Saturday, June 30, 2012

Simple Antennas for Amateur Radio Operators--a continuing series

KH6JRM's Amateur Radio Blog, post 160

NEW USES FOR OLD COAXIAL CABLE

ANTI-THEFT PROTECTION FOR EQUIPMENT

One of the things I enjoy when I'm not behind the key or microphone at my amateur radio station is reading historical material pertaining to amateur radio.  This sub-branch of the amateur radio hobby has given me several ideas on antenna improvement, reusing old materials in new ways, and protecting valuable equipment with a minimum of effort.

What do you do with old coaxial cable?  I tend to follow the advice of E.A. "Whit" Whitney, W1LLD, who wrote a brief article about reusing lossy cable in the 11th Edition of "Hints and Kinks for the Radio Amateur" (published by the ARRL in 1982).  Whit's article is found on page 5-13 of this excellent compendium of practical ideas from past issues of "QST", the official journal of the American Radio Relay League. 

In Whit's own words, coaxial cable "that's become too lossy for use as  transmission line" can be used "for radials in your ground system.  Lengths of the sheathing can be removed from the cable and installed as ground or bonding straps around your equipment, in your boat or on your car.  A length of such cable makes a good shielded lead from your car battery to your mobile radio."  In the past, I've used old lengths of RG-6 obtained as scrap from cable installation companies for radial and counterpoise systems.  In most cases, these old cables work well in this new application.  In my case, I got old cable for free or for just a few dollars.

Another problem amateur radio operators face is the loss of equipment through theft and the identification of such equipment when police recover the stolen radio and station accessories.  As in the previous discussion on coaxial cable, the 11th Edition of "Hints and Kinks for the Radio Amateur" contains a few suggestions on how you can handle the issue of anti-theft protection.  On page 7-4, Paul Zender, AA6PZ, has a few ideas to make the recovery of your lost equipment a bit easier.  Paul writes, "amateurs wishing to protect their equipment from theft shold mark it with the abbreviation of their state and driver's license number.  This makes it easier to trace through police computers than using social security numbers or an amateur radio call."  Check with your local police department to see if it participates in "Operation Identification".  You may be able to borrow engraving tools for marking household valuables, including your radios.  Stickers can be attached to indicate that the property is marked and the identification recorded with local law enforcement authorities.

I've marked my equipment and I hope you will do the same.  Have a good, safe weekend.

Aloha es 73 de KH6JRM--BK29jx15

Thursday, June 28, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

PURPOSE OF THIS SITE

Over the past few days, some of my readers have asked why I put this site together and to whom  the information is directed.  These are fair questions, since my interest in Amateur Radio (Ham Radio) may be far from your concerns.

I have two reasons for writing this blog:

1.  The blog serves as a personal journal about my journey through interpersonal communications and my love for all things electronic.  I've been a licensed amateur radio operator for 35 years.  I've enjoyed every moment of the experience, from building equipment to designing my own antennas (the things that launch signals into the atmosphere).  I was fortunate to have had a good electronics background courtesy of the United States Air Force and over 40 years in the commercial broadcast business.  Very early in my radio journey, I helped design and build the student FM radio station at the University of Hawaii (Manoa), worked at various radio stations, and even put a part 15 (unlicensed, low power) AM station on the air from my house.  Before I became a school teacher, I retired as the news director of Pacific Radio Group stations on Hawaii Island.  So, you could say electrons run in my blood and may have scrambled my brain.  Everyday, I look forward to contacting friends around the world.  Sometimes, I even get to practice my Russian with hams in Moscow and in other parts of the Russian Federation.

2.  The blog also serves as a record of my experiences in overcoming obstacles presented to the pursuit of my radio hobby.  One of the things amateur radio operators do the most is design and build antennas.  Sometimes an efficient antenna creates friction with neighbors, who consider towers and supported wires a detriment to their sense of aesthetics.  In fact, restrictions placed on amateur radio operators by CC&Rs (covenents and restrictions), HOAs (Home Owners Associations), and the sheer lack of physical space have led many amateurs to seek other ways of continuing their hobby.  Presently, the U.S. Congress has mandated the FCC (Federal Communications Commission)  investigate how housing laws restrict the emergency operations of amateur radio operators.  One of the requirements of an amateur license in the United States is to provide emergency backup communications should regular channels go down.  Amateur radio operators have provided communications support to local agencies during times of emergency, such as hurricanes, fires, tsunamis, earthquakes, and other natural disasters.  Many hams feel that the growing restrictions against outside antennas will restrict their ability to respond in times of emergency.  Congress and the FCC will eventually figure out  some sort of solution to this problem.

Meanwhile, many amateur radio operators, including yours truly, are trying to make the best of a contentious situation.  That's where I come in.  After three and a half decades on the air, I have accumulated a lot of experience in designing and building simple, cheap, and inobstrusive antennas that will serve those operating in restricted situations.  The antennas I use in my crowded neighborhood are nearly invisible from the street and can be lowered to ground level during periods of inactivity.  Eversince I adopted this low impact antenna philosophy, there have been no complaints about unsightly structures or ruined views of the countryside.  So, I share what I've learned with other hams in the hope they, too, will find something useful in their situation.

Amateur radio operators are the descendants of Marconi, Popov, Hertz, De Forrest and others who have pushed back the frontiers of knowledge.  To paraphrase Sir Isaac Newton, "I stand on the shoulders of giants."

Have a good and safe weekend.

Aloha es 73 de KH6JRM--BK29jx15

Wednesday, June 27, 2012

SOMETHING DIFFERENT FOR THE ANTENNA EXPERIMENTER

The weather has improved to a point that I can get outside and play with antennas again.  Other than a twice-daily walk and jog with my xyl, the weather has kept both of us inside.  June on Hawaii Island often brings many days of showers, and this past week was no exception.  So, when the sun finally broke out for several hours, I rushed through my daily chores and proceeded to the postage stamp lot in back of our rental house for some serious antenna work.

Because the inverted vee, loop, and "upper and outer" antenna were doing well, I decided to make a vertical helix for 40 meters using some short pvc pipe, extra #22 AWG wire in the shack, and some 450-ohm balanced line into a balun and the trusty Drake MN-4 ATU.

According to information I found in several ARRL publications, a quarter wave vertical could be created by winding a half wavelength of wire around a sturdy pole and topping the end with a capacitance hat.  I've seen amateurs use vertical helix antennas designed for 80 meters with some good results.  Of course, a good radial field is necessary to make these shortened antennas perform.

Anyway, I wound 66 feet of #22 AWG wire along a 10-foot piece of schedule 40 pvc I had under the qth.  According to theory, that arrangement should give me an antenna roughly equivalent to a 33-foot vertical.  I attached an 18-inch capacity hat to top of the wire helix, connected one lead of 450-ohm wire to the helix, connected the other lead to a 33-foot counterpoise, and joined the entire system to a 4:1 balun and the Drake MN-4.  The homebrew vertical helix had a very narrow tuning range, but it did work on 40 and 15 meters with the help of the Drake MN-4.  I tried the helix on 20 and 10 meters with some degree of success, but the antenna seemed to work best on 40 and 15 meters.  The Drake MN-4 remained cool on all bands and I did not get any rf "bite" in the shack.  I was running 15 to 20 watts cw with no problem.  I tried a few SSB contacts at 50 watts and was pleased to get some good reports.  The vertical helix probably has more losses than my trusty inverted vee, but it does work and it does let you be heard.  Of course, results could be better if I had enough room to establish a decent radial system.

The vertical helix is easy to build, easy to disguise, and very portable.  The antenna is nearly invisible from the street in front of the qth, owning to its small size and proximity to local trees.  As is the case with my other antennas, the vertical helix can be swiveled down to ground level when I am not using it or when storm clouds approach.

I may use another helix on a longer pvc pole to get on 75 and 80 meters--frequencies which are difficult to operate from my location. 

I will let you know how that project turns out.  Meanwhile, have a good day and get on the air with something you have designed and built yourself.

Aloha es 73 de KH6JRM--BK29jx15

Tuesday, June 26, 2012

A VHF ANTENNA FOR YOUR APARTMENT

Apartment dwellers face unusual antenna problems, whether they be the  installation of HF antennas or VHF antennas.  Like many of you, I've resorted to using my handheld attached to a mag mount atop a refrigerator or other piece of interior metal.  While this arrangement works, it can be unsightly or even dangerous.

It seems Yvon Laplante, VE2AOW, has come up with an apartment antenna which is not only effective and cheap, but also disguiseable and safe.  Laplante's idea can be found in the "Hints & Kinks" column of "QST" for July 2012.  In Laplante's words, "I made a small dipole antenna using telescoping antennas I took from old, broken FM radios.  The antenna is mounted on a...3 x 5 inch piece of Plexiglas with two suction cups.  With my radio placed close to a window, I attached the antenna to the window and adjusted the two elements for 2 meters--about 19 inches.  The antenna gives very good results."  This antenna has low visibility and can be easily moved to better locations in the apartment. 

This afternoon I tried a similar antenna in the bedroom facing the island of Maui (a repeater there is about 75 miles from my qth.  The repeater is on the slopes of Mt. Haleakela).  Getting 2 meter signals to a local Hilo repeater is quite difficult with several ridges and mountain slopes directly in the path from my qth to Pepeekeo (just outside of Hilo--about 22 miles from my house).  So, most of us along the Hamakua Coast rely on the Maui Island repeaters for coverage.  Anyway, I taped two 18 inch pieces of #22 AWG wire to the bedroom window and fed them with  RG-6 coax via a HI-Que coax connector.  My old Kenwood handheld (TH-21) was able to raise two Maui repeaters with this arrangement.  My usual 2 meter antenna is a Larson 5/8 wave mag mount on the metal roof of my garage.  The Larson provides a better signal, but the "lash-up" I copied from VE2AOW seems to work fairly well.  I'll keep this homebrew antenna as an emergency backup to the Larson on the garage roof.

I have a similar set up in my van.  I placed an 18 inch vertical element and an 18 inch horizontal element fed by RG-6 coax on a window attached to the right sliding door.  I provided some slack so opening the door won't damage the coax.  While this antenna is a compromise, it does serve me well in Hilo town, where I can hit several local repeaters with my Kenwood TH-21 handheld.  I keep this old Kenwood as a spare and as a mobile rig for the van.  Even at the low power setting, I  can get solid copy in and around Hilo.

Aloha es 73 de KH6JRM--BK29jx15

Monday, June 25, 2012

Simple Antennas for Amateur Radio Operators--a continuing series

A NEW ANTENNA FOR APARTMENT DWELLERS

The July 2012 issue of "QST" contains an interesting antenna article by Jeffery Brone, WB2JNA.  The article entitled "A Dipole Doesn't Have to be Straight--There's always a way to put some kind of antenna into service" runs from page 36 to page 37.  Brone's idea may give you another way to get on the air despite severe space restrictions.

Simply put, Brone ran approximately 35 feet of light gauge wire (#22 or #24 AWG) to  a balcony of his third floor apartment and ran another 35 feet around the apartment, "tacked up along the ceiling and corners, resulting in a full size dipole for 40 meters."  He fed the antenna through a MFJ manual tuner with  3 feet of homemade laddder line (2 inch spacing between the wires)  "and it loads up on all bands--40 through 10 meters."  Running low power (15 watts cw), Brone has been able to work Chagos Island, Africa, and South America.

Brone says common sense applies when you use this homebrew antenna--avoid folding the wire back on itself and use low power to minimize RFI and exposure to RF.  Brone concludes his excellent article with what he calls the "10 rules of stealth/apartment/restricted antennas":
"Something for an antenna is better than nothing."
"More wire is usually better than less, unless the antenna is only meant for one band."
"Balanced (center fed dipole or vertical) is better than unbalanced (end fed wire), all other things being equal."
"All other things are seldom equal.  Try different arrangements.  Read up on the subject."
"Get a tuner.  A low priced manual one is okay.  You'll want it for some bands and will appreciate the flexibility it gives you."
"Get a dummy load, too."
"Keep the power low for safety and less RFI."
"CW and digital modes produce more contacts than SSB."
"Listen, listen, listen."
"Put up the best antenna you can manage, then get on the air and have fun!"

Indoor antennas do work if you allow for their limitations.  When I first became a Novice operator back in 1977, my first antenna was a 70-foot loop tacked to the ceiling of the teacher's cottage my wife and I shared in Honokaa.  Fed with 300-ohm twin lead and hooked to a balun and a Drake MN-4, the homebrew loop did a good job on 40 and 15 meters.  I still have the old Drake MN-4, so I guess the tuner survived my initial efforts at antenna design.

Now, I have an inverted vee, an "upper and outer" vertical with counterpoise, and an under-the-house 40 meter loop.  My small backyard can just accommodate the vertical and the vee.  I suppose I'm luckier than many who face CC&Rs, HOAs, and no backyard space.  Give this bent dipole of WB2JNA's a try--it could open an entire new frontier for you.

Aloha es 73 de KH6JRM--BK29jx15

Sunday, June 24, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

FIELD DAY IN HILO, HAWAII

The Big Island Amateur Radio Club endured rain, heat, and wind to complete another successful ARRL Field Day at Hilo's Wailoa Visitors Center.

Frequent rain showers and unsafe track conditions led to the cancellation of the June Points Meet at the Hilo Drag Strip.  The closing of the track freed a few hours to enjoy the ARRL Field Day with the Big Island Amateur Radio Club.  I was only able to spend about 3 hours with club members, but I did see some interesting antennas and displays at the visitors center.

When I arrived for the 0800 W start of the event, the sky was overcast with scattered showers--a perfect time to erect antennas!  By the time I got squared away, the club had erected a 40 meter vertical and a hardy cw operator starting logging in contacts on 15 meters.  The erection of the triband beam had to wait until the skies cleared and the threat of thunderstorms subsided.  While all of this was going on, the trusty vertical and a Yaesu-857D kept KH6EJ (club call) on the air.  The rig ran off several deep cycle marine batteries until the tribander and a 3-element yagi could be erected.  The club also had a mobile station (class 1-C) using a 20 meter hex beam.

About 35 club members and 50 or so local residents attended this edition of Field Day.  A reporter from the "Hawaii Tribune-Herald" newspaper interviewed several club members and took a long series of photographs for the paper.  By the time I left at 1130 W, a second rig was added to the mix, making the club fully operational as 2A Pacific.  A small Honda generator and a bank of solar cells were used to charge our batteries.

The weather was quite wet and gusty through Saturday night.  There was some clearing by early Sunday morning, so some of the weather was favorable for raising and lowering antennas.  Club members, friends, and family brought sufficient supplies of food and drink to keep the over night operators fully fueled.  The club also had a media display, handouts from the ARRL, and an emergency communications kit for the public to examine.  Hawaii County Mayor Billy Kenoi declared Saturday, 23 June 2012, as "Amateur Radio Field Day in Hawaii County".  So, the club got quite a bit of print and electronic publicity.  My former employer (Pacific Radio Group) ran public service announcements about Field Day, as did some of the other radio stations in Hilo.

Considering the poor weather conditions, participation by both amateur radio operators and the general public was excellent.  The Wailoa Vistors Center was large enough to accommodate club members, county officials, and the public.  All told, club members did an excellent job of getting out the word about Amateur Radio.  Several local residents expressed an interest in upcoming license classes taught by club members.

I trust your Field Day went well.

Aloha es 73 de KH6JRM--BK29jx15

Friday, June 22, 2012

Simple Antennas for Field Day

FIELD DAY ANTENNAS

The ARRL's traditional Field Day Emergency Communications Exercise begins shortly.  For Amateur Radio operators in the state of Hawaii, the fun begins this Saturday at 0800W and ends Sunday at 0800W...a full 24-hours of emergency operations, a near contest atmosphere, and, most of all, outrageous fun!.

This year, the Big Island Amateur Radio Club will use the grounds of the beautiful Wailoa Visitor's Center in Hilo.  The site is open to the public and is covered in case of summer rains.  Although the club will be running 2A Pacific with solar and generator power, there is commercial AC available for the evening and morning meals.  Ah yes, the food.  As was the case last year, club members will prepare something at home and bring their surprises to the center.  I'll be bringing a case or so of soda and fruit juce to keep the operators fueled throughout the long, sticky night.  Once I get through with the drag races at the Hilo Drag Strip (I'm the tower announcer for this event),  I'll drive over to the operating site and settle in for a few hours of logging and operating.

Field Day brings out all kinds of operating equipment.  Last year, the club had a variety of rigs, including the latest Kenwood and Yaesu transceivers.  But what brought me out last year was the diverse selection of antennas available.  The club put up an impressive tribander, a set of phased verticals for 40 meters, and, on one occasion, strung a full wave, 80 meter loop between several palm trees.  That antenna was quite a performer.  This time, the club will have a tribander, a phased vertical array (most likely for 40 meters), and a surprise for 80 and 160 meters.  Satellite operations are also on the schedule.

Most likely, I'll spend some time with our newly licensed amateur radio operators, giving them some experience in a contest-like situation.  As was the case last year, I'll be doing logs while the new operators try to make contacts.  All of this is great fun.  At about 10 p.m., I'll  bid farewell to my fellow amateurs and head home for a good night's sleep.

For those of you who can't get to a club site, a home-based operation, running 1E (emergency power) or 1D (commercial mains) could be quite an experience.  I ran 1E a few years back and thoroughly enjoyed the excitement.  My equipment was modest--an old Swan 100 MX and a homebrew inverted vee fed by balanced 450-ohm line.  That old antenna is still in use as is the venerable Swan.  I think I made around 150 contacts before my eyes and fingers gave up at around 3 a.m. Sunday morning.  I wasn't worth much of anything on Sunday, but I surely had fun!

So, even if you can't make it out to a club site, give Field Day a try.  You might even run a mobile operation for some added excitement.

I hope to hear you 23/24 June.

Aloha es 73 de KH6JRM--BK29jx15

Wednesday, June 20, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

AN "ALL-BAND" ANTENNA THAT REALLY WORKS

The best laid plans of man and beast often go astray.  Such was the case today, when planned antenna maintenance took a back seat to heavy showers and gusty winds rolling off the Pacific Ocean.  Along the Hamakua Coast, such occurances make travel a bit hazardous and any outdoor work a study in frustration.

So, with tools in hand, I returned to the ham shack for plan number 3.  Plan number 2 was doing some repairs and maintenance around the house.  Now that I'm semi-retired, I find there is sufficient time to keep the house orderly while pursuing a variety of amateur radio interests.  Once the housework was done, it was once again out to the shack for some general clean up and antenna research.

One of my favorite research tools is the "Antenna Wire Classics" published by ARRL.  I'm currently paging through volume two of this outstanding series.  What I was looking for was a simple, multi-band antenna that was easy to build and didn't cost much money.  OK, I'm cheap.  A retirement income doesn't permit me to indulge in my wildest antenna schemes.  Besides, the size of my rental house and lot is small, which requires  antennas of simple, functional design.  And since I'm a complete idiot when it comes to building complicated things, I'd rather settle for antennas that even a bumbler such as I can do.

On page 3-20 of volume two, I found an article by R. L. Cope, W8MOK, entitled "All-Band" Antenna.  The original article was published in the Hints and Kinks column of the December 1954 edition of "QST."

According to R. L., "the arrangement consists of dipoles, cut for each band and connected in parallel at the center.  although I have not checked standing-wave ratios, the results seem to indicate that it gets out as well as a bunch of individually-fed doublets.  If you haven't tried it, you're in for some surprises."  This amateur fed the arrangement with a random length  of 70-ohm coaxial cable.  I suspect RG-6 would work well (nominal impedance is around 72 ohms).  Since I have some of this cable in the shack and a good supply of 22-gauge wire in a storage box, the actual time required to get this antenna in the air should be minimal.  I might even build it as an inverted vee, if I can't find an extra 30-foot length of pvc pipe.

Some of you may recognize this antenna as the proverbial "fan dipole" which is often cited in various antenna forums.  Anyway, this simple design is worth a look.  Once the weather clears, I'll build a copy and see if results are as good as described.

Have a good day. 

Aloha es 73 de KH6JRM--BK29jx15

Monday, June 18, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

More emergency antennas for hams:

There is a wealth of wonderful and somewhat curious antenna ideas in the amateur radio library.  I have several books published by the ARRL which I 've found useful in my restricted space environment.

As I was paging through "More Wire Antenna Classics, Volume 2" (Copyright 1999-2006 by the ARRL), I ran across two articles on using ordinary lamp cord for both antenna feedlines and antenna elements.

"A Zip-Cord Special Antenna" on page 1-6, Chapter 1 (taken from the "QST", May 1972) describes how one ham pressed about 80-feet of ordinary lamp cord into service as both feedline and radiator for  a 75-meter  schedule he was running with some of his friends.  Apparently, this operator was on vacation and lacked some materials to maintain his contacts with  his hometown.  He found that the emergency dipole performed well in his temporary location.  He also fashioned a version for 40-meters, which he found useful on 15 meters.  While this antenna was truly a compromise affair, it did allow this amateur to maintain a schedule with his friends at very little cost.

On the next page, 1-7, Chapter 1, Jerry Hall, K1TD, did a careful analysis of a zip-cord antenna at the ARRL laboratory.  His findings were first reported in the March 1979 issue of "QST".  Hall found that the zip-cord used as a balanced feedline had an impedance of 105-ohms with a velocity factor of 69.5 percent.  Hall believes you could use this type of feedline on 80 and 40 meters if you kept power low and the feedline length under 100 feet.  A graph constructed by Hall shows significant line loss above 7 Mhz. 

Hall says zip-line used as a radiator presents little problem for the operator.  In fact, the insulation on the wire could add to the durability of the antenna elements.  As Hall states, "How efficient is a zip-cord antenna system?  Well, that does depend on the length of the wire used for the feed-line section and on the frequency.  In a pinch on 160, 80, 40, and perhaps 20 meters, communications can certainly be established with this kind of antenna.  For higher frequencies, especially with long line lengths for the feeder, your're on your own."

And, there you have it.  Another idea worth trying if you're short on coax or someother kind of balanced line.  Although I haven't used an antenna fed with zip-cord, I have made my own balanced line feeders out of #14 gauge house wire.   My homebrew feed line wasn't pretty, but it did the job.

I trust your Father's Day went well.  Take care.  'See you down the log.

Aloha es 73 de KH6JRM--BK29jx15

Friday, June 15, 2012

Simple Antennas for Amateur Radio Operators--a continuing series

ANOTHER SIMPLE ANTENNA

While I was reading the 13th edition of the ARRL's "Hints and Kinks for the Radio Amateur (copyright 1992),"  I came across an interesting article by J.A. Ciciarelli, WB3DDM, on strain relief for coaxial cables.  It wasn't the excellent suggestion of using garden hose or automotive heater hose to reduce strain on the coax that caught my eye,  but rather the type of antenna he chose for his operation.

Apparently, WB3DDM prefers to use long-wire antennas in the inverted -vee configuration.  According to J.A., " I feed the antennas 1/4 wavelength from one of  the leg ends so that I can use coax transmission lines (each leg is an odd multiple of a 1/4 wavelength).  Thus, the feed point is not at the apex, but along one of the sloping legs.  This arrangement frequently creates a sharp bend at the coaxial connector."  And so enters his idea of using hose to relieve some of the strain.  The process is illustrated on page 7-8 of this edition.

Anyway, I decided to apply his idea to a 20-meter antenna I was trying to design.  Although I had good performance with the vertical 20-meter dipole, I wanted to try something else.  Since I had about 50 feet of RG-6 with suitable connectors in the shack, I thought it might be a good idea to erect a long-wire 20-meter inverted - vee where the old vertical dipole used to stand.

I measured out 66 - feet of # 14 gauge hosehold wire and attached a Budwig coax connector to 16  1/2 feet of wire and strung the remaining 49 1/2 feet through the top of my 31-foot mast and then down to an anchor stake near the front yard.  The orientation was generally NNE, which gave  me a bit of gain to the U.S. mainland and Europe from my Hawaii Island location.

The Drake MN-4 ATU seems happy with the arrangement, since the tap is at a low impedance point and the remainder of the antenna is about 3/4 of a wavelength on 20-meters.  Reports have been good with the old Swan 100 MX running about 25 watts or so. 

Since the mast and wire are painted a dull green, the antenna is barely visible from the street.  As is my usual practice, I lower the antenna when I'm not using it--good protection from wind, storm, and curious neighbors.  I may try this idea for 15 and 10 meters.  The 40-meter vertical with tuned counterpoise (the "upper and outer" antenna described by the late Lew McCoy) will stay as my main 40 to 10 meter antenna.  I feed this creation with 450-ohm balanced line into a 4:1 balun and then run RG-6 to the Drake MN-4.  The Drake MN-4 seems happy with this arrangement.  The under-the-house 40-meter loop continues to serve as an emergency and local net antenna.

I'll keep you posted on my newest 20-meter skyhook.  Many thanks to WB3DDM for the idea.

Have a good weekend!

Aloha es 73 de KH6JRM--BK29jx15

Wednesday, June 13, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

WHEN DOUBT, IMPROVISE!

During a recent read of the articles posted on eham.net, I came across an interesting antenna story by Dale Kubicheck, N6JSX (12 June 2012).  The article entitled "HF 18VT Vertical Fence Mounted With an Ugly-Balun" caught my eye because of the way this ham recovered, rejuvinated, and restored an old vertical antenna to its former glory.  This article contains a series of pictures and descriptions of the creative process leading to a semi-homebrew antenna that really works.  Once Dale rewound a few coils, cleared the corrosion from the antenna sections, and fashioned a new balun, he attached the antenna to a chain link fence, which formed part of his counterpoise system.  Although he may need some radials in the future, the antenna apparently delivers the results Dale wanted.  Dale's pictures and explanation are excellent.

Eventhough you may not have the tools Dale uses, you can still make a good antenna with what you have on hand.  Even an old 108" CB whip can be modified to perform well on 10 meters.  Check out the ads for the Solarcon A-99 vertical, which is only a modified CB antenna.  Many amateurs have used this antenna with a decent radial field or counterpoise system to work stations from 20 meters to 10 meters.

I once lived in a house that had a wooden fence surrounding most of the yard.  I used the 5' high fence to support a 40-meter loop.  The antenna was nearly invisible unless you looked closely at the fence.  This antenna worked all bands from 40 meters to 10 meters when I fed it with 450-ohm balanced line, balun, and a tuner.  Although most of the radiation went straight up, I managed to snag many DX contacts.  The antenna was great for NVIS applications, such as local rag chew and emergency nets.  I have a 40-meter loop under my house for that very purpose.  The loop also works as a great MF and SW antenna for my Hallicrafters SX-62A.

So, let your creativity loose.  Use what you have on hand or can buy locally.  Your local hardware or building supply store can provide you with all kinds of things--wire, pvc poles, connectors, tools, etc.  Also, don't be afraid to ask your local cable company for any unused lengths of RG-6 coax.  You might get lucky and stumble upon 50 or more feet of this cable.  I've used RG-6 for patch cords and antenna feed lines.  The slight mismatch of this cable (75 versus 50 ohms) can be handled by most antenna tuners.  A careful search through various on-line catalogs can help you find suitable connectors which will enable you to convert the type F connectors to UHF connectors for your rig.

You are only limited by your imagination.

Have an excellent day!

Aloha es 73 de KH6JRM--BK29jx15

Monday, June 11, 2012

Stealth antennas for the Amateur Radio Operator

STEALTH ANTENNAS FOR CHALLENGING SITUATIONS

In my last post, I outlined a few ideas that could get you back on the air despite restrictive covenants, HOAs, and limited space.  I've tried many of those designs myself with varying success.  Despite their shortcomings, hidden antennas can work if you're creative, run qrp, and use digital modes.  Since I enjoy SSB at times, I've had to be certain that my signals don't overload nearby stereos, tv sets, and even telephones.  Some of the newer electronics have very little filtering and are subject to overload with even moderate power levels (100 watts).  Add to this the proliferation of apartments, condominiums, and generally closer neighbors, and you get a situation where amateur operators can get blamed for everything.  I've had my share of complaints, even when I was off the air! The mere sight of an antenna can let some people's imaginations run wild.  A few years ago, I had a neighbor who complained that my Yaesu FT-7 was tearing up his television.  Considering that the Yaesu FT-7 peaks out a little under 20 watts and over-the-air television is marginal to non-existent along our coastal area, I had a real problem on my hands.  Of course, this scenario was played out before direct tv and cable fully penetrated the Hamakua Coast area of Hawaii Island.  Anyway, my neighbor found me in the garage workshop cleaning the venerable Yaesu.  When I explained that I wasn't on the air and that my feedline was disconnected, he mellowed out a bit.  The problem was finally traced to a corroded tv antenna and salt-encrusted power lines from the Hawaii Electric Light Company.  At night you could see arching along the pole insulators--quite a sight.  Salt air and rain have given the local power company fits.  Crews spend a lot of time keeping the lines clear of fallen tree limbs, corrosion, and broken insulators.  I don't fault the power company--those elements cause havoc with vehicles, metal poles of all types, and even amateur radio antennas.  That's one cost of living in a warm, maritime environment.

So, with that experience in mind, I vowed to make my station as clean as I could, run only enough power to get the job done, and conceal my modest antenna farm from peering eyes.  Armed with light gauge wire, some antenna swivels from DX Engineering, and camoflagued fiberglass  poles, I've been able to have a decent station that get a good number of contacts.  When I'm done with operations, all I do is lower the mast, disconnect feed lines, and "keep beneath the radar."  Most of my new neighbors are tolerant of my hobby, have cable or direct tv, and seem open to cooperation.  Most of my former rfi complaints are gone since I shifted to qrp power levels and disguised antennas.  This arrangement won't work for everyone, but it seems to keep me out of harm's way.

I've made a secondary hobby of researching hidden antenna designs with the object of making my radio imprint even smaller.  Today, I ran across an article in the "radiosurvivalist.com" website by Dave Hassell, Sr. (N5IW).  He believes amateur operators can return to their hobby despite the retrictions of modern life and those ever present CC&Rs and HOAs that seem to corner the housing market these days.  Dave's article is positive, upbeat, and useful.  You can find some valuable tips by visiting his web site--http://www.qsl.net/n5iw.html.  He is particularly favorable to flagpole-type antennas, attic antennas, and disguised loops.  Granted, these compromise antennas won't break a major pileup, but they will get you on the air.  When I first moved into my small rental home, the first antenna I used was an under the house 40-meter loop fed by 450-ohn balanced line.  The house sits on a 5-foot pile and pier system (for flooding and earthquake resistance), which gives me plenty of room to string a full wave loop.  Dave recommends stinging a loop under the eaves of your house or laying a dipole on a shingled or wooden roof.  I've used full wave loops for a long time and they work.  I realize that my low level loop won't perform as well as a yagi mounted on a tall tower.  But, for local statewide nets, this NVIS antenna puts out a strong signal reaching out almost 300 miles.  And for local emergency and daily rag chew nets, that's good enough for me.  My 20-meter vertical dipole and 40-meter "upper and outer" antenna (ala Lew McCoy) fill in most of the other bands.  If I need 80 meters, I have an inverted vee assembly ready to mount on a spare fiberglass mast.  I also have an emergency HF and VHF station that can be deployed from my van.

Don't be discouraged by your restricted operating situation.  Get creative, study those antenna books, and return to the air. 

Have a good day!

Aloha es 73 de KH6JRM--BK29jx15

Saturday, June 9, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

HIDDEN ANTENNAS

Are restrictive covenants, limited space, and nosey neighbors ruining your amateur radio hobby?
There is no need to retire your amateur radio activities because of antenna issues.  With a little creativity, low power (QRP), and light gauge wire, you can enjoy amateur radio again.  While this "below the radar" or stealth operating technique can't rival the performance of a mono band beam on a tall tower, it can get you back on the air.  You might even have some fun and save money at the same time.

I'm always on the lookout for interesting antenna ideas, especially since my "antenna farm" is confined to a small backyard and faces close-in neighbors and high voltage lines.  Although I've used indoor antennas with some success, I prefer getting the rf outside if at all possible.

Today, I revisited a website maintained by Julian Moss, G4ILO.  Julian's well-designed blog provides a compact, easily understood tutorial on hidden and low visibility antennas.  He covers all the basic low visibility antennas in an easy to read, lively style.  The major types are here:  flagpole, invisible wire (long wire, inverted L), magnetic loop, short vertical diploe (the Transworld Adventurer), and loaded whip (screwdriver antennas and their variants).  Julian recommends these types of antennas rather than the Hamstick dipole, tripod mounted vertical, the Buddypole type of antennas, and the slinky dipole.  These later types, he says, are inefficient.  Julian also provides basic information on attic mounted antennas such as loops and shortened dipoles.

I've found several of Julian's ideas useful in my operating situation.  He could help you, too.  For details, visit http://www.g4ilo/com/stealth.html.

As for my own antenna situation, I feel comfortable with what I'm using.  Most of my 20 meter activity is fed to a vertical dipole in the back yard.  I feed the dipole with either RG-6 (for 20 meters only) or 450-ohn balanced line (20 to 10 meters).  Along the side of the house, I have an "upper and outer" antenna (33-foot vertical on a fiberglass pole with a 33-foot counterpoise) fed with 450-ohm balanced line.  That antenna can work from 40 to 10 meters with a suitable balun and my trusty Drake MN-4.  The design of this antenna goes back to the 1920s and 1930s and was popularized by the late Lew McCoy (W1ICP).  Speaking of McCoy, CQ Communications, Inc. still offers his outstanding book "Lew McCoy On Antennas.  Pull Up A Chair and Learn From The Master." 

The rest of the day will be spent paging through McCoy's book, reassembling the Drake MN-4 (after a thorough cleaning), and cleaning all contacts and switches in the venerable Swan 100MX I use for ragchewing.

I hope your weekend will be one filled with dx and other interesting radio adventures.

Aloha es 73 de KH6JRM--BK29jx15

Thursday, June 7, 2012

Simple antennas for the Amateur Radio Operator--a continuing serie

STEALTH ANTENNAS

During the past few weeks, I've read many articles from amateur radio operators who are facing restricted options because of HOAs, CC&Rs, and limited space.  Although I'm not in a restricted zone, my small lot and proximity to power lines makes me feel some of their pain.  People move into restricted quarters for a variety of reasons, so I'm not going to rehash the obvious arguments presented in the media.  Suffice to say, we amateurs must use our creativity if we are to enjoy our hobby to the fullest.

I've made a practice of reading as much information as I can about stealth and hidden antennas to get an idea of what's possible for my hobby.  Every once in a while I come across articles which peek my interest and get the creative juices flowing.  Today, for example, I ran across WB0DGF's Antenna Site (wb0dgf.com/stealth.htm), which provides a practical antenna plan for a home and various links to antenna designs and options.  Among the ideas is the trusty "Grasstenna" by K3MT.  I've tried this antenna and it works well for local contacts.  The antenna is laid out on the ground and fed by coax.  Obviously, this quickly deployed antenna is no yagi, but it will get you contacts if you have few alternatives.  Another site mentioned in WB0DGF's page is "Stealth Antenna Experiences from Cliff's ham radio connection."  Cliff outlines several antennas that could work for you, including a 10 meter attic antenna and a 40 meter twin lead Marconi antenna in your attic.

In my case, I have enough room in my small back  yard for two verticals--a 40 meter inverted vee and a 20-meter vertical dipole.  I recently tried an "upper and outer" vertical with a horizontal counterpoise along the side of the house.  That antenna was easy to build and use.  I've since taken it down and will save it for emergency use.

Those of you with severe space restrictions may want to try a mobile antenna on a tripod in your backyard.  With a few radials attached, this antenna could get you back on the air.  I've even used a "Hamstick" antenna with a mag mount on my van to get on the air.  Add a few radials and you have an antenna that should work reasonably well.  Of course, none of these ideas will perform as well as a beam or a full-length  dipole mounted 50-feet in the air.  The idea is to get on the air and enjoy amateur radio as best you can.

Another option is to operate remotely with your amateur station and antenna located in a more favorable location.  There have been several articles in the amateur radio press outlining the procedures involved in remote operations.  In this case, a good, high-speed internet connection will make the transition a bit smoother.

Have a good weekend and get on the air.

Aloha es 73 de KH6JRM--BK29jx15

Saturday, June 2, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

ANOTHER EMERGENCY ANTENNA

There are quite a few birds in my area that often use my antennas as perches or launching platforms for their flights.  Normally, the smaller birds (finches, cardinals, and an occasional native bird like a honey creeper) don't create problems.  However, a sizeable bird such as a pu'eo (Hawaiian Owl) can damage a dipole or even the bird itself.  Such was the case yesterday when some kind of bird bumped into the 450-ohm twin lead feeding my 40-meter inverted vee.  I cut out the damaged section of the feedline and decided to replace it temporarily with about 50 feet of RG-6 I had stored in the "junque" box.  I didn't have the Drake MN-4 ATU handy at the time, since the MN-4 was being cleaned on the workbench (the kitchen table).

So, I borrowed an idea from Dean, KH6B, and rigged up what he called a "James Bond" antenna--named after the famous fictional spy created by Ian Flemming.  All I did was connect the coax to one end of a UHF "T", ran another piece of coax to my Heathkit Dummy Load, and ran some coax to the venerable Swan 100 MX at the operting position.  Results on 40 and 15 meters were good and the rig didn't seem to mind.  I was even able to round up a few contacts on 20 and 10 meters.  The old Swan remained cool and stable with this temporary and inefficient antenna system.  Although I was perhaps losing a good deal of signal due to the mismatch, I still made some contacts.

After experimenting with this antenna arrangement, I reconnected the inverted vee with a new section of 450-ohm twin lead, fed the new feed line to a 4:1 balun, and ran some coax to the newly cleaned Drake MN-4.  Everything was back to normal in short order.

You may find the "James Bond" antenna a useful addition to your emergency kit.  All  you need is a 50-ohm dummy load, some short pieces of coax, and a UHF "T" connector.

Have a good, productive weekend on the air!

Aloha es 73 de KH6JRM--BK29jx15