Dixie Ham Radio Newsletter March 2018

Transcription

1 Dixie Ham Radio Newsletter March 2018 Amateur Radio works when all else fails! We are an ARRL Affiliated Club Officers (positions not yet determined): Board Member... Harold Wells, KE7OZG Board Member... Bob Vosper, KZ1B Board Member. Lynden Kendrick, KG7SXQ Board Member... Deborah Porter, KE3FY Board Member... Justin Grenier, KE7JJG For information or comments send to: or Text Notice: Articles, statements and opinions are those of the authors. The Club is not responsible for accuracy of the information contained herein. Ham Radio Special events: The Dixie Amateur Radio Club meets on the 3rd Wednesday at 7 PM at the St. George Community Building. It is found at the Southwest corner of Washington County's Gayle M. & Mary Aldred Senior Citizens Center property, which is located at 245 North 200 West, St. George, Utah. This year, the WCARES (Washington County ARES) monthly training meeting will be held on the 3rd Saturday each month at 9:30 AM at the Washington County EOC training room located in the basement area of 197 E. Tabernacle in St George. Learn more or how to join Washington County ARES at Put June 23rd and 24th on your calendar. That's when the National Field Day is happening. DARC members and guests can get on the air with diverse antennas and different radios to talk with hams across the world. "Band" of Brothers By Lyn Kendrick, KG7SXQ As Editor, I get to be reflective on occasion. I've had my license for 3 years. Not a long time. While driving, I was mulling over how many friends I have made in ARES and at DARC meetings. I've been lucky to steal ideas from mentors and young and old confederates. I've shared stories and lies at breakfasts, Marathons and emergency mock-ups. I've helped take down antennas that went to a new back yard. I've helped put up antennas. Some worked. Being active on net's has allowed me to recognize voices and put faces to respected operators with more or less experience. I've seen new hams soar with new knowledge and become excited to serve with their radios. I've learned to love HF (when I didn't think I would). I was able to get 4 "whole" QSO's on CW before giving up. I've made friends from Malad, Phrump, Central, Hurricane, Colorado City, St George, Kanab, Page and even Rhode Island because we could talk on the "bands." We have something in common and we are a band of brothers hopefully for...a long long time. 1

2 Activities By Lyn Kendrick, KG7SXQ Wow, it seems like we've had a bunch of activities. It's great to be of service to the community whether it's for motorcycle riders or runners, etc. 1. Mac and Bob made a presentation to Jeep and off-road enthusiasts at Dixie 4x4. 2. We served the community by helping with the Half Marathon. 3. A dozen operators helped at the annual Rhino Rally (motorcycle races in the middle of nowhere--almost ). 4. The Club had a great turnout for the Silent Auction but Harold was disappointed he had to lug some stuff back to his house. 5. Six Club operators participated in a Southgate Stake Preparedness Fair. Here are some pictures: 2

3 Whispers over the Wireless (Editor: "Whispers over the Wireless" is for qrp, SOTA and cw related articles since these operators often whisper using 2 to 5 watts) Simple Tuning of a Linked Dipole (or Any Dipole) By Mike Cartmill, ACØPR With an antenna analyzer in hand (RigExpert AA-30), and needing to tune my newly homebrewed linked dipole to take to the mountains, I put the antenna on a temporary mast to test it out. With a linked dipole (several lengths of wire cut to specific frequencies that can be linked together to change bands), you have to short with shortest length of wire and progressively move down the bands to the longest length. 3 My particular linked half-wave dipole is made to cover three bands: 20, 30, and 40 meters. Naturally, you need to start with wire that is cut a little longer than you want in order to trim it specifically to the frequency desired. To use some of the great features of the software that comes with the analyzer, I had my antenna connected to the analyzer, which in turn was connected to the computer. After a preliminary scan and graph of the SWR, you start trimming the wire and analyzing again and you ll see the lower portion of the SWR curve move towards the frequency you want. Just be careful to not cut off too much. You want to pick a frequency in the middle of whichever portion of the band you will use the most. Of course, you don t need to have an analyzer to tune a dipole, although it does make it easy, just using the SWR reading will do the job as well.

4 --What does an analyzer do? The antenna analyzer is a small broad band transmitter with calibrated meters and chart producing circuitry that allows you to place a very small signal on an antenna in order to determine that antenna characteristics. By charting these characteristics an antenna may be cut to a desired resonant frequency. A transmitter transfers the most power to an antenna that is tuned to the frequency the transmitter is operating on. This condition is called resonance. With a linked dipole, once one band is done, you link the next set of wires and tune them as well following the same procedure until all bands have been tuned. When I connected my radio to the antenna and tried each band, it was very gratifying to see an SWR of 1:1 on each one (the analyzer is more precise showing 1.3:1). --Why is it better than just a SWR meter; either built in or outboard? The SWR meter was designed for quick checks of your total system SWR. When you check your SWR you are putting a signal out which causes interference and in most cases is illegal since most folks don t ID. Additionally, the transmitter may be placed under stress due to a high SWR. It is not uncommon to burn up a set of final amplifier devices by transmitting for long periods of time with a high, over 3:1 SWR. Because you are limited to transmitting only in the Ham Bands it can take a long time to discover whether or not the antenna is too short or too long. In short; it is just good practice not to use an SWR meter to tune your antenna. Since then I have taken it out to the field a number of times and enjoyed knowing my antenna is right on with no tuner required. Good luck with yours! Misc Club Articles Antenna Analyzer Talk By Mac Harmer, K8NG (Ed: This is from a presentation Mac made in November. It is published with permission) 4 --How does it help tune an antenna? Let s walk through an example antenna tune up using the antenna analyzer. It does not mater, well it may matter to some, which analyzer you use. The MFJ units get the job done. The more expensive units offer more bells and whistles and it is up to you to decide if your needs require the additional expense. The MFJ C model covers 220 MHz but not 440 MHz. Lynden s AA-30 only covers HF (Ed: He likes it but does now wish it covered 2M). This CAA-500 covers up to 500 MHz and comes recommended by QSTt. OK, we hook up the analyzer to the antenna feed line and the first thing I do is find the

5 resonant frequency of the antenna. This is indicated by X = 0. X is reactance and is the subject of a very technical talk that most of us don t give a hoot about anyway. The take away here is to attempt to get the X=0 at the center frequency of the band you are tuning the antenna to operate on. All your readings are recorded. I make an Excel Spreadsheet to record mine. Make the font about 16 or 18 so that on your printed out blank sheet you can write the number is for future recording on the computer version of the spreadsheet. You will see two versions of my spreadsheets as an example of what they may look like. Let s look at an actual field antenna tune that I did on my 40 Meter NVIS antenna that many of you have seen in operation at DARC Field Days. Here is my 40 NVIS project SWR Frequency R X 50' RG8X cut 6" off ant cut 6" more off ant. This would indicate the wire was too short so equal amounts of wire would have to be added to EACH end. What I would do is twist & solder a 1 foot length of wire on each end and let it hang down from the insulator. Take a reading and start folding the hanging wire back on itself until I was at the desired frequency. --Where do you hook it up? Close to the antenna or close to your radio? My experience indicates that the analyzer should be placed at the end of the antenna feed line. If the antenna, tuner, and transmitter are treated as a single system your results will be more useful. Therefore; I suggest connecting that analyzer at the feed line just before the tuner or transmitter. Adjustments are made to the antenna based upon the charts you generate with the analyzer. Once the antenna is tuned to the desired frequency you move onto the next step. The question generally comes up as to how long the feed line should be. My answer has always been that the feed line should be long enough to reach from the antenna to the transmitter. Note: that I stayed at the X=0 frequency was below the target of meaning the wire was to long so 6 was cut off and new reading taken. At 7.2 we see that were are moving in the right direction but not there yet. 6 more was cut off putting us at 7.25 which was close enough for me. Now a caution I did not CUT the wire off the antenna. I just pulled it through the insulator and wrapped it around the antenna wire. Ah you say; What if the frequency had been 7.3? Now, having said that, for those of you who want a little more perfection the answer is slightly different. The antenna feed line should be half wave multiples of the electrical length of the feed line used at the frequency desired. This means you have to calculate the electrical length, using the velocity factor of the line you are using. Note; this repeats the actual characteristics of the antenna every half wave resulting in readings at the shack being the same as at the antenna. At the frequency desired means that this only works on that frequency. Perhaps you may now understand why I don t worry about perfection. 5

6 ATR V Quick Tune 40 D Code of Conduct (for Hams) Suggested for republishing by Mike Cartmill, ACØPR DX Code of Conduct: Frequency TX ANT IND TX ANT IND CH CH CH CH CH The antenna is now connected to the antenna tuner and the tuner coax that is connected to the transmitter is connected to the analyzer. The analyzer is then tuned to your desired frequencies on your Antenna tune Excel spreadsheet. If you turn you receiver to this frequency you will hear the beat note from your analyzer. At each desired frequency you adjust the tuner for Zero SWR entering the setting on your spreadsheet. When you are done it will look something like my Quick Tune sheet. What you have just done is tuned up your station to a set of frequencies that you generally operate. If you choose enough of these frequencies you will be close enough to put out a call to that DX station. And, more importantly, you have not interfered with your fellow Hams while tuning up nor have you stressed your transmitter finals. 6 --I will listen, and listen, and then listen again before calling. --I will only call if I can copy the DX station properly. --I will not trust the DX cluster and will be sure of the DX station's call sign before calling. --I will not interfere with the DX station nor anyone calling and will never tune up on the DX frequency or in the QSX slot. --I will wait for the DX station to end a contact before I call. --I will always send my full call sign. --I will call and then listen for a reasonable interval. --I will not call continuously. --I will not transmit when the DX operator calls another call sign, not mine. --I will not transmit when the DX operator queries a call sign not like mine. --I will not transmit when the DX station requests geographic areas other than mine. --When the DX operator calls me, I will not repeat my call sign unless I think he has copied it incorrectly. --I will be thankful if and when I do make a contact. --I will respect my fellow hams and conduct myself so as to earn their respect. Mike S.W. Utah 2Mtr SSB Roundtable If you happen to have SSB capability on 2 meters on your multiband radio, tune your rig to MHz USB at 7:00 p.m. each Sunday and check into this fun and informal roundtable net. More details on this will be provided in a future newsletter article.