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Marine Mobile Rig on 2m?

Discussion in 'VHF/UHF - 50Mhz and Beyond' started by WA7F, Jul 13, 2021.

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  1. WA7F

    WA7F Premium Subscriber QRZ Page

    Or an eye poker. Or fly line catcher. Beyond wide band SDR RX applications, I can’t really think of a good use for a discone.

    On second thought … the discone does make an excellent sock dryer.
     
    K6CLS likes this.
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Icom makes VHF marine radios, typ coverage 156-162 MHz or something; but because they also manufacture 2m stuff, Icom tech support may have information about using one of their VHF marine radios on 2m in such a way that doesn't violate any regulations (I don't know, but it can't hurt to ask).

    Have you contacted them about this?

    I wouldn't worry much about the antenna, if the rig can cover it. A whip tuned to about 152-153 MHz is likely "good enough" to cover 2m and VHF marine channels with a good enough match that the rig will be able to transmit into it.
     
  3. WA7F

    WA7F Premium Subscriber QRZ Page

    Hi WIK,
    I haven’t attempted to contact Icom but, I can give that a try. We have the same thought process on the vertical antenna. Take HT antennas as an example, they probably aren't much better than dummy loads and they are Ok for VHF/UHF. With only a couple of feet of coax a tuning network might actually be feasible as well.
     
  4. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    The solution is 2 radios or go illegal.

    Just about anything from China will do those Frequencies.
     
    KJ7OTM likes this.
  5. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I can tell you that Icom will not recommend doing that l/ for sure.
     
  6. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I don't think marine VHF radios use CTCSS, which is required for most amateur repeaters. Not required for some, and not required for simplex.

    If one doesn't need CTCSS, I can design a transverter (external to the radio) that down converts 156 to a frequency in the 2m ham band, say 146 MHz. Analog circuit, L.O., mixer, lots of filters, amplifier (and same stuff in reverse for receiving, except "amplifier" would become "preamplifier").:p

    Hams can build and use anything they want if they can measure spectral purity of transmissions when they're done. That wouldn't be a rig modification, it would be a separate box, though. A usability problem persists doing that, as Marine CH 05A through 28A are spaced 50 kHz apart each (not 15 or 30 like hams use on 2m) and all simplex. Then, CH 24-28 are all split frequencies, etc. My approach would probably work best if the op could stick to 146.52 or some common simplex channel and just leave it there, for simplicity.:)

    Surely a separate 2m rig would be cheaper and easier, but a very good duplexer could be built to use a single antenna on both radios; Marine HPF with a low cutoff of 155 MHz and Amateur LPF with a high cutoff of 149 MHz. These are pretty close, but it's possible, especially at the low power the Marine rigs run (typically 25W output max). That would be an interesting project.
     
  7. WS9K

    WS9K Ham Member QRZ Page

    Why buy a boat, if you can only mount one radio in it

    the way I see it, . . . . you need 3

    VHF Marine

    Dualband ham

    HF

    I've operated AIR MOBILE before, but never been HF maritime mobile.
     
  8. WA7F

    WA7F Premium Subscriber QRZ Page

    I did send an email off to Icom and I’ll share the response if I receive one. Steven, thanks for the offer to build a transverter but, the whole idea was a simple solution. I’ll probably just install a marine rig and carry a HT for 2m when needed.

    I actually did buy the boat for fishing rather than operating so HF isn’t an option. If the XYL ever gets her way and we buy a big slow pontoon floating deck of a boat with plants and humming bird feeders then maybe a HF rig would help maintain my sanity. :)
     
  9. K7JEM

    K7JEM Ham Member QRZ Page

    Kenwood TK5720 is a mobile radio that has part 80 certification. There are actually lots of older part 90 mobile radios that have part 80 certification, but not all of them.
    upload_2021-7-14_22-31-13.png
    https://www.ameradio.com/doc/FCC_Part_80_Marine_Band_Certification.pdf
     
    WA7F likes this.
  10. K7JEM

    K7JEM Ham Member QRZ Page

    upload_2021-7-14_22-40-45.png
    upload_2021-7-14_22-42-52.png
     
    WA7F likes this.

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