The Kaw Valley Amateur Radio Club Newsletter THE TRANSCEIVER. October I lost it!

Transcription

1 The Kaw Valley Amateur Radio Club Newsletter THE TRANSCEIVER October 2015 Editor: Doug Dunton ARRL Affiliated Since Club Officers President: Paul Mills Vice President: Leo Hoffman Secretary: Susan Sims Treasurer: Todd Brandenburg I lost it! Yes me, your There is room for everyone! president lost it recently. I was reading mail from the reflector of one of the Great American Radio Manufactures, was drinking the Cool Aid and I just could not take in any more nonsense. I was about ready to grab a jug of rum and join Capt n Dave on 40-meters. Some things, the little girl wearing nothing but a diaper and playing in the mud puddle in front of the mobile home down the road knows. She can check an antenna, with a SWR meter, and tell you if it is matched or not. She can even tell you if the antenna needs to be chopped off, or extended. Now maybe that is an exaggeration, but hopefully you get the point! There are just things that a ham operator should take it upon themselves to learn. And many of these, are things that were questions on you Technician or General Class examinations. They are there for a reason. You should know your band limits, at least roughly, and have a chart nearby in case you need a reminder when venturing away from you favorite frequencies. See or

2 Additionally, you should know how close to the upper end of the band your upper sideband signal can be without danger of being out of band. Same goes for the lower end and your lower sideband signal. If you don t know, better get to studying. Likewise, you should know this information for your digital, CW, or FM signal. If you don t know most of these answers, time to study! The only one not likely to need to know is your FM signal, since we tend to use channelized frequencies. And yes, you should probably know how to check your own antenna. Additionally, you should at least have a rough idea of how long a half-wave dipole is on each of your favorite bands. Or perhaps the length of a quarter-wave antenna on some bands. Yes, even if you are an appliance operator, you should know these things. They are not hard to learn, even if you are not technically inclined. And they will help you stay out of trouble and/or be valuable in a time of emergency. 73 de AC0HY, Paul Guest Writer:Todd Brandenburg The homebrew vertical in use at KØKAN A few years ago I became interested in the HF bands again, particularly the cw bands on 40 and 20. When I first got into ham radio I spent a lot of time there, and after putting up a G5RV between three trees in my yard, I realized I'd missed it. I tried to rehab a vertical I got secondhand many years ago, but could never get it to work right, so that went back to the shed and I started looking for other options. After combing through QST, QEX, and a couple ARRL antenna books, I saw that it would not be difficult to build my own vertical. Since I was mainly interested in 40m, I decided to make one specifically for that band. Disclaimer: Any business name mentioned is not meant to be an endorsement, but is simply where I got the various materials.

3 To start, I looked through DX Engineering's website, and ordered enough aluminum tubing to make a 1/4-wave telescoping mast for the cw end of 40 meters. Each piece of tubing is 6 ft long, with 1/16 thickness. Bottom piece is 1 5/8" diameter, and each of the next six pieces is incrementally 1/8 smaller. Standard hose clamps hold each piece to the next. DX Engineering offers two versions of their tubingone with a slit in one end, and one without. I ordered the pieces without, since it saved me $2 per tube and I could cut the slit myself with a hacksaw. With each piece of tubing being smaller than the last one- working my way from bottom to top- it looks like an oversize version of the telescoping whip antenna that is attached to many portable AM/FM radios. I have not had to guy this antenna. That s not to say it doesn t sway in a stiff wind. That it does. But had I used the same size tubing for the whole antenna, guying would have become necessary, which would have made this project a non-starter. A word of advice... Get one or two more pieces than you think you will need. After sliding each piece 6-8" into the next bigger piece, the end result may be shorter than you want. Now that I had the tubing, I needed to make a mount. A few visits to the hardware store netted me a 5- ft natural gas pipe to pound into the ground, plus a 2-ft piece of Schedule 40 PVC- to keep the telescoping mast electrically isolated from the bracket, and two pieces of thin-gauge sheet steel that all clamps were bolted to. One piece by itself was too thin. Two pieces were adequate. I didn't like the U- bolts from the hardware store, so I used automotive muffler clamps, about $1.10 each from Kansas Automotive. Admittedly the muffler clamps are prone to rust while stainless is not, but I could not find stainless clamps that I liked. Some time earlier I'd found a radial plate at Associated Radio. I still needed wire for radials, so for that I got a 1/4-mile spool of stainless electric fence wire at TSC. Think it cost me $13. I got one box of the U- shaped yard stakes at a big-box store, and found more at a couple hamfests, at much better prices. Radials are pretty much a necessity for most vertical antennas, mine included. There are some that do not, but they are the exception rather than the rule. Picture a magnet, and its positive and negative ends. A vertical is much the same, in that the vertical radiating part is the positive, and the radial system is the negative. A vertical without radials may be a very good receive antenna, but it will be horribly inefficient if you transmit through it, despite what your SWR meter might tell you. There is no easy answer to how many radials one needs, or how long they should be, since too many variables are involved. I decided to use 16 radials. Mounting bracket was assembled, so I picked a spot in the back yard, and set out the radials. Most of the radials are 1/4 wavelength at the bottom part of 40m- about 34 feet, but some are shorter given the proximity to the property line, not to mention the corn field behind the house. I still have enough wire and stakes to lay out another 16 radials, should I ever get the proverbial Round Tuit. I never thought to take pictures of the first version of this antenna. It looked very simple, and it worked very well. I entered the upcoming ARRL CW Sweepstakes with the goal of working 48 states. I got about 40, plus several Canadian provinces including the Yukon, running about 90 watts to this antenna. The next CQWW cw contest was another surprise, working four continents and 20+ countries with the same 90 watts. The antenna consistently worked very well, but only on 40m. I might add that it is also a great receive antenna for both AM broadcast and the aircraft beacons that live below 500 khz.

4 Earlier this year I wanted the antenna to work on more bands, so I took it down. Since it was down, I also wanted to remake the antenna mount. The original sheet metal held up, but seemed flimsy and I was never comfortable with it. I found a remnant piece of 11-gauge sheet steel for $8.00 from Cycle Zone on Hwy 24. The owner also runs the HME metal plant on Button Road, and sells retail metal through the motorcycle dealer. I also got more muffler clamps from Kansas Automotive, since the original clamps were rusting. I primered and painted the metal and clamps, and assembled my new mount. This mount is much sturdier thank you. I decided to use 450-ohm ladder line to add coverage on four more bands. I used one length for 30m and 20m, and another for 17m and 10m. I used schedule 40 PVC to keep the ladder lines separated from the main whip by two feet, and added an LDG current balun at the coax feed point. After plenty of trial and error, plus one remake, I finally got it to work on all bands. Discovered that the antenna also likes 12m, but it won t work on 15m without a tuner. The attached pictures show the current version of the antenna. Another word of advice... I would recommend not using ladder line for radiating elements. Yes I made it work, but the SWR on 30m and 20m is a little higher than I d like, and I ve already re-cut new pieces of ladder line once. Each wire is somehow capacitively coupled to the others, and pruning one wire will affect the other bands, sometimes negatively. It s not worth the hassle. How does it work? Well, my first contact with version 2.0 of this antenna was a 30m chat with VK3CWB in Australia, and Moz gave me a 579. I ve worked a few Europeans on 20m- nothing earth-shattering there, and I recently worked New Caledonia (FK8) on 40, to complete Worked All Continents on 40m cw. Once upon a time, I could not have imagined WAC on 40 without a large yagi and lots of power. This antenna was not difficult to make. It took some time to plan it, a few extra trips to the hardware store to get various small items that I had forgotten, and some elbow grease to assemble it and get it tuned the way I wanted. In all I probably have $150 invested in it, with most of that tied up in tubing, radial plate, and current balun. It s not a ground-breaking design by any stretch, and it s not pretty. But it works much better than any HF antenna I ve used in the past. I d do it again.

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8 Reminders: Annual 2015 Membership form at Ham FAQ: For Hams new to the area or are just licensed - Ham bands Chart from ARRL - Larrys List web page - KVARC Club meeting October 2nd 730pm at Topeka Public Library. Eyeball QSO starts around 7pm Regular test session at October 10th at Topeka Library at 2pm. Pre-register with Paul at ham.test@kvarc.org. Regular test session at Nov 13th at Carbondale City Hall at 7pm. Pre-register with Paul at ham.test@kvarc.org Tuesday night Alpha 1 ARES net on (88.5 tone) at 830pm Thursday night Charlie 1 ARES net 800pm on Ottawa repeater only on the first and fourth Thursdays. Wednesday night Wild on Wednesday simplex net on at 730pm run by KB0WOW Dan 10th Annual KB0WOW Tailgate Swap & Shop Saturday, September, 26th 2015 from 1100 to 1300 at Solid State Sonics and Electronics (see details below) Technician Class Oct 3 and 10 th, 9am till 5pm at the Topeka Library. Test session following the class on the 10 th General Class Nov 7 th, 14 th, 21 st, 9am till 5pm at the Topeka Public Library. Test session following the class on the 21 st. Extra Class January 9th, 16 th,23 rd, and 30 th. 9am till 5pm at the Topeka Public Library. Test session following the class on the 30th.

9 Other info: Announcing the 10th Annual KBØWOW Mr. Wild On Wednesday Tailgate Swap & Shop A benefit for the Kaw Valley Amateur Radio Club Repeater Fund. All proceeds of the Tailgate Swap & Shop food sale plus any donations will go for the Topeka area repeaters. Saturday, September, 26th 2015 from 1100 to 1300, at Solid State Sonics and Electronics 4137 NW Lower Silver Lake Rd. Topeka, Ks Just off Highway 75 and Lower Silver Lake Rd, next to Skinner s Nursery. Food is available for sale. Available items are: Pulled Pork Sandwiches $3 Pulled Pork Sandwich Dinner w/ Coleslaw, Potato Salad, and Baked Beans $6 No charge to set up booth at event, and is open to all kinds of items, not just ham related. Talk-in on (-) CTCSS 88.5 For information, call: Dan Green, KBØWOW at or Frank Kent, NØFWK at fkent@kentsafetyllc.com Please send any equipment you have for sale and I will include in next month s issue

10 Elmer-ing Attached is a form for letting me know what you might be interested in having help with. Or If are available to help someone. Please fill in as appropriate and back to me or bring to the club meeting Friday. I have mentioned this new item to a few people, I would like to suggest adding a get together some other time of the month as a learning session. I am open to suggestions as to a day and time. I can try to schedule time at the library or if a different location is available I would take that as a suggestion also. So what do you think? Let me know by or at the club meeting. Number of Elmer sheets received: 2 ARRL Affiliate since 1926

11 Need / willing to be an Elmer Info Call Name How to contact Phone Other Location City Long/Lat Grid square want/need help Interests level of expertise Willing to help Antennas CW Digital General Info Radio to buy APRS ATV Level of expertise (1-5) 1=beginner, 5=expert Give to Doug(WD0DBS) or to wd0dbs@arrl.net