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Which mobile antenna would you choose for distance?

Discussion in 'CB Antennas' started by Capt Crunch, Apr 20, 2021.

?

Which one would you choose for straight talk distance?

  1. 5ft Skipshooter

    35.3%
  2. Predator 10K K-1-17

    64.7%
  1. HomerBB

    HomerBB Sr. Member

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    Now, DB, I didn't expect you to take me seriously, but thanks!


     
    Capt Crunch and Slowmover like this.

  2. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    The one thing that gets me is you will see someone switch antennas and report 5 S units of improvement.
    Unless the Antenna replaced was a total dummy load, I have never see increases like that.

    73
    Jeff
     
  3. Slowmover

    Slowmover Supporting Member

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    Do much fishing, do ya?

    .
     
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  4. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    Not as much as I'd like.

    73
    Jeff
     
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  5. Dmans

    Dmans Sr. Member

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    Same for most of us- I am sure!

    73
    David
     
  6. Recon

    Recon NY 881

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    I stand corrected and agree. The coil is not welded. I was thinking of another open coil antenna with a flat aluminum coil. Another reason to store the 10K antenna in a protective tube in the bed of a pick-up is to prevent the coil from distorting. Now how would I know that? Ha! ha! ha!
     
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  7. Slowmover

    Slowmover Supporting Member

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    5db gain antenna . . . or 5” & 15-lbs bigger fish
    I swear!
     
    #52 Slowmover, Apr 30, 2021
    Last edited: Apr 30, 2021
    Capt Crunch likes this.
  8. Slowmover

    Slowmover Supporting Member

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    Was a 6” SS riser from rfjunk and antenna whip base-trimmed so as to match the same total antenna height it had with 6” spring.

    And that other thread has taken off again.
     
  9. freecell

    freecell BANNED

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    the one with the least amount of loss
    and the highest radiation efficiency.

    • Physical antenna length = 45° (λ/8)
    • L = 1.37 meters
    • Design frequency = 27.205 MHz.
    • Ground-system loss resistance = 15 Ω.

    Quarter-wave full size
    (reference values):
    Rrad = 36 Ω
    Rground = 15 Ω
    Rant loss = 0 Ω
    Zfeed = 51 Ω
    Eff = 71%
    Loss = 1.5 dB

    Top-loaded vertical (capacitance
    hat or horizontal T wire, λ/8 size):
    Rrad = 18 Ω
    Rground = 15 Ω
    Zfeed = 33 Ω
    Eff = 55%
    Loss = 2.6 dB

    Top-loaded vertical (coil with
    capacitance hat at top, λ/8 size):
    Rrad = 18 Ω
    Rground = 15 Ω
    Coil Q = 200
    Rcoil loss = 2.1 Ω
    Zfeed = 34 Ω
    Eff = 53%
    Loss = 2.8 dB

    Center-loaded vertical
    (coil with whip, λ/8 size):
    Rrad = 12.7 Ω
    Rground = 15 Ω
    Coil Q = 200
    Rcoil loss = 8.6 Ω
    Zfeed = 33.5 Ω
    Eff = 38%
    Loss = 4.2 dB

    Base loading, λ/8 size:
    Rrad = 6.2 Ω
    Rground = 15 Ω
    Coil Q = 300
    Rcoil loss = 1.3 Ω
    Zfeed = 22.5 Ω
    Eff = 28%
    Loss = 5.6 dB

    (λ/8 size = 4.5 feet, 1.37 meters
    (physical length) @ 11 meters

    Rrad divided by Zfeed = Eff. %
    50Ω divided by Zfeed = VSWR

    this data also provided in response to the article on copper electronics
    linked to elsewhere in this site entitled "big coil antennas exposed......" http://www.copperelectronics.com/articles/big_coil_antennas_exposed.php

    that's some funny stuff.
     
    #54 freecell, Aug 21, 2021
    Last edited: Aug 22, 2021
  10. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    Thanks for posting this, I am running a Sirio 5000 mag mount on my truck. Looking at the data you shared, I really need to try the 9 ft whip I have laying around. I have a fiberglass cap on the truck, so I am thinking bumper mount unless there is a better idea?
     
  11. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    One of the many questions on antennas' I get asked is...

    Where should I put this - "thing" - referring to the antenna itself.

    You can show pie charts, radiation charts, even the mental health charts of the one producing all the charts...

    But it doesn't do you any good if you don't follow an old adage...

    "Let your light shine" - can also apply to antennas, you don't put it under a table, lay it on the floor or hide it under a cap.

    No, you place it on the highest spot - on the vehicle, you and the vehicle can tolerate.

    Radio is a lot like light, proof above when it comes to charts - you work with ohms law to make a circuit complete.
    (Read that as SWR - closer to Resonance or 50 ohms - depending on what antenna design you use changes the Radiation Resistance - the antenna can work like a resistor in a working load - the better -higher- resistor factor - the more the antenna can "load into it's system" and become a more effective radiator.)

    How well it works, depends on your abilities to mount the antenna in a spot that lets' it "shine" - you want the antenna to radiate, so put it in a spot that will let it do just that.

    Sometimes the light needs a "reflector" so you use the body of the vehicle to offset that condition - makes it more like a spotlight.

    Sometimes you can mount the antenna in a fashion that makes it work for "general illumination" - so the antenna gives you good all around performance of radiation, its radiative pattern is equal in all directions.

    You pick the best, and work with the rest, to develop the system with the best trades in performance, coverage, reception and pickup patterns - you' don't need a book, you just need some common sense.

    The antenna; once you provide for it, makes SWR tuning pretty easy and straightforward.

    Don't overthink this.
     
  12. freecell

    freecell BANNED

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    3M aluminum foil adhesive backed tape in a 2 - 2.5 inch width can be used to lay out a ground plane grid either underneath or on the top of the fiberglas roof. i make it a rule to avoid side panel and bumper mounts. antennas don't perform well when the body running away from the base of the antenna is higher than the mount, causes the antenna to become electrically shorter with metal in the near field, becomes directional in the direction away from the body metal and becomes difficult to establish both the impedance match and resonance.

    don't forget the hd spring and ball mount (the other 6.5 inches) as they contribute to the total electrical length and the (Rrad) radiation resistance of the antenna in addition to the 102" inch whip.
     
    #57 freecell, Aug 22, 2021
    Last edited: Aug 22, 2021
  13. secret squirrel

    secret squirrel Lustrous Potentate

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    I am doing a experiment with a cheap top loaded antenna- a Procomm 4 foot flexible whip. The standard 4 foot OEM replacements found at any truck stop. Not trying to hijack this thread. I had some extra time this week so I wanted to do a simple test. To see how an inexpensive top loaded antenna performs when its just put on a decent antenna system, then not adjusting SWR- just screw it to the antenna stud and go. I used a 4 foot antenna because that's what was on hand.
    My daily driver is a 2017 Nissan Rouge. the antenna mount is a Firestik Door Jam mount. its the stainless steel tilt-able mount, with set screws to adjust and hold the final angle of the mount. The mods to the mount are: I upgraded the mounting screws to course thread stainless steel screws to get a better grip into the metal in at the hatchback door jam and second, I changed the Firestik stud to a Drivers Extreme Bee Hive Mount, the center stud in the bee hive is stainless steel, its similar to the Wilson Bee Hive mounts. I changed the stud to increase the surface area contacting the mount to improve strength of the mount. The mount is installed at the driver's side rear in the hatchback door jam just below the brake light. My concern at this location is rotational torque stressing the antenna and mount. The coax is 18 feet Browning rg8x with Amphenol connectors, coax made at Bob's CB. What I wanted to see by trying the Procomm 4 foot top load was will an inexpensive top load antenna perform satisfactory if it placed on a antenna system with a decent mount and coax with OK ground plane. I am running with a barefoot 10 meter radio, the baby Stryker 89MC v2. Its tune is 10 watt dead key swinging to 40 PEP. The antenna that normally resides on the Nissan Rouge is a Hustler HQ27, 4 1/2 feet, center load.
    My results were after install and no adjusting for SWR. On Channel 20= 2.1, Channel 1= 1.4, Channel 40= 2.1. Its obviously too long, thus the center frequency is not center of CB band. I just wanted to confirm it will be safe to operate the radio. I've been running it for just over a week. The receive is noisier than the Hustle HQ27. On the road I am getting about 6-7 miles transmit and receive with clarity. I was just speaking to drivers on I-70. I-79, no formal testing. My conclusion was if I can hear the other guy, then he could hear me. Channel 6 skip, and other skip comes in ok, just with more noise. My comparison for noise is level of annoyance you get with driving by roadside electronic marquee signs with the unavoidable 60 cycle interference. I can conclude with some confidence that 4 foot Skip Shooter or 4 foot Firstik II, which have better manufacturing quality and better surface area in their wire windings will outperform the Procomm Tiger. Also using a 5 footer top load will inprove the ground plane for the antenna system with the increased height.
    We have lots of discussions about everything with installs. I wish I could have the money back from all the radios I have given to friends and family, because he had expressed curiosity about CB radio. We all have given away older antennas that we no longer use or have just lost the curiosity factor. My point as being that if I give my extra Uniden 510XL to a friend because He mentioned putting a radio in his farm truck I do not expect him to call and say, "Hey that CB works great, I bought I Mr. Coily Double Coil antenna down at the truck stop." I expect he will pick up whatever was free or cheap to install. Additionally, if we are in situations where snapping an antenna may happen, I would hope the antenna goes before the mount and coax.
    It was all just a thought I had floating around my head, that if I spent the time to do a proper install on a vehicle and not running extra power then in the situation with a damaged antenna, is it safe to say that I could replace the antenna with one of similar height and expect reasonable operational performance until I could properly adjust the antenna.

    **Disclaimer- There is not scientific basis for anything I just said.
     
    #58 secret squirrel, Aug 22, 2021
    Last edited: Aug 22, 2021
  14. Slowmover

    Slowmover Supporting Member

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    IMO:

    1). 5’ or taller (topping out at 13.5-14.0’)
    2) In da middle of de metal.

    You can look at my thread (started; far from finished) “Puck Mount” (etc) as some of this was discussed.

    — I’d bet on the current Sirio over bumper-mount SS whip.

    At home. Where’s the feedpoint? Stuck it on a 2’ pipe behind the garage?

    Mobile is compromise. Any vehicle or antenna location thereon. Go backwards from what’s “best” on that vehicle and lose MUCH more than what a base loses in compromise.

    My .02

    .
     
  15. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    That is quite alright - much of the subject is - er, Subjective.

    You make the case - an excellent analogy for direct useable comparison - of course there will be the deviations - some work better whiel others - well, wind up in the trash heap because the proof it not there to sustain the effort to use it.

    As in;
    It only matters to those that trust in their equipment.
    Trust being defined as;
    I know the equipment used well enough to understand and utilize it function.
    There is nothing less to consider. Cannot? Then you don't trust the equipment as that result...​
    To the above then;
    You can only conclude...
    "Use what works for you and your situation. If you want more; then you must place your efforts in making the ideal system, your system, including the mounting, location and what will be used in that system - effectively."
    So to ask "Which mobile antenna would you choose for distance?" depends largely upon the ability of the operator to use what works for them - even if it means to compromise.
    Meaning;
    What could have been used, versus what is being used, may be two different things;
    - with the operators own design considerations taking precedence versus the esoteric or performance efficiency
    - looks aren't everything,​
    - as well as physical limitations of the ability to mount and use the system safely
    - a 1/2 wave dipole may not survive the next bridge abutment.
    Again, heading back to "Use Common Sense"...
     

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