Welcome to the N1IR Electronics Website. Totally off the cuff, one take, unrehearsed video projects for anyone interested in amateur radio, electronic design, makers, hardware hackers and science.

Get off your duff and build something!
Training the hand and mind since 1982.

Tuesday, December 22, 2015

PCB from China 3

Just got in the new blimp boards for work. From http://dirtypcbs.com/ . Turned out great really impressed

Heres some pics

Text size
Hole Size
Trace Size

Tuesday, December 1, 2015

Camper fan speed control

During our last camping trip we really need to control the exhaust fan over the stove,  it was really cold out and the fan was a bit to strong. So I came up with a couple ideas:

1. Use a resistors to drop the speed. The problem with this is the power loss. Don't forget were on batteries and do no wish to dump energy as heat.

2. PWM - this would be the most efficient use of power and would not required expensive components.

Here is the schematic:

Used vero-board for this project since it was so small

Frequency of PWM is out of the range of hearing so it's quiet, I originally tried 1khz PWM frequency on the breadboard but it made the motor sound like a screeching cat. So I made C1 smaller until i could no hear the PWM.

Sunday, February 22, 2015


PRESS RELEASE                                                     FOR IMMEDIATE RELEASE

Christopher Johnson, N1IR
Genesis Amateur Radio Society
Education Officer


Plymouth, MA N1IR is pleased to announce the launch of a no-cost on-line Technician Course. In as little as 20 minutes a day for 20 days you can pass the FCC Technician Element 2 Examination.

Each day there is a two part video series. The first part is on specific sub-element theory and the second video covers all the questions and answers of the sub-element you are studying for that day. After watching the videos for that day all the student have homework assignment for the day and quiz for that days class. An on-line webinar will be available to ask questions and offer guidance for the course. A list of webinar dates will be posted on top of the n1ir tech course page. If you have any questions please email me at n1ir@arrl.net.


Please play introduction video first and course navigation second.

Hope to see you there,

Christopher Johnson, N1IR
Genesis Amateur Radio Society
Education Officer


The Genesis Amateur Radio Society is a non-commercial association of persons interested in Amateur Radio, organized for the promotion of interest in Amateur Radio communication and experimentation and education, for the establishment of emergency communications in the event of disasters or other emergencies, for the advancement of the radio art and the public welfare, for the representation of the radio amateur in legislative matters, and for the maintenance of collegiality and a high standard of conduct.

Wednesday, January 14, 2015

Backup Power Source

Here is my latest project a 2500/5000 watt inverter with two group 27 marine batteries.


Two group 27 Batts at 90 AH Each or about 2100 Watt Hour

Cobra  CPI 2575 2500 Watt Continuous / 5000 Watt Peak

0000 AWG Welding Wire (see http://www.n1ir.com/2014_08_01_archive.html for why I use 0000 AWG)

1/2 inch copper pipe as bus

Works great powering up the forced hot air furnace, handles the 2400 Watt Start-up for the blower without a sweat and keep the furnace going at 960 Watt running. I figure a run time of 15 min 4 times a night, this set-up would last about 2 nights without recharging on paper ignoring losses and efficiency, in practical application I would only rate it at 1 night.

Would work really well with electric blankets (180 Watts)

*** Note: if connecting battery in parallel use the same type and age battery. If Different age or type please use an isolator pack.