Halogen SpotLight Beacon

During the several unsuccessful attempts we (Robo OM1LD and me) have found that the good spotlight is very important.

We chose several main points of good spotlight:

Narrow light beam - Less than 10Deg pattern
High light power - At least 50W halogen or 20W xenon light
Beacon mode - It has to be a keyed light to differentiate from other light sources
Tripod - Light beacon on the tripod = free hands

Some calculations:

Spot size calculation in Length = 1000m
Angle [DEG]	1	2	3	4	5	6	7	8	9	10
Spot [m]	17	35	52	70	87	105	122	140	157	175
Area of the spot [m2]	239	957	2154	3831	5989	8629	11752	15362	19459	24047
Area proportion to 4 DEG	0.06	0.25	0.56	1.00	1.56	2.25	3.07	4.01	5.08	6.28

Halogen SpotLight Beacon

In the chart you can see that good compromise between Spot size and the optical power density is somewhere 4 - 6 DEG. The spot size is 70m - 105m in 1000m. I found 50W halogen lamp from Osram. Halospot 41835 SSP is a 50W lamp with 4DEG diameter light beam. Lamp beam is pretty sharp. Its spot size in 1000m is 70meters. Halospot Lamp has diameter wich fits accurately in to the 110mm canalization pipe joint. The pipe joint with pipe ending is good enclosure. I mounted also the foto tripod reduction to the bottom of the pipe joint.
Electronic for the lamp beacon is identical with my sequencer (unfortunately only in Slovak language). Because of the higher output current replace output transistors with IRF540 and do not forget the cooling. Than you need to program micrprocessor AVR Tiny12 with this HEX file. Procesor produces identical keying on all 4 output ports.

The keyed character is "Z". The dot is 0.5sec, so the output is:

DAH	Pause	DAH	Pause	DIT	Pause	DIT	3 x Pause
1.5s	0.5s	1.5s	0.5s	0.5s	0.5s	0.5s	1.5s

Halogen SpotLight Beacon Video (1MB)

Robo OM1LD SpotLight
Robo has a different aproach to SpotLight. His 20W Xenon light is modulated with mechanical chopper. Pictures are here. Video of his modulated spotlight is here (8MB!).

Photo Gallery Of the Halogen SpotLight Beacon: