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First mobile Jeep (jk) Antenna

Discussion in 'On the Road' started by K2IRE, Aug 18, 2016.

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  1. K2IRE

    K2IRE Ham Member QRZ Page

    I'm ready to put a mobile antenna on the Jeep for use with my HT. Don't plan on putting it on the front (I know the front would probably be optimal), so I was thinking either something off of the (former) tire carrier, a magnetic mount (steel bumpers), or even drilling a hole and installing something permanent in the bumper (I'm having the bumper Linex'd in the fall). Being that I'm new, and having a hard time sorting through all the info on the internet I figured I'd start here. For antenna I'm thinking maybe 36"-50ish".

    Thanks for any advice.

    IMG_20160817_170701378.jpg
     
  2. HB9FUH

    HB9FUH Ham Member QRZ Page

    What sort of antenna are you planning?
     
  3. K2IRE

    K2IRE Ham Member QRZ Page

    I'm not even sure. I was initially thinking a Comet 2x4SR off of the gate area with a mount like this. For a clean easy look I could run my coax through the door vent behind my license plate. But this is a cb antenna mount I think and with my little knowledge they are different.

    (not my pic)

    [​IMG]
     
  4. KD2IAT

    KD2IAT Ham Member QRZ Page

    The real question is not so much what type of antenna you're considering, but what frequency range? Then, what type?

    I don't profess to have all the different antenna model numbers memorized, so when you toss out "Comet 2X4SR" with no other info, I have to scratch my head and then go google it. So, in the absence of other info, I am assuming that you do mean 2M/70CM

    You also haven't mentioned that removable fiberglass roof. If it is going to stay on the Jeep most of the time, we need to know that.

    And what is your intended use of the Jeep and the HT? Daily driver? Off road hawg? Somewhere in between? All of these factors greatly influence what recommendations you will receive.

    And do you plan to upgrade to a mobile someday? If you do, that hood location goes from very good to not so good based on the power of the mobile.

    Assuming that you are talking 2M/70CM, ground plane is very important, especially if you're trying to boost performance of an HT.

    A quarter wave 2M spike is about 19" tall. Mounting it in the center of the metal hood is the best location as long as you're using a low power HT and don't want to do any install on the roof. And, has been mentioned many, many times before here, it will also work just fine for 70CM. The other best location is the center of the fiberglass roof. Yes, you will have create a ground plane, but that is very easy to do with a variety of materials.

    Yes, that mount is sometimes marketed as a CB mount, but it's really a 3/8" bolt mount. HF antennas in many frequency ranges can be purchased with 3/8" bolt bases and people get very good results with that mount at HF. But it's a bad, bad location for 2M/70CM unless you split for a no ground plane mobile antenna. There's no mention of that in the info on the Comet. You can get that bracket with a 3/4" hole for NMO mounting which most 2m/70CM antennas are anyway.

    So let's flesh out what you want do and how you want to use the Jeep first and then we can offer solutions and ideas. Otherwise, we're just shooting in the dark.
     
  5. K3UJ

    K3UJ Ham Member QRZ Page

    Forget the bumper, too low.
    Agree with IAT, lets get usage and band answered.
    Spend some time looking around here; http://www.wranglerforum.com/f40/ They have discussed this many times, though not all the information is correct.
     
  6. WA2LXB

    WA2LXB XML Subscriber QRZ Page

    Agree with above posters. I'm going to talk CB for a minute...

    I've had a Jeep Wrangler for 25 years, and have worn out and broken several CBs and antennas. I also have experience with other Jeep owners' CBs in RF environments ranging from gorges to open roads to mountain tops to cities. As with my Wrangler you don't have a steel roof, which makes the optimal mobile ground plane tough. Get the radiating section of the antenna above all steel, especially the windshield frame, will give you the most even omnidirectional propagation-which is important for the best propagation of CB, simplex and repeaters..and mobile DX. If you leave the roof on, you may want to go with a roof mount with wire mesh adhered to the underside of the roof for a ground plane (mentioned in some of the references below) or an antenna with an attached radial ground plane. If I were to be honest, I'd admit that the best propagation I've had with CBs on my Jeep are with a base-loaded 62 inch Wilson 1000 whip mounted magnetically and located in the center of the hood. The radiator did not completely clear the windshield frame.

    RE my dual band HT...I stick my Smiley Triband telescopic antenna out the sunroof and call it good. If I were to mount a permanent 2M/70cm antenna on a vehicle I'd want more power than a HT, and I'd spend a few hours researching antennas and vehicle-specific installs.

    If I had your Jeep and an HT, I'd go for the best hood-mounted base-loaded mag mount I could find based on a thorough internet search and see how you like it. If you want a more permanent mount, I'd go for the roof and mesh ground plane and get used to breaking it off on parking garages :) or with a dual bander with its own radial ground plane. It also wouldn't hurt to borrow an antenna analyzer/SWR meter to see what is really happening with each configuration/option.

    A few reads for you RE mobile antenna ground planes:
    http://www.olypen.com/craigh/antennab.htm
    http://www.jk-forum.com/forums/jk-c...-mount-your-cb-ham-antennas-your-jeep-227276/
    http://www.hamradioschool.com/going-mobile-install-a-station-in-your-vehicle-part-1/
    http://www.eham.net/articles/21303
    http://www.eham.net/ehamforum/smf/index.php/board,21.0.html
    https://forums.qrz.com/index.php?threads/increase-mobile-performance.531117/
     
    Last edited: Aug 18, 2016
  7. K2IRE

    K2IRE Ham Member QRZ Page

    Sorry about the lack of info and I appreciate the questions and constructive criticism. We have a saying around work that applies here, "I don't even know what I don't know." This is all so new I've gotten pretty overwhelmed with all the info.

    I was thinking a 2/70 dual band antenna. I do have a hardtop (that doesn't come off). As a side, I prefer to take the doors off, leaving the top on for shade. I do park in a garage every night, which is one reason that I was thinking of going off of the back somewhere. As for usage, I try to get out on trails twice a month, but with two small children (and work) it doesn't always happen. The Jeep is also my daily driver.

    I do plan on going with a dedicated mobile someday, but to be honest the HT (Baofeng 82HP) will probably be in the Jeep for awhile. I need to first figure out something for the home, pay for it lol, and then start saving for a mobile.

    As for mounts, I obviously open for suggestions.

    I hope I answered the questions so far. Sorry again about being the FNG...
     
  8. KD2IAT

    KD2IAT Ham Member QRZ Page

    Erik,

    You are following an ideal path here. I suspect that this thread may well end up being great reading for anyone contemplating outfitting a Jeep with 2m/70cm. The info that's coming up is fantastic. And you will be fairly well educated about this when done.

    My daughter has a 4door Wrangler and her hard top comes off in the spring, replaced with a soft top for the summer months. If memory serves, she has one of those hoists made for Wrangler hard tops in her garage so pulling or remounting it is a breeze. I'm guessing you may want to remove yours someday, too. Coming from the world of commercial and public safety installs, I tend to think first in terms of roof mounted 1/4 wave antennas in both frequency ranges. Typically, a 1/4 wave VHF antenna is at most 19" tall, and easily handles being bent over a bit in garages, at least on passenger cars and medium height vehicles. Depending on lift and tires, you may or may not fit in that category. My 4x4 Super Duty sits pretty high, but the only time I scrape the VHF antenna is in ramp garages. I've yet to break one off, but I do have spares. The UHF antenna is barely 7" tall so it isn't in danger of being bent or broken off in a garage.

    A lot of folks get the vehicle specific bracket and mount an antenna on the side of the hood/fender. You get a very lopsided radiation pattern when you do this, and if you're running any mobile power, you've got that rf at chest height and just a couple of feet from the driver or passenger. Many folks think that is a recipe for medical problems down the line, and I generally agree with that. Better to have the rf above my head and shielded from me with the metal roof, or whatever ground plane is installed on a fiberglass one. But then I run a 50 watt mobile on public safety and amateur frequencies. 10 watts or less isn't enough to raise a concern.

    I really like Hugh's suggestion on the mag mount in the center of the hood for starters with your HT. You will get a good radiation pattern, and you can always move the antenna to a permanent mount someday. That's why NMO in both mag mount and permanent is the way to go. And, believe me, you'll find another use for the mag mount, too. The HT is low power so rf is not a concern.

    The Comet you looked at is available in a fold-over configuration so the roof mount may be an attractive choice at some point. There are several different methods of creating a ground plane in a fiberglass roof so don't rule it out.
     
  9. K3UJ

    K3UJ Ham Member QRZ Page

    I'll join in, the mag-mount is a good way to start. Inexpensive and not permanent.

    On my Wrangler I had a ball mount on each side of the tub. One for CB the other for 2M. Using quick disconnects sometimes using the 7' Hustler collinear, other times a shorter Hustler. Now I would guess you are not ready to take a hole saw to your Jeep, mine was old enough to not matter.

    Take your time, read around.
     
  10. WA2LXB

    WA2LXB XML Subscriber QRZ Page

    Erik,
    Check this one out: http://www.k0bg.com/ Looks like Alan has collected a cornucopia of mobile RF goodness.
     

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