Simple Antennas for Amateur Radio Operators-go kit antennas, post #223


Simple Go Kit Antennas

In light of the current hurricane emergency along the eastern seaboard of the continental United States and Hawaii’s recent tsunami scare over the past weekend, it might be prudent to consider how well amateur radio operators are prepared to provide service in an emergency situation.

Since natural disasters are part of the living experience in Hawaii (hurricanes, earthquakes, tsunamis, and severe flooding), many Hawaii amateurs have prepared both their families and themselves for emergency survival until the storm or other natural occurance has passed.

Diehl Martin, W4TI, has assembled an excellent guide on how to build and use an emergency “go kit” for amateur radio operators (http://w4ti.net/gokit.html).  I found the article useful in updating my own go kit, especially in light of Hawaii’s recent tsunami warning and evacuation of shoreline areas.

When I volunteered to help my former employer (Pacific Radio Group on Hawaii Island) during this past weekend’s tsunami event, I made a quick check of the communications equipment available at home and in the Odyssey van.  Once I assured myself that there were sufficient food and water supplies at home, I did a quick inventory of the mobile shack and found everything in order.  Earlier, I had placed a large plastic Rubbermaid storage tub in the van with my emergency radio supplies.  In the tub were:  a Yaesu FT-7 (10 watt HF transceiver), pre-assembled 40 and 20 meter dipoles, a broken down 30-foot pvc mast and stake, guy ropes, a small MFJ antenna tuner (941-E), patch cords, two 50-foot lengths of RG-8X coax with UHF connectors, a small solar panel, cw key (J-38), Yaesu microphone, various power connectors, a large marine, deep cycle battery, and 100-feet of #14 gauge wire.  In another plastic container  I had my backup VHF HT (an old Kenwood Th-21A), spare akaline batteries, and a homebrew 2 meter vertical dipole made from an old rabbit ears antenna (see previous post).

This arrangement was tested early last week, so I knew it worked.  I also brought along my iPhone to coordinate activities with the Hawaii County Civil Defense Office and take pictures of any damage, should that be required.  Fortunately, I had “topped off” my gas tank on Friday, so I didn’t face the long lines of cars waiting for fuel before any waves rolled ashore.  The staff at the radio station often practices for events such as tsunamis and had plenty of fuel for our standby generators at the transmitter and studio sites.  Although I had several days worth of food in the van, I found supplies at the radio station adequate for the short period of time required by the emergency.  Luckily, only small waves impacted Hawaii Island, with little damage reported.  Those of us here on Hawaii Island tend to get concerned when tsunami warnings are issued–Hilo suffered loss of life and property in the 1946 and 1960 tsunamis, so we take warnings and alerts seriously.  This time around, the state of Hawaii dodged the proverbial “bullet”.  Had the situation proven otherwise, I could survive with what I found at the radio station.  As for the home station, everything is solar powered through deep cycle marine batteries and several pre-fabricated antennas stand ready to be put into service.

Most of my neighbors, as well as myself and my xyl, are well-prepared for emergencies.  We have at least a month’s supply of food on hand and fresh water is readily available from reservoirs far up the mountain (Mauna Kea).  The water supply is a gift from the former sugar cane plantation which closed in Laupahoehoe about 17 years ago.  Most of us in this Hamakua Coast Community can supplement our food supplies with garden crops grown on our small lots.

When the Hurricane Sandy emergency is over, you may want to inventory your situation and see if your “go kit” is ready for service.  When there is no emergency, you can use your go kit for portable operations, mini dxpeditions, or public service events, such as marathons, parades, and other non-profit events.  I find it pays to “exercise” your backup equipment every now and then, just to see if it works.  Besides, operating an emergency field station is an exciting and educational experience.  Sort of like a small field day operation without the mosquitos.

Perhaps all of us can learn from the disasters that befall us.  Meanwhile stay safe and support those who have suffered through this hurricane.

R E F E R E N C E S:

Amateur Radio “Go Kit”, W4TI–Building a Go Kit (http://w4ti.net/gokit.html).

Portable Go Kit Radio Station (http://www.emergencyradiogokit.com).

(PDF) Amateur Radio Go Kit Suggestions (http://www.desotoarc.org/jumpkit.pdf).

Until next time,

Aloha es 73 de Russ, KH6JRM–BK29jx15–along the Hamakua Coast of Hawaii Island

 

Simple Antennas for Amateur Radio Operators-a 2 meter antenna made from a TV Rabbit Ears Antenna, post #222


A HOMEBREW 2 METER ANTENNA MADE FROM A DISCARDED TV RABBIT EARS ANTENNA

Are you looking for a cheap, reliable, and easily fabricated 2 meter antenna that can be used both as an emergency antenna and a permanent inside the home antenna?  You may have such an antenna already in your home.

A few years ago, most portable televisions came with a detachable set of “rabbit ears” antennas for local reception.  Like many of us, I removed this antenna, stuck it in a back room, and connected the tv set to an outdoor antenna.  In my fringe area of Hawaii Island, I used a multi-element winegard yagi for both VHF and UHF reception.  Now, this antenna does a fairly good job in picking up digital tv signals from the Island of Maui.  Signals from Hilo are blocked by the slopes of Mauna Kea.  Although many of my neighbors have satellite or cable delivered television, some of us, including me, still use the over the air antennas for tv and fm radio reception.  And what about the neglected rabbit ears antenna?  Well, it’s being put to good use as an emergency 2 meter antenna.

The best thing about this detachable tv antenna is the terminating screw on each collapsable rod.  You can screw in your coax cable to each dipole leg.  After that step, extend the collapsable elements to the desired length as determined by the formula 468/f (Mhz).  For my purposes in reaching a Maui repeater, I selected a length of 18.5 inches (your mileage may vary).  Because of ridges and the shadow effect of Mauna Kea, reaching Hilo repeaters is difficult from my location unless a tall mast is employed.

You can orient the homebrew 2 meter rabbit ears antenna to suit your operating preferences.  In most cases, amateur radio operators would prefer vertical polarization to reach mobile and repeater stations.

Once you decide on your preferences (horizontal or vertical), attach the rabbit ears/2 meter antenna to a convenient wall or wooden dowel and you’re ready to start talking on your favorite 2 meter repeater.  If you attach the antenna to a wooden dowel or length of pvc pipe, you can take the antenna with you for emergency or portable use.  I have built several variations of this antenna using tv rabbit ears, bronze brazing rods, and even strips of aluminum foil.  All of these antennas worked and got contacts.  I have placed a “rabbit ears” 2 meter antenna on a piece of pvc pipe in my van as an emergency antenna.

MAIN ADVANTAGES OF THIS HOMEBREW ANTENNA:

Very easy to build.

Lightweight and transportable.

Can be adjusted to any frequency, because of its adjustable telescopic elements.

REFERENCES:

“Ham Antenna Blog”, http://ham-antennas.blogspot.com/2011/02/homebrew-2-meter-amateur-radio-antenna.html.

http://www.hamradiosecrets.com/short-ham-antennas.html.

ARRL Antenna Handbook, 21st Edition, ARRL, Newington, CT, o6111.

Have fun with this inexpensive and useful antenna.

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

Until next time,

Aloha es 73 de Russ, KH6JRM–BK29jx15–along the beautful Hamakua Coast of Hawaii Island.

Simple Antennas for Amateur Radio Operators–the 20-meter sloper, post #221


A 20- METER SLOPER ANTENNA

The familiar half-wavelength dipole antenna is a favorite of amateur radio operators.  It is easy to build, erect, and maintain.  Materials for this type of antenna are available at most hardware stores.  Erected at a reasonable height above ground (at least a 1/4 wavelength), the dipole gives good performance at a modest cost.

What can you do if it’s not possible to fit a full length half-wave dipole in the horizontal space available on your property?  You can still maintain most of the performance advantages of a dipole antenna by building a half-wave length sloper.  This type of antenna needs only one tall support, such as a tree or tall mast, and uses less horizontal space than a conventional flat-top dipole.    You can feed the sloper dipole with 50–ohm or 75 ohm coaxial cable for mono band use or with 450-ohm ladder line, balun, and an antenna tuner for multi-band use.

I decided to design and build a 20-meter sloper dipole and feed it with ladder line owing to my lack of backyard space and the desire to have one antenna work on the 20, 15, and 10 meter bands.

MATERIALS NEEDED:

Two, 16 1/2-foot  pieces of copperweld wire or #14 gauge household wire.  These wires will be the sloping dipole elements.

A coax center insulator, such as the MFJ-16B01 or the MFJ-16G01.  Or, a plexiglass center insultor to support a ladder line connection.

Two ceramic end insulators, such as the  MFJ-16C01.

Dacron rope for tie offs and mast support.

A suitable support, such as a tall tree or a mast of at least 33-feet tall.

A suitable length of 50-ohm coax (RG-58, RG-8X, or RG-8) to connect the sloper elements to your rig.

An antenna tuner with an swr meter.

A dummy load for testing and adjustment purposes.

Soldering equipment.

A suitable HF transceiver.

An amateur radio license that covers your operating privileges.

ASSEMBLY:

Attach the center coax connector to each element.  Solder each element to the connector and cover each solder joint with

Attach insulators to the end of each dipole element.

Tie one end of the dipole to the top of a tree or the mast.  The other end will slope down at a convenient angle.

Be sure the transmission line (ladder line) is routed at a 90-degree angle from the sloper for at least a 1/4 wavelength (approximately 16 feet, 6 inches for 20 meters).  This will avoid distortion in the radiation pattern.  If you are using a coaxial cable transmission line, you may want to install a “choke” balun at the center insulator to keep unwanted rf currents from traveling back to your shack over the coax shield.

Raise your mast or attach one end of the dipole element to a tall tree (use a slingshot, bow and arrow, or even a rock to guide the antenna element through the foliage.  Be sure to attach a guide rope to the top sloper element which will help you pull the element to the top of the branch or tree you have selected).

Secure your mast and tie-off the bottom half of the sloper to a post or stake.

Run your coax to your antenna tuner and, through patch cables, to your transceiver.  If you are using 450-ohm ladder line, attach the end not connected to the antenna elements to a 4:1 balun.  Then run a short length of 50-ohm coax to your antenna tuner.  Use a patch cable to attach the tuner to your transceiver.

Tune and adjust your transceiver with a dummy load.

Using low power, transmit a short duration “test” message and give your amateur radio call.

Adjust for the lowerst SWR.

Once everything is adjusted, go “live” and have some fun!  The radiation pattern should be almost omnidirectional, with a slight advantage toward the direction of the slope.

SAFETY PRECAUTIONS:

Keep your sloping dipole away from utility and telephone lines.

Be sure to disconnect and ground all unused feedlines when your operating day is done.

Use only the power necessary to maintain clear communications.  Most of the time, I find 50 watts more than adequate for most contacts.  I usually run considerably less power…more in the neighborhood of 10 watts or less.

A sloping dipole is an easy, inexpensive antenna that will give you hours of enjoyment.  The best part about this antenna is that you can build it yourself at a modest cost.  Have fun.

REFERENCES:

VE2DPE, “The Ham Radio HF Antenna for Smaller Real Estate”, http://www.hamradiosecrets.com/ham-radio-hf-antenna.html.

“MF/HF Slopers–American Radio Relay League, http://www.arrl.org/mf-hf-slopers (members only data).

ARRL Antenna Handbook, 21st Edition, ARRL, Newington, CT, 06111.

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

Until next time,

Aloha es 73 de Russ, KH6JRM–BK29jx15–along the beautiful Hamakua Coast of Hawaii Island.

 

 

Simple ham antennas for Amateur Radio Opertors–A 20 Meter Delta Loop, post #220


A SIMPLE 20 METER DELTA LOOP

A few weeks ago, I removed my original 20-meter delta loop to make room for an experimental 40-meter vertical helix dipole.  That antenna is working well, despite its very narrow bandwidth.  The Drake antenna tuner gets a real workout with this antenna.  I’ll leave this up in the backyard and continue my work on taming this little beast.

Meanwhile, the original 20-meter loop needed some repairs.  The combination of the tropical sun, salt air, vog (volcanic haze), and rain was taking its toll on this “temporary” antenna.  So, I lowered the MFJ fiberglass mast and recovered most of the wire, ceramic insulators, the 4:1 balun, and most of the RG-8X coaxial cable.  Parts of the cable were a total loss–rats and other rodents were dining on the cable and had eaten into the braided shielding of the coax.  No wonder my results with this antenna were going downhill.  Apparently, the rodent-caused holes had let water in and destroyed the integrity of the cable.  I kept busy Saturday afternoon building a new delta loop.  This time around, I opted to use 450-ohm ladder line instead of coax.  With ladder line and the trusty W9INN 4:1 balun, I could tune the antenna from 20 meters to 10 meters.

MATERIALS NEEDED:

Fortunately, I had most of the materials on hand.

70 to 75 feet of #14 gauge house wire for the delta.  As many of my fellow amateur radio friends have suggested, you may want to use copperweld wire for the loop.  This wire is sturdy, stands up to the weather, and doesn’t stretch much.

A 30 to 40-foot mast to support the top of the loop.  I had an old MFJ fiberglass mast which served as an antenna support.

Several ceramic or plastic insulators to help form the loop ends and to attach dacron ropes for support.

Dacron rope for guys and loop supports.

A 4 to 5-foot wooden fence post or stake to support the mast.

A length of 450-phm ladder line sufficient to run to a remotely mounted 4:1 balun.

A suitable length of RG-58, RG-8, or RG-8X to reach your antenna tuner.

Other cable patch cords to attach a dummy load, low pass filter, and various meters to your transceiver.

And, of course, an amateur radio license covering the frequency ranges you wish to use.

PROCEDURE:

Lay your mast on the ground.

Measure out approximately 70-75 feet of copperweld wire or whatever wire you have on hand for the delta loop.  To calculate the exact length in feet for the delta loop, use 1005/f (Mhz).  For the 20-meter band, a length of 70 feet, 6 inches (70.546 feet) should be sufficient to cover the 20-meter band with a SWR of 2:1 or less.

Shape your 70 feet, 6 inches worth of wire into a triangle approximately 23 feet, 6 inches (23.515 feet) on a side.

Attach ceramic insulators at the top and the bottom corners.

Thread antenna element through each insulator and attach dacron tie off ropes at the bottom two insulators.

Attach your 450-ohm ladder line to the bottom right hand corner for vertical polarization.  Attach your feedline to the top for horizontal polariszation.  My 40-meter horizontal loop under the house does an exceptional job for NVIS (near vertical incident skywave) contacts throughout the Hawaiian Islands.

Raise your fiberglass mast and slip it over the supporting stake.  Tie off guy wires and the bottom portion of the loop.  In my case, the bottom portion was a few feet off the ground and fairly well disguised by my backyard garden.

Connect the feedline to your remote 4:1 balun and run a length of 50-ohm coax to your antenna tuner.

Test and tune your transceiver on your dummy load.

Go “live” with low power, announce your amateur call sign, and make final swr adjustments.

RESULTS:

The 20-meter delta loop fed with ladder line does a good job from 20- through 10 meters.  The Drake antenna tuner is able to adjust any mismatch in the antenna system.  If you want single band operation on 20-meters, you can use 50-ohm coaxial cable attached to a 4:1 balun at the feedpoint.  If you are using coaxial cable as a feed line, it may be a good idea to wind 6 to 8 turns of coax about the diameter of a coffee can at the feedpoint to keep RF out of the shack and to provide a higher impedance path for lightning.

SAFETY CONSIDERATIONS:

Always disconnect and ground antenna feedlines after you turn off your amateur radio station.

Keep your mast as far away from utility lines as possible.

It may be a good idea to lower your mast after you finish your radio activities.  This will add a measure of safety in case of thunderstorms and lightning.  Also, a nested mast will draw less attention from curious neighbors.

WE GET MAIL:

Today, I received a nice note from James Kaufman, the editor of “The Amateur Radio Community.”  Kaufman invites “Amateur radio broadcasters, Ham radio operators, Amateur radio enthusiasts and experts, clubs, etc.” to join his group.  You can reach Mr. Kaufman by visiting http://www.vorts.com/amateur_radio/.

REFERENCES:

http://www.cebik.com

“20 meter delta loop” (http://www.dxzone.com/cgi-bin/dir/jump2.cig?ID=9313).

“A Vertically Polorized Delta Loop for 40 Meters” (http://www.dxzone.com/cgi-bin/dir/jump2.cig?ID=9038)

KC4HW, “40 Meter Delta Loop” (http://www.kc4hw.net/deltaloo.htm).

Andrew Roos, ZS1AN,  “A Vertically Polarized Delta Loop for 40m” (http://www.qsl.net/zs1an/vpdelta.htm).

W5SDC, “Delta Loops for HF” (http://www.w5sdc.net/delta_loop_for_hf.htm).

You can follow this 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.

Simple Antennas for Amateur Radio Operators–the “static” mobile antenna, post #219


THE “STATIC” MOBILE ANTENNA

Sometimes the only antenna available to those of us restricted by CC&Rs, HOAs, or just plain lack of space is a mobile antenna, either mounted on your vehicle or in a small space next to your back yard.  I faced that problem several years ago when I was living in an apartment and had no way to erect a dipole or random wire from my second floor location. Fortunately, the parking lot was in back of the apartment and I had some room to run a length of coax to my small Toyota Tercel.  On the roof, I placed a mag mount with a “Hamstick” antenna attached.  As you can imagine, performance was marginal, but I did get some contacts with the 20 meter stick.  Not a perfect solution by any means.  I was on the air, albeit in a very limited fashion.

Now, fast forward to the present.  Among the antenna pieces stored in the garage was that old 20 meter Hamstick (the manufacturer, Lakeview has apparently closed shop) and an old, but serviceable mag mount.  So, while I washed and waxed the van in the front yard, I hatched a plan to use the Honda Odyssey as part of my antenna system.  I left the van in the front yard and proceeded to collect the remnants of my apartment antenna.  This time around the course, I placed the Hamstick and its mag mount in the center of the roof and attached four, 16-feet, 6-inch radial wires to the mag mount.  I ran about 25 feet of RG-8X coax to my Drake MN-4 antenna tuner and then to the old Swan 100 MX.  I spent most of Saturday (20 October 2012) running about 20 watts from the venerable Swan 100 MX into the “static” mobile antenna system.  The van, being much larger than my old Tercel, provided a bit more of a ground plane.  With the added radials, the SWR was 1:6 to 1 across the 20 meter band.  Not bad for “quickie” antenna system.  I spent several hours on Saturday talking with hams from Hawaii (my homestate) to California.  Most reports on SSB were between 56 and 57–not outstanding, to be sure, but thoroughly readable.

Based on this limited experience, I decided to add the “Hamstick” and mag mount combination to my emergency/portable gear in the van.  I already have a 40 and 20 meter dipole antenna in the “go” box.  The “Hamstick” won’t take much room and it will come in handy if I have to set up a portable station in a hurry.

Since the Lakeview Company doesn’t make or distribute the “Hamstick” antennas anymore, I began a search for suitable replacements.  The 2012 MFJ Catalog has a variety of mobile antennas and mounts that could be used as emergency mobile or portable antennas.  On page 65 of the current catalog, the “MFJ HF Mobile HamTenna (TM) Whips “, and the “HF mini-Bugcatcher” antennas look promising.  The Ham Tenna whips vary in price from $14.95 each for the 6-40 meter bands and $19.95 each for the 60-75 meter bands. The “HF mini-Bugcatcher” is priced at $89.95.  MFJ also sells a variety of mag mounts that can be used for temporary or emergency use, including the “MFJ Triple Mount” on page 61 of the 2012 catalog.  That mount is priced at $34.95.  Or, you may be as lucky as I was and have saved an old mag mount from days gone by.

This antenna system is not especially efficient, but it does work, particularly if you attach some radials to the mag mount.  I’ve found that mobile antennas can be pressed into service, sometimes with unexpectedly good results.  So, the next time you find antenna options limited, try using your HF/VHF mobile antenna as part of your home system.  While not perfect, such a system will keep you on the air.

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

Until next time,

Aloha es 73 de KH6JRM–BK29jx15–along the beautiful Hamakua Coast

Simple Antennas for Amateur Radio Operators–A 40 meter NVIS antenna, post #218


IMPROVING THE 40 METER NVIS ANTENNA

Are you interested in building a simple, cheap, and portable 40 meter antenna that can serve as an emergency backup antenna or as a reliable antenna for state and regional nets?  Then the NVIS (near vertical incident skywave) antenna may be for you.  Military communications units have employed NVIS arrays for decades to provide HF coverage out to 200 to 300 miles.  A NVIS antenna is the perfect choice for local nets and emergency networks.  I’ve built several NVIS antennas over the past few years and have found them to be quiet and effective in maintaining local contacts throughout the islands of Hawaii.

MATERIALS REQUIRED:

Three non conductive masts approximately 7 to 10 feet tall (you can use fiberglass fishing poles, pvc pipe, or wooden dowels).

Approximately 270-feet of #14 gauge housewire for the dipole and reflecting screen.

A center coax connector such as the Hy-Que center conductor (you can also make your own connector out of plastic or wood).

Ceramic or plastic insulators.

Fifty feet of 50-ohm coaxial cable (RG-58, RG-8, or RG-8X).

An antenna tuning unit to reduce any swr to low levels.

An amateur radio HF transceiver.

A 50-ohm dummy load to tune your transceiver off the air.

And, of course, an Amateur Radio License appropriate to the frequency band of the antenna.  For this discussion, I’ve chosen 40 meters.

ASSEMBLY PROCEDURE:

Attach 33-feet of #14 household wire to each end of the center coax connector.  Connect 50-feet of 50-ohm coaxial cable to the center insulator.

Attach end insulators to each dipole element.

Attach a 7 to 10-foot mast to each section of the antenna–one for the center insulator and one for each end of the dipole elements.

With the help of a friend, raise the masts so that you have a “flat top” dipole, measuring 66-feet in total length.  Secure each mast section to a stake or other support.

On the ground, directly below and parallel to the dipole, lay three reflecting wires of 65 to 70 feet.  One wire is placed directly under the dipole, while the other two wires are spaced 6-feet from the center and parallel to the first reflecting wire.

Using the dimensions given above, you should find your swr below 2:1 accross the  the entire 40 meter band.

Once everything is in place, tune up your transceiver with a dummy load.

When you go “live”, run low power and give your callsign.  Tweak the swr reading with your antenna tuner.  When the swr is adjusted to its lowest reading, you’re ready to launch that first signal on the local net.

PERFORMANCE:

As with any “homebrew” antenna, results will vary with the location, type of materials used, ground conductivity, and propagation.  Since this antenna shoots most of its signal straight up, don’t expect significant dx contacts.  On the Big Island of Hawaii, I find this NVIS antenna can reach the Island of Kauai (approximately 275 miles from Laupahoehoe) without any problem.  When I do get on the Hawaii Afternoon Net (7.088 Mhz LSB), my signals range from 57 to 59 with just 10 to 20 watts from the old Swan MX-100.

I built and used this antenna for several weeks while my next door neighbors were on vacation.  Since my lot is quite small, the antenna overlapped their property a bit.  So, I removed the antenna before they returned.  Presently, my NVIS antenna is a full-wave 40 meter loop strung under my house.  Performance is still good, considering the loop is only 5-feet off the ground.  The house is built on a pier and post system and affords just enough room to hang a loop for 40 meters.  The loop is used mostly for local contacts, although I’ve snagged a few dx stations on 20 meters when propagation is good.  My dx antennas are the 40-meter vertical helix dipole and the 40-meter inverted vee.  All of my antennas, save the temporary NVIS dipole described earlier, were fed with 450-ohm ladder line.

REFERENCES:

“A Super Gain Antenna Project for 40 Meters”, by Jerry Berry, K5AXN, “73 Magazine” (October 1969.  Reprinted–http://www.hamuniverse.com/supernvis.html.

“Understanding Amateur Radio NVIS Antennas and Propagation”, Harold Melton, KV5R, http://www.athensarc.org/nvis5.asp.

“Near Vertical Incident Skywave (NVIS) Antenna, Pat Lambert, W0IPL, http://www.W0IPL.net/ECom/NVIS/nvis.htm.

I find NVIS antennas a good way to keep in contact with amateur radio operators in Hawaii.  The signals are strong out to 250-300 miles and there is no problem with falling into the “skip zone”.   All of my materials were either bought at the nearest hardware store or were already secreted in my “junque” box.  If you enjoy “ragchewing” with the “locals”, a NVIS antenna could provide reliable, strong signals at a modest cost.

Good luck with your NVIS antenna!

Join 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.

 

 

Simple Antennas for Amateur Radio Operators–the impromptu inspection, post #217


THE IMPROMPTU INSPECTION OR ‘WHERE IS MY ANTENNA?”

When I served in Uncle Sam‘s Air Force many moons ago, one of the things I dreaded most was the unannounced inspection. It always seemed to happen on a Friday afternoon or early Monday morning–the time when the admin folks (you know the men and women who really run the office) were out running errands or arranging for command briefings. The inspectors really knew their stuff and you had better have a good explanation for anything out of place. Thankfully, my admin staff was aware of this tradition and made sure that “shavetail” Lieutenants such as yours truly had enough checklists, filed procedures, and required techncial stuff to cover emergencies. I’m forever in debt to my admin sergeant and those who knew the “system.”

Although I’ve been out of the USAF for many years, I still retain the “better safe than sorry” axiom of my military days. The Boy Scouts have a motto, “Be Prepared”, which can serve all amateur radio operators and keep them on the air despite what Nature or mankind throws at us.

I tested that old saying today, when my xyl and I returned from a day of shopping in Hilo, some 30 miles southeast of the qth. Since we weren’t tabbed to teach today at the Laupahoehoe Community Public Charter School (we’re substitute teachers in our retirement years), we decided to make an early supply run before the weekend. When all was done, we found a few spare hours on our collective hands. Janice (my better half) had some lesson plans to review, while I finally had some time to inventory radio equipment used in our van for emergency or portable use. I hadn’t gone on an informal “dx”-pedition in months, so now was the time to see if all my assorted transceivers worked as specified.

This time around the maypole, I was lucky. When I last ran a short-term portable HF operation in a small park above the qth last April, I assembled two plastic storage bins with things I needed to run an amateur radio station for several days.

Upon inspection, I found the following:

two dipole antennas (40 and 20 meters), with Hy-Que center connectors, 50-feet of RG-8X coax, a small MFJ antenna tuner, two microphones, a J-38 key (left over from my military days), a dummy load, and the trusty Yaesu FT-7 transceiver. In the other plastic bin, I had deposited a deep cycle marine battery (very heavy), connecting cables, two small solar panels and anciliary charging equipment, a small inverter, dacron rope for guys, and a small tool kit. Five, 5-foot sections of pvc pipe, plus fittings for joining the pieces together into a mast, rounded out the equipment. Wonder of wonders, everything was there. So, before the xyl and I took our daily 5-mile walk, I quickly assembled the station and sent out a few CQs. I made a few contacts in the 56 to 57 range on 20 meters, and two cw contacts on 40 meters with a 559 to 569 report. Not overwhelmingly impressive, but I did make some contacts with low-slung dipoles. The only antenna parts missing were the two “Hamstick” antennas for 40 and 20 meters, the mobile mag mount, and a set of counterpoise and radial wire. For some reason, I left those items in the garage, promising myself that I would divise some sort of dipole for mobile operations. With a proper dipole connector from MFJ, I could order two more “Hamstick” equivalents and make a “quick and dirty” dipole for emergency operations. I believe “Hamsticks” are no longer being made, so MFJ may be my sole source for these useful antennas. More research is needed in this category.

Anyway, I came away satisfied that my initial planning for emergency operations was viable and that the homebrew system actually worked. I have several amateur radio friends that operate entirely from their vehicles, owing to the CC&Rs and HOAs that restrict their home stations.

Perhaps you could use your vehicle to support a small dipole or vertical antenna and run the coax to your home station. Surely beats not getting on the air.

Join our blog community with a free email subscription or by tapping into the blog RSS feed. You can share your thoughts in our comment section.

Until next time,

Aloha es 73 de Russ, KH6JRM–BK29jx15–along the beautiful Hamakua Coast of Hawaii Island.

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