VATSIM 8.33 kHz Frequencies Trial

Starting on September 7, a trial with 8.33 kHz frequency spacing will take place in Germany, the Netherlands and the UK. The trial will run for a maximum of 3 months (likely shorter).

What is 8.33 kHz Spacing
Reducing the spacing between consecutive frequencies to 8.33 kHz adds two additional channels for every 25 kHz.

This means that the difficulties some divisions and subdivisions have had with reduced frequency availability, which often caused conflicts with neighbouring frequencies, will be resolved.

Why now?
This has been an aviation standard since 2007. VATSIM is always striving to make the operations on the network more realistic. With more and more simulators and addons supporting 8.33 kHz spacing, now is a great time to introduce this to VATSIM.

Minimal impact!
For the vast majority of pilots, there will be no impact. Almost all modern simulators and addons support 8.33 kHz frequency spacing, and you will be able to tune your frequency just like normal.

Over the last few months a network wide connection audit was made, which showed that this change will affect less than 5% of all flights. This means that the vast majority of flights on the VATSIM network will not be affected by this change.

Using legacy addons
If you are flying with an addon or simulator which does not natively support 8.33 kHz frequency spacing, you will need to use your pilot client to tune to a 8.33 kHz frequency.

This can be done through the command .com1 XXX.XXX or by using the Online ATC List.

Affected frequencies for legacy addons
When using legacy addons, frequencies that end in x00, x25, x50, x75 will work as usual, you can still tune them from within your aircraft.

When using legacy addons, frequencies that end in x05, x10, x15, x30, x35, x40, x55, x60, x65, x80,x85, x90 will need to be tuned using the command .com1 XXX.XXX or by selecting the frequency through the Online ATC List within your pilot client.

Native Support
Known addons/simulators that currently do not support 8.33 kHz

Microsoft Flight Simulator X (FSX) and older versions
Lockheed Martin Prepar3d v4 and older versions

PMDG aircraft (for FSX & P3D)
Quality Wings 787 Series
Majestic Software MJC8-Q400

This list is by no means complete. Other (older) simulators and addons may not support 8.33 kHz either.

If you have any questions, you can ask them on the VATSIM Community Discord in the 8.33khz Channels.


Can you please clarify some terminology and the implementation? x05, x10, x15, x30, x35, x40, x55, x60, x65, x80, x85, x90 are channels and the actual frequencies they tune may be slightly different. for example channel x05 actually tunes frequency x00 on a real world 8.33 kHz radio. Likewise channel .030 actually tunes frequency .025.

There are some simulator aircraft that do this correctly, e.g. selecting channel .805 will correctly tune frequency .800.

How is this being implemented on VATSIM? It seems like, for example, .x05 is being treated as a discrete frequency.

Every channel is treated like an individual frequency. For VATSIM purposes 118.000 and 118.005 aren’t the same frequency (even though they would be IRL). So if you’re on 118.000 and someone else is on 118.005 you couldn’t hear one another (even though IRL you could).

This is going to be a problem with some aircraft that model 8.33 kHz radios with real world accuracy.

WEL, here was an interesting situation that happened the other day. I was on approach into EGLL in the Boeing 747-400 when the controller had me descend down to 8,000 to be level by OCK. Fine. Problem was the plane wasn’t doing what I wanted to do, and I didn’t think it would slow down in time, so I disconnected the autopilot. They then ended up having me switch to director on 119.73. I told them the plane wasn’t able to do that, they ended up having me manually type it, which is hard to do when you’re hand-flying the airplane since I don’t have four hands. Plane ended up busting 8,000 feet and ended up descending as I tried to do this.

One other thing that happened was when I was on the ground, I switched to 122.8, so it would be quieter when I was doing my flight preparations. When I manually type into VPilot the switch to 119.73, it shows 119.73 on VPilot, but on the airplane itself, it now shows 122.8 on both the active frequency and the standby frequency. This means that in order to go back to 122.8, I have to re-tune the standby frequency to another frequency before going back to 122.8 since simply switching to the standby frequency does nothing. Overall not a great experience.