Signal mirror flash shown on video

Posted by: unimogbert

Signal mirror flash shown on video - 01/03/21 02:19 AM

Back in the last century I was climbing mountains looking for airplane crash sites (I still do this). My father and I were out 4 wheeling and camping on a trip where I decided to climb yet another mountain while he stayed down in the valley fishing.

Using FRS radios we coordinated my flashing him with a USN glass jet seat pack survival signal mirror from the mountain.

By radio he could tell me if I was on target and then I could concentrate on that area so he could video the effect.

It's really quite awesome!

Here it is posted to my YouTube channel-

BNCAntenna's YouTube channel
Posted by: hikermor

Re: Signal mirror flash shown on video - 01/03/21 04:07 AM

Signal mirrors rock! I nearly always have one handy. If necessary, they can be readily improvised....
Posted by: rafowell

Re: Signal mirror flash shown on video - 01/05/21 06:33 AM

Nice video!

Do you remember what the range was?

I've seen the flash from a similar 3"x5" US military signal mirror at up to 44 mile range, though at that range it looks more like a real star (point source) than the dazzling flash you see at closer range here.

Those 3"x5" signal mirrors are still made for the US military by S.I. Howard Glass, and sold to civilians through distributors - if you want one, Google for MIL-M-18371E. That's pretty much the only decent 3"x5" glass signal mirror sold in the USA today (don't buy the lookalikes with non-functional aiming grids - see Doug Ritter's warning article: Warning: Phony Signal Mirrors to see how to spot those.)

Note that the S.I. Howard MIL-M-18371E signal mirrors come in both a 2"x3" and 3"x5" size, so make sure you get the size you want. In the 2"x3" size, the Coghlan's Survival Signal Mirror is more widely sold, much cheaper, and pretty much as good (as long as you don't leave it under water - that rapidly penetrates to the aimer and fogs it up - for a while they had that problem licked, but units I've tested recently, leak),

There's a Boy Scout event called Operation On Target where teams get up on peaks to signal each other with signal mirrors. We mainly use foot-square signal mirrors, but I always try to see how far we can see 3"x5" and 2"x3" mirrors as well.

Operation On-Target was held in pretty much every Western state for decades (including Colorado), but since the LDS pulled out of Scouting, we've just been hanging on in Southern California.

On the "Operation On-Target" web site, we have a nice resource page on signal mirrors:
Making Your (own signal) Mirrors with DIY instructions and links to articles about the evolution of US signal mirrors in World War II.

My YouTube channel: rafowell YouTube Channel is mainly devoted to signal mirrors and related topics.
Posted by: Phaedrus

Re: Signal mirror flash shown on video - 01/05/21 07:21 AM

Great video! I always have at least one signal mirror along and sometimes two.
Posted by: unimogbert

Re: Signal mirror flash shown on video - 01/08/21 02:38 PM

I simply don't know the range. Maybe 2 miles?
Posted by: hikermor

Re: Signal mirror flash shown on video - 01/09/21 03:22 AM

This thread causes me to recall the heliograph network established by the US Army during the Geronimo campaigns of the 1890s. They established outposts on prominent mountain peaks throughout southern Arizona. Heliograph peak in the Graham mountains was one such. The network focused on Ft. Bowie, where messages were sent dirctly to the parade ground in the fort. When I worked at Ft. Bowie in 1968, the post which supported the heliograph on that peak was still there.

There is still a remnant of a huge rock cairn on Rincon Peak, east of Tucson, which was part of the heliograph there. According to accounts, the helio network worked well and effectively. One source states that Geronimo knew the jig was up when he saw the system in operation.

I am not sure of this, but i believe the Apaches, and possibly other groups, used mirror flashes tactically.
Posted by: unimogbert

Re: Signal mirror flash shown on video - 01/09/21 03:52 AM

Internet search suggests that the British used heliographs into the 1940s.

Solar powered telegraph.
Posted by: hikermor

Re: Signal mirror flash shown on video - 01/09/21 04:48 PM

Originally Posted By: unimogbert
Internet search suggests that the British used heliographs into the 1940s.

Solar powered telegraph.


Interesting and intriguing!
Posted by: rafowell

Re: Signal mirror flash shown on video - 01/14/21 05:46 AM

Originally Posted By: unimogbert
Internet search suggests that the British used heliographs into the 1940s.

Yes - the British used heliographs in World War 2, and most of the British heliographs that come up on Ebay these days were built during World War 2.

The first six seconds of this video show British operational use of a heliograph at Sollum Bay in 1942:
[video:youtube]https://www.youtube.com/watch?v=ydHuSUZffnY[/video]

There are a fair number of photos of British heliograph training in WW2, and I've read military dispatches describing their use for ship to shore communication during the D-day and Italian landings. (One made the point that, unlike signal lamps or radio, they didn't consume batteries).

I have documentation of the Australians using heliographs in the 1950s, and I have two (second hand) accounts of the Australian military teaching their personnel to use heliographs in the early 1960s.