Gary @N8DMTMar 2
Today’s distraction from the news: Build a DIY LED tuning indicator for the magnetic loop antenna. Searched for information on the AlexTune LED indicator which just attaches to the PL259 loop connector. No joy on finding details/schematic on that. Instead found a video by VK3YE on a simple clamp-on ferrite core with a couple of turns of wire through it connected to a LED indicator. Works great! #ChameleonMagLoop #HamRadio
Show threadGary @N8DMTMar 2
How does that old story go? If it appears to work well on 10 meters, it must work on all the bands right? As it turns out, the same indicator seems to attenuate the RX signals down on 20 meters by more than 10 dB. Removing the indicator returns signal strengths to normal. More experimentation ahead (will try a few other core materials and vary the number of loop turns feeding the LED)! #DIYFail #HamRadio #MagLoopAntenna
Show threadGary @N8DMT
Turns out that adding ferrite to a loop antenna “dampens the loop RF flow”, i.e., degrades the antenna efficiency. Doh! But, taking out the ferrite and just coupling a small three turn loop to the mag-loop’s main loop does not degrade the antenna much (if at all). This version built with a few turns around a water bottle cap and close coupled to the loop works pretty well down on 40m. Will continue testing and optimizing, then write up as blog post thereafter.
#HamRadio #DIYSuccess #MagLoop
Mar 2 at 12:43amWeb
Show threadGary @N8DMTMar 5
Mag-Loop Antenna Tuning Indicator Project - Collected a few plastic caps, dug out the #30 wire-wrap wire, and tested LEDs for brightness using DVM diode-check function. Found some really bright RED LEDs to try in next version (super bright using IC-705 20% TX power level). Plan to make a few versions using different number of loop turns. Maybe red cap for higher power (less turns) and white for lower power (more turns)? Still thinking about how to best attach to loop. #HamRadio #DIY #MagLoop
Show threadGary @N8DMTMar 5
Now where did I put that wire-wrap stripper? (Last used maybe 30 years ago for a home-brew 68HC11-based cub-scout pinewood derby race car scoring system?) Should have kept the wire-wrap wire and the tool together, maybe? Stripping #30 wire can be a challenge, especially with short leads. More fun ahead! #WireWrap
Show threadvk3kriMar 6
@n8dmt One of these? or did you have the fancy one?
Show threadGary @N8DMTMar 6
@vk3kri That’s it! Also had a wrapping tool with a stripper in the center of the handle, but can’t lay hands on that one either at the moment. (Moving three times in the past few years has taken a toll.) I know I still have them, but exactly where they are amongst the boxes is a mystery. TNX & 73 #WireWrap #HomeLab