K4CHE/3 Field Day Operations 2016



Mission Objectives:

                       1. Primary Mission -Accomplish the majority of contacts using a hand crank generator. (Actually a G-76 modified for foot pedals)

                       2. Evaluate the T-10 parachute as a shelter.

                       3. Make all contacts with either generator or solar power at QRP power levels.      No batteries.

                       4. Evaluate the ME-61 modified field strength meter at QRP power levels. The ME-61 is modified with an internal Op Amp amplifier.

                       5. Evaluate 300 ohm twin lead (TV lead) as feed line for a doublet.

                            6. Avoid the State Bird the Mosquito.



                Primary Mission was to conduct operations with the G-76 gen set. Secondary mission lose 2 pounds during the week end.                                   

                            G-76 Voltage Demo Video


              Just for the challenge my main mode of operation was CW - primarily to prove if I could pedal and key at the same time. Shown above is a very low current setup using a older Emtech QRP set that I built as a kit years ago for a product review for Wayne Green and "73" magazine.

                         Video CW contacts using G-76 for power.


                                                         kcerb drone photo

              I was very pleased with the T-10 parachute shelter. Roomy and plenty of air circulation. My survival school instructor would be proud.



              The T-10 chute has been around for ages and has had several modifications. When purchasing one on the surplus market expect it to be de-milled and all 30 risers cut off. Usually the Anti-Inversion net is attached. Diameter laying flat on the ground is 35 feet and with the center raised the diameter is reduced to approx 25 feet.


               A little parachute history



               The anti-inversion net attached to the bottom of the riser panels is awkward and probably overall it would be easier to manage the parachute shelter by removing it..

              Lines can be attached to the parachute panels by using a small smooth object and placing it under the material. In the USAF survival schools we just used a rock.            


              Another method of attaching a line is to bunch up the nylon and secure with twine then attach your guy line.


              With the parachute sides folded and raised several feet you can get plenty of air circulation.

                        Angela Williams Photo



                    Lead weight inside a tennis ball to prevents those vehicle windshield mishaps that occur when that wrench that you tied to the end of the line hits.
                                                       Possible example


              Home brew fixture fabricated from lexan used to secure the 300 ohm line. "Line Grabber". Note that # 18 wires were soldered to the end of the 300 ohm line to provide a more robust connection.                 Knurled nuts allow "Easy On - Easy Off".


              The 300 ohm TV twin lead termination end feeding a balun. Again a fixture from lexan was used to hold the line and #18 wires allow easy rugged connections.

                        The SGC-715 was another low power rig that was easy to power with the G-76.

                           SSB video with SGC-715

                       My Frankenstein antenna tuner made from bits and pieces collected from Ham Fests.

                                  PRC-71 ops on CW. Kind of a pain as you have to manually switch from receive to transmit using the front panel switch.

        No break in on the PRC-71 - you have to manually move the rotary switch from REC to XMT.

              Interior of the Frankenstein tuner. Note the use of wood as a insulator. Simple and easy to mount.


                          Dupe sheets keep you from contacting the same station twice.

                         No one seems to know where Chickenland (Delaware) is.

                                       Video SSB ops Delaware


              G-76 collapsed and mounted on a platform for foot pedal use. Held in the collapsed position by straps.

              Small foot pedals were fabricated to mount on the hand crank handles.

               The fabricated pedal is held onto the generator crank handles with a hose clamp.


                          Central control monitoring. Contains a 13.8 volt voltage regulator using a simple LM138. Not too efficient as the 24 volt voltage drop from the G-76 to 14 volts results in power lost as heat but overall is simple and easy to repair. TIP: Use the LM138 instead of the usual LM317 as the LM138 is rated at 5 amps with 7 amps peak. Same pin out.

     A Future Field voltage regulator circuit may use the LM2576 series but the circuit becomes more complicated with an addition of a schottky diode and inductor and large value capacitors. However efficiency levels of 75-85 percent can be obtained but the devices when used solo are rated at 3 amps. (Suggested by Ray KA3EKH)



             Commercial 24-12 converters can boast efficiency of 85 percent. Picked this one up in the flea market at the Aberdeen Rally. It has a 15 amp rating.

              A large master buss voltmeter at the operating position comes in handy. During receive when the voltage dropped below approx 8 volts it was time to give the "system" a few cranks to charge the capacitors for more receive time.

            One of the voltage distribution strips. Easy to use. Easy to make changes in the field. Simpler to use than the famous Power Pole connectors. Note the Red and Black paint.

                             Ham fest purchases. Many thousands of uF.

                           My first attempt at using the ME-61 with an op amp inside. Failed as I was using the original 50 K pot and adjustment was too sensitive. More info on modifying the ME-61 below.



                       Night ops. I did cheat and use D cells in the lantern.


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