Mobile setup help

Discussion in 'On the Road' started by KJ7BRR, Aug 15, 2019.

ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: MessiPaoloni-1
ad: Left-3
ad: Left-2
ad: L-MFJ
  1. KJ7BRR

    KJ7BRR Ham Member QRZ Page

    Hi all, I am super green with antennas and I trying to get a 2m mobile setup in my '10 FJ Cruiser. I could use a little guidance with connectors/adapters.

    I have been following this particular setup, trying to get something similar going for my own ride: N4LS/M mobile ham radio installation (I will note that I am currently just planning to connect into an HT radio, as I am still looking for the right mobile station for the truck. So eventually will have a more substantial setup but is just going to connect to an HT at the moment)

    Right now I have the following items:
    Hamstick: ProComm PC144 - 2-Meter 144 MHz 3dB Gain Ham Stick Antenna 350-Watt Black
    Antenna mount w/ coax: K400S Trunk/Hatchback Mount

    The antenna mount is an SO-239 base and the hamstick is a 3/8-24 threaded connector. How the heck do I get those two connected together? My internet sleuthing and research has not been fruitful so far, as I guess I just don't have enough knowledge/experience yet.

    In the video, N4LS appears to have something substantial connecting the two, but not sure what it is (photo for reference):

    Not sure if this is better suited for the antenna forum, but thought I would try here first. Any help that can be provided is much appreciated!!
  2. K7JEM

    K7JEM Ham Member QRZ Page

    OK, I think I found the video. In the one I am looking at, the antenna mount he has is a 3/8-24 mount, not an SO-239 mount. He also has a quick disconnect on it, it is used primarily for HF operation on that side, not VHF.

    He has a VHF/UHF antenna on the other side of the vehicle. A 3/8-24 mount is not really ideal for VHF, but it will work.

    I think you have a couple of choices: Get a mobile antenna with a PL259 that will screw directly to your mount, get a similar mount to what you have, but with 3/8-24, then attach your 2M Hamstick, or get a PL259 to 3/8-24 adapter, like the MFJ 7710:


    The best option is to get a totally different mount, something similar to what you have, but using an NMO mount. Then get an NMO antenna to fit that. NMO is the preferred mount for VHF and UHF, there are hundreds of different antennas that will attach to it. 3/8-24 is mostly used for antennas below 30MHz, although it can be used up to 2M, but not really much higher than that. The same antenna mount with an NMO is called the K400SNMO.
  3. N7EKU

    N7EKU Ham Member QRZ Page


    Looks like what you needed to buy was the K400-3/8c mount. If you can exchange it, that's what I would probably do.

    However, searching for UHF to 3/8 adapter you can find many brands. MFJ has one: and I'm sure many others have them too. Probably available at HRO and DX Engineering too.

    73 and cheers,

  4. KJ7BRR

    KJ7BRR Ham Member QRZ Page

    :eek:oh my gosh, you are right! That would solve the entire problem. I will see if I can exchange for the correct antenna mount! I didn't realize they made one for 3/8-24, not sure how I missed that. (And if worse comes to worse and I can't exchange, I will take a look at that adapter.)

    Thank you very much! 73!!
  5. KJ7BRR

    KJ7BRR Ham Member QRZ Page

    Can you explain why it typically isn't ideal? Looking to learn! :) And thank you for all the info!
  6. K7JEM

    K7JEM Ham Member QRZ Page

    The 3/8-24 is designed for lower frequencies, typically below 30MHz. The mount, and antennas that screw onto it, start to become "lossy" in the VHF area. That mount, which is just a bolt, poses no problems when the frequency is low, and it is a pretty strong mount, hence the popularity on HF frequencies.

    The SO239 and NMO mounts function very well at VHF and UHF frequencies. The NMO, especially, is the choice of virtually every fire dept, police dept, utility, railroad mobile, and every other sort of professional radio user. You will not find any other type of antenna mount used in the professional world on VHF, and also most amateur antennas as well. Hence, the number of antennas abounds, virtually every antenna maker will manufacture an antenna to fit that mount.

    That being said, the SO239 mount you have is OK too. You just won't find the sheer quantity of antennas available for that mount. Manufacturers like Diamond and Comet and a few others will make a variety of antennas for that mount.

    The other thing to be aware of is the connector on the end that fits your radio. The current mount you have is specified as an SMA connector, which fits handheld radios like Yaesu. Many mobile mounts that come with cable will come with a PL259 connector, which will fit a mobile radio, so make sure that what you order will fit the radio. The K400-3/8C mount mentioned above comes with a PL259, which is different than the model you have.
    KJ7BRR likes this.
  7. N7EKU

    N7EKU Ham Member QRZ Page

    KJ7BRR likes this.
  8. W5LZ

    W5LZ Ham Member QRZ Page

    The mainest (technical word, don't worry about it) thing with an antenna mount is will it securely hold the antenna that's being put on it. An NMO is a fine mount but not for larger antennas, HF for example. So the lower in frequency you go the larger the antenna -and- the mount. Not much harm in using a mount too large, but there's a definite reason not to use one too small. You can make anything 'work' if you want to bad enough. Sometimes it makes for a very interesting topic of discussion.
    KJ7BRR likes this.
  9. KC9ONY

    KC9ONY Ham Member QRZ Page

    I guess I am not clear as to why you are using a hamstick for 2m. Are you planning to also
    use an HF rig and just one antenna mount? Are you planning to have two mounts like he has? One for HF and one for VHF/UHF? Are you looking for a 2m all-mode rig? Not being critical,
    just trying to understand your setup goal.

    As noted in his video, he has a VHF/UHF mount with an antenna that looks to be a Larsen
    The Larsen antenna is pretty highly rated, especially by K0BG. Again, that is an NMO mount.

    Nothing wrong with starting out with an HT. Many of us have done that!
    Some of us used a mag mount, too. ;) I'm now using a K400C/NMO on my
    hatchback. Just have to remember to check the Allen screws are tight, now and then.
    The purists would say to drill a hole in the roof, but this works for my situation.
    I also installed an Icom dual band radio after a while, as I needed more power than
    the HT would provide.

    Good luck with the project, and take pics so we can follow along! :D

    P.S. You could also post to the Mobile Radio Systems forum, as some might not look here.
    Last edited: Aug 15, 2019
    KJ7BRR likes this.
  10. KJ7BRR

    KJ7BRR Ham Member QRZ Page

    Hello all, apologies for the delinquent response! I am still working on my mobile setup. The 2m hamstick I ordered turned out to be on backorder, so it won't ship out until Sept 30 and then I will finally assemble everything once I have the antenna in hand. To answer some questions above, the goal is an all 2m rig for the moment, since that is my main method of communications currently. I actually purchased an ICOM IC-2300H since I last posted, so that is the radio I plan to use in my rig. I will likely expand to another radio and other bands later, but figure this setup gives me the ability to easily switch out hamsticks should I choose to head to another band.

    Thanks all for the great replies and dialogue. As a newbie, this is much appreciated! I have quickly learned that...well, I still have a lot to learn! :D


Share This Page

ad: portazero-1