TYT MD-380/MD-390 VHF Frequency Steps

Discussion in 'General Technical Questions and Answers' started by K1FDD, Oct 4, 2016.

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  1. K1FDD

    K1FDD Ham Member QRZ Page

    Good Evening All,

    I am trying to find out if the VHF 380 and/or 390 will do the US Commercial (Part-90) frequency steps (2.5Khz, 7.5Khz, etc). I know the deviation is 2.5 narrow, but I'm looking for the specific frequency steps. For example, can they do 156.2325 or 158.4075?

    Thanks,
    John Marcel / K1FDD
    Penacook, NH USA
     
  2. WA7DU

    WA7DU Ham Member QRZ Page

    Suggestion:

    If you cannot get your hands on a user's manual, download the programming software to see what frequency step options are included in that software.
     
  3. KD4MOJ

    KD4MOJ XML Subscriber QRZ Page

    12.5 & 25 Khz.

    ....DOUG
    KD4MOJ
     
  4. K0RGR

    K0RGR Premium Subscriber QRZ Page

    Looking at the programming software, that is what I thought, too, but on my 400 MHz unit, I could input a frequency 400.9999 MHz, and it took it. I don't have the radio in front of me to play with it, so I don't know if it will actually load that and work. I bought mine for DMR, but it does work well on analog FM. I don't see a way to set it for narrow FM, though, so probably not Part 90.
     
  5. K1FDD

    K1FDD Ham Member QRZ Page

    The radio is Narrow FM automatically, at least to 12.5Khz. The misconception 12.5Khz also indicates channel spacing, regardless of deviation. 12.5Khz (or 6.25Khz). Spacing is typically accurate for the UHF band, but not for Commercial/Public Safety VHF High-Band. In their segments, they've gone to 7.5Khz spacing w/3.75Khz planned sometime in the future. For example, with a few exceptions, 2 Meter ham will normally go 146.790, 146.805, 146.820 (15Khz). Commercial VHF High Band will go 155.790, 155.7975, 155.805, 155.8125, 155.820 (7.5Khz).

    The reason I ask is most established ham radios from Yaesu, Kenwood, etc will do narrow, but will not center. So 155.7975 is either 159.795 or 155.800. The Wouxun radios I've had in the past (KG-UV6X) will center properly. I was kind of hoping before I purchased a VHF MD-380 (or 390), I knew if it would center properly.

    FCC Part 90 PS Pool
     
  6. KA9JLM

    KA9JLM Ham Member QRZ Page

    If you set the radio on a even frequency, Like 155.800, Then set the step rate, It should step the proper amount.

    I have chased my tail trying to figure it out before.
     
  7. KD4MOJ

    KD4MOJ XML Subscriber QRZ Page

    Technically the MD-380 does a 6.25 bandwidth (in DMR mode) but the CPS in the bandwidth section cannot set it to 6.25. DMR takes care of the two 6.25 splits within the 12.5 khz "channel". Now you can type the 6.25 frequency in the software (e.g. 444.00625) and it saves, but I haven't tested it out yet to see if that is the actual transmit frequency.



    ...DOUG
    KD4MOJ
     
  8. K1FDD

    K1FDD Ham Member QRZ Page

    Thanks everyone for teh replies and info. I did end up getting a VHF MD-380 to add to my UHF. They're pretty good radios. I don't expect Commercial Grade, but they definitely give more than $100 worth of performance and quality.

    73's all.
    John/K1FDD
     

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