but I have a brand new set of tubes that I will include with the Amp. $500 including the new tubes. Amp is wired for 110 but can be wired for 220. Or I will sell all of the above (Tuner, Radio, Amp and tubes) for $1000 as a package deal. I also have a 700watt 70cm amp that I will sell for $600. Amp is wired for 220. I have a watt amp that I will sell for $200 Amp is wired for 110. Contact Burch, K4QXX via burchakin@verizon.net Page 7

8 Club Meetings Monthly Meeting November 7, 2017 Bible Baptist Church 2113 Morgan Johnson Rd Monthly Board Meeting November 21, 2017 TBA 7 PM Monthly ARES Meeting November 28, 2017 Manatee County EOC 7 PM Club and Other Nets: MARCI Info Net Sunday 7:00 PM Hz. ARES Net Monday 7:00PM Hz. Manatee Skywarn Net Thursday 7:00 PM Hz PLEASE PARTICIPATE IN ALL THE NETS ANY TIME YOU CAN. The nets on Monday and Thursday ( ) are logged for the Manatee County Emergency Management and create billable hours of Volunteer Participation which results in County provided equipment for ARES. WCF ARES & INFO Net Monday 7:30 PM Hz. WCF Eagle NTS Net Nightly 8:30 PM Hz. WCF Skywarn Net Tuesday 9:00 PM Hz WCF Technical Net Thursday 9:00 PM Hz (The WCF nets are also available on Hz.) Don t forget the Christmas Party coming up on December 5 th 2017 and please don t forget the Nets on Sunday, Monday and Thursday. Page 8