OPTICAL COMMUNICATIONS - 1935 STYLE, D.W.ROLLEMA, PA0SR
|Serial No 187511
Serial No 196086
Serial No 217675
Serial No 211093
This is a 2-way audio communication
The light beam is modulated with a
light phase modulator.
Red or IR filter can be inserted in the
Technical data from the handbook:
|Optic||Receiver - 80 mm
Transmitter - 80 mm
|Tubes||Receiver, 3 - RV2P800
Transmitter, 2 - RV2P800
Reed, IR, invisible
|Range||4 km without filter
4 km with reed filter
2-3 km with IR filter
|Power||2 VDC, filament
4.8 VDC, bulb
50 VDC, detector
60 VDC, anode voltage
Here are pictures from
the second 2-way test of my LiSpr-80s.
The distance between station A and B was 2000 meters.
The test was done on the island Fur in Denmark 12. jun. 2004.
Egil adjust the direction of the optic at position A.
Station A is located on an old barrow.
Here is the direction finder of LiSpr.80.
The red area in the picture is the actual light beam transmitted from LiSpr-80.
This is the size of the beam at a distance of 2km.
The black rectangle at bottom of the photo is the transmitter modulation monitor.
This is the actual distance from position B to position A.
The light beam from station A can not been seen on the photo, but it can bee seen with the eyes.
Marie at position B.
The communication is very good.
We also tested communication with red filters
with good results. The light beam was invisible with red filters at 2km.
Here are pictures from the first
2-way test of my LiSpr-80s.
I have worked on the equipment in one year before this test.
Both the optics and electronics are restored. A new power supply is also designed.
The power supply deliver all the voltages needed for operation of the LiSpr-80.
The distance between the two LiSpr-80 were 300 meters.
Egil at position A. The first signal received.
Marie at position B.
Egil have here switched on the reed filter.
Marie has fine-tuned the direction with the direction-finder optic.
Here is the light from position A. Here with white light.
These are pictures from
the first test of communication to and from a reflex.
Output: 2V, -1.5V, 4.8V and 60V
|Remco Caspers have sent me this interesting
I am attaching some pictures related to the Li.Spr.80 that you may find interesting.
These were taken near Ohama Beach in Normandy in Wiederstands Nest 62 (W.N. 62) which
caused a lot of problems for the Americans on D-day (This is in front of the beach
sector where Frank Cappa took his famous photographs). This little bunker actually
used to house a Li.Spr.80 and was used for communication with the command bunker
further inland. In the first picture you can see the church spire of Colleville in
the distance, the command bunker with the other Li.Spr.80 was situated slightly to
the left of the church, currently obstructed by dense vegetation. The distance was
about 1500 m, so well within the range of the Li.Spr.80 although I can imagine that
during the bombardments on D-day, visibility must have been significantly reduced.
One of the surviving Germans described that before D-day, they often placed the
microphone of the Colleville station near a radio, so that they could listen to
music in W.N. 62! The second picture shows the slit through which the light beam was
projected. One of the survivors describes that when they abandoned W.N. 62 in the
afternoon of D-day, he actually carried the Li.Spr.80 with him, only to discard it
in the bushes halfway through the journey to the command post, it might still be there!
I found it quite interesting to find out that this piece of equipment actually played a
role during one of the most famous operations of the war.
Further equipment used on W.N.62 was a Torn.Fu.b1, used by an artillery observation
party to communicate with the battery placed about 6 km inland. Again the observation
post and small radio bunker still survive.
Lichtsprechgerät 80 in use.
Lichtsprechgerat 80 in use. Communication via light.
Pictures are owned by LA6NCA.
Li Spr 80, part two