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.

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Thanks for joining us today!

Aloha es 73 de Russ (KH6JRM).

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