Related to this question about flight services: when I talk to FSS over the generic or the local receive-only frequency while listening to the VOR voice channel, how do I avoid talking over others on the same frequency?

Intuitively, I'd listen to the frequency I'm going to be transmitting on for a bit, then send my request, and then wait for a reply on the other frequency, but that seems like it would be distracting to configure in the radio.

So how would I configure my radio for contacting FSS in this way?

Edit: this is specifically about the case where other aircraft do not necessarily hear the controller speaking to you, so they may start transmitting at any time while I'm receiving the response.

  • $\begingroup$ Thats exactly the way you do it for normal 2-way radio communications, only you are listening on the VOR, so why is that distracting? $\endgroup$
    – Ron Beyer
    Aug 2, 2016 at 21:20
  • $\begingroup$ I'd have to listen to one frequency while waiting to send, and to the other while waiting for a reply, so I have to either switch frequencies (= look at the radio) or listen to both (but 122.2 is going to be busy with talk that doesn't concern me). $\endgroup$ Aug 2, 2016 at 21:36
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    $\begingroup$ Possible duplicate of How do I get attention on a busy radio channel? $\endgroup$
    – fooot
    Aug 2, 2016 at 22:01
  • $\begingroup$ I don't think it's a duplicate. This question is about talking on a channel you don't monitor and seems difficult to monitor (the purpose of the question is to know if this transmit only frequency should be monitored). My suggested answer is in that case it's the business of ATC to sort out simultaneous traffic, and in practical this may not be a problem as there could be multiple antennas pointed in different directions on the frequency (so limited RFI) and multiple ATCO behind. Just a guess. $\endgroup$
    – mins
    Aug 3, 2016 at 16:06

2 Answers 2


In the specific case of a flight service receive-only frequency you will be able to hear other aircraft transmitting in that frequency (you still listen to your com radio, so treat the transmitting part just like any other transmission and wait for a break before you key the mic).

In the more general case when you have one controller (or Flight Service Specialist) working multiple frequencies you call in when the one you're transmitting on is quiet (and in the case where you're receiving Flight Service over a VOR wait for that to be quiet too).

The controller or FSS will answer you if they're free. If they're busy on another frequency or a landline they'll respond with "Aircraft calling, stand by" (or if they're really busy and don't hear you you won't get a response and you'll try again in a minute).
It's not a perfect system, but it works pretty well most of the time.

  • $\begingroup$ So I listen to both COM and NAV, and hope that no one else speaks on the COM frequency while the controller answers my request on the NAV frequency? $\endgroup$ Aug 3, 2016 at 5:18
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    $\begingroup$ @SimonRichter anyone else transmitting on the COM frequency should also be listening on the NAV frequency and so will know not to transmit while the controller is speaking. $\endgroup$
    – IanF1
    Aug 3, 2016 at 5:55
  • $\begingroup$ Yep, everyone should hear the controller or FSS operator's responses. Other aircraft just may not hear you calling the controller or FSS and you may not hear the other aircraft. $\endgroup$
    – hemp
    Aug 3, 2016 at 7:05
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    $\begingroup$ @IanF1 That's not always the case, in fact there's a counterexample right by me: Hampton VOR (HTO) and Groton VOR (GON) both have 122.1 listed as a receive-only frequency. If you're transmitting on 122.1 receiving via HTO someone transmitting on 122.1 and receiving via GON won't hear the replies going to you, and if we go to the extreme ends of the service volume for that RCO you might not hear each other's calls on 122.1 either. (This is admittedly a contrived edge case, but it's still possible: We basically count on the FSS being able to do 2 things at once in this case.) $\endgroup$
    – voretaq7
    Aug 3, 2016 at 7:34
  • $\begingroup$ @voretaq7 thanks for the correction! I assumed they were paired 1 to 1. $\endgroup$
    – IanF1
    Aug 3, 2016 at 11:25

One thing you can do is pay attention to what the controller or FSS says. If you tune in and hear them ask someone a question (i.e. "Cessna 42F, please say type, position, and state request") then it would be wise to give it 30 seconds or so before keying the mic, since they're likely listening to 42F's reply even if you don't hear anything. Otherwise, just make your call and if they don't hear you, usually they'll ask "aircraft calling" to "say again". If you get no response, wait for a break and try again.


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