Repairing Portable Rotatable Dipole

For portable operations, we have been using a portable rotatable HF dipole from EmComm-Products (model RADS 9-11/A) since 2008.  The antenna provides HF (160m, 80m, 40m, and 20m) and a second VHF/UHF antenna on top of the dipole which is fed by a separate cable enabling concurrent operations of both a HF and VHF/UHF radio on one mast.

Activating Hatteras Island, NC

KC2VSR (Field Day at Fort Ord, CA) rotating the dipole by giving the mast a simple twist

When setting up the antenna for portable operations to teach the radio merit badge in 2018, we discovered that we could no longer tune up when using the 20m elements.  SWR was extremely high.  The was the first time we had an issue when using the antenna after a decade of use.  It was time to give the antenna some attention and bring it back to working order. 

Diagnosis

Once back home, we brought out each of the elements and check them individually for continuity using a ohmmeter.  To perm this test, we placed one of the ohmmeter probes on one end of an antenna element and the other problem on the other end of the antenna element.

All the elements passed this basic test with the exception of one of the 20m elements.  The 20m element had no continuity indicating that the wire had a break somewhere along the fiberglass element.

I visually inspected the element for apparent damage and found none.  This suggested that something was amiss with connection between the wire and one or both end connectors.

Corrosion on the joint between the antenna wire and antenna connector

Using an X-acto knife I carefully cut a window in the shrink wrap at the junction between the antenna element wire and the end connector to inspect the connection.  This revealed corrosion on the junction.  Using the continuity tester, I checked for continuity between the wire and both end connections.  This showed continuity at the junction to the far end connector and no continuity to the near connector.  Ah ha!  We found the issue.  The corrosion was likely caused from a decade of operating near saltwater and in the rain.

Repair

A brass wire brush was used to remove the corrosion.  The connector was then resoldered to the wire along with a copper wire wrapped all the way around the connector to assure positive contact.  The connector was recovered with shrink wrap and relabelled as a 20m element.  This was a straightforward and easy repair.

Repaired 20m element

Results

We setup a wilderness radio station to teach the radio merit badge at summer camp with the portable rotatable dipole as one of the antennas.

Portable rotatable dipole back on the air at summer camp near Truckee, CA

We setup the antenna with the 20m elements and it performed flawlessly all week while at summer camp.  We made numerous SSB contacts on 20m.

Several people have contacted me asking about buying their own portable rotatable dipole antenna.  Sadly, the manufacturer, EmComm-Products, is no longer in business.  It has been an outstanding antenna.

Good DX and 73,  

NJ2X

Radio Scouting: Earning the Radio Merit Badge at Summer Camp

The Radio Merit Badge was earned by 5,205 Scouts in the US in 2018 representing a 10.9% drop from the year prior.  We hams need to make sure we step up our support of scouting and act as counselors for the radio merit badge.  The Radio Merit Badge requirements are demanding and require both classroom learning as well as applied learning in front of a radio.  The radio merit badge looks great on a scout uniform sash with its wonderfully designed Morse code message and lighting bolts.

Scouts BSA Radio Merit Badge

I had the privilege to teach the radio merit badge with my daughter's Scouts BSA troop while at summer camp in the Sierras in Northern California in 2020.  We had a small group of scouts and parents which provided the scouts with more radio operating time and more time for discussion and questions about radio.  This made the merit badge class sessions more fun and engaging.

The scouts had a blast learning hands-on on how to setup the entire wilderness radio station including:

1. Generator
2. Power supply
3. Kenwood TS-480SAT (HF+6m transceiver)
4. Yeasu FT-8800 (2m / 70 cm FM transceiver)
5. Kenwood TH-F6A (triband FM HT)
6. External speaker
7. 40 Meters home brew wire dipole
8. 20 Meters rotatable dipole
9. VHF/UHF antenna

Emergency communication rotatable dipole and VHF/UHF antenna packed up in its storage bag

The scouts made numerous contacts on 40 Meters, 20 Meters, 2 Meters, and 70 Centimeters.  We also tuned up and down on the shortwave broadcast bands and listened in on various programs from around the world.  This was an eye opening experience for the scouts who had never heard shortwave broadcasting nor made amateur radio contacts before.

Kenwood TS-480SAT Transceiver

The rotatable dipole worked like a champ having been serviced in the work prior to camp.  While on the workshop bench before camp, it was discovered that one of the elements had developed a break due to corrosion.  The repair was straightforward requiring a quick cleaning of the corrosion, resoldering, and shrink-wrapping.  The rotatable dipole helped demonstrate the directional nature of dipole antennas to the scouts.

Emergency communications rotatable dipole with VHF/UHF Antenna on top setup at summer camp 

One of our scouts, Sadie, earned her FCC Amateur Radio Technician license (KN6JYE) just prior to arriving in camp.  She had a blast using her license for the first time on VHF/UHF simplex calls, calls over area repeaters, and checking into various area nets including a fun 2m simplex net.  By the way, Sadie and her troop are running a popcorn fundraiser to help keep their scout program going.  Please stop by Sadie's Trails End popcorn storefront to make a purchase and support scouting and her troop.

Sadie, KN6JYE making contacts at elevation 3187m on top of Mount Lassen, California

The scouts were amazed and excited to experience the thrill of DX communication for the first time.  We made contacts on 40 Meters to other states and countries including Hawaii and New Zealand.  DX is alive and well even at the bottom of the solar sunspot cycle.

Amateur Radio Operator scout uniform strip

A big THANK YOU to the patient hams who talked with the scouts and helped them log their very first amateur radio contacts.  These hams helped the scouts to successfully earn their radio merit badges and we couldn't have done it without them.  It is the hands-on learning and radio operations that is the most inspiring and engaging aspect of the radio merit badge.  Several of the scouts expressed their enthusiastic interest in earning their own amateur radio licenses.  Please support scouting, radio merit badge activities, the annual Scout Jamboree on the Air (JOTA) special event, and youth learning the ropes on the air.  The next generation needs our support and encouragement just as much as we all did when we were their age.  Remember, it is youth who are the future of the amateur radio.

Good DX and 73,

NJ2X

Wildfire Evacuation Tactics

It is August 20, 2020, wildfires continue to rage along the central coast of California in Santa Cruz County and the neighboring Santa Clara County affecting tens of thousands of people and tens of thousands of acres.  There is zero containment so far.  Evacuation of entire communities is occurring.

I received a helpful list from a neighbor on preparing for a wildfire evacuation. I am sharing this information in case it is helpful to others.

- BE PREPARED
- TURN ON yard sprinklers.  Turn them off before you evacuate.

- MOVE outdoor furniture / anything flammable to IN garage.

- TAKE DOWN shades 

- CLEAN gutters / leaves of debris

- RUN hose lines around property, brass nozzles are best. 

- Turn OFF natural gas - wrench next to meter 

- Turn ON outdoor house lights (front of house/garage) 

- CLOSE windows and doors - Remove all cloth and plastic curtains 

- EMAIL / TEXT / CALL Let family outside of area know individual / group plans - Leave a letter on kitchen counter of who you are, who is with you and where you are going and how you’re getting there - INFORM all neighbors of your plans and learn theirs 

- MOVE indoor furniture away from windows / doors to center of room 

- MOVE flammable materials to the center of the garage, ideally not on the ground. 

- PLACE extension ladder leading to roof 

- CLOSE OFF roof / eave vents - duct tape 

- DISCONNECT automatic garage door opener, manually close. 

- TAPE any gaps between garage door and ground, so no embers can blow under 

- LEAVE car unlocked with keys in ignition 

- WRITE note and paste to front door informing you have evacuated and the date. Note where the closest fire hydrant is to you. 

- POSITION security cameras to see your surroundings better 

- CUT all branches that are too close to your house. Form pile away from house, not under trees (center of driveway for example) 

- REMOVE flammable plants (lavender, etc) within 3 feet of home 

- HELP your neighbors and COMMUNICATE regularly 

- EVACUATE while you have time on your side

If you are a amateur radio operator, remember, cell phone and internet services are prone to failure.

- BRING your fully charged amateur radio HTs and charger with you (already programmed with your area's repeaters).

- LISTEN to your radio to monitor for news updates.

Do you have additional tactics to add to this list?  Please leave a comment.

Be safe,

NJ2X