Discussion in 'Ham Radio Discussions' started by I0SJX, Jun 27, 2019.

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  1. KD8TUT

    KD8TUT Ham Member QRZ Page

    There goes 4 meters.
  2. WA6III

    WA6III Ham Member QRZ Page

    You're right!
    Right now, en-route VHF aviation communications in Canada has already moved to CPDLC (if aircraft equipped) for routine clearances. When they actually want to speak to the crew, they send them a message to contact them via VHF (Ancient Modulation ) voice.

    The planned switch in the CONUS was implemented in stages starting with "Clearance Delivery" where Aircrews at major busy airports used to receive their clearance via a voice call to Clearance Delivery on a discrete frequency (NOT "Ground control" or "Tower"). [It's not uncommon however for all these three freqs to be combined "after hours" though at small airports]

    In 2017, Aircrews starting getting clearances either via print-out prior to getting in the airplane or in airlines via a system called PDC (Pre-Departure Clearance) which would print out in the aircraft. Now most are using using a CPDLC system (log-on) for clearances. (In the US, there's only ONE log-on. (KUSA is the log-on ID)

    Routine en-route communication (sector "hand-offs" altitude and route changes) will be primarily via CPDLC and again, if the controller wants to actually "speak" to the crew, they'll send them a CPDLC message to give them a call on a discrete freq (during the "transition" period, it'll be on current ATC sector freqs)

    There's also a plan for this system to eventually be able to support digital voice "channels" which would relegate VHF voice to a "Back-up to the backup" I would expect airliners to eventually have a VHF or UHF radio that would have "emergency channels" only and not just 121.500 or 243.0 MHZ but several that would be automatically selected based on location etc.

    It's already happening on "over-water" Aviation HF SSB. Just about all the major airlines are doing position reports automatically (via CPDLC) And major airlines that you might hear still doing position reports, simply don't have the equipment installed (yet) or the CPDLC system is INOP.

    As they approach over water airspace, they make an HF radio call to ARINC for a "SELCALL CHECK" and when successful they turn the HF audio OFF.

    When they're approaching "land" they get a CPDLC message to contact (ON VHF) the next controlling sector. If that sector has CPDLC capability (like Canada or soon, the US) they'll just get a message to contact the sector on VHF for a radio check, then each subsequent sector change just results in a message to "monitor" a particular freq, but not to "contact"

    Eventually, they'll stop doing that and just tell them to monitor appropriate freqs until reaching the destination.

    Now, for those that have stayed with me so far, the main point of all this is that at least in the US and Canada.......VHF voice communications will eventually DECREASE not increase. If it decreases not only are the frequencies no longer needed, it's unlikely they'll need more (at least for aviation) .........eventually the VHF AM communication equipment will go the way of the ADF

    And NO, they'll NEVER go to NBFM, SSB or any other out-dated mode.

    That's reserved for "State-Of-The-Art" Amateur Radio!! (HAW!)

    The sky is in fact, NOT falling.

    K3XR likes this.
  3. N3HGB

    N3HGB Ham Member QRZ Page

    Totally missed the point. 2 meters for airmobile is *nothing* to do with ATC or voice comms or any other air traffic function. It is all about data links and remote sensing. Having more or better comms with ATC has zero impact on this idea.
  4. WA6III

    WA6III Ham Member QRZ Page

    You're right, you totally missed my point. It has EVERYTHING to do with the idea if there's less pressure on the current VHF allocation and less frequencies are needed for voice communications.

    Once the need for discrete AM channels are reduced, additional ones will not be needed. There'll be plenty of room in the current 118.000 - 137.000 range) Actually Europe even made room for more channels by going 8.33 khz channel separation. (and they're still running out)

    Don't know about the "third world" but Data links will not be on VHF here. Right now ADSB (IN and OUT) is operating at approx 900mhz and above. They are not going to screw with VHF for any of it. It's true that the (very old) ACARS data system operates on current VHF (AM) "channels" using AFSK......But that severely outdated system will be abandoned as well.

    I will agree that anything we do on this side of the world won't necessarily be "copied" in the EU but at some point when the system is fully implemented in the US and Canada, foreign operators will have to have the same system to operate here and the IATA will likely push for standardization world wide.

    And of course the bottom line for any Amateur frequency allocation is unfortunately at the bottom of the priority barrel. Hobby "services" will always get whatever is left. If the Govt decides 2m will be allocated to another service. There's not much any of us are going to be able to do about it.
  5. WU8Y

    WU8Y Ham Member QRZ Page

    That's irresponsible. Running about with one's hair on fire, "sign my petition!" etc. is counterproductive unless and until the proposal is evaluated and a thoughtful, measured response is in place. Stomping one's foot and shouting "NO!" does nothing to advance the amateur service's position. In fact, it sets it back by showing hams as irresponsible.
  6. SM0AOM

    SM0AOM Ham Member QRZ Page

    According to information I have from one of my clients, the Swedish Air Navigation Services, the ICAO intentions are to use VHF datalink (VDL Mode 2) for CPDLC for the forseeable future.

    During the 90s, the FAA developed a digital voice system for air-air and air-ground traffic, VDL mode 3.

    Due to excessive latencies and a very expensive implementation, it became solidly impopular by the airline business, and was finally abandoned in the early 2000s.

    For voice traffic, the VHF/AM system is likely to be with us for a quite long time. Any successor will need to be very much better than both AM and VDL mode 3 in voice quality, latency and frequency economy to be accepted by the airlines and their international body, IATA, which has a quite strong negotiating position.

    That radio amateurs are irresponsible is unfortunately already a quite wide-spread opinion among current spectrum regulators.

    Last edited: Jul 22, 2019
  7. WA6III

    WA6III Ham Member QRZ Page

    You are quite right. CPDLC in the near future (like next year or so) is going to cause voice traffic on VHF-AM in the high altitude enroute structure to drop dramatically. It already has in Canada between Seattle and Anchorage, AK on one of the most busiest routes in the North West. This will in the short term free up frequencies for other use.

    Sadly, also quite true. While Amateur Radio tries to be a viable emergency "service" It falls short. I am not sure that's going to be a very supportable argument for maintaining spectrum in the future.
  8. SM0AOM

    SM0AOM Ham Member QRZ Page

    The problem with this is that those responsible for the safety of manned aircraft do not want to be mixed in spectrum with unmanned aircraft and vice versa.

    The UAV business has already coined a name for this;
    "USpace" which means a completely separate traffic control system for UAV:s which is designed according to very different principles and with its own spectrum.
    The work for finding "new" spectrum for UAV operations has already started in the ICAO FMG.

    It is highly unlikely that the manned air transport industry will give up any of their existing VHF spectrum.

    Last edited: Jul 22, 2019
  9. WA6III

    WA6III Ham Member QRZ Page

    It could be more likely than you think, because VHF (AM) voice is starting to become the "backup" in the enroute structure (again US & Canada) as we speak, and will become more so once the data systems and digital voice systems become more widespread.

    But more to your point, the "reduction" in spectrum currently allocated to VHF voice, very likely will not happen in your or my lifetime and in reality, at least in the Europe, might even increase in size long before it starts to reduce.

    Similarly, as Aviation, Marine, military and other commercial (primary) users of HF move to VHF/UHF/SHF, SAT based comm, I would look to more (secondary) allocations in HF for Amateur Radio worldwide. (again however, not in my lifetime!)


  10. N3HGB

    N3HGB Ham Member QRZ Page

    IMHO there is absolutely no way the VHF-AM voice band will be shrunk to accommodate fast data links. Not going to happen no how no way. You have to get the whole world to agree on it or the latest drone IR camera thing wipes out a couple of FSS stations, an enroute center, and me ordering pizza on the ARINC channel.
    2 meters might not be the band picked, but I will bet my entire shack it doesn't end up anyplace between 118 and 137.999 MHz.
    My other prediction is hams have not seen anything yet, it is pretty easy to "prove" we aren't the best or highest use of pretty much anything we have if you do it right ;) If anyone still wanted HF bands some 7.200 recordings would be exhibit A for the prosecution :rolleyes:

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