Editing 1st Marine Expeditionary Force (section)

==Limitations==
===Time===
Although beaming is quick, it has its limits. A person cannot stay within the matter stream too long. If this happens, his or her molecular pattern would degrade and the transporter signal would be lost. 

This signal must stay above fifty percent to be able to re-materialize the person. A time-frame of around 90 seconds was about the maximum before that fifty percent signal loss was reached. (TNG|Realm of Fear)

The crew of USS|Voyager was able to extend this time by using pattern enhancers.  In an effort to transport refugee Telepathy|telepaths to another world, Captain Kathryn Janeway|Janeway was able to hide many telepaths, in addition to a few of her crew, in the pattern buffer|transporter buffers.  This process is referred to as transporter suspension.  

However, this process produced serious complications.  Because ''Voyager'''s guests and crew had to hide from Devorian authorities repeatedly over the course of several weeks, acute cellular degradation was found in many of the refugees and in Tuvok.  

Although The Doctor was able to treat them, the degradation is cumulative.  If the process is continued, the person may not survive the transport.  (VOY|Counterpoint)

The longest recorded instance of a person remaining in transporter suspension was that of Captain Montgomery Scott, who was also able to survive for a period of 75 years while suspended in an extensively modified transporter buffer. (TNG|Relics)

===Shields===
In general, transporters could not be used while the deflector shield of a ship was active, or a deflector shield was in place over the destination.  However, it was possible to take advantage of EM "windows" that were created by the normal rotation of shield frequencies.  During these periods, a hole opened through which a transporter beam could pass. To use this window, timing needed to be absolute and usually required substantial computer assistance. This technique was theorized and first practiced in 2367 by USS Enterprise-D transporter chief Miles O'Brien. (TNG|The Wounded)

Magnetic shields could also be used to prevent beaming. Rura Penthe was protected by such a shield to prevent prisoners from escaping. (Star Trek VI: The Undiscovered Country)

There was a type of shielding that allowed transport, although it had the limitation of not allowing phasers to be fired through it. (TOS|The Return of the Archons)

The limitation of transporters versus shields was not universal, however.  The Aldeans were able to pass through their own shielding using transporters, though the shielding was impenetrable to other forms of technology and weapons. Similarly, both the Borg and Dominion used transporter technology that was able to penetrate standard Federation shielding.  Some adaptations, including rotating shield frequencies, could inhibit this ability but not eliminate it altogether.  (TNG|Q Who; DS9|The Jem'Hadar)

===Warp speed===
Transporters were not allowed to be used while a ship was at warp speed because of the severe spatial distortions caused by its warp field. (TNG|The Schizoid Man) Transport at warp was highly dangerous and had been attempted safely only a handful of times. (TNG|The Best of Both Worlds|The Emissary) There were, however, ways to circumvent this limitation.

* If both ships maintained exact velocity (i.e. the warp field on both vessels must have the same integral value/factor) transport at warp speed was possible. Failure to maintain the same velocities would result in severe loss of the annular confinement beam (ACB) and pattern integrity. 
* If the ship was traveling at warp speed and the object to be beamed was stationary, transport was possible by synchronizing the ACB with the warp core frequency. This would cause difficulties in obtaining a good pattern lock. The Maquis were known to have used this method. (VOY|Maneuvers)

"Near-warp" transport was also possible, but required extensive adjustments to the transport procedure.  It involved the transporting ship energizing its transporters at the same time as it dropped out of warp for just long enough for the matter stream to be transmitted.  The ship would then immediately jump back into warp. 

Persons who had experienced this form of transport remarked that there was a sensation of being merged with an inanimate object briefly before the transporter beam reassembled them. (TNG|The Schizoid Man)

:''Near-warp transport has also been referred to as "touch-and-go downwarping".''

===Faster-than-warp speeds===
In 2374, ''Voyager'' personnel successfully used ShipClass|Intrepid transporters to beam stranded crewmembers from the USS|Dauntless while both ships were traveling within a quantum slipstream drive|quantum slipstream. ''Voyager'' accelerated on a pursuit course during the transport, bypassing the velocity limitations imposed by warp field dynamics. (VOY|Hope and Fear)

:''Based on ''Voyager'''s launch date, presumably an unmodified Mark VII transporter was used for transport at quantum slipstream velocities.''

===Range===
During the 22nd century, standard Earth transporter systems had a range of 10,000 kilometers; however, by the 24th century, standard transporter systems maximum range was about 40,000 kilometers, though a special type of transport, called subspace transporter|subspace transport could beam over several light years. (ENT|Rajiin; TNG|A Matter Of Honor|Bloodlines) Many 24th century starships were equipped with an emergency transporter system, but these only had a range of at best ten kilometers. (VOY|Future's End)

Although having a maximum range of about 40,000 kilometers, some conditions adversely affect the effective range.  In at least one instance &ndash; due to missing components of Voyagers primary computer systems, &ndash; the starship ''Voyager'' had to be within 500 kilometers of a planet's surface to use transporters on Kathryn Janeway and the hologram character Leonardo da Vinci. (VOY|Concerning Flight)
:''For context, 500 kilometers above the surface of Earth would place the ship inside the ionosphere.''

The maximum range of a transporter differs per species, depending on what kind of technologies they've used to build it. The transporter with the longest known range is that of the Sikarians, with a range of about 40,000 light years; however this was due to their planet's large quartz mantle which amplifies their transporter signal. Because of this, Sikarian transporter technology works only on Sikaris|their planet. (VOY|Prime Factors)

Gary Seven's mysterious sponsors possessed transporter technology with a range of at least a thousand light-years according to Spock. Scotty later noted that Seven's beam was so powerful it fused all of recording circuits, and therefore he could not say exactly how far it transported Seven, or even whether it transported him through time. Exactly how they achieved this effect remains unknown, since there has been no subsequent contact with them, and they hide their entire homeworld in some fashion. There were, however, other indications that their technology was considerably advanced beyond what that of the 23rd century Federation. (TOS|Assignment: Earth)

Dominion transporter technology, enhanced with a homing transponder, was said to have a range of ''at least'' three light years. (DS9|Covenant)

===Radiation and substances===
Some forms of radiation and substances, usually minerals such as kelbonite, prevented transporters from working. In most instances the interference was caused by scattering of the annular confinement beam or sensor interference preventing a transporter lock.  Interference could be natural or artificial and usually occurred during surface-to-starship transport but might also occur between vessels.  Examples of other radiation and substance limitations are:
*Magnesite
*Thoron radiation
*Dampening field
*Ion storm|Ionic interference
*Hyperonic radiation
*Electromagnetic storm

===Devices===
Over the centuries numerous devices have been designed to overcome some limitations of transporters, and still others to intentionally interfere with transporters.  


By the 24th century, usage of pattern enhancers was common aboard most Starfleet vessels, most often deployed to a planet's surface during emergency situations where transport was critical.  

Devices that were specifically designed to block transporter signals or to interfere with them were usually deployed under hostile conditions, thus making use of a transporter impossible or very dangerous and hampering maneuverability of personnel or material. Some of these devices were:
*Transporter scrambler
*Transport inhibitor
*Remat detonator
*Scattering field

In 2375, Vedek Fala, gave a small crystal to Colonel Kira Nerys as a gift.  The device, of unknown origin and design, was actually a homing transporter tag, which instantly transported her to Empok Nor several light years distant. (DS9|Covenant)

Also, in 2293, Spock used a viridium patch to locate and lock on to Captain James T. Kirk and Dr. Leonard McCoy on Rura Penthe.  While not a transporter device, it was used to locate the subject with the transporter. (Star Trek VI: The Undiscovered Country)

===Injuries===
Although someone with minor injuries could be transported, this was not possible when the injuries were extensive. When the brain stem was damaged and autonomic functions were failing, transport was only possible if a volunteer controlled the person's autonomic functions. This was done by placing a neural pad at the base of the skull of both individuals and then connect both people via a medical tricorder. This way autonomic functions could be stabilized for a short period of time and made transport possible. (TNG|Transfigurations)