Upgrading from 25 kHz to 8.33 kHz

Why do we need to do this?

Well basically, the airwaves are becoming increasingly crowded with more and more users of commercial and general aviation. To assist in making it easier for a larger number of users to be able to communicate at the same time you simply need more channels available. So way back in 1994 it was decided to introduce a channel split from 25 to 8.33 kHz. Subsequently, 8.33 kHz was introduced above FL245 in the ICAO EUR Region from October 1999 and above FL195 from the 15 March 2007. At the time of writing, 8.33 kHz channels have been implemented in the airspace of over 20 ICAO EUR Region States. On the 16 November 2012 it was also agreed to further extend 8.33 kHz to all European airspace by the beginning of 2018.

When will we need to upgrade to 8.33kHz radios?

As described above, Euro Control have scheduled that all remaining airspace users will need to be equipped with 8.33 kHz radios from the beginning of January 2018. This will affect all GA users and it is expected that there will be a huge rush to upgrade in the last 24 months or so in the UK. Many other European countries and gliding associations have already made the move or are putting together programs now to upgrade club fleets and private owned gliders. The general advice is don’t leave this to the last minute but at least have a plan in place and think about how you will upgrade in the future.

Who will this affect?

Well again as described, this affects all European airspace users so effectively if we want to keep flying our EASA aircraft in the UK and the rest of Europe we will all need to have upgraded by the beginning of 2018.

Will there be an extension or exemptions for gliders?

The BGA have been working on this for many years and at the moment there looks like there is no likelihood of a delay or extension to the time scales. The timetable has been set since 2012 and the implementation of the 8.33 kHz change at the higher flight levels have all happened on time. At the time of writing, discussions are taking place to allow a short window of dispensation for training organisations with aircraft that do not leave the circuit. This obviously does not cover anyone thinking of going cross country.

What is the benefit to the gliding community, general aviation and other air band users of 8.33 kHz?

It does mean that gliding will be able to maintain the existing number of dedicated gliding channels and possibly add more in the future. Again the BGA are working on this with the interests of glider pilots nationwide. The increase in the number of available frequencies also means that the pressure on licensed airfields and sporting aviation to give up frequencies for commercial users will lessen and allow the general aviation community to operate with less restraint.

Are there any other benefits to fitting an 8.33 kHz radio?

Yes, the new 8.33 kHz radios all have at least the features you had before and many of them now have “dual watch” as standard, 99 channel memories with a label field so you can give a frequency a name. Many can also be controlled externally via moving map systems so as you navigate to an airfield; the moving map system can send the airfield frequency to the radio automatically saving you time and reducing work load in the cockpit. The technology used in the latest 8.33 kHz radios also use less power than the older clunky radios and on the whole, are also considerably lighter. The solid state nature of the components used means they should be more reliable, but time will tell!

Is my old 25kHz radio worth anything?

Sadly, the answer is not very much. There are other regions around the world who do not yet need to change to the 8.33 kHz radios such as the US, Australia, New Zealand, South Africa and South America. However, the flood of European good quality second hand radios has already swamped these relatively small markets. So unless you have a nearly new 25kHz radio with its form 1, there is little or no value in the old radio.

How do I upgrade from my old 25 kHz radio?

This should be easy but actually, there are a number of considerations to bear in mind when planning your upgrade. It would be great if you could unplug your existing radio and simply plug in your new one. For a limited number of users this will be possible, for instance if you have a Becker 4201 and change to a Becker 6201 it is a simple radio swap. For others, there may be a few challenges ahead.

Physical size and panel space

The majority of the new 8.33kHz radios fit in a standard 57mm or 2.25” panel cut-out. So if your radio is an old oblong or square cut out you may need to think about a blanking plate with a 57mm cut out. Whilst most of the new 8.33 kHz radios are shorter than the older radio types, it is worth just measuring the space behind your panel to make sure your shiny new replacement will fit where the old one used to be!

Existing wiring loom and cable length

Chances are that the existing wiring loom carrying the microphone, speaker, PTT and power connectors will have a different plug than that on the new radio. Some manufacturers offer an adapter to change from existing plug type and wiring to the new connection but please bear in mind all adapters are a compromise. It is also worth checking that the existing wiring harness is long enough to reach the back of your new radio which may be physically shorter than the old one! The antenna cable and connector should also be considered, typically these are a standard BNC connector and should be a direct swap from one radio to another however, there may be some radios out there with a screw thread TNC adapter and this will require a change of connector to BNC. Once again, check there is enough slack in the existing antenna cable to reach your new radio and or have enough spare to change the plug.

Can you just solder on a new plug on to the existing wiring harness?

In theory yes this could be done but a word or two about how difficult this is. Identifying which wires do what is relatively straight forward, one pair of wires for the speaker, one for the PTT switch, one pair for the microphone and a power and ground wire. However, physically soldering this lot into a new plug in the constraints of the back of an instrument panel is quite demanding. This work also needs to be singed off by an inspector! A simpler method would be to replace the wiring harness so you can then run these wires to the speaker; microphone and PTT switch or join the appropriate wires to existing where appropriate in a more convenient location. Again this re-wiring will need to be signed off or carried out by an inspector.

Will your new radio match your existing microphone and speaker?

This is probably the hardest bit to get right because it is almost impossible to tell which of the likely two different types of microphone (Electret or Dynamic) you have in your glider or indeed the power and impedance of your speaker. An external examination of a microphone or the wiring is no guarantee of the type of microphone unfortunately. The same goes for the speaker. If you have the original documentation for the installation you may be in luck and you will be able to match the wiring and settings of your new radio accordingly. Other than that, it is trial and error which I know is not ideal and can be very time consuming.

What happens if the wiring is not long enough, too old, broken or too difficult to work with and the microphone and speaker are beyond identification?

Well there are kits available to replace the wiring harness, speaker and microphone and we would be happy to help in putting together a matched kit of parts or carrying out the work for you.

What paperwork do I need to do?

Replacing a radio will need to be noted in the log book of the glider and a work pack complete. If the installation involves any change to the wiring then it either needs to be carried out by an inspector or signed off by an inspector. Only the installation of a radio with the same plug or a suitable adapter is considered pilot/owner installable at this time.

Once the radio is installed, tested and commissioned with the log book and work pack completed. You then need to notify the radio licensing department of the CAA of the change of radio for your aircraft.

What to do next?

Take a look at the range of Radio’s on offer and then give us a call to discuss you requirements, time scale and existing setup at this link




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