Welcome to the KC0JCA Beacon Page!
The whole beacon runs 24/7 broadcasting my callsign every 5 seconds at 13 WPM. The whole beacon is powered by a 100 W solar panel connected to a deep cycle lead-acid battery.
Transmitter is a Hendricks QRP Tayloe Simple Transmitter (TST) running at 4 Watts. Built-in keyer prevents key down longer than 7 seconds, so it runs at a power amplifier efficiency: ~70%. This allows the 2N7000 finals to stay relatively cool in a TO-92 plastic package. This transmitter was built from a kit from http://www.qrpkits.com/tst.html
(Note: 6/16 Due to frequency drift caused by temperature fluctuations, the transmitter is forced-air cooled by a 0.5W brush-less cooling fan salvaged from a PC power supply.) The transmitter uses approximately ~350 mA.
On Air: 16 January 2015 – Current
The keyer is a PicoKeyer Plus from N0XAS. Assembly was simple, but programming it was not. My CW skills were a little rusty but it slowly came back. You have to program it using code using a paddle. Being that I am a straight key person, I did not have access to one. With advice from Doug at Gateway I took a 3-wire stereo plug and soldered a SPDT switch onto it. BOOM! a paddle! After programming it, it was easy to plug into the transmitter. I chose D Cells because I was curious to see how long D cells would last on the keyer. I buy batteries from Dollar Tree so cost isn’t a problem. I may add the included zener diode and put it into the battery. The total cost of the keyer was 17.99 plus shipping.
Pretty simple, a half-wave dipole pointing north-south up 15 feet in the air. I have built these things so often that it only took 10 minutes to build and another 10 to set it up.
Renogy 100W mono-crystalline Solar Panel (R). It is connected to charge controller which handles my solar cell and 12 volt battery system. The panel supplies 22 volts of 100 watt power (~4 AMPS) to a CMG-2420 charge controller and a deep cycle cell battery. The beacon itself is tied into the load circuit using a 1 Amp fuse in the unlikely event of a power surge. The power system powers my ham station as well as my work bench (meter, oscilloscope, and soldering iron) using a 1kW inverter attached to the battery. I have on the grid power available, but I don’t remember when I plugged it in last. The old poly-crystalline solar panel(L) supplied ~480 mA, but efficiency dropped significantly after 8 years to less than 300.
CMG-2420 20A charge controller
The whole reason for this beacon project was to see if I could make and operate a beacon from scratch with the minimum amount of money and resources available. This project brings together my love of electronics tinkering, 10 meters, solar energy, and QRP. I could have modified an old CB radio to use, but I wanted to keep it simple, and minimize its impact on the environment.
Old Beacon (PROJECT LAIKA) IN RESERVE
The forced air-cooled trasnmitter is a Hendricks kit kindly supplied by KJ4VYI to replace the old board. It is driven by a 2N3553 transistor. The circuit uses a JFET VXO (variable crystal oscillator), driver stage and PA stage that’s capable of producing almost 2 Watts of power.
On Air: 16 November 2014 – 16 January 2015
Old Beacon (PROJECT TENER) Decommissioned
If you are on this page, chances are that you have heard it on the air! This is the result of a good year of planning, building, and testing the transmitter, keyer, and dipole.
The previous Transmitter was a modified Pierce Oscillator using a 28.224 MHz crystal and one NPN transistor. The variable capacitor \”bends\” the crystal to its current spot at 28.2252 MHz. I chose this design because it only has 11 total components and a reputation for low-power consumption and reliability. The RF transistor is a 2N3553, The 2 coils are wound using #24 wire around a Amidon T37-2. I found the schematics in an old CQ magazine and had the board custom made by FAR circuits. Construction was simple, with most of the difficulty in acquiring a suitable crystal for operating on the 10 beacon sub-band, and the Amidon core. The core wasn’t stocked by Gateway Electronics and had to be special ordered. Once the transmitter was completed, I had to search for a suitable keyer. This design lasted for 1 year and 2 months of continuous operation until a lightning storm knocked it out.
On Air: 24 July 2013 – 15 August 2014
Have any comments or want a copy of the schematics? Please send me a comment!