Is Frequency Spacing limitations still a thing?

Kyle Sanders

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Is Frequency Spacing limitations still a thing?
« on: January 22, 2022, 04:46:51 PM »
I was told a while back that if the RW frequency we (ATC) are using has a .xx5 at the end, just make it .xx0. So we did.

Our normal CTR combine frequency is 120.275 but we prime as 120.270.
I get a good amount of pilots responding via PM from the ContactMe that they can't tune to that but when they tune to the RW 120.275, it is fine.

I know that AFV handles this "forwarding" but I am curious if we can just start priming as the RW frequencies now or not?
Best Regards,
Kyle Sanders

Evan Reiter

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Re: Is Frequency Spacing limitations still a thing?
« Reply #1 on: January 23, 2022, 07:18:58 PM »
Not sure what, if any, official policy exists on this. We have seen several of our neighbors elect to use the .xx5 recently, and have had to update our POFs to accommodate.

We're under the impression that we're supposed to leave it with .xx0 and thus have done so.

If you or your FE has access to the AFV Discord, there have been several heated conversations on this subject but never a resolution. (And, do yourself a favor, don't bring it up again!)


Evan Reiter
Boston Virtual ARTCC Community Manager
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Simon Kelsey

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Re: Is Frequency Spacing limitations still a thing?
« Reply #2 on: January 24, 2022, 04:06:25 AM »
The problem is that whilst vPilot and xPilot automatically “normalise” the displayed frequency (ie if you enter .x20 the pilot sees .x25), xSquawkbox (in particular, there may be others) does not.

This means if you set your actual primary frequency to xxx.x25 there is a good chance that at least some pilots will not be able to receive text.

Also (albeit this may be less of an issue in VATUSA) there have been issues in Europe where facilities or individuals have unilaterally gone to xxx.xx5 and screwed up their neighbours because their ATC client position files, which rely on the primary frequency to identify neighbouring sectors, were then wrong.

In short: any change needs to be coordinated and whilst there are still clients which don’t handle .xx5 properly I would personally suggest it to be inadvisable!
Simon Kelsey
Vice President, Pilot Training

Kyle Sanders

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Re: Is Frequency Spacing limitations still a thing?
« Reply #3 on: January 24, 2022, 10:12:37 AM »
Good advice. Thanks for the input!
« Last Edit: January 24, 2022, 01:22:16 PM by Kyle Sanders »
Best Regards,
Kyle Sanders

Kyle Sanders

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Re: Is Frequency Spacing limitations still a thing?
« Reply #4 on: January 31, 2022, 01:40:55 PM »
Lol... so I guess upon launching of Velocity today, the frequency spacing won't be an issue anymore. We will be changing everything tonight hopefully.
Best Regards,
Kyle Sanders