Simple Ham Radio Antennas

KH6JRM's Amateur Radio Blog Post # 170 A Simple 20-meter loop antenna I've always had a fascination with full-wave loop antennas for the amateur radio bands.  While loops take up a lot of space, they are easy to make and generally quieter antennas than verticals.  Most of the materials for loop antennas can be found at your nearest hardware store or in your garage.  If you're a radio packrat such as I, you probably have extra wire and coax stashed somewhere near your shack.  While there was a break in the rain showers that have soaked Hawaii Island for the past few days, I ventured into my flooded backyard to examine my antennas for signs of damage or loose connections.  Apparently, a tree branch struck the 20-meter vertical dipole in back of the garage, necessitating lowering of the fiberglass mast and the removal of the wire elements.  I decided to restring the 20-meter antenna as a full-wave loop fed by approximately 40 feet of RG-6 coax.  I cut three, 23-foot l

KH6JRM's Amateur Radio Blog Post #169 NOVICE ANTENNAS The remnants of Hurricane Emilia are sweeping Hawaii Island with frequent showers and gusty winds--not the sort of weather conditions I prefer to do antenna maintenance.  So, bowing respectfully to the wiles of Mother Nature, I continued my antenna research via my personal library and notes from years past. One of my favorite amateur radio magazines besides Radcom (RSGB), QST, and CQ is the quarterly volume issued by the Quarter Century Wireless Association (QCWA Journal).  The magazine features interesting articles about hams who have been licensed 25 years or more and have contributed to the "radio art" in both their professional and personal lives.  The current issue (Summer 2012, Volume 61, Number 2) has several intriguing articles articles including a review of the venerable Barker & Williamson 6100 SSB, AM, and CW 80-10 Meter Transmitter and a continuing series of articles on Amateur Radio Novice Ope

KH6JRM's Amateur Radio Blog Post 167 A MINI-EXPEDITION I've always wanted to go on one of those heavily funded DX-peditions to some exotic place and be on the receiving end of a DX pileup. I'm sure I could enjoy myself, even after days of stress, QRM, and unforeseen operating problems in some isolated locale.  For now, those fantasies will be explored in the pages of QST or CQ until I become sufficiently rich to afford such a trip. Meanwhile, many amateur radio operators (including yours truly) will try to live life as it comes and operate whenever circumstances permit.  Such was the case over the past weekend, when I did my regular assignment of being the tower announcer at the monthly drag races held by the Big Island Auto Club.  Unlike past weekend stints at the Hilo Drag Strip, I brought along my HF "Go Kit" and decided to operate at the track before and after the regular races were run.  Since I arrive very early on Saturday and Sunday morning (0500

KH6JRM's Amateur Radio Blog Post 167 INTRIGUING ANTENNAS Hawaii Island dodged a potentially wet weekend with the passing of tropical depression "Daniel" Thursday evening.  The island is receiving some high surf and a few heavy showers, but that's about all the storm could do.  "Emilia" is still churnging about about 1000 miles to our east, but, it too, is predicted to track south of Hawaii Island.  The hightened alert gave amateur radio operators here a chance to check out their emergency "go" kits and review their own procedures for such continguencies. While I waited for the bad weather to pass, I found three articles in the 13 July 2012 edition of "e-ham.net" that could provide antenna ideas. For those amateurs involved in emergency communications, a good NVIS (near vertical incident skywave) antenna is a must for regional HF  operations out to about 300 miles.  Pat Lambert, W0IPI, has published an excellent tutorial on NVIS

KH6JRM's Amateur Radio Blog Post 166 EMERGENCY ANTENNAS Hurricane season has arrived in the Hawaiian Islands and local civil defense officials are encouraging local residents to prepare for some rough seasonal storms.  In the Central Pacific, hurricane season runs from June to November.  Presently, there are two storms which will impact Hawaii Island--Daniel, now a very wet tropical depression, and Hurricane Emelia, located about 2,000 miles east of Hawaii Island.  Although the storms are predicted to weaken as they pass below Hawaii Island, they will bring heavier than normal rain, gusty winds, and storm surf ranging up to 10 feet in some lowland areas.  This is a challenging time for surfers, who have been warned to stay clear of rough spots, and for local residents, who could lose power and suffer building damage. With the exception of Hurricane Iniki in 1992 and Hurricane Ewa in 1982, Hawaii has been spared the full force of seasonal hurricanes thanks to the storms ente

KH6JRM's Amateur Radio Blog Post 165 BACK TO BASICS One of the creative things amateur radio operators can do these days is to build simple, effect wire antennas.  Although most commercial antennas are well made and perform well, there is nothing quite like building your own antenna and working DX on a shoestring budget.  So, let's begin with my favorite band--20 meters. After I took down my temporary "long wire" antenna this morning, it was time to rebuild a 20-meter antenna that had seen better days.  As mentioned in post 164, rodents and other unnamed creatures chewed on my feed lines and elements, creating an ugly mess.  Fortunately, I still had a homebrew 33-foot mast made from 2-inch pvc pipe which could be pressed into service.  I attached 16 1/2 feet of AWG 22 wire to one half of the mast and another 16 1/2 feet of wire to the bottom of the mast.  At the midway point of the mast, I attached and soldered 40-feet of 450-ohm ladder line.  The line ran i

KH6JRM's Amateur Radio Blog Post 164 A QUICKLY DEPLOYED "LONG WIRE" ANTENNA Most of my weekend chores are done, which gives me a few hours to play with antennas before Monday arrives.  Yes, even for those of us in the "semi-retired" category, there are things to do before the warm glow of vacuum tubes draws us back to the rf circus. I've been able to build and test numerous antenna designs over the past few weeks, thanks to a break from my substitute teaching duties.  My xyl and I expect to be called shortly for another assignment since Hawaii public schools begin during the first week of August.  So, there's lots to do--clean up the "shack", inventory equipment, and otherwise try to find stuff I misplaced over the year.  As for antennas, I decided to take down the inverted 40-meter vee for maintenance.  Rats and other small animals have chewed up some of the wire elements and a piece of coax I used to connect the 4:1 balun to the Dra