AI6YR BenGot to teach a former US Marine a better technique on how to use a signal mirror today! (friend of mine) LOL.
(to be fair, he was career USMC, as a dentist 🤪 )
(flashing a mirror at another ham radio friend of ours down in the valley, just for fun).
Signal mirroring! #signaling
John Francis 🇨🇦🦫🍁🫎@ai6yr 400 THz digital ham
Anil@ai6yr I learned how to signal to a helicopter, but that's because we could see it. How do you acquire the angles if both locations are unknown to each other?
@nil It's a challenge for sure, but it happens we knew the location of the other ham, and I gave him a bearing from his location to where we were on my compass, plus we were flashing at him before there to give him a target to aim at.
@ai6yr ah that makes sense. Anyone who hasn't done it just thinks it's easy to point a mirror at someone 😂
Probably those same people think shooting a bearing is trivial too
@nil Yeah, I teach all of my Wilderness First Aid students how to aim a mirror (my favorite technique is extending out your arm with a "V" in between fingers and aiming the mirror in the same plane as your arm, so you have a near target to your location--I'm sure you are familiar with it, but for the peanut gallery). It's not easy, a lot of people think they can use the reflection of the mirror, but that doesn't work when the person you are signaling is 3 or 5 or 10 miles away.
Iris Young (he/they/she) (PhD)
Bill Witte
Cliff'sEsportCorner@CliffsEsport @nil I teach it mostly for ground to air so someone can spot you if you are lost or needing help. You could use it to flash messages to your buddy at the next watch tower when you see the enemy approaching.
@ai6yr @nil Yeah I tend to think more strobes than mirrors for signaling. With flash like I said practice more not doing that. I know it was used for semaphore and and some military use. Just not something I've ever had reason to study. Is relative sun position not a problem for stuff like your video?
@CliffsEsport @nil Sun position definitely has to be in your favor, or in the case of the video, neutral between the two parties.
@CliffsEsport @ai6yr accuracy and consistency. Dead reckoning is a real time saver when you trust your systems, and often you might not have visibility to a landmark after you start on a path. But if your error rate is 5 degrees you could easily end up in the wrong terrain over 2000 feet.
All that said, I haven't had to do straight-line bushwhacking outside of SAR. GPS has also gotten much better over the years instead of going haywire in a couloir
@nil @ai6yr well is this with topo maps or ? What I recall learning is breaking things into legs and picking landmark that is close enough per leg to desired bearing. It's a different story if fog/snow/smoke/etc limiting visibility or cloud cover at night. IME if you have maps compass not needed much unless visibility or line of sight is big issue. Some types of trees or other vegetation can make compass necessary if contours/drainage isn't clear enough to match to map.
David Sacerdote@ai6yr did you submit a POTA log for the 500nm band?
@ai6yr I hope you told knock-knock jokes in Morse code.
n2epe - Erik@ai6yr All that from a dentist mirror? Not bad ;-) Btw, what's the better technique?
@n2epe So, you hold the mirror in one hand (in my case, the right hand) somewhat behind your head. You extent your other hand out with thumb extended, and shine the mirror at that hand, so you know which way your beam is going.
Then, you put the "L" in your left hand (between index finger and thumb) on your target and then toggle the mirror... the "target" will see flashing, and you know you are aimed at them properly because you have that arm extended as a nearby target.
@ai6yr That makes a lot of sense!
Scott VE3QBZ@ai6yr @n2epe You are putting the target in the crook of a vertically formed L in front of you, or are you pointing at the target with gun fingers, and using the vertical thumb as a crude iron sight? Just trying to visualize this aspect based on your description, which mostly makes sense to me other than this one point.
Very cool stuff, the vid was great!
@scott @n2epe The target in the crook of the vertically formed L in front of you. If you are so inclined, you could also do the "Live Long and Prosper" sign and aim in between the "V", but put it out in front of you. I am not that limber, lol.
The technique is pretty much identical to how you'd use a slingshot, you could put the mirror up against your face or behind your head a little bit, and hands out like the arms of a slingshot.
wishwish@ai6yr
Thank you for the mirror signaling lesson and the diagram for us visual learners!
Thank you for the mirror signaling lesson and the diagram for us visual learners!
Darth Osler
me_valentijn
oheso
@stevewfolds@ai6yr Had a glass signal mirror in ‘60s. Lots of people have been rescued by using them. Heliographs have been used since ~1800,
Morse code added in 1830.
Morse code added in 1830.
@ai6yr I've now done way too much thinking about this. Experimented with various sized tiny mirrors. Concluded it would take about 400 square feet of front-reflecting mirror to do a morse code heliograph to the ISS that an astronaut would notice when looking at the Earth but not explicitly looking for the signal. Only about 1 order of magnitude too big to be practical as a one-off hobby project.
Dharma Cowboy@dsacer Surely you could talk 399 other people into each holding a square foot of mirror for a 'flash' mob?
@dharmadan it needs to be aimed too accurately to that; it takes a satellite tracking motorized mount capable of being within about 0.4° of the right place. Not as accurate or expensive as an astrophotography mount, but still a roughly $1000 piece of equipment for each few square feet of mirror
@dsacer @dharmadan *digs into pocket for loose change *
Solarbird 
Michael K Johnson@ai6yr Most QSOs on the 380-750nm wideband harvested power mode use less equipment than this!
FreddyB Aviation Photography@ai6yr that’s pretty cool. We used to go Ridge to Ridge with the semaphore in the scouts. It’s been a while, but I could probably throw off a profanity or two.
Oh, but God, it would take forever to relay a simple message and that’s if we weren’t screwing around, trying to burn up the other guy up by signaling faster than he could receive then he would get pissed and send a message back faster as confirmation before he would relay it
you always wanted to be the first to start the message