Splitter Filter
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 White Rectangle Phone ADSL Modem RJ11 Splitter Filter  US $6.91
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 Phone Telephone ADSL Modem 6P2C RJ11 Splitter Filter US $3.93
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How Reflex Sights Work
Red dot sights use the optical collimator. The collimator aligns a stream of particles from a source into a parallel stream. The collimator can be refractive or reflective The collimator takes the image of the reticle illuminated by a radioactive or fiber-optic light source or an LED and projects it to infinity. This image is directed onto a dichroic mirror or beam splitter which uses a special reflective coating so as to reflect only the exact colour of the reticle whilst allowing all other colours to pass through. This allows the shooter to see the reticle in the distance in an otherwise perfect image from which only the exact wavelength of the reticle has been subtracted.
Holographic reflex sights substitute a holographic image of the aiming mark or reticle created by a laser diode. Holographic reflex sights employ a laser to generate a holographic reticle or aiming mark which the collimator then projects to infinity. This results in an aiming mark that is optically centred in its entirety. It also makes the sight less sensitive to head position relative to the sight, allowing for more variety in shooting position. This makes the sight invulnerable to all but total blockage or removal of the aiming window as the reticle can be seen if any part of the window is visible. The main disadvantage of the holographic sight is its laser diode's greater power consumption than an LED - battery lives being measured in hundreds rather than tens of thousands of hours.
The location of the collimator dictates the shape of the sight. If it is mounted beneath you can have a sight that is less bulky, with the sighting screen taking the form of a small head up display. This configuration can have the drawback of putting the sight line high up - this suits AR15 rifles or others with a straight-through stock configuration, but works poorly with other configurations. It can also make for a somewhat less robust sight. Side mounted collimators enable a tube to be used to contain the workings of the sight. Whilst heavier, this is inherently robust and allows much lower mounting. Some sights - the Aimpoint CompM2 for example - can be configured with the adjusters on the preferred side just by rotating the unit in its rings.
Reflex or red dot sights are most often non magnifying - this enables them to be employed with both eyes open for very fast target acquisition and engagement. This is best accomplished with a red dot or circle reticle, the dot size being a compromise between fast acquisition (larger dot better) and precision (smaller dot better). Magnifying reflex sights have become ubiquitous in the War on Terror where target identification is at a premium A bright illuminated aiming mark is used for close ranged shooting, backed by a traditional reticle for longer ranged engagements. The Trijicon ACOG is the best example of this philosophy. However 1x magnification or 'unitary' reflex sights can often be fitted with detachable or flip to side magnifiers to provide a very versatile combination. The ubiquitous ACOG can attain similar versatility with the mounting of peep battlesights and/or a small rear mounted red dot sight on their housings.
Adjustments are typically internal, the sight remaining in a fixed position whilst the reticle is moved up and down with adjusters. These are calibrated and, almost universally feature audible/tactile clicks. The calibrations vary from manufacturer to manufacturer and model to model. The Aimpoint CompM4s (the most recent incarnation of the US Army M68) for example uses clicks that are 16mm at 100 meters or 1/2" at 80 yards whilst the USMC's AN/PVQ-31B has clicks that move the point of impact 0.33" at 100 yards.
The sights have to cope with different brightnesses of daylight and thus employ variable reticle brightness settings. Night vision compatible sights have a wider range of adjustments to suit this role. Some sights will adjust automatically, either employing sensors or a fiber-optic light gatherer that pulls in light from its surroundings. The latter system can be problematic when shooting into a brightly lit area from a dark one. A polarising filter can be employed on some models to reduce the brightness of the image - rotating two polarised lenses can graduate the image from complete brightness to complete black-out. As the sight itself often incorporates a polarising filter, mounting a single adjustable polarising filter can have the same effect. In the past this caused problems with protective eyewear which was also polarised, but the leading manufacturers now use polarities selected so as not to obscure the target when used with polarised glasses.
Co-witnessing iron sights with non magnifying red dot sights has become popular. It is important to realise that it is unimportant where the reflex aiming mark is relative to the foresight post as long as both are zeroed to hit the target. Some shooters attempt to shim the sight to get the red dot to sit directly on top of the foresight, but this is completely unnecessary. A popular method is to have the iron sights in the bottom 1:3 of the sight picture and manufacturers like Eotech are starting to make sights with optional risers to facilitate this; for example their Model 557.AR223.
Copyright Chris Pieterman 2010
Are my phone/DSL jacks faulty?
I have only one jack that works with DSL, but all of the other ones seem to only work with the phone. The jacks that only work with the phone seem to be more dated, but I have tried using a splitter/filter. Is this a problem I can fix or should I call somebody (who?). Any help would be greatly appreciated. Thank you!
They (ATT) said they would charge $80 plus $25 per minute. Any way to diy??
If the dsl was put in by the phone company, they should have checked all jacks before leaving.
Call them and ask if they can fix it at no charge or tell you how.
ACS 901E2+ Inline Splitter/ Filter!
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