unicom question

[Brian Shindledecker]

I am a new Vatsim user, have only flown in "observer" mode so far as I am learning the ins and outs.  My specific question is with regard to Unicom.  I know that the universal unicom freq is 122.800 in Vatsim.  However, my home airport (KBTP) lists on the airport charts their unicom as 123.050.  So do I disregard the airport chart info being that I'm in Vatsim?  Does this question make sense?  Should I use 122.800 or the 123.050?

[Franz Nord]

Yup, that question makes sense and I was searching for this too when I was new to VATSIM. The answer is easy: On uncontrolled airports that have an UNICOM or CTAF frequency or a Radio Mandatory Zone (RMZ) in Europe you use 122.8 on VATSIM. In Europe (not sure about the US), depending on the airport, there can be an Info Controller position that gives out wind and traffic advisories that has a frequency like every other station and is visible on the maps and pilot clients when online.

[Brian Shindledecker]

So disregard the real life airport chart frequency and stay on 122.800 because I'm in Vatsim?  That's my understanding   

[Kirk Christie]

I dont believe you should be flying around in observer mode.... I'm certain the intent for that is to sit on the ground and observe.

Observer's aren't permitted to transmit on any frequencies.

Not all airports around the world have a CTAF, those that have 24/7 ATC, VATSIM doesn't have 24/7 ATC, so there needs to be a universal frequency to use at these airports, which is 122.800, it doesn't conflict with any other ATC frequency.

[Tobias Dammers]

8 hours ago, Brian Shindledecker said:

So disregard the real life airport chart frequency and stay on 122.800 because I'm in Vatsim?  That's my understanding   

Yes. Unicom / CTAF on VATSIM is generally 122.8.

Historically, this was necessary due to technical limitations of the voice protocol: Voice comms were only possible on frequencies for which a controller was active, and 122.8 was hard-coded into the system as an exception to make Unicom possible at all. The current voice protocol (AFV) does not have such a limitation, and could, in principle, support real-world CTAF's, but for historical and practical reasons, the 122.8 standard is being upheld, at least for the time being. There is some talk of changing that, but I don't think there's anything concrete in the works yet, and I doubt we'll see much progress in the near future.

[Brian Shindledecker]

Thank you Tobias, this is a very clear answer to my question and is understandable to a rookie like me.  I appreciate you all for your help.  Thank you so much.  

[Kerby Stoudt]

On 4/3/2022 at 11:26 PM, Kirk Christie said:

I dont believe you should be flying around in observer mode.... I'm certain the intent for that is to sit on the ground and observe.

Observer's aren't permitted to transmit on any frequencies.

Not strictly true. For ATC positions, this is correct. However, for pilots, observer mode is needed for shared-cockpit situations. Both the main connected pilot and the copilot are allowed to speak, but one of them must connect as an observer, or two aircraft will show overtop of each other both on the ATC scopes and in the sims.

I can see what Brian is trying to accomplish here. Get a feel for what the communications should be like, and maybe practice without actually making radio calls. That being said, once you are ready to start making those calls and talk to other traffic and ATC, make sure you are connected without observer mode unless you are the copilot in a shared cockpit.

[Tobias Dammers]

On 4/4/2022 at 7:26 AM, Kirk Christie said:

I dont believe you should be flying around in observer mode.... I'm certain the intent for that is to sit on the ground and observe.

Why would it be a problem to fly around? It's not like anyone can see you, so as long as you don't talk on the radio, you're never going to disrupt anything, which is the whole point.

The rules says you must not stay connected as observer for excessive periods of time, but it says nothing about whether or not you can move.

[Kirk Christie]

7 hours ago, Tobias Dammers said:

Why would it be a problem to fly around?

I didn't say it was.

7 hours ago, Tobias Dammers said:

but it says nothing about whether or not you can move.

I didn't say it did.

The section of the COC you referenced says members not actively participating in the network. A pilot flying point A to point B in observer mode, is not actively involved in the network. 

What communications can you learn flying, vs being parked on the ground, you can listen to all positions that are in range.

[Robert Shearman Jr]

Kirk, I'm sorry but I completely disagree with your stance that "observing" while flying is any more or less "active" participation than "observing" while motionless.  If one is a valid use of the network, then the other is, as far as I can see.

[Kirk Christie]

Robert you are free to disagree with my opnion you are also free to have your own opinion, not sure why you need to be sorry for.

However, I also disagree with you, observing while flying removes all interaction with other people ATC and pilots, and therefore does not fit the purpose of the network. More so if you Observe on the ground you are only likley to be connected for short periods of time, if you complete a 2 - 5 hour cross country flight while Observing, then that would be considered an excesive period of time, not activly contributing to the network.

We should be encourging people to interact more, rather than identifying paths that people can use to avoide ATC. While there is no such rule that prohibits it, whats stopping those people who need to use the network for their VA flying time, but dont want to interact with ATC, connecting as OBS and flying?

Edited April 9, 2022 at 01:39 AM by Kirk Christie

[Tobias Dammers]

On 4/9/2022 at 3:31 AM, Kirk Christie said:

We should be encourging people to interact more, rather than identifying paths that people can use to avoide ATC.

Yes, but that doesn't mean that you should under no circumstances be moving while connected as observer.

Connecting as observer for the purpose of observing is fine, whether you are moving or not. You're not getting in anyone's way, nobody gets to see you unless they go looking for you on purpose, you're not using any more or less bandwidth either way. As long as you're observing, you're observing.

Connecting as observer for the purpose of practicing your flying skills with other traffic around is a bit of an edge cases, but I would say that since you are doing it for educational purposes, it's probably still fine. Maybe not the best way to learn, and I don't think it should be actively encouraged, but I don't think it should be prohibited either.

Connecting as observer for the purpose of seeing some traffic in your sim for decorative purposes is not fine though. VATSIM is not a screensaver.

[Tim Waldon]

Going back to the original question about the 122.80 UNICOM frequency, does anyone know what the "range" is when listening on this frequency? For example, If I am in the traffic pattern at XYZ airport, is there a particular radius in which I would hear other traffic on the frequency?

Edited July 1, 2022 at 06:42 PM by Tim Waldon

[Kirk Christie]

9 hours ago, Tim Waldon said:

Going back to the original question about the 122.80 UNICOM frequency, does anyone know what the "range" is when listening on this frequency? For example, If I am in the traffic pattern at XYZ airport, is there a particular radius in which I would hear other traffic on the frequency?

Voice is 15nm per aircraft, two aircraft can be approx 30nm apart and hear each other.

Not sure on the text range.

[Tim Waldon]

Hi Kirk,

Thanks for your help answering my question, I appreciate it.

[Tomas Johansson]

On 7/2/2022 at 5:48 AM, Kirk Christie said:

Voice is 15nm per aircraft, two aircraft can be approx 30nm apart and hear each other.

Is that range specific for Unicom or is it the same for all frequencies?

[Sean Harrison]

Tomas,

This link will show the effective range of each frequency.  122.800 is much larger than any other pilot tuneable frequency.  As others have said if you are both got 200M range, you could effectively communicate at 399M due to overlap.

https://afv-map.vatsim.net/

 

OBSERVATION: VATSIM rules state you must monitor 122.800 when not with ATC, yet simply looking at the link there are numerous numbers of pilots that don’t tune to 122.800 outside of Controlled Airspace.

Edited September 2, 2022 at 08:58 PM by Sean Harrison
Added comment, not to intentionally complain.

[Tomas Johansson]

Thanks Sean,

By bigger I assume you mean that Unicom is used by many more pilots at the same time. The range seems to be less on Unicom then on most other frequencies. 

[Tomas Johansson]

It seems that range for Unicom is independent of altitude, while it incrises with altitude for other frequencies. Is it true?

[Alistair Thomson]

VFR comms is mostly line of sight. So an aircraft on the ground at airfield A might not hear ATC at airfield B until some time after takeoff. There's a formula for the distance or radius of circle of comms: d = 1.25 * √h.

[Robert Shearman Jr]

On 122.8 the range is artificially reduced by AFV to around 15nm x2.