70cm Spectrum Usage (United States)

Discussion in 'Survey Center' started by K2GOG, Aug 29, 2018.

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What are your personal TOP TWO most FREQUENT uses of the 420-450 MHz spectrum in the US?

Poll closed Dec 29, 2018.
  1. Make analog voice contacts via FM repeaters

    44.7%
  2. Point to Point FM Simplex

    23.4%
  3. Single Side Band Voice

    14.9%
  4. Make digital voice contacts via fixed mode or multi-mode capable repeaters.

    17.0%
  5. ATV

    4.3%
  6. Contact involving some form of digital hotspot (MMDVM, etc)

    21.3%
  7. Contact involving some form of analog hotspot (Echolink, AllStar, *, etc)

    4.3%
  8. Some form of two way weak signal work including Morse Code, EME and beacons

    4.3%
  9. Satellite Uplink/Downlink

    29.8%
  10. Do not use 70cm at all, but may listen sometimes. (So that is why I only voted once, not twice!)

    12.8%
Multiple votes are allowed.
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  1. K2GOG

    K2GOG Ham Member QRZ Page

    It would be good to learn in the United States who is making frequent use of 420-430 MHz.

    This poll runs through the end of 2018. A new one will start in 2019.


    70cm amateur spectrum covers much of the United States with a few exceptions. We are fortunate to have 420-450 MHz whereas in other parts of the world they only have 430-440 or 430-450 MHz.

    The United States 10 MHz wide allocation from 420-430Mhz is only supposed to be used below Line A (FCC Details here), so what is everyone using it for on a frequent basis?

    According to the ARRL 70cm suggested band plan below, ATV and weak signal take up 13 MHz in total, which is a lot of spectrum for few users, so this is why I want to start a poll.

    As it stands, there are already many unlicensed devices raising the noise floor in the 432-434 range that go unnoticed. And, some parts of the country are not even able to use 70cm due to military operation interference.

    Can parts of this band be allocated for use with the growing population of hot spot devices or other more modern use cases?

    Can the US possibly decide to authorize different use of part of the 70cm band? Lets find out!

    Current ARRL Suggested Band Plan
    [​IMG]

    I hope as many people as possible can take this brief poll and/or share comments below as the results could be used for the ARRL, AMSAT, regional coordination bodies and others.
     
  2. W6RZ

    W6RZ Premium Subscriber QRZ Page

    I'm a little confused. Is the poll about the entire band (420 to 450 MHz), or just 420 to 430 MHz?
     
  3. W7UUU

    W7UUU QRZ Lifetime Member Number 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    446.00 isn't on your poll options.

    That's what I use

    Dave
    W7UUU
     
    K3XR likes this.
  4. ND5Y

    ND5Y Ham Member QRZ Page

    I operate FM on frequencies between 438-440 MHz (there is no ATV in this area) and occasionally 446.0.
     
  5. K2GOG

    K2GOG Ham Member QRZ Page


    This poll is for what activities are most common for the entire band from 420-450.

    Since different activities "are supposed to" take place is certain parts of the band, the results of the poll can be useful in determining if some narrow parts between 420-430 can be used for other things just by understanding what people do most often.

    I think you are one of the more prominent DTV folks if I am not mistaken. Would be great to chat if you have some time one day.
     
    WG7X likes this.
  6. K2GOG

    K2GOG Ham Member QRZ Page


    446.000 = point to point simplex.

    This was covered in the poll as an activity. Glad to hear you are making use of the official FM calling frequency. Share more about what you do on that frequency if you want. Thanks!
     
  7. K7JEM

    K7JEM Ham Member QRZ Page

    The biggest users of 420-430 around here are point to point links for repeater systems, etc. Not a lot of channels being used by that, but very little activity in the rest of that 10MHz window around here. The frequency separation from the 440-450 area make it work very well on the same site. Point to point links are not on your poll.
     
  8. K2GOG

    K2GOG Ham Member QRZ Page

    Ran out of total number of choices to include. I hit the maximum number possible. :)

    Good to know about this use case though. Probably even less signal fade then up higher on the band too.
     
  9. W6RZ

    W6RZ Premium Subscriber QRZ Page

    Thanx for clearing it up. Yes, I'm the developer of the DTV component of GNU Radio. One thing you may find interesting is that off the shelf televisions can be used for DTV on 420 to 450 MHz by just putting them in cable TV frequency mode. The mapping is:
    Code:
    cable channel 57 = 420 to 426 MHz, center = 423 MHz
    cable channel 58 = 426 to 432 MHz, center = 429 MHz
    cable channel 59 = 432 to 438 MHz, center = 435 MHz
    cable channel 60 = 438 to 444 MHz, center = 441 MHz
    cable channel 61 = 444 to 450 MHz, center = 447 MHz
    
    I use channel 58 (429 MHz) for testing.

    [​IMG]

    However, hardly anyone is using ATSC or cable QAM for ham DTV. In the US, it's all DVB-S or DVB-T with no channelization. Also, 23cm is more popular than 70cm. More room and easier to avoid repeater links mentioned by K7JEM.
     
  10. K8JD

    K8JD Ham Member QRZ Page

    There are parts of the country, around Detroit, Cleveland, and Buffalo where 420-430 MHz are not for amateur use, for Public safety and business radio only !
     

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