fv1609

A few hours ago I emailed Rex with my comments positive & negative. Within a short time I received a courteous & comprehensive reply that was most reassuring & looks to address most of the points raised by others as well.

Roy there was a stage when you were submitting answers with 4 components of which the first 3 were correct! After that you went off course a bit

Andy sorry I see I missed replying to your post. When I come back to the PC there are often a number of posts to respond to, then if new posts appear whilst I'm replying then that can get lost in my replies. Phew lucky for me you didn't give the correct answer in your post! Anyway I hope you enjoyed the journey through the mysteries of the jungle to discover an ungooglable Japanese curiosity

The way in which this worked was for a jungle patrol to be equipped with the receiver & would periodically stop to obtain fresh instructions. The receiver head would be hoisted on the pole towards the transmitter that remains at a fixed point. A torch was flashed into the receiver's mirror to give the location. The transmitter was aligned & an IR beam was sent with a beam width of 0.15 to 3 degrees. This made it pretty secure, the beam was modulated with speech or keyed with a tone. The receiver had an IR filter and lens with a photoelectric cell at the focal point of the concave mirror. The signal was amplified & fed to headphones. The transmitter was arranged so that it could also receive, but a receiver was unable to transmit.

Lauren obviously if you were in the path of the beam yes. Whether you could see anything laterally would depend on dust or mist in the same way that visible light would be scattered with a beam from a torch. There were some WW2 expectations that IR could be used to see through fog etc but these expectations were not realised.

No bouncing this was a line of sight receiver only with a range of about a mile. It was a one-way IR photophone for either telephony or MCW. There is no description of it on the internet other than the transmitter at the other end. See page 4 of http://www.hmvf.co.uk/pdf/Tabby03.pdf It also repeated on some other sites who have lifted the article without my permission :shocked:

"I'd assumed this was the receiver" In that case you have one well done Lauren! When I re-read it I wasn't sure which way round you had it. Up until now everyone seemed to assume this was an IR source of some sort

Don't understand Lauren. But did you see my second reply to your post on the previous page?

No you're going off beam there Roy.

Lauren where were you thinking they would have a receiver?

I know what you are driving at Roy its not for that sort of purpose. Lauren was so very very close.

Yes Gary sort of, but more sophisticated than that but in a different direction

Andy you've lost me on that one, we are in the jungle

Lauren you are getting complicated again, although the answer is buried amongst what you have said

One other device only & one way communication only

All ingenious stuff Lauren but not that complicated (ah troposcatter & rain scatter used to do a lot of that on 10GHz used to get further than on 2 metres )

So very very close Andy. So how would the system operate?

In a sense yes, but probably not quite in the sense you mean.

You were nearly there Roy, now you are going off track

If it helps the thing on the right contains amongst other things, a concave mirror.

No its not that Andy, that was something Lauren was also thinking

Yes, yes, yes & no

Ah I see what you mean Lauren, no its not that.

Yes, yes, yes & no

Well there is an amplifier in it. Roy can expand what you mean?