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Digital modes on vhf

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by W1RLP, Jun 24, 2019.

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  1. W1RLP

    W1RLP Ham Member QRZ Page

    Is ssb needed on a vhf radio to operate digital?
     
  2. KF5LJW

    KF5LJW Ham Member QRZ Page

  3. AA4PB

    AA4PB Ham Member QRZ Page

    If you are talking "sound card modes" like FT8 or PSK31, it is possible to send their audio tones through an FM radio system BUT you loose most of the advantages because the resulting modulation is still FM. The advantages of the digital signal like the narrow bandwidth, weak signal detection, and decoding multiple stations on a waterfall are all gone. You'd also need other stations to be operating through an FM station in order to have QSO partners and you are not likely to find many people doing that. FT8, for example, is popular on 6M and 2M but generally stations are using a SSB radio just like they do on the HF bands.
     
  4. W1RLP

    W1RLP Ham Member QRZ Page

    Thx. Do you need ssb on the vhf radio?
     
    AI7PM likes this.
  5. KB0MNM

    KB0MNM Ham Member QRZ Page

    If the geographic information listed in QRZ is correct, you may need a tall antenna and an SSB system to reach Boston or another big city on VHF. The issue here is whether or not you could participate in digital modes, which on VHF are often APRS and regular AX.25 Packet. If you are looking to communicate with a particular group of hams who use a digital mode- why not just ask a few 'elmers' within a club centered around the city/cities that interest you? Getting the hardware before thinking about who you might connect to is somewhat like 'putting the horse behind the cart'. The ARRL maintains lists of radio clubs, and the repeater guidebooks have hints about digital modes supported. The answer is "No", you do not need SSB on a VHF radio. You may WANT it for increased range, however. You can operate digital modes such as APRS and AX.25 on a VHF FM-only radio with a correctly modulated carrier. If you have no service monitor or spectrum analyzer to check your own modulation, you might do well to purchase a radio that has a data connection for AX.25 packet or APRS built in. This would assume that you are expecting to connect to a similar station within approximately 15 miles. Most Terminal-node controllers will require that you enter your callsign before attempting to transmit out- and if you buy a used one- you may wish to ensure that any internal batteries are in good shape. Wiring these to a conventional VHF FM radio and a personal computer is half the battle. That service monitor or spectrum analyzer should be used to check FM deviation ( which should not be necessary if you buy the packet/APRS ready radio instead ). Remember that if you use SSB on the radio end- both ends of the data circuit need to have an SSB radio.
     
  6. AA4PB

    AA4PB Ham Member QRZ Page

    It depends on what data mode you want to use on VHF. For example, PSK31 and FT8 require a SSB radio while packet modes require an FM radio on VHF.
     
    KB0MNM likes this.
  7. K8JD

    K8JD Ham Member QRZ Page

    Yes you can do DIGI with a FM VHF radio !
    I tried packet radio using an FM radio back when it was the big thing. It took me a week to connect and set up all the stuff that needed done. The manual for the controller was 40 pages (I had to print it off a disk) and near incomprehensable to me.
    Finally I figured how to make sense of the garble appering on my screen when someone came on the freq. Then I got all the procedures figured out and contacted someone who sent an invitation to QSO. (kinda like a DIGI CQ). Made one "connection" that lasted two text lines and that was it !! End of my DIGI experience.....
    The packet controller is buried on a shelf in my garage.
     
    AD5HR likes this.
  8. KC3RN

    KC3RN Ham Member QRZ Page

    There is some limited digital activity on 2m FM outside of packet. Our club runs a weekly NBEMS training new via our linked repeater system. We use the FLDIGI software and usually run MT-63 as the operating mode, but will occasionally move to MFSK or even Olivia (rarely).

    The main point of the net is to practice handling messages and emergency traffic. We usually start by sending around an ICS-214, and move on from there as time permits.

    Some of us are using mutli mode rigs like the FT-897/857 or IC-746/7100 etc with a soundcard interface. In other cases guys are using simple handhelds, an Android tablet, and acoustic coupling, which works just fine.
     
  9. AI3V

    AI3V Ham Member QRZ Page

    What part of no is confusing?

    Rege
     
  10. WA9SVD

    WA9SVD Ham Member QRZ Page

    Perhaps the "N," or maybe the "O?" Now I'm confused:confused::rolleyes:.
     

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