Friday, November 29, 2013

Antenna Safety. Post #246

In the excitement of designing, building, and erecting my "homebrew" wire antennas, I've often neglected to consider important safety issues which could affect the location of my antenna and perhaps save my life.
A few years ago, I erected a vertical antenna which gave me excellent service until a lightning strike turned my work of art into a mess of shattered fiberglass, pvc pipe, wire fragments, charred coaxial cable, and a severely damaged ego.  Fortunately, I had disconnected the feed line from my shack and had it connected to a ground rod.

Ever since that lucky escape from Mother Nature, I've had a firm respect for the weather and "Murphy's Law" (whatever will go bad will fail at the most inconvenient time).

Over the course of my amateur radio "career", I've followed a few basic guidelines to erecting antennas, whether they be commercially bought or built from my own resources.

PLAN AHEAD

I know this sounds pretty basic, but thoroughly outlining your antenna project, assembling all of the parts beforehand, and doing a general survey of your property for hidden dangers can pay big dividends later.

Before I build an antenna, I walk over the area for the proposed antenna site.  I note any safety hazards such as uneven ground (especially dangerous when you have to disconnect your antenna at night), proximity to power, telephone, and cable lines, and visibility concerns (there's always someone who hates antennas and will tell the world about it).

After I'm done with my initial inspection, I ask someone else (my xyl or another ham) to look around for anything I might have missed.  Another set of eyes is always helpful in picking out questionable objects on the antenna field.

I also draw a rough diagram of the proposed antenna and its placement on the property.  This drawing is filed in my antenna notebook and will be used to make revisions to the design.

Once the basic plan is drawn and the property checked for suitability, I then advance to the second phase of the antenna project.

BASIC SAFETY ASSUMPTIONS

Assume that everything connected to the antenna structure is conductive.

Assume that the antenna or any part of it, including supporting masts, guy lines, feed lines, and antenna elements will fail or break at the most inconvenient moment.  Be sure your construction is sturdy and can stand up to the weather.

Antennas should be kept far away as possible from utility lines, both from the pole carrying the energized lines and the entrance of these wires into your home and shack.  At my current location in a crowded neighborhood, I've had to resort to small verticals and low slung dipoles and loops to maintain a safe distance from power lines.  At my new home in the Puna District, my nearest antenna structure (a 33-ft/10.06 meters fiberglass mast) is about 100 ft/30.48 meters from the nearest utility line or cable entrance.

If possible, lower your antennas to ground level after you are done operating.  This will present less of a target for lightning or snoopy neighbors.

Disconnect all antenna feed lines from your equipment when the operating day is over.  I use a window patch panel to run coaxial or ladder line feeders into the shack.  The external leads are connected to an 8 ft/2.43 meters ground rod at the base of the antenna mast.  A set of four, 33 ft/10.06 meters radials are connected to the ground rod and form a spoke pattern around the base of the antenna.

Be sober when you build and erect your antenna.  Alcohol and antenna building are a bad combination, especially if you are erecting a tower.

If you are uncertain about erecting a mast or tower, get help from your local amateur radio club.  Even if you are working alone on a simple vertical, be sure you have safety equipment for use, including gloves, hard hat, and good work boots.  If your project involves the use of a tower, be sure to get climbing belts and other tower climbing equipment.

If you are using a commercial antenna, be sure to follow all instructions and procedures exactly.

Be sure you have a written outline of how the antenna erection will  proceed. Give copies to your antenna crew if you have one.  Include in your plan the procedures you'll use to correct any failure of equipment or parts.  Before you erect your antenna, do a "dry run" of the antenna construction and raising.

If at all possible, build as much of the antenna on the ground as you can.

If you'll be using a mast to support your dipole, inverted v, or vertical, install a simple halyard-pulley system on the mast to raise or  lower the antenna should the need arise.  This system will come in handy for antenna adjustments or to lower the antenna during bad weather.

Avoid bad weather, especially storms with thunder and lightning.  Build and erect your antenna during a calm, sunny day if possible.  The antenna can wait.  Your life won't mean much if you're in the way of a lightning strike.

OTHER THOUGHTS

When I get through working DX or some laid back local contacts, I always do the following:

Disconnect antenna feed lines and connect them to the ground rod at the base of the antenna.

Unplug all station equipment.

Install a static discharge system on your antenna feed lines.  While this step won't protect you from a direct lightning strike, it will "bleed off" static electricity that builds up on antennas.  Some of the newer solid state transceivers are quite sensitive to electrical discharges.

There are probably many other steps you can take to insure a safe, efficient antenna system.  I've listed a few articles which explore antenna safety issues in depth.  These essays are worth reviewing.  Good luck in your next antenna project.

REFERENCES

http://www.arrl.lorg/files/Technology/tis/info/pdf/016091.pdf.
http://www.universal-radio.com/catalog/wideant/safewide.html.
http://www.hamuniverse.com/antennasafety.html.
http://www.cisco.com/en/US/docs/wireless/bridge/350/installation/guide/BR350apC.html.
http://www.k2zs.com/indoor-antenna-tips/constructiontips.

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Thanks for joining us today.

Aloha de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.




Monday, November 25, 2013

Simple Ham Radio Antennas: The sloping 30 through 10 meter delta loop. Post #245

How would you like to build a simple, effective antenna for 30 through 10 meter coverage with some gain over a dipole at a moderate cost?  The answer is as simple as designing, erecting, and using a sloping delta loop antenna designed for 30 meters and fed with 450 ohm ladder line into a 4:1 balun connected to a sturdy antenna transmatch.  The ladder line will permit you to cover frequencies between 10.100 MHz through 29.7 MHz with low SWR.  You can also design the antenna for 30 meter use only by feeding the antenna with 50 ohm coaxial cable in conjunction with a 1/4 wavelength matching section made of 75 ohm coaxial cable.  The latest ARRL Antenna Book has more details on how to make the matching section should you decide for that option.

Now that I have more room for my expanding "antenna farm" at my new home site in the Puna District of Hawaii Island, I can set aside some space for antenna experiments without worrying about HOAs, CC&Rs, or unsympathetic  neighbors.  For many years, I've had to use compromise antennas at my amateur radio station.  They all worked well considering the severe space restrictions at my present location.  Once I complete the housing move next year, I'll have enough room to erect some decent antennas.  I already have a few antennas in place--most of them are well disguised by the tall trees surrounding my property.

Over the past few years, I've found the 30 meter band a welcome escape from the heavily used 20 and 15 meter bands.  The 30 meter amateur radio band is the place for the cw and digital signal enthusiast.  Even with the modest 30 meter sloping dipole I made a few weeks ago, contacts were easy to manage and the band was full during my early morning and late afternoon operating hours.  I wanted to try a full wavelength loop on this interesting band.  I've always enjoyed full wavelength loops because of their modest gain over a dipole, fairly quiet operation, and ease of construction.  With the considerations mentioned in the opening of this post, I decided to build a simple sloping delta loop for 30 meters in back of my Puna District home.  The loop would be used for frequencies ranging from 10.100 MHz to 29.7 MHz, with the main design frequency set for 10.125 MHz--the midpoint of the band.  With 450 ohm ladder line, a 4:1 balun, and my trusty MFJ 941E Versa Tuner antenna transmatch, I could roam around several bands without worrying about excessive SWR.

I started the project early this morning before the arrival of the afternoon showers predicted by the National Weather Service.  I had the following materials on hand:

One 33-ft/10.06 meter MFJ telescoping fiberglass mast.

Three 6-ft/1.82 meters wooden stakes.  One stake would support the fiberglass mast.  Two stakes would support the bottom of the delta loop.

One "ladder lock" connector to support the 450 ohm ladder line and its attachment to the delta loop at the apex of the fiberglass mast.

Two ceramic insulators attached to wooden stakes at the bottom of the delta loop.  The wire would run from the mast apex through the insulators.  Small lengths of dacron rope would tie off the insulators to the stakes.

Fifty feet/15.24 meters of 450 ohm ladder line.  This would serve as the antenna feed line.

Twenty-five feet/7.62 meters of RG-8X coaxial cable with UHF connectors.

One W9INN 4:1 balun.

One MFJ 941 Versa Tuner antenna transmatch.  Unfortunately, my Drake MN-4 wasn't configured to work on 30 meters.  The old Versa Tuner has given good service as a standby transmatch.

One Ten Tec Argosy II transceiver.  This is the only rig I have that can access 30 meters.

One solar charged deep cycle marine battery to serve as a power supply.

Basic tools, nylon ties, soldering gun, tape, etc.

Enough wire to make a full wavelength antenna for 30 meters.  Using the general formula 1005/f(MHz)=L(ft) and #14 AWG housewire, I cut the antenna for a resonant frequency of 10.125 MHz (the band midpoint). The total length of the antenna came out to 99.25 ft/30.26 meters.  Each side of the three-sided delta loop would measure 33.08 ft/10.08 meters.

ASSEMBLY:

The antenna was built on the ground.

I attached the top of the delta loop to the 450 ohm ladder line with the "ladder lock" device.  The center connector was secured to the top of the fiberglass mast with a short piece of dacron rope.  All connections were soldered and wrapped with several layers of vinyl electrical tape.  The "ladder lock" device with the 450 ohm feed line and its connection to the top of the delta loop was secured to the top of the mast with several nylon ties.  I ran the ladder line down the mast approximately 5 feet/1.52 meters.  I tied off the ladder line to the mast with another nylon tie.

I hoisted the fiberglass mast onto its 6 ft/1.82 meter wooden support stake.

I led the delta loop off at a 45-degree angle from the mast and secured the bottom portion of the delta loop to two 6 ft/1.82 meters wooden support stakes.  The antenna wire was threaded through 2 ceramic insulators, which were attached to the wooden support stakes by 2 inches/5.08 cm of dacron rope.

The delta loop was adjusted for a uniform shape.  The loop was configured as a sloper with the apex of the loop attached to the top of the mast and the two sides swung out at an angle and secured to wooden support stakes. Since the bottom of the delta loop is close to the ground, I attached yellow warning tape along the bottom element of the loop.

The 450 ohm ladder line was led to the W9INN 4:1 balun attached to the garage wall in back of the house. The balun is mounted approximately 6 ft/1.82 meters above ground.

Twenty-five feet/7.62 meters of RG-8X coax with UHF connectors were attached to the balun and run through a window patch panel in the garage.  The coax was then connected to the MFJ 941E Versa Tuner. Short lengths of RG-8X coaxial cable interconnected the Ten Tec Argosy II transceiver to the transmatch, low pass filter, and the dummy load.

After 2 hours of leisurely work, the antenna was done.

INITIAL RESULTS:

Thanks to the MFJ 941E Versa Tuner, I was able to keep SWR near 1.1 to 1 between 10.100 MHz and 29.7 MHz.  I made a few 30 meter contacts late this afternoon, with reports ranging between 569 and 599 using the Argosy II running approximately 20 watts.  Contacts were also made on 20 and 15 meters, with SSB reports ranging from 56 to 59 on 20 meters and 54 to 56 on 15 meters.  Again, power used was near 20 watts from the Argosy II.  I'm sure a little tweaking will be necessary to get the most out of this antenna. So far, results have been satisfactory.  For a homebrewed antenna made from available parts, I really can't complain. Most of the materials can be bought at the nearest hardware store.  You can also substitute pvc pipe, surplus military mast sections, or even a high tree branch for the mast.  This antenna is simple, cheap, and a joy to use.

REFERENCES:

http://www.hamuniverse.com/kl7jrloopnotes.html.

http://www.wikihow.com/Build-Several-Easy-Antennas-for-Amateur Radio.  See section 20 for loop antenna ideas.

http://www.southgatearc.org/articles/g0ftd/loop_antennas/simple-loop-antennas.htm.

http://arrl.org/hf-loop-antennas.

http://www.youtube.com/watch?v=y3-LIQ6G6e4.

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

Saturday, November 23, 2013

Simple Ham Radio Antennas--the 40 meter NVIS loop. Post #244

In this age of natural and man made disasters, it's important to have back up equipment, antennas, and power available during periods of emergencies.  A set of homebrewed wire antennas can keep you on the air when your beam or tower have been damaged by forces beyond our control.

One of the best standby antennas is the NVIS antenna, which, because of its portability and ease of operation, can be tucked away in a convenient spot for future use.  NVIS (near vertical incident skywave) antennas are perfect for local or regional use out to about 300 miles/480 kilometers.  NVIS antennas are close to the ground (between 1/10 to 1/5 wavelength above ground) and shoot most of their signals straight up.  Sometimes called "scatter beams" or "cloudwarmers", these antennas can cover a wide area (especially mountainous terrain) with little power.

A NVIS antenna can be configured in several ways, including low-level 1/2 wavelength dipoles or low-level full wave loops.  If your present HF dipole is lower than a quarterwave length, you probably have the beginnings of a simple NVIS antenna without knowing it.  All you would have to add is a halfwave length "reflector" wire on the ground below the main dipole.  Make the reflector element about 5% longer than the main dipole antenna.  This crude arrangement works rather well in putting strong signals into a local or area net.  This is not a DX antenna.  But, for local emergency HF use, this dipole/reflector combination will do the job.

Although I've used such an antenna arrangement in the past, I felt a low-mounted loop would do a bit better in the gain and noise department.  I have an under-the-house 40 meter loop at my present location.  I feed the antenna with 450 ohm ladder line connected to a W9INN 4:1 balun.  The balun is connected to the station rig through a Drake MN-4 antenna transmatch  with a 10 foot/3.04 meters length of RG-8X coaxial cable with UHF connectors.  This antenna does an excellent job on the daily Hawaii Afternoon Net on 7.088 MHz.  The loop is mounted horizontally, approximately 5 ft/1.82 meters above ground.

At my new Puna District home, I've put up several "permanent" antennas to compliment the 80-10 meter flat top dipole (classic doublet) mounted about 50 feet/15.24 meters above ground in two Norfolk Pine Trees.  This past Saturday, while there was a lull in the scattered showers over Hawaii Island, I built a more or less permanent low-mounted 40 meter NVIS loop near the backyard garden. Now that I have more space than before, I'm trying a variety of full-sized antennas, including a "cloudwarmer" to use in emergencies or for general portable use.  The backyard NVIS loop is mounted close to the ground, just like the loop used at my Laupahoehoe qth.  The only difference is that the new loop was built in an open area far removed from power lines and neighbors.

MATERIALS:

Using the general formula 1005/f (MHz)=L(ft) and the resonant frequency of 7.088 MHz (the frequency of the daily Hawaii Afternoon Net), I cut a full wavelength loop measuring 141.79 feet /43.22 meters.  I would configure the loop as a square mounted close to ground level.  Each side would then measure 35.44 ft/10.80 meters.  I used #14 AWG housewire for the antenna.

Four 6 ft/3.04 meters wooden stakes to support the loop.

Four 6 ft/3.04 meters wooden stakes to support the 450 ohm feed running to the 4:1 balun mounted on the garage wall.

A W9INN 4:1 balun.

A Drake MN-4 antenna transmatch.

Ten feet/3.04 meters of RG-8X coaxial cable with UHF connectors to run from the balun to the Drake MN-4 antenna transmatch.  A 3 ft/0.91 meters piece of RG-8X coax connects the transmatch to the station rig (Swan 100-MX or the Ten Tec Argosy II).

Short lengths of RG8X coax to connect the dummy load and low pass filter to the antenna system.

Basic tools, including a soldering station.

Vinyl electrical tape, five ceramic insulators, and nylon ties.

Four short pieces of dacron rope to secure ceramic insulators to the wooden support stakes.

Fifty feet/15.24 meters of 450 ohm ladder line.  This will serve as the antenna feed line.  Used with a 4:1 balun and a sturdy transmatch, the loop will be capable of operating on all amateur radio bands between 40 and 10 meters.

ASSEMBLY:

Four, 6 ft/3.04 meters wooden antenna support stakes were placed at each corner of a square measuring approximately 35.44 ft/10.82 meters on a side.  The loop would be horizontal to the ground, approximately 5 ft/1.82 meter above the lawn.

The tip of each wooden stake had a ceramic insulator attached by a short piece of dacron rope.  The attaching tie off rope measured approximately 2 in/5.08 cm.

The full wavelength loop of antenna wire (141.78 ft/43.22 meters) was threaded through each ceramic insulator.  A fifth ceramic insulator would support the 450 ohm ladder line and its union with each end of the loop.  All connections were soldered and wrapped with several layers of vinyl electrical tape.

Once the feed line was attached to the square loop, I adjusted the tension of the horizontal square loop so that the loop had a uniform height above ground of approximately 5 ft/1.82 meters.

I ran the feed line at a 90 degree angle away from the attachment point to a series of four, 6 ft/1.82 meters wooden stakes, which led to the W9INN 4:1 balun mounted on the garage wall.  The balun was approximately 6 ft/1.82 meters above ground.

A 10 ft/3.04 meters piece of RG-8X coaxial cable with UHF connectors ran through a window patch panel and onto the Drake MN-4 antenna transmatch.  Small patch cords connected my rigs, low pass filter, and dummy load to the transmatch.

INITIAL RESULTS:

As expected, the low-mounted 40 meter loop did an excellent job for local and statewide nets.  Most of my SSB reports ranged from 57 to 59+10 and from 579 to 599+20 for CW contacts.  There was little or no DX worked at the time of testing (early afternoon Hawaii time).  During the evening hours, I was pleasantly surprised by some mainland U.S. contacts on CW, with signal reports ranging from 559 to 579.  My contacts were made with the Swan 100 MX running 20 watts on both SSB and CW.  When I used the Ten Tec Argosy II, I kept power down to 05 watts qrp.  Even at this power, local contacts ranged from 54 to 56 on SSB and from 559 to 599 on CW.

The antenna can be quickly assembled and broken down for portable use.  Best of all, this simple NVIS antenna is inexpensive, easy to build, and requires no ground radial system.  If you want a basic antenna that puts in a strong local or regional signal, try a NVIS antenna in one of its many configurations.  I found the full wavelength loop useful for my purposes.  A low-slung dipole may work better in your location.  Either way, add a NVIS antenna to your collection of amateur radio tools.

REFERENCES:

home.century.net/w9wis/NVIS.html.

http://www.emcomm.org/projects/nvis.htm.

http://dxengineering/com/techarticles/miscinfo/learn-how-to-build-a-nvis-antenna.

http://www.youtube.com/watch?v=aAshymGZ8Ww.

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.


Tuesday, November 19, 2013

Simple Ham Radio Antennas: The slanting 80 meter delta loop. Post #243

One of the joys of moving out of my cramped quarters at Laupahoehoe to more spacious property (1 acre) in the Puna District is the ability to erect some decent antennas.  For most of my 36 years as an amateur radio operator, I've had to "make do" with compromise antennas that often performed poorly compared to full-sized antennas.  Thanks to 450 ohm ladder line, a sturdy W9INN 4:1 balun, and a trusty Drake MN-4 antenna transmatch, I've been able to get some excellent multi band contacts with the 40 meter inverted v in the backyard and the 40 meter loop under my post and pier house.  I can't complain.  These antennas have done a good job with my older equipment in the shack.

Once I complete the slow move to my new home in the Orchidland Estates, I won't have to worry about lack of space for antennas and any ground systems I might install.  To date, I erected the following antennas at the new QTH:

A 135 ft/41.15 meters long horizontal dipole (the classic "doublet antenna") with ends supported by two Norfolk Pine trees.  The antenna is approximately 50 feet/15.24 meters above ground.  Fed with 450 ohm ladder line into a 4:1 balun and the Drake MN-4 antenna transmatch, the antenna works on any amateur radio band from 80 to 10 meters.  As a general purpose antenna, the doublet is perfect for my  location.

A 20 meter half square antenna.  This two element vertical doesn't require a ground system.  Two vertical antennas are connected at the top of each mast by a 1/2 wavelength phasing line.  A 50 ohm coaxial cable feed line is attached to the upper left hand corner of the system, with 1/4 wavelength vertical wires running down each fiberglass mast.  The antenna is bi-directional and can add an additional 3 to 4 dB gain over a regular dipole.

A 40 meter inverted v antenna fed with 450-ohm ladder line.  Used with an antenna transmatch and a 4:1 balun, I can get good performance from 40 through 10 meters.  Best of all, I don't need a ground radial system.

A homebrewed 10 meter ground plane vertical cut for 28.4 MHz.  The antenna is attached to the top of a 33-ft/10.06 meter fiberglass mast and fed with 50 ft/15.24 meters of RG-8X coaxial cable with UHF connectors.  I use this antenna for monitoring purposes.  As a single band antenna, it works well.

The temporary 40 meter delta loop fed with ladder line has been taken down to make room for the 80 meter sloping delta loop.

This brings me to the current project.

During my amateur radio "career", I've never had a good antenna for 80 meters.  The 80 meter vertical helix I built several months ago performed better than expected, considering the lack of space for a ground radial system at my Laupahoehoe qth.  I knew I could do better if adequate space were available.

Now that my xyl and I are relocating to our new "homestead", space won't be a problem.  So, this past Saturday and Sunday (16-17 November 2013), I built a simple, inexpensive full size 80 meter loop in the spacious back yard of our property.

MATERIALS:

Most of the materials I had at the new location.  I reused the 33 ft/10.06 meter MFJ telescoping fiberglass mast from the old inverted v and adapted it for the 80 meter delta loop.

I also reused two ceramic insulators, one 5 ft/1.52 meters wooden support stake for the mast, and two 6 ft/1.82 wooden stakes from the old antenna to support and tie off the loop elements.

One "Ladder Lock" connector to attach the 450 ohm ladder line and the delta loop elements.  The connector would be attached at the top of the mast, with the loop running below the apex of the mast.

Fifty feet/15.24 meters of 450 ohm ladder line, one W9INN 4:1 balun, and one Drake MN-4 antenna transmatch.  This system would be used to make the 80 meter delta loop capable of use on all amateur frequencies between 80 and 10 meters.

Short lengths (5 ft/1.82 meters) of dacron rope to tie off the bottom portion of the delta loop.

Short lengths (3 ft/0.91 meters) of RG-8X coaxial cable with UHF connectors to attach station equipment (transceiver, low pass filter, dummy load) to the Drake MN-4 antenna transmatch.

Sufficient wire to build the loop.  Using the general formula 1005/f(MHz)=L(ft) and the design frequency of 3.775 MHz, I cut the loop to a length of 266.22 ft/81.66 meters.  Each side of the delta loop measured 88.74 ft/27.05 meters.  I used #14 AWG housewire bought at Home Depot in Hilo.

ASSEMBLY:

The delta loop was built on the ground.

Once the loop was made, I attached the "Ladder Lock" connector with the 450 ohm ladder line attached  to the tip of the mast.

Because of the low height of the loop (the mast was only 33 ft/10.06 meters tall), I decided to make the antenna into a sloping delta loop, a design I had used with the 40 meter delta loop.

I then hoisted the mast onto its support stake, ran the loop at a 45 degree angle from the mast , and attatched the bottom of the loop to its wooden support stakes.  I adjusted the shape of the loop so it resembled a sloping delta.  The antenna is very close to the ground.

I ran the 450 ohm ladder line from the apex of the mast to the W9INN 4:1 balun attached to the garage wall.

Twenty five feet/7.62 meters of RG-8X coaxial cable with UHF connectors ran from the balun to the Drake MN-4 antenna transmatch in the radio room (in the corner of the garage).

To minimize rf in the shack, I attached a counterpoise measuring 66 feet/20.12 meters to the ground lug of the Drake MN-4 transmatch.

INITIAL RESULTS:

With the help of the trusty Drake MN-4, I've kept the SWR below 1.3 to 1 on all amateur bands from 80 through 10 meters.  Obviously, some antenna trimming will be done in the future.  But for now, I have no complaints about the loop's performance.  Depending on the band of choice and propagation, I've received ssb reports varying from 57 to 59+10 and cw reports ranging between 569 to 599 +10.  During the short testing period, I was running between 20 and 50 watts from my old Swan 100 MX.

So far, I'm satisfied with the performance of this slanting 80 meter delta loop.  This was a fun project.  Other than buying some extra antenna wire, I had all of the ingredients for this antenna in my garage.  Sometimes, being a "packrat" pays off.

REFERENCES:

Noll, Edward M. (W3FQJ).  73 Vertical, Beam, and Triangle Antennas. Editors and Engineers.  Indianapolis, Indiana, 46268.  First Edition, 1979.  pp.126-127.

Orr, William I. (W6SAI). and Cowan, Stuart D. (W2LX).  The Radio Amateur Antenna Handbook.  Radio Publications, Inc.  Wilton, CT, 06897.  First Edition, 1978. pp.113-128.

DeMaw, Doug. (W1FB).  Novice Antenna Notebook.  American Radio Relay League, Newington, CT, 06111. First Edition, 1988.  pp.78-90.

Thanks for joining us today!

You can follow our blog community with a free email subscription or by tapping into the blog RSS feed.

Aloha es 73 de Russ (Kh6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.


Thursday, November 14, 2013

An Emergency "Go Kit" for the home station. Post #242

A few days ago I described the simple emergency "go kit" installed in my Honda Odyssey van.  This simple station has served me well for both portable and Field Day use.  I have no doubt the system will work during emergencies.  In fact, I've set up my "go kit" station in the backyard with excellent results using a  simple inverted v antenna and an under-the-house 40 meter loop on my lot.

Although this arrangement worked very well, I wanted to make a special "standby" station in case my main station didn't work for some reason.  Fortunately, I had a few spare rigs in the shack, and I decided to employ them in my home emergency station.

My main amateur radio station has the following equipment (most of it old, but totally functional):

One Ten Tec Argosy II transceiver and Ten Tec power supply.  I can run this rig off the electrical mains or with a solar panel/deep cycle marine battery combination.

One Drake MN-4 antenna transmatch.  I can use 450 ohm ladder line as a feed line once I attach a W9INN 4:1 balun.

Several 50-foot/15.24 meters lengths of RG-8X coaxial cable with UHF connectors.

Several RG-8X coaxial cable patch cords with UHF connectors.  These short (3 feet/0.91 meters) cables are used to connect equipment to the transmatch, low pass filter, and dummy load.

Ten Tec microphone and J-38 key.  I'm old school and I prefer the old J-38 key for my slow speed rag chews on 40 meters.

Assorted tools, radio log, note paper, HP Pavilion Slimline PC, landline telephone, and cell phone.

Much of this equipment will be integrated into my home emergency station.

THE BACKUP STATION;

I had two options.  First, I could just use the proven portable station installed in my van.  I've done this on occaison with good results.

Second, I could use some of my older equipment that is stored in the garage.  With continuous use, the equipment would be less prone to deterioration in Hawaii's tropical climate.

I elected to build a backup station with the extra equipment I had in the garage.  I'm one of those hams that rarely throws anything away, so I had plenty of choices for antennas, rigs, and power.

My rig selection narrowed down to my venerable, but dependable Swan 100 MX (early solid state rig) and the reliable Kenwood TS-520 (a hybrid rig with 2 6146B finals).  I decided to keep both rigs on a table next to the main station.  Both stations would be within easy reach in my large garage.

Although both classic rigs have their own power supplies, I've elected to use a solar panel/deep cycle marine battery combination to provide power to the backup rigs.  Fortunately, a 12 volt adaptor came with the old Kenwood.  I also have an old inverter to convert the battery power to 110 volt AC if I have to.  In most non-emergency cases, I power the TS-520 with its own power supply.  The Swan 100 MX usually runs on battery power.  I run both rigs at 50 watts or less to conserve power.  This power level appears adequate for my use.

My backup microphones include a Shure 444 for the Swan and the standard microphone that came with the Kenwood TS-520.  For CW purposes, I have another J-38 key.

With some modifications, I can use the home station's 40 meter inverted v and the under-the-house 40 meter loop for antennas.  I just replace the RG-8X feed lines with either 50 feet/15.24 meters of 450 ohm ladder line for the inverted v or 25 feet/7.62 meters of 450 ohm ladder line for the under-the-house loop.  I use a W9INN 4:1 balun with the Drake MN-4 antenna transmatch to create a decent match for the antenna.  If the Drake MN-4 develops problems, I have an old MFJ-941E Versa Tuner to take its place.

The antenna measurements remain the same.  Both antennas use #14 AWG housewire for the antenna elements.  For the inverted v, I use the general formula 468/f(MHz)=L(ft).  For the loop antenna, I use the general formula 1005/f(MHz)=L(ft).  I designed both antennas to be resonant on 7.088 MHz ( the frequency of the Hawaii Afternoon Net).  The loop was cut to a length of 141.78 feet/43.22 meters, while the inverted v dipole was cut to a length of 66.02 feet/20.13 meters.  The dipole was cut into two equal pieces, measuring 33.01 feet/10.06 meters.

Once the antennas were restrung and hoisted into position, I tested them with my new backup station.  Thanks to the ladder line, the 4:1 balun, and the Drake MN-4 transmatch, I was able to keep SWR below 1.3 to 1 on the 40, 20, 15, and 10 meter bands.  The inverted v proved to be a good DX antenna during the early evening and early morning hours.  The low level loop was usable on the 40, 20, 15, and 10 meter bands.  However, this loop was not intended to be a DX antenna.  For all practical purposes, this low-level antenna served as a NVIS (near vertical incident skywave) antenna, giving excellent, local coverage out to 300 miles/480 km--perfect for statewide coverage.

During an emergency, I would most likely be using the low-level loop to check into local emergency nets in Hawaii.  For that purpose, the loop does an excellent job.

I hope my experience in building an emergency "Go Kit" for your station has proved helpful.  Experiment with what you have.  Be creative.  Get your materials locally at the nearest hardware store or home improvement outlet.  Build your backup station now.  You never know when some emergency will force you to operate in less than optimum conditions.

REFERENCES:

Check out antenna projects in the recent edition of the ARRL Antenna Book.  This resource is full of simple, effective antenna ideas.

http://www.emergencyradiokit.com.

http://arrl.org/forum/topics/view/870.

http://www.youtube.com/watch?v=_BrHsMfEZT4.

http://www.orgsites.com/oh/soaraares/_pgg5.php3.

You can follow our blog with a free email subscription or by tapping into the blog RSS feed.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

Tuesday, November 12, 2013

A simple "Go Kit" for emergencies. Post #241

In light of the recent natural disaster in the Philippines (super Typhoon Haiyan), it might be useful to review just how prepared we amateur radio operators are for natural and man-made disasters.  Many of the hams running emergency traffic in the Philippines are using low powered rigs and simple antennas to maintain a communications lifeline in devastated areas of the Central Philippines.  Perhaps, we should do the same.

In my 36 years as an amateur radio operator, I've always followed the policy of having spare equipment, antennas, parts, tools, and standby power should an emergency arise.  While those of us living in Hawaii aren't prone to the series of disasters befalling southeast Asia, we do get our share of hurricanes, severe thunderstorms, earthquakes, and, occasionally, tsunamis.  Most hams living in the 50th state are prepared to provide emergency communications should the need arise.

It's prudent to have an emergency radio system installed in your home as well as in your vehicle if you are cut off from your family and job.

With the story of Typhoon Haiyan still etched in my mind, I began an inventory of my station to determine what was available for emergency use.  In other words, I wanted to make sure I had a "go kit".  A "go kit" is a portable amateur radio station which the amateur can use when he/she is asked to lend support for an event or emergency.

I first concentrated on a "go kit" for my personal vehicle--a 2010 Honda Odyssey Van.  My home "kit" would be assembled later.

A quick check of the van showed I had already assembled a basic portable station which could be used in an emergency.  I often travel to a state or county park near my Laupahoehoe home and operate portable for a few hours with some simple equipment and basic antennas.

Here's what I found:

One MFJ telescoping fiberglass mast that could be extended to 33 feet/10.06 meters.  I've used this inexpensive mast to support sloping dipoles and inverted vee antennas.

Pre-made dipole antennas for 40, 20, 15, and 10 meters.  I used the general formula 468/f (MHz)=L (ft) for each antenna.  In my situation, my 40 meter dipole was cut for a resonant frequency of 7.088 MHz (the frequency of the Hawaii Afternoon Net).  The length of this dipole was 33.1 feet/10.06 meters for each dipole element.  The 20 meter dipole was cut for a resonant frequency of 14.200 MHz.  The length of this dipole was 16.475 feet/5.022 meters for each dipole element.  The 15 meter dipole was cut for a resonant frequency of 21.250 MHz.  The length of each dipole element was 11.01 feet/3.35 meters.  The 10 meter dipole was cut to a resonant frequency of 28.400 MHz.  The length of each dipole element was 8.23 feet/2.51 meters.  Each dipole antenna was attached to a Budwig Hi-Que coaxial center connector (available through Fair Radio Sales, Lima, Ohio).  The end of each antenna was attached to a ceramic insulator which could be tied off at a wooden stake.

Two 50-foot/15.24 meters lengths of RG-8X coaxial cable with UHF connectors.  These cables would be my feed line.

Three 5-foot/1.52 meters wooden stakes.  One stake would support the fiberglass mast.  The other two stakes would be tie off points for the inverted vee antenna.

One solar charged (pv panels) deep cycle marine battery.

A Yaesu FT-7 QRP transceiver with microphone and cw key (J-38).  This old, low powered rig has served me well for many years.

A Kenwood 2500 series 2 meter HT with extra battery.  This is an old HT, but it works very well on the local repeater system.  I'm in the process of buying a more modern HT with better capabilities.

An old 4-channel Bearcat public service scanner with extra AAA batteries.  This handheld relic from the 1980s still works.  I have crystals installed for police and fire dispatch, as well as Medivac, and NOAA weather.

An old Radio Shack TRC 23 channel CB transceiver with magnetic mount roof antenna.  CB is still used on Hawaii Island.  Many community centers, which serve as Red Cross Shelters, have CB installations.  CB still serves a useful purpose on this largely rural island.

A three-day supply of dried food, water, clothing, and toiletries.

All of this equipment is contained in three large plastic storage bins and placed in the cargo area of the van.

For all practical purposes, my "go kit" is already made.  All I will add are some more batteries for the HT and scanner, a small table, a collapsible chair, and a small antenna transmatch.  The system has been tested and it works.

Next, I'll start on a backup system for my home station.

REFERENCES:

http://www.emergencyradiokit.com.

http://www.arrl.org/forum/topics/view/870.

http://www.youtube.com/watch?tv=_BrHsMfEZT4.

http://www.orgsites.com/oh/soaraares/_pgg5.php3.

You can follow our blog with a free email subscription or by tapping into the blog RSS feed.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

Sunday, November 10, 2013

Super Typhoon devastates the Central Philippines. Post #240

Today, our prayers are with the residents of the Central Philippine Islands, who are just starting to recover from the devastation of super typhoon "Haiyan."  According to Ramon Anquitan (DU1UGZ) of the Philippine Amateur Radio Association, amateur radio operators in that island nation are providing emergency communications links to the government, as well as handling health and welfare traffic from impacted areas, such as Tacloban City--one of the hardest hit areas southwest of Manila.

Although the Philippine Red Cross says there are at least 1,000 dead from the devastating storm, reports from the Associated Press and Radio Australia put the dead and missing total somewhere near 10,000.

Typhoon "Haiyan" was an especially strong storm system with winds exceeding 175 mph (280.5 km/hr) in some areas.  Storm surge, heavy rain, and flooded rivers have destroyed thousands of homes and damaged hundreds of businesses in the Cebu area.  Government officials have sent  relief workers to the area, with amateur radio operators providing needed communications links.  Ramon Anquitan (DU1GDZ) says emergency traffic is being sent on a HF frequency of 7.065 MHz, on some 2 meter repeaters and simplex, and through surviving parts of the internet.  Ramon is asking fellow amateurs to stay off 7.065 MHz unless you are relaying health and welfare traffic into or out of the Philippines.

If you wish to aid survivors of this catastrophic storm, please contact your chapter of the American Red Cross.  You can make out your checks to "Typhoon Haiyan Relief."

I'm proud of my fellow amateur radio operators in the Philippines, who are maintaining communications links under very difficult conditions.

REFERENCES:

http://www.southgatearc.com.
Radio Australia
"The Honolulu Star-Advertiser", 10 November 2013.
The "Hawaii Tribune-Herald", 09 and 10 November 2013.
Ramon Anquilan (DU1UGZ), Philippine Amateur Radio Association, 09-10 November 2013.

You can join our blog community with a free email subscription or by tapping into our blog RSS feed.

Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.

Tuesday, November 5, 2013

My favorite Amateur Radio antenna books. Post #239

If you've been an amateur radio operator for any length of time, you probably have a good collection of parts, books, magazine articles, wire, coaxial cable, connectors, and basic tools to support your hobby.  This "junk box" is part of our amateur radio tradition...making do with what you have on hand.  I'm no exception.  In my 36 years as a licensed amateur radio operator, I've accumulated a wide collection of items, ranging from books to spare rigs.  Of course, the collection circulates a bit through trades, upgrades, giveaways to newly licensed hams, and, finally, to the recycling station.

One of the things I rarely sell or giveaway is my growing collection of books related to Amateur Radio and Amateur Radio antennas.  Many of these volumes were bought when I was newly licensed or successfully upgraded my license.  Nowadays, the task of assembling an Amateur Radio library is easier, thanks to the internet, Amateur Radio-related websites, and the outstanding archive of technical information available to ARRL (American Radio Relay League) members.  Nonetheless, I still collect books about radios and antennas.  This tendency must have been acquired when I was once a librarian at the University of Hawaii at Hilo Library.  But, that's a strange tale best told at another time.

As mentioned previously, my xyl and I are moving our household to a larger rural property in the Puna District of Hawaii Island.  As part of that process, I've been going through my "junk box" and sorting out the items I wish to transfer to our permanent home.  The items worthy of retaining include my old rigs (Swan 100 MX, Kenwood TS-520, Yaesu FT-7, and the Ten Tec Argosy II).  My antenna transmatches (Drake MN-4 and the MFJ 941-E Versa Tuner), the slightly used Elecraft K3, and my collection of wire, coax, and connectors are also coming with me.  My antenna book collection was the last category to be inventoried.  I'm still in the process of sorting that collection into the "keep" and "no keep" category.  Over the next few weeks, I'll make a complete list of the antenna reference materials that will make the "cut".

So far, these volumes have been retained, many for sentimental reasons:

A current edition of the ARRL Handbook and ARRL Antenna Handbook.  Both of these works are basic reference materials that every Amateur Radio operator should have.

"The Radio Amateur Antenna Handbook" by William I. Orr (W6SAI) and Stuart D. Cowan (W2LX).  This book provides many simple, practical, and inexpensive antenna ideas using locally available materials.

"73 Vertical, Beam, and Triangle Antennas" by Edward M. Noll (W3FQJ).  A basic book for antenna experimenters.  All you need to make Ed's simple antennas are a telescoping mast, some aluminum tubing, ingenuity, and a desire to explore antenna design.

"Novice Antenna Notebook" by Doug DeMaw (W1FB).  A concise introduction to antenna theory, construction, and maintenance of simple wire antennas.  I've tried most of Doug's ideas with great results.

As I continue my packing routine, I'll list some more of my favorite antenna books.  Building antennas and simple kits are a good way to expand your knowledge of Amateur Radio.  Besides, all of this "hands on" experience is fun.

REFERENCES:

The ARRL Handbook and ARRL Antenna Handbook are available from the ARRL, 225 Main St., Newington, CT, 06111.

These books may be out of print.  They occasionally turn up on e-bay:

DeMaw, Doug (W1FB).  Novice Antenna Notebook.  ARRL, Newington, CT, 06111.  First Edition, Copyright 1988.

Noll, Edward M. (W3FQJ).  73 Vertical, Beam, and Triangle Antennas.  Editors and Engineers.  Indianapolis, IN, 46268.  Seventh Printing, 1979.

Orr, William I. (W6SAI) and Cowan, Stuart D. (W2LX).  The Radio Amateur Antenna Handbook.  Radio Publications, Inc. Box 149, Wilton, CT., 06897.  First Edition, 1978.

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Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

BK29jx15--along the beautiful Hamakua Coast of Hawaii Island.