1. Welcome to Tacoma World!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tacoma discussion topics
    • Communicate privately with other Tacoma owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Help! Antenna Behind Cab Mount and Ground

Discussion in 'Technical Chat' started by CowboyTaco, Mar 29, 2015.

  1. Apr 16, 2015 at 1:04 PM
    #41
    VE7OSR

    VE7OSR нет войне

    Joined:
    Dec 12, 2011
    Member:
    #68608
    Messages:
    5,774
    Gender:
    Male
    First Name:
    Rob II
    Okanagan, Canada
    Vehicle:
    05 DCLB TRD Sport
    Armour: All-Pro Skid plates - IFS, transmission, and transfer case. Pelfreybilt rear standard plate bumper, Metal Tech Sliders w/ kickout and dimple die filler plates. Front Suspension: OME 885 + NitroCharger 9000 shocks + 1/2" spacers for a 3" lift. Superbumps replacing stock bumpstops. Camburg ball joint UCA SS braid brake lines Future: ADS Extended length, extended length UCA BJ to increase droop capability Rear Suspension: All-Pro Expedition rear leafs, Walker Evans 27" rear shocks, extended rear brake lines (Wheelers Offroad), U -bolt flip kit, rear Timbren bumpstops. Future: Hammer Hangers, Shock relocate, ADS 12" or 14" shock. Interior: Weatherteck floor liners - front, Wet Okoles- front, ScanGauge, LED interior & map lights. Power moonroof. Exterior: Raider Cobra canopy, retrofit headlight by Insight, LED bulbs all around, modified flasher unit for LEDs. Rear diff breather mod. Front diff vibe problem, driver's side needle bearing replaced with ECGS bushing. yet to install: HID Blazer Fog Retrofit, LED Flood & Spot, + switches, fuse panel. swaybar relocate blocks (build my own)
    Here's a link
    http://www.cbantennaguide.com/Coax_Basics.htm

    EDIT: (there should be printing on the outside of the cable to let you know which cable you have.)

    Impedance of the transmitter output, cable, and antenna all need to be the same in order to achieve a 1:1 SWR. That is the ideal. electrical properties such as resistance, capacitance, inductance all combine to produce the overall term called impedance. Here's the kicker - Impedance is dynamic, these properties change with frequency. That's why you trim the antenna length to the frequency you intend to use the most.

    Impedance matching is important to maximize the energy transferred. In a 1:1 SWR 50% of the energy is absorbed in the transmitter/receiver, and 50% is RF energy into the atmosphere. If the impedance is less than matched, then when transmitting power is reflected back to the transmitter, overheating or damaging the transmitter.

    http://en.wikipedia.org/wiki/Standing_wave_ratio
     
    Last edited: Apr 16, 2015
  2. Apr 17, 2015 at 5:52 AM
    #42
    maineah

    maineah Well-Known Member

    Joined:
    Mar 24, 2011
    Member:
    #53641
    Messages:
    6,585
    Gender:
    Male
    First Name:
    Tim
    Maine
    Vehicle:
    4X4 SR5 V6 6spd
    There is not such a thing as 1:1 match no install is perfect it would mean every thing transmitted went out the antenna that would be a wonderful thing but it ain't happening. 1.1:1 yes that is possible. If your SWR is up in the 3:1 range some thing is wrong. The cargo rails are grounded the coax braid is soldered or crimped to the outer shell of the PL259 it is the return path to the transmitter so it's mounting needs to be a good ground it does not need to have 5 extra ground wires frankly it only needs to have a good ground at the mounting point. There should be nothing more than meter resistance between both ends of the coax braid (very close to the same reading as touching both meter leads together) and both ends of the center connector and infinite resistance between the two. Do not get over whelmed with ground planes no matter what you do vehicles are terrible ground planes the biggest issue with them is ground losses due to the fact they are close to the earth in order to deal with that your truck would need to be at least 5.5 meters high. If some one tells you it is a ground plane issue ask them how come hand held radios work. Standing next to an antenna while you are trying to tune it will throw your reading off. When you test the antenna test it in the center frequency of the band do not try to tune it on ch one and expect it to be tuned on ch 40 the band width is too wide for a perfect match on both ends. In most cases ch 19 is fine because that is most likely where it will be used the most any way. If you have a friend that is a general class ham or higher ask them for help most probably have made their own antennas close the the same frequencies you are trying to fix.
     
  3. Apr 22, 2015 at 8:38 PM
    #43
    CowboyTaco

    CowboyTaco [OP] $20 is $20

    Joined:
    Aug 19, 2010
    Member:
    #41928
    Messages:
    6,744
    Gender:
    Male
    North Georgia
    Vehicle:
    11 TRD Sport
    Impedance of the receiver says 50 Ohm.

    https://midlandusa.com/wp-content/uploads/2012/06/1001LWX-Manual.pdf

    According to the Q&A on Amazon, the cable is also 50 Ohm.

    http://www.amazon.com/RG-58A-Coaxia...=UTF8&qid=1429757291&sr=8-1&keywords=cb+cable

    Reading through the manual also suggests grounding the body of the radio. I'm going to look into this as a next step.

    Not sure the impedance of the antenna, but it is a Firestik II and I'm pretty sure that one is compatible.

    I'm also thinking that maybe the L connector being so close to the power inverter might cause some interference.

    Next steps:
    *Possible grounding radio body.
    *Removing Radio from current location, though not sure where else to locate.
    *Re-routing coax cable.
     
  4. Apr 23, 2015 at 4:20 AM
    #44
    maineah

    maineah Well-Known Member

    Joined:
    Mar 24, 2011
    Member:
    #53641
    Messages:
    6,585
    Gender:
    Male
    First Name:
    Tim
    Maine
    Vehicle:
    4X4 SR5 V6 6spd
    They are all 50 ohm radio, cable, and antenna. Grounding the radio that is are ready grounded probably won't do a thing. If the radio plays it is grounded both through the power cord and (hopefully) the coax. If the inverter is off it makes no electrical noise and will have no effect on SWR even if it's on . Inverters are noisy but it is unlikely it is coming down the cable if there is inverter noise in the radio more than likely it's coming from the power cable.
     
  5. Apr 27, 2015 at 1:12 PM
    #45
    Sandman614

    Sandman614 Ex-Snarky TWSS elf, Travis #hotsavannahdotcom

    Joined:
    Oct 26, 2010
    Member:
    #45273
    Messages:
    35,541
    Gender:
    Male
    First Name:
    Tim
    Garner, NC/Boone, NC
    Vehicle:
    '06 SR5 Off Road
    ARB Front Bumper, Projector Headlights w/Slimcubby 4300K HID's, Oznium LED's, LED taillights, DIY Washable Cabin Moose Filter, Sockmonkey SR5 Off Road, Aux Audio plug, OME 886x, OME Nitrochargers, Wheelers 3 Leaf Progressive AAL, ImMrYo Rear-View Mirror Lift Bracket, Dodge D-Rings
  6. Jul 6, 2015 at 6:37 AM
    #46
    ancient11

    ancient11 Well-Known Member

    Joined:
    Dec 23, 2013
    Member:
    #119094
    Messages:
    519
    Gender:
    Male
    First Name:
    robert
    tallahassee
    Vehicle:
    2019 4 cyl srsx ac
    A $10.00 radio with a $100.00 antenna will out talk a $100.00 radio with a $10.00 antenna. Don't skimp on any antenna parts. Wilson, Hustler, etc.and you'll be heard.
    The local deer hunters all use modified 10 meter radios with 102" whips...otherwise we would never know where anybody was at in this 600,000 acre national forest
     
  7. Jul 6, 2015 at 2:33 PM
    #47
    maineah

    maineah Well-Known Member

    Joined:
    Mar 24, 2011
    Member:
    #53641
    Messages:
    6,585
    Gender:
    Male
    First Name:
    Tim
    Maine
    Vehicle:
    4X4 SR5 V6 6spd
    If you are using a modified 10 meter radio on 11 meters you are over the power limit by a wide margin even on AM. A 102" whip on 11 meters is to short by about 6" In a radius of 600,000 acres I would not rely on 11 meters if it meant staying alive even with a 25 watt carrier. But you are right a junk antenna will make a merger 4 watts a lot worse. A whip at 108" is right about a 1/4 wave antenna on 11 meters and if you are going to get top notch results it would be the hot lick a right pain in the backside because of it's size but it's the best you can do on 11 meters.
     
  8. Jul 6, 2015 at 5:37 PM
    #48
    ancient11

    ancient11 Well-Known Member

    Joined:
    Dec 23, 2013
    Member:
    #119094
    Messages:
    519
    Gender:
    Male
    First Name:
    robert
    tallahassee
    Vehicle:
    2019 4 cyl srsx ac
    We talk on the low bands, not 11 and most of the whips have hd springs and a ball mount, making them 108". We hunt quite a few miles from paved roads to reduce the chances of our hounds being hit by cars.
    In the background on most channels there are Spanish folks talking with unthinkable power.....they can barely be squelched out. Cell phones don't work after about a mile into the woods. Without the radios we would have to send smoke signals.
    Most have enough respect not to jabber on them in town.
     
  9. Jul 7, 2015 at 5:12 AM
    #49
    maineah

    maineah Well-Known Member

    Joined:
    Mar 24, 2011
    Member:
    #53641
    Messages:
    6,585
    Gender:
    Male
    First Name:
    Tim
    Maine
    Vehicle:
    4X4 SR5 V6 6spd
    A lot of the Caribbean countries have different restrictions on power output and don't enforce the restrictions any way. In the woods here in Maine they use the VHF marine bands that's not legal either. A tech class license will give you privileges in the 10 meter band and you can run 100 watts. 10 meters with no opening is strictly ground wave and not something I would be comfortable with for emergency communications. Being a ham and going to the effort to become licensed I feel very strongly about using equipment with no regard for those that are licensed to use those bands either as hams, public service personal, or commercial operations. When the low bands are open you can be heard thousands of miles away radio waves have no boundaries.
     
  10. Jul 7, 2015 at 6:55 AM
    #50
    ancient11

    ancient11 Well-Known Member

    Joined:
    Dec 23, 2013
    Member:
    #119094
    Messages:
    519
    Gender:
    Male
    First Name:
    robert
    tallahassee
    Vehicle:
    2019 4 cyl srsx ac
    Thanks for the info. Going to be looking into getting the entry level tech license.
     
  11. Jul 7, 2015 at 4:11 PM
    #51
    maineah

    maineah Well-Known Member

    Joined:
    Mar 24, 2011
    Member:
    #53641
    Messages:
    6,585
    Gender:
    Male
    First Name:
    Tim
    Maine
    Vehicle:
    4X4 SR5 V6 6spd
    Good for you it's a whole new world outside of CB.
     
To Top