May 3^rd and 4^th, 2013 marked the 50^th anniversary of this historic experiment!


There are two other articles about the 50th anniversary of Operation Red Line :

• 50-years-since-operation-red-line - A recounting of the event at Blogspot
• Retrotechtacular: First laser transmitter built 50 years ago - An account of this event at Hack-A-Day.  Note:  It wasn't actually the first laser transmitter, but it was one of the earliest.

For more information about optical communications in general, don't forget to visit other pages at the Modulatedlight.org web site!

Please note:

Where possible, people appearing in the photographs have been identified, but due to the nature of the photograph and passage of time, some persons are unknown or may be mis-identified:  If you can identify  people in any of these pictures and/or correct any of their captions, please let me know at the email address in the link at the bottom of this page.  If you have additional archival material about this event that you wish to contribute, please feel to contact me at the same link. 

Figure 1:
Three of the participants of "Operation Red Line"
From left to right:
Robert Legg - in charge of  the receive site.
Duane Erway - in charge of laser construction.
Jack Pattison - in charge of the transmitter site.
Click on the image for a larger version.

Figure 2:
Left:  The Laser in the EOS (Electro-Optical Systems) lab on the workbench.  The laser tube and associated components are shown mounted in a 6-foot long steel channel that was 12 inches wide and 4 inches deep.

Center:  With the lights in the lab switched off, the Helium-Neon laser lit up the room with its characteristic pale, red-orange glow.  If one looks closely at this picture dark bands may be seen on the laser tube which were strips of foil attached to the outside surface of the laser tube.  Because the tube had no internal electrodes it was necessary to use external excitation and to do this, alternate strips were connected together and the two sets of strips were fed with RF from a balanced-line antenna tuner to provide a consistent source of excitation along the entire length of the laser tube.

Right:  The laser tube in the lab, energized.  In the background, toward the right, can be seen the large box which is the Johnson Viking transmitter, the source of the RF excitation (note the plate current meter!)  It produced about 100 watts of RF energy at 28.62 MHz and was amplitude-modulated, which also allowed the laser's output to be modulated.  On the top shelf at the far right, just to the left of the coffee cup, may be seen a corded device that looks like a soldering iron:  This was a "zapper" - a probe that provided a low-current, high-voltage source - a tool often used in the manufacture and test of neon signs.  To "strike" the laser this device was brought near the tube to provide an ionization potential - a principle very similar to that of a trigger coil used in xenon flash units as the RF alone was not enough to start the ionization of the gas.  Once "struck" the gas tube remained ionized as long as RF was present - provided that the operators were careful to avoid modulating the AM transmitter to zero percent!
Considering that about 250 watts of electrical power was required by the transmitter to produce the 100 watts of RF energy that were required to produce 125 microwatts of usable laser light, the overall efficiency of the laser transmitter was a whopping 0.00005%!
Click on any image for a larger version.

Figure 3:
Left:  The "business end" of the Laser.  At each end of the laser tube was a confocal mirror with a micrometer adjustment.  Through precise alignment, optical energy could be reflected between the two confocal mirrors, resulting in oscillation and lasing at the visible wavelength of 632.8 nanometers.  Neither mirror was completely silvered so a small portion of the light reflected between the two mirrors during lasing escaped:  Because each mirror was identical, laser light was emitted from the "rear" mirror as well, but that light was not beamed toward the distant receiver.

Right:  Another view of the laser in the EOS lab.  At the foreground end of the steel channel can be seen what looks like an optical stop.  This was, in fact, a neutral-density filter with extremely high attenuation used to simulate the path and atmospheric losses that were expected over the 118 mile path.  The silver tube just behind the optical stop was a "10 power" telescope that collimated the beam to roughly two inches in diameter.
Click on any image for a larger version.

Figure 4:
Left:  A close-up view of rear of the laser showing the confocal mount with the micrometer adjustment.  On the left side of the picture can be seen the laser tube and one of the Brewster's windows used to polarize the light.  Polarized light was desired as it was originally anticipated that a Kerr cell would be used to modulate the beam, but the use of the AM transmitter for RF excitation eliminated the need for such a fragile and potentially dangerous device.  The laser tube used for this experiment was constructed at EOS by their own glassblowing shop.

Right:  The modulated light from the laser was tested at night in the EOS building using mirrors to direct light around corners and up and down halls.  In a room separate from the laser itself was set up the telescope owned by Parks Squyres - an Alika Herring-Cave 12.5 inch Newtonian reflector.  Its eyepiece assembly having been fitted with a photomultiplier for receiving, the entire transmit and receive system could be tested together using the attenuation-simulating neutral-density filter.
In this picture, left-to-right:  Bob Legg (partial view in the foreground), unknown (against door), Dick Stultz (blue shirt with pencil above ear.)  Left-to-right on the floor:  unknown (partial face with glasses), Duane Erway (blue shirt) and Chuck Cunningham (partial face, lower-right corner.)
Click on any image for a larger version.

Figure 5:
Left:  The "staging area" in Ballarat for the crew headed to the receive site.  In 1963, Ballarat was an "almost" ghost town, having been built up at the time of a mining boom around the start of the 20th century.  As with many mining towns, it went bust only a few year later, leaving the buildings to return to the desert over time.  The then-sole inhabitant of Ballarat at this time was a man who called himself "Seldom-Seen Slim" (born Charles Ferge) - a miner who stubbornly continued to work claims.  Several of the vehicles were left at Ballarat to be looked over by Seldom-Seen Slim and equipment and personnel were transferred to the vehicles deemed capable of traversing the rough, steep mining roads.

Right:  Another view of the staging area at Ballarat.  In the background, behind the vehicles, can be seen some of the few remaining buildings in Ballarat (see below.)
Click on any image for a larger version.

Figure 6:
Left:  Some of the few remaining structures in Ballarat.  The trailer in the distance was that of Seldom-Seen Slim.  In the background can be seen the rugged hills of the Panamint mountains.

Right:  The remains of one of the buildings in Ballarat - the bank.
Click on any image for a larger version.

Figure 7:
Left:  One of several old mining establishments along the road into the Panamint range.  In order to access the higher roads in the Panamint range, permission had been obtained to cross a mining claim that was still being worked by its holders - but that was not the claim pictured!

Center:  The paths ascending into the Panamint mountains were steep and rugged mining roads.  Bob, in the Plymouth Valiant, was often ahead owing to the "taller" gears of the car while Dave McGee, in the low-geared Dodge Power Wagon and Ron Sharpless, carrying fragile gear such as Parks' telescope in his GMC 4x4, took it more slowly.  Often, Bob would stop and wait, giving the valiant Valiant time to cool off.

Right:  An example of some of the steep roads encountered by the expedition.  Just over the crest of the hill can be seen the roof of a vehicle and an HF antenna - both belonging to the Valiant.
Click on any image for a larger version.

Figure 8:
Left:  Eventually, the road became too steep to be climbed by the Valiant - not because of loss of traction, but simply because too little power could be applied to the wheels to ascend the slope.  The Valiant was actually Bob's wife's car (that's her callsign on the license plate) and to her dying day, he never told her where, exactly, he'd taken her car on that day in May of 1963!

Right:   With only about 500 feet of road to go, Ron returned to the Valiant and towed it up the steepest portion of the hill to the receive site.
Click on any image for a larger version.

Figure 9:
Left:  The receive-site team arrived at about 3:15 PM and this picture shows much of the crew.  Left-to-Right:  Dick Stultz, Dave McGee, Bob Legg,  Parks Squyres, and Ron Sharpless, in the truck with the telescope.

Right:  Immediately after arriving, there was a flurry of activity as radio links were established and equipment was set up.  Shown here is Parks working on a 6-meter "handie-talkie."  (That's the battery pack on the ground!)
Click on any image for a larger version.

Figure 10:
Left:  To aid in the aiming of the laser by the transmit site, a very high-power flashlamp was brought along.  This consisted of a helical Xenon flashlamp mounted in front of the reflector inside a modified WWII signaling lamp shown here with a protective shield of tape.

Right:  Another view of the flashlamp and power supply.  The power supply for the flash lamp (the large rack on the ground) was very heavy, laden with transformers, capacitors, and other weighty components.  In front of the tree, just to the right of center in this picture may be seen the 2-meter antenna.
Click on any image for a larger version.

Figure 11:
Left:  Several of the party working to ready the telescope, a Herring-Cave 12.5 inch Newtonian owned by Parks.  (This telescope was made by the Cave Optical Company (link) of Long Beach, California in 1956.  More info about Cave Optical may be found here.

Center:  Upon setting up the telescope, the crew looked to see if they could identify various landmarks - including the transmit site.  Left-to-Right:  Dave McGee, Parks Squyres, and Ron Sharpless.

Right:  At the receive site, several of the team members looking toward the transmit site.
Click on any image for a larger version.

Figure 12:
Left:  The telescope in the tent and the flashlamp - ready for business.

Center:  Looking through the telescope (during the daytime) to spot the transmit site.  In the picture is Bob Legg (on the left) and Dick Stultz, looking through the eyepiece.  If you look carefully, you can see the spiral Xenon flash lamp laying on its side atop the piece of gear (the photomultiplier's high voltage supply) near Dick's left hand.

Right:  A view of the telescope from inside the tent.  The box strapped to the side of the telescope near its front contains the photomultiplier tube at the focus.  On the bottom is a lever used to move a mirror that, when out of the way, allowed normal viewing through the eyepiece, or the mirror could be moved into the optical path to direct light to the photomultiplier tube.  This box also allowed the placing of filters or stops in the optical path.  If you look carefully, you can see the photomultiplier's socket and the wires that disappear into the housing that connect to the dynode resistors which were located in the smaller box atop the enclosure with the eyepiece.
Click on any image for a larger version.

Figure 13:
Left:  The front of the telescope, in the tent.  The spotting scope is at the bottom..

Right:  Another view of the telescope inside the tent.  The thin enclosure with the rack-mount ears was the power supply for the photomultiplier tube.  The flashlamp may be seen, laying on its side, atop the power supply.  The "table" on which the gear is resting was a fiberglass instrument case that had been used for transporting the fragile gear.
Click on any image for a larger version.

Figure 14:
Left:  Looking toward the northwest from the receive site

Right:  Looking toward the southeast from the receive site.
Click on any image for a larger version.

Figure 15:
Left:  The Valiant wasn't towed all of the way to the receive site as the camp itself and trucks took up most of the flat area:  It was left down the road slightly, as can be seen in this northwest view.

Right:  The location of the transmit site was south-southwest of the receive site.  In this view, it would have been in the center, on the horizon.
Click on any image for a larger version.

Figure 16:
Left:  Parks and Ron at the receive site.

Right:  Dave McGee and Dick Stultz at the campfire.
Click on any image for a larger version.

Figure 17:
Left:  Sunset, as seen from the receive site

Right:  Just after sunset, a campfire at the receive site.
Click on any image for a larger version.

Figure 18:
Left:  Despite its tremendous brightness, the high-power Xenon flashlamp was not visible at the transmit site.  As a fallback measure, a military rescue flare was set off to help the team at the transmit site sight-in the receive site - a strategy that turned out to be successful.  It was decided that along with the very short duration of the flash, perhaps the spectra of the Xenon strobe favored blue, reducing its visibility through a long atmospheric path. Bob happened to have a clear 100 watt bulb and a clamp-on work light (shown in the picture) and this was placed at the focus of the lamp's mirror:  This combination was visible at the transmit site!  If you look carefully, you can see the upside-down reflection of the photographer in the mirror.

Center:   The team at the receive site, signaling their location with the incandescent lamp/reflector combination.  (This picture was probably taken on the second day.)

Right:  The receive site in the morning.
Click on any image for a larger version.

Figure 19:
Left:  The transmit site.  The laser assembly can be seen protruding from the right side of the tent, next to the car.  (Left to right:  Darell Wilcox, WA6THK and Bob Fuller, W6KHK)

Right:  Jack, W6POP, on 2 meters.
Click on any image for a larger version.

Figure 20:
Left:  A view of the transmit site from up the hill.

Right:  Adjustments of one of the laser's mirrors being done by Darrel Wilcox, WA6THK.  Note the sheet of paper taped to the wall of the tent behind the laser:  Because both of the laser's mirrors were partially-silvered, about the same amount of laser light was emitted from each end.  Even though the light shining rearwards was "wasted" power in that it wasn't being sent to the receive site, it was still useful to tell if the laser was working properly and was used to tweak the mirrors for maximum output - without needing to block the "front" beam.
While provisions were made to adjust the elevation of the beam, similar means for adjustment of the azimuth had been overlooked.  Improvising, rough azimuth adjustments were accomplished by tapping the end of the steel channel using a large rock - and using a small rock for "fine" adjustments.  At 118 miles the width of the beam was estimated by those at the receive site to be about 150 feet across - a divergence of approximately 0.014 degrees or 0.25 milliradians - a fact that explains the difficulty encountered in aiming the beam!
Click on any image for a larger version.

Figure 21:
Left:  Chet Campbell (?) at the microphone on the transmitter.

Right:  A celebration of success, having transmitted voice across a laser over a distance of more than 118 miles!  Click here to hear some of the first night's transmissions.  Darrel Wilcox, the one in a blue jacket closest to the laser, ground and coated the confocal mirrors in the EOS optical shop.
Click on any image for a larger version.

Figure 22:
Left:  Believed to be sunset, near Grassy Hollow, the transmit site.

Right:  Believed to be sunrise as seen from the transmit site at Grassy Hollow.
Click on any image for a larger version.

Figure 23:
Left:  A view toward the receive site, from the transmit site.

Right:  Another, slightly wider-field view of the receive site, from the transmit site.
Click on any image for a larger version.

Figure 24:
After the event, each participant receive a certificate recognizing the achievement.  This certificate was presented to Ron Sharpless, then WA6LMV, who was present at the receive site.
Note that the certificate's graphical depiction of the laser includes Brewster's windows at the ends of the tube as well as the interleaving electrodes used for RF excitation.
Click on the image for a larger version.

Figure 25:
In the months following, several articles appeared in various magazines, including this one from either June or November, 1963 EDN.
Click on the image for a larger version.

Figure 26:
This is one of the articles that appeared in a local paper about the event.  Note, in particular, the last paragraph of this story!  This clip was from either the Pasadena Star News or the San Gabriel Valley Tribune:  The date of publication is unknown.
Click on the image for a larger version.

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Comments and further attributions pertaining to the event itself, the people involved, and the images on this page:

• The photographs on this page came from a variety of sources.  Where possible, images as close to the original were used, but some are from poor-quality reproductions.  They were all taken during early May, 1963 and in the weeks prior to this.
• The color images with "w7pks" in the filename and the scan of the EDN article were kindly supplied by Parks Squyres, W7PKS, one of the participants at the receive site.  We thank him for supplying these images as well as additional details of the event.
  
• The other color images on this page are scanned from slides:  Although they were properly stored, some of the slides suffered from severe dye-fading and color shifting while other slides were internegative copies of the originals, resulting in high-contrast, slightly-soft pictures.  As much as is practical, color has been restored to something resembling the original scene, but in a few cases the dye fading was too severe to restore colors of the original image without causing the appearance of a considerable amount of noise - this, despite having been digitized to 64-bit RGBI images using a high-quality scanner operating in "multi-pass" mode.
• Where possible, people appearing in the photographs have been identified, but due to the nature of the photograph and passage of time some persons are unknown or may be mis-identified:  If you can identify people in any of these pictures and/or correct any of their captions, please let me know at the email address in the link at the bottom of this page.
• Except as noted, most of the images above were scanned from slides on February 2 and 3, 2008 with the assistance of Bob Legg during a visit to his home in California, and the images in Figure 16 were scanned from photographic prints at this same time.  Additional information and preliminary identification of persons in the photographs was also provided by Bob.
• Thanks to Ron Sharpless, ex WA6LMV (now N7ERC) for supplying an electronic copy of his certificate of achievement as well as additional detail of the event.
• The newspaper article in Figure 26 was kindly provided by Sharon, Jack Pattison's daughter.
• We note with regret that Jack, W6POP, passed away on April 17, 2009.
• It's worth noting that the callsign W6POP is now held by Jack's daughter, Julie, while Sharon, Jack's other daughter, holds her mother's callsign, K6DPX.
  

Acknowledgments:

I would like to thank Bob Legg for his invaluable assistance in providing specific details of this event as well as access to most of the pictures.

I would also like to thank Dave McGee and those others that assisted Bob in his gathering of materials and researching of data, as well as Parks Squyres and Ron Sharpless for some additional information.

Of course, I wish to thank all those - named and unnamed - who were involved with this project those many years ago who had the motivation, ambition, and foresight to undertake a project that was, at the time, at the leading edge of technology.

Comments, corrections, or questions?  Send an email.

In February of 2008, Chris (VK3AML) and Clint (KA7OEI) visited Bob and completed a two-way optical contact across Yucca Valley - read about that contact here.

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