From: Graham <[email protected]>
To: [email protected]
Sent: Thursday, 25 October 2012, 19:07
Subject: Re: LF: OPERA OPTICAL BEACON (way off topic) but is based on 17 KHz :)

Ah yes  , but those  are   not  liner ? ,  cannot  modulate  a  laser  , only   on/off  serial  ? 

 

 

G. 

From: M0FMT

Sent: Thursday, October 25, 2012 6:15 PM

To: [email protected]

Subject: Re: LF: OPERA OPTICAL BEACON (way off topic) but is based on 17 KHz :)

Hi All

 

You need erbium doped glass amplifiers like we used on long distance fibre networks.

 

73 es GL Pete M0FMT IO91UX

From: Graham <[email protected]>
To: [email protected]
Sent: Thursday, 25 October 2012, 17:43
Subject: Re: LF: OPERA OPTICAL BEACON (way off topic) but is based on 17 KHz :)

Like  you Stefan,  these  pioneers are  pushing  the  limits  , using  heat pumps  to  cool the  light  source, the  source is  as small  as possible to  ensure  good coupling ..  reducing  the  duty cycle  as  in radio  can  be a  big  help ...  but  as I say  its a  tool  , if  anyone  wants to  try , it  puts  all the  features in one  box 

 

G..

From: Stefan Schäfer

Sent: Thursday, October 25, 2012 11:21 AM

To: [email protected]

Subject: Re: LF: OPERA OPTICAL BEACON (way off topic) but is based on 17 KHz :)

Am 25.10.2012 01:34, schrieb Graham:

[...]

 

fsk  , of  course , but  simplicity is  the  object  , switching the (led)  light  off  and  on could   reduce the  duty  by  50%  where  heat is  a problem ,

[...]

Why should it be an advantage to reduce the duty cycle to 50% and where do you expect heat problems when driving a LED?

Yes there are some high power modules but even 10W power dissipation should be managable for everyone.

73, Stefan/DK7FC