ARRL

Secure Site Login

KF4HOJ

Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

Latest Topics

Topic Created Posts Views Last Activity
DIY Crystal Radio - Capacitive Tuning Aug 28th, 05:14 1 213 on 28/8/17
Field Soldering Without A Soldering Iron - Video Link Mar 2nd 2015, 03:24 1 1,285 on 2/3/15
How to Build A Portable Solar Power Supply Video Series Mar 2nd 2015, 03:18 1 1,886 on 2/3/15
Ground Rod Driver Tool - DIY Feb 27th 2015, 03:05 1 1,541 on 27/2/15
Grab N' Go Solar "Generator" Box - DIY Feb 27th 2015, 02:58 1 1,665 on 27/2/15
Crystal Radio DIY Video Feb 27th 2015, 00:52 1 1,258 on 27/2/15
Forum Rules Question Feb 17th 2015, 13:53 1 825 on 17/2/15
Is There A Foreign Operations Forum? Apr 12th 2014, 12:22 3 1,408 on 27/2/15

Latest Posts

Topic Author Posted On
DIY Crystal Radio - Capacitive Tuning KF4HOJ on 28/8/17
I found a 1997 ARRL article on a capacitor tuned crystal radio. I've tried many of these and none worked. I started with this design and modified it for both looks and function (new earphones require a change, different coil design). It works very well. You can tune in even very faint stations with little to no cross-talk. This is a link to the video I made about its construction. It includes the circuit diagram.

https://www.youtube.com/watch?v=AaNpFYe5dSo
HBR 14 coils conversion to toroidal coils cathoderay on 21/3/15
I built some coils for non-radio purposes. I used the formulas from a book called, "LC Circuits". It's not very big, but it's really clear and concise. I bought cores for the freqs I wanted, then ran the calculations per the book. Wound them and tested them with a scope and variable oscillator (and precision capacitor).
Field Soldering Without A Soldering Iron - Video Link KF4HOJ on 2/3/15
Video about how to do field soldering without a soldering iron, using matches, lighter, ... I tried many ways (and failed) until I found this simple trick about using the wire as it's own soldering iron.

https://www.youtube.com/watch?v=udZja8xRElc
How to Build A Portable Solar Power Supply Video Series KF4HOJ on 2/3/15
These are links to 4 videos (basic level) I made on how to build a portable solar power supply (aka "generator"). Thought some might find it useful.

Part 1 - Intro & Background
https://www.youtube.com/watch?v=eIZ0cx-QKrk

Part 2 - Power Output / Battery Matching
https://www.youtube.com/watch?v=I_OGdvyDNpI

Part 3 - Solar Panel / Controller Matching
https://www.youtube.com/watch?v=NWnEqyoEIf8

Part 4 - Building Tips & Tricks
https://www.youtube.com/watch?v=AWvz2jGno7o
Ground Rod Driver Tool - DIY KF4HOJ on 27/2/15
This is a video of how to make an inexpensive ground rod driver tool. It allowed me to put in a 3 meter long rod in just over 2 minutes flush against a wall. No mushrooming, no smashed fingers, no collateral damage (do know if there's anything underground before you drive!!!) I stopped about halfway down and got out a small sledgehammer to compare the difference and quickly went back to the driver tool.

It fits on the end of a hammer drill. I have just a smaller size hammer drill and it works fine. Hope it's useful.

https://www.youtube.com/watch?v=cP6fglxx7Ps

KF4HOJ / HS0ZEY

Back to Top