Small fixes

website/docs/hardware/antenna/antenna.md

@@ -1,7 +1,7 @@
 ---
 id: antenna
 title: Antennas
-sidebar_label: Antennas
+sidebar_label: Overview
 slug: /hardware/antenna
 ---
 

website/docs/hardware/antenna/non-aerial.md

@@ -5,7 +5,7 @@ sidebar_label: Non-aerial factors
 slug: /hardware/non-aerial
 ---
 
-Unless you're using your devices in a vacuum with clear line of sight between aerials:
+Unless you're using your devices in a vacuum with clear line of sight between aerials the following will have an affect:
 - Weather (temperature, humidity & air pressure),
 - Transmission power, spreading and other associated channel factors,
 - Number of nodes within reach in the mesh (affects retries consequent duty cycle hit),
@@ -13,7 +13,7 @@ Unless you're using your devices in a vacuum with clear line of sight between ae
 - Reflection off surfaces (and channeled through material tunnels, including warm / cold air tunnels commonly present in the atmosphere),
 - Diffraction around obstacles (over forests and around corners).
 
-### Environmental
+### Environmental factors
 
 For a bit of light reading on environmental research:
 - [RF attentuation in vegetation](https://www.itu.int/dms_pubrec/itu-r/rec/p/R-REC-P.833-9-201609-I!!PDF-E.pdf) (yes really); if you wander through the woods wondering how your RF is bouncing off leaves dependent on their variety, and wind speed … well you do, now.

website/docs/hardware/antenna/resources.md

@@ -29,6 +29,8 @@ slug: /hardware/resources
 * [Solwise Link Budget Calculator](https://www.solwise.co.uk/link-budget.htm)
     * Predict the received signal strength
 
+* [Amateur Radio Toolkit](https://play.google.com/store/apps/details?id=com.daveyhollenberg.amateurradiotoolkit)
+    * Android app with lots of antenna information
 
 ### Antenna designs
 

website/docs/hardware/antenna/testing.md

@@ -30,4 +30,6 @@ Here are a [couple](https://medium.com/home-wireless/testing-lora-antennas-at-91
 
 ## Antenna matching & vector network analysers
 
-One of the first things to ensure is that the antenna you have is tuned to the frequency that you are using. A lot of cheap antennas come labeled with an incorrect working frequency, and this will immediately reduce the emittted signal stregth. A Vector Network Analyser (VNA) can be used to ensure that the antenna is appropriately matched to the tranmission circuit, ensuring that it is operating at the correct impeadance and has a low level of power reflected back from the antenna to the transmitter at the desired transmission frequency. Andeas Speiss (the 'guy with the Swiss accent') gives a great explanation of [how to use Vector Network Analysers](https://www.youtube.com/watch?v=ZpKoLvqOWyc) to correctly tune your antennas, as well as a more [in depth tutorial of how to use VNAs](https://www.youtube.com/watch?v=_pjcEKQY_Tk). It is important to remember however, that VNAs can only tell you if the antenna is well matched, not how well it is transmitting. A 50 ohm resistor across the transmitter output would show as ideally matched, but it would be useless at transmitting a signal. There are a number of VNAs now available for less than $100, making this no longer out of reach for most hobbiests unlike expensive spectrum analysers.
+One of the first things to ensure is that the antenna you have is tuned to the frequency that you are using. A lot of cheap antennas come labeled with an incorrect working frequency, and this will immediately reduce the emittted signal stregth. A Vector Network Analyser (VNA) can be used to ensure that the antenna is appropriately matched to the tranmission circuit, ensuring that it is operating at the correct impeadance and has a low level of power reflected back from the antenna to the transmitter at the desired transmission frequency. 
+
+Andeas Speiss also gives a great explanation of [how to use Vector Network Analysers](https://www.youtube.com/watch?v=ZpKoLvqOWyc) to correctly tune your antennas, as well as a more [in depth tutorial of how to use VNAs](https://www.youtube.com/watch?v=_pjcEKQY_Tk). It is important to remember however, that VNAs can only tell you if the antenna is well matched, not how well it is transmitting. A 50 ohm resistor across the transmitter output would show as ideally matched, but it would be useless at transmitting a signal. There are a number of VNAs now available for less than $100, making this no longer out of reach for most hobbiests unlike expensive spectrum analysers.