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Frequency differences on VATSIM


Damo

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I did two flights today. EGCC -> ELLX and EGCC -> EGLL

 

Both flights I found that some of the frequencies listed in the ATC ribbon didn't match the VATSIM frequencies per the screen shots attached. 

I had to manually retune on several occasions

Is this a EFB issue, I've done something wrong or VATSIM issue?

 

 

vPilot_2021-04-03_16-20-14.png

vPilot_2021-04-03_16-33-04.png

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It's basically VATSIM still living in the 25 kHz times. Back then, there was no need for 3 decimals and you were fine with 2. Old simulators also still have this kind of display. So it would show 129.42 or 119.72. You could only tune that and a RL equipment would know that 129.425 is the frequency to be tuned. So the precision basically doesn't need a 3rd decimal. And this is exactly what VATSIM askes it's facility engineers to consider and enter data only up to a precision of 2 decimals, which basically means that the 3rd decimal always is a 0. Not all facility engineers though work according the requirements, which might result in EFB eventually showing also a 5 at the 3rd decimal.

VATSIM software generally does all the cosmetics by itself. So it will complete the 3rd decimal according the actual 25 kHz scheme and display it that way. This kind of "auto-completion" is also done by many addon developers.

VATSIM servers will then ensure that people tuned on 129.420 and 129.425 will hear each other, even if that wouldn't be the case nowadays in RL (because there is already 8.33kHz spacing). Simulators not yet ready for 8.33 kHz will automatically add a 5 for the 3rd decimal according the 25 kHz channels, and so will the VATSIM clients. For simulators supporting 8.33 kHz, you can tune both. However VATSIM servers will reroute these to the same "channel", disregarding the precision of 8.33 kHz channel spacing.

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Hi Jonas, 

 

 

If I didn't manually correct to .xx5 from .xx0, I couldn't hear the controller (or any other traffic) and the controller couldn't hear me. I had centre contact me to ask me to 'contact him' and I got no response until I changed to .xx5. 

 

So something isn't working which coincides with the EFB update to use the new JSON API from VATSIM. 

 

 

 

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7 hours ago, Damo said:

If I didn't manually correct to .xx5 from .xx0, I couldn't hear the controller (or any other traffic) and the controller couldn't hear me. I had centre contact me to ask me to 'contact him' and I got no response until I changed to .xx5.

What simulator do you use? I seems then you are able to fool the VATSIM pilot client and bypass the correction logic. Technically seen, there are no actual .xx5 frequencies on VATSIM. It's all just made to look alike. See here the extracts from the AFV configuration.

image.png.7118f685196022f77b51c94557abdbe1.png

image.png.3bef2040a17749d6549184df236e4719.png

 

This is what the controllers use when connecting on these positions.

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I had the same issue today at EDDB: 

image.png.f11eb6b9f57cf464973a53452bc1aca9.png

 

vPilot required:

image.png.000c4ce9b22c8b844b56d37eb4c78d4b.png

 

I had to manually change in the plane to hear the controller:

image.png.6a5091f4b970d4b99f6db18e0200dc17.png

 

I use MSFS2020 and the plane was the Working Title CJ4. Haven't tested other planes yet.

EDIT: Have tested the FlyByWire A320n now - same issue.

 

Also I noticed that ATIS is sometimes not displayed in EFB2 as you can see above.

EDIT: ATIS also has a third digit which makes me believe this has nothing to do with the sim or plane if EFB2 also has issue displaying ATIS at all with a freq of 123.775

 

Thanks

 

image.png

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22 hours ago, KiloJuliett said:

What simulator do you use?

 

I'm using MSFS. 

 

 

22 hours ago, KiloJuliett said:

This is what the controllers use when connecting on these positions.

 

Interestingly, when centre told me to 'contact them' - they gave me a frequency which didn't match the vPilot side bar or the frequency from the API (as used by EFB). It was .xx5 off. Couldn't communicate until I manually corrected. 

 

It seems something isn't joining up. If VATSIM doesn't 'care' about .xx0 vs .xx5.... what gives?

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46 minutes ago, Damo said:

Interestingly, when centre told me to 'contact them' - they gave me a frequency which didn't match the vPilot side bar or the frequency from the API (as used by EFB). It was .xx5 off.

Exactly the issue I tried to explain. While center is actually using the correct/raw frequency, vPilot puts a 5 there when the 25 kHz channel spacing requires it. But this is just a vPilot thing. And it seems vPilot also requires you to use the adapted frequency to connect it back to the original channel, which is technically without the 5. I thought vPilot would also accept the actual/correct frequency (ending with the 0), but maybe this is not the case for the MFS client. I'll check with my setup for P3D and let you know.

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11 minutes ago, KiloJuliett said:

Exactly the issue I tried to explain. While center is actually using the correct/raw frequency, vPilot puts a 5 there when the 25 kHz channel spacing requires it. But this is just a vPilot thing. And it seems vPilot also requires you to use the adapted frequency to connect it back to the original channel, which is technically without the 5. I thought vPilot would also accept the actual/correct frequency (ending with the 0), but maybe this is not the case for the MFS client. I'll check with my setup for P3D and let you know.

 

I also raised this in the vPilot forum:

Frequencies which are given with 2 digits but actually need 3 (eg. .220/.225) not working - vPilot - VATSIM Community

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8 hours ago, the.nuke.ch said:

Same here, various aicrafts in msfs. Always the last digit is 0 instead of 5. I think its vatsim Data related. 

It's an even more general problem as this discussion in theVATSIM forum shows:

Frequency inaccuracies in VATSIM API - General - VATSIM Community

 

Not sure if this is a problem with different planes in MSFS - do the planes usually really take care of this? Should they?

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On 4/7/2021 at 8:13 AM, aivlasoft said:

After reading all this information and the threads in the VATSIM forum, I decided to change it in EFB to properly display the 25 kHz frequencies.

Hi Urs,

 

one interesting fact to add...

 

The FlyByWire A320N for MSFS does not allow to set .x20 or .x70 via the user interface (dial knobs in the cockpit). It jumps from .x15 to .x25.

But you can set them via a programmatic interface like SIMCONNECT.

I tested this with the EFB and could see that the plane accepts the .x20 and .x70 in this case.

 

As you will fix this in EFB this is might then be not an issue for EFB any longer. I will also raise a ticket in the FlyByWire github for this.

 

Thanks

Frank

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