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faq.md

-# Frequently Asked Questions (under construction\!)
+# Frequently Asked Questions
 
 ## GPS Time Transfer
 
@@ -57,23 +57,23 @@ level.
 
 The GPS system itself distributes a real time approximation of
 ionospheric delays. On top of that geodetic receivers are able to decode
-the so called ionosphere-free code (P3), which is transmitted over the
-L1 and L2 carriers. Notice that L1 and L2 are being transmitted over two
-different frequencies. As ionospheric delay changes affect differently
-to L1 and L2, it is possible to calculate an additional correction the
-ionospheric delay model. Additionally the common view technique helps
-reducing the impact of ionospheric delays on base lines at the 800Km
-level, by selecting satalites which are visible simultaneously by both
-base stations. On top of that, the use a cesium atomic clock allows for
-additional filtering of daily delay oscillations. Once all these
-techniques are applied the overall impact of ionospheric delays is
-inferior to 1ns. See [USE OF GEODETIC RECEIVERS FOR
+the so-called ionosphere-free code (P3), which is transmitted over the
+L1 and L2 carriers. Notice that L1 and L2 are two different frequencies.
+As ionospheric delay changes affect differently L1 and L2, it is
+possible to calculate an additional correction to the ionospheric delay
+model. Additionally the common view technique helps reducing the impact
+of ionospheric delays on baselines at the 800 km level, by selecting
+satellites which are visible simultaneously by both base stations. On
+top of that, the use a cesium atomic clock allows for additional
+filtering of daily delay oscillations. Once all these techniques are
+applied the overall impact of ionospheric delays is inferior to 1ns. See
+[USE OF GEODETIC RECEIVERS FOR
 TAI](http://tycho.usno.navy.mil/ptti/ptti2001/paper35.pdf) by P.
 Defraigne, G. Petit and C. Bruyninx.
 
-If needed, the time transfer could still be improved by adding a posteri
-knowledge of the satellite orbits, atmospheric delays and GPS carrier
-frequencies.
+If needed, the time transfer could still be improved by adding a
+posteriori knowledge of the satellite orbits, atmospheric delays and GPS
+carrier frequencies.
 
 ### Why the GPS receivers are installed on the surface?
 
@@ -96,26 +96,26 @@ considerations:
     the ~1ns level. 
 2.  Lab tests show that swapping the transmitter and receiver over a
     ~5Km optical fibber roll induces a change in the delay at the order
-    of 0.1ns. Sagnac effects over an extended 10Km fibber would add an
+    of 0.1ns. Sagnac effects over an extended 10 km fiber would add an
     additional asymmetry of only ~0.1ns on the earth equator. This means
     that a simple two-way scheme over an spare fiber has the potential
-    to do a time-transfer between two points separated by 10Km with ~1ns
-    accuracy (or better if especial care is taken during the measurement
-    and monitoring of the feedback delay is enabled). 
+    to do a time-transfer between two points separated by 10 km with
+    ~1ns accuracy (or better if especial care is taken during the
+    measurement and monitoring of the feedback delay is enabled). 
 3.  Delay paths should include as many components as possible in order
     to reduce any systematic error.
 
 
 ### These fibers are not length-compensated on-line. What is the length change throughout the year?
 
-The fiber delay tempco is at the order of 50ps/Km/C. The fibbers in Gran
-Sasso are buried deep underground where temperature changes below 1C are
-expected. This represents a maximun change inferiour to 1ns thourghout
-the year in the OPERA fibber. At CERN we have ~2Km of fiber between the
-CERN's Control Room (CCR) and HCA442. This fiber is not buried as deeply
-as the one used in LNGS. If we take that the fiber is buried at 1m ,the
-temperature change could be of ~15C. This implies a possible change on
-the fibber delay of 1.5ns.
+The fiber delay tempco is of the order of 50ps/km/°C. The fibers in Gran
+Sasso are buried deep underground where temperature changes below 1 °C
+are expected. This represents a maximum change of less than 1 ns
+throughout the year in the OPERA fiber. At CERN we have ~2km of fiber
+between the CERN Control Room (CCR) and HCA442. This fiber is not buried
+as deeply as the one used in LNGS. If we take that the fiber is buried
+at 1m, the temperature change could be of ~15°C. This implies a possible
+change on the fiber delay of 1.5ns.
 
 Additionally the electronics could be affected by temperature changes.
 We have tested in the lab that after heating with a hot gun the CTRI