Radios & Phones

By | February 1, 2019

A note that a good friend at Middle Wallop wrote about the danger of mobile phones:-

It’s is a very bad idea for anyone to have a mobile phone, tablet, etc. or basically any device that contains a SIM card anywhere near your Tx or Rx while flying or setting your system up.

There are various reasons which are all technical and pretty obvious.

1. Bluetooth systems:

Bluetooth is a wireless technology standard for exchanging data over short distances using short-wavelength UHF radio waves in the ISM band from 2.400 to 2.485 GHz from any mobile device. Nowadays every mobile device will be equipped with Bluetooth and it will generally be on by default.

Guess what the radio gear you have runs on exactly the same system on exactly the same frequency.

If you don’t use Bluetooth switch it off on your mobile device as your RC gear is basically a Bluetooth system but bigger and slightly more powerful. Switching Bluetooth off on your mobile device will help your radio gear and those around by removing needless signals from the bandwidth = less filtering = faster control speeds = less lag = better range etc…

2: Mobile Phone Frequenters:

There are a total of 5 different frequencies used in the UK used by the mobile networks to deliver their 2G, 3G and 4G mobile services.

· 800MHz (Band 20)

· 900MHz (Band 8)

· 1800MHz (Band 3)

· 2100MHz (Band 1)

· 2600MHz (Band 7)

Each operator in the UK utilises different frequencies to deliver their mobile networks with the core networks being EE, O2, Vodafone and Three. Then there are also operators, called mobile virtual network operators (MVNO), who utilise the backend of the core networks to offer their own services.

3: Working around your gear with your phone on the bench, pit etc…

When setting up your RC system keep your mobile device away from your RC gear as your mobile device emits much stronger RF signals than your RC equipment is designed to cope with.

Basically your RC RX is designed to pick up relatively weak signals, amplify them, filter them and translate those signals in to something usable for your servo control. The problem occurs when your phone is left near your TX or RX as the poor old receivers amplifier keeps taking a powerful RF hit from your phone and this can potentially damage the RX which if your lucky will break it and it will stop working but if your not it may just damage the RX amplification chip set which will give you a lack of signal amplification which will equate to a reduction in range, crash bang wollop.

As an FYI your phone can damage your TX as well in 2 ways,

1: by creating powerful SWR signals ( RF eddies that travel down the TX antenna and bugger the transmission module) which again if your lucky will break it but if not you will get a reduction in range etc. the same scenario as the RX above.

2: remember that lots of Tx’s & RX’s these days are actually transceivers i.e. they are both TX’s and RX’s in one so everything I’ve said above applies to both.

Basically leave the phone in the car.

On a personal note, if your a Futaba flyer you will probably be fine flying with a mobile phone in your pocket but sensible separation is recommend, but if your a Spektrum flyer it’s only a matter of time before something bad happens.

I have done various tests and Spektrum failed in a lot of instances but I could not get a Futaba setup to fail. Basically there are various technical reasons why Spektrum particulate here in the UK (EU for now) will never be as good as Futaba in this scenario.

I fly both so I have no bias towards either in fact I have tried working with Spektrum and Logic here in the UK to try and improve the Spektrum system as it does have some excellent plus points that are just let down by some other (crucial) parts of there system.

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