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Anyone running the Sirio P5000 in their mobile

Discussion in 'CB Antennas' started by Supspt454, Feb 12, 2017.

  1. Supspt454

    Supspt454 Member

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    just wondering if anyone is using the P5000 in their mobile. I've had this antenna along with the magnet base for three years now and it is still rocking along like it was new. Just like my Gain Master base antenna, Sirio is a rock solid performer. I do have some slight noise issues in my mobile with static but it's not that big of an issue. The only real issue I have is on my radio, in the instruction manual it clearly states to ground the mounting bracket. I have tried this and it messes up the radio. I always wondered if it was because the antenna was magnet mounted? Thoughts or comments?


     

  2. The DB

    The DB Sr. Member

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    I've tuned several of those over the years. If I ever decided I needed something shorter than a 102" whip the Sirio 5000 line of mobile antennas is at the top of my list as far as the CB side of things is concerned. That being said I, personally, would use something other than a magnet mount. They can cause problems that a more permanent solution wouldn't have, and make other potential problems worse. Operative word, can, not necessarily will.

    When it comes to grounding the radio causing a difference, several things could be happening, and the magnet mount may be related, but not necessarily.

    Radios don't need to be grounded to function, at least as far as transmitting and receiving are concerned. It is more a safety issue. Your radio is actually grounded already, the negative power lead is also a ground, and while many people run it straight to the battery, many others run as short a length as possible to a chassis ground. Their are advantages and disadvantages either way you run the negative lead.

    Adding a different ground wire, as you are doing, should not "mess up the radio", and in fact should have no effect at all. Very likely you have either a common mode currents issue of a ground loop issue.

    Questions:
    1. How is this ground wire "messing up" the radio?
    2. How is the radio bracket grounded, it is bolted directly to bonded metal or is a wire running from the bracket to the vehicle's chassis? If a wire is used how long is it?
    3. If you add a three foot jumper and a barrel connector between the SWR meter and the antenna, does SWR change noticeably? If so how much?
    4. Are you running an amplifier, and if so how big is it and how is it wired to ground/negative?


    The DB
     
    Tallman likes this.
  3. Supspt454

    Supspt454 Member

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    I'd rather not discuss the make and model of radio to keep negative comments at bay lol. However, let's just say it can either be mounted conventional or remote mounted with the included disconnect kit:). Now back to the grits... I currently have the radio mounted under the dash. It is screwed directly into plastic. The bracket is ungrounded. Positive and negative both go directly to battery. The manual states if the radio is picking up engine noise or static, that you may ground the chassis of the radio through the bracket or rear of the radio. Anytime an extra ground is installed (either by jumper wire or bolting the bracket to the metal body) the radio loses most of the transmit power and there is no change in receive.
     
  4. Supspt454

    Supspt454 Member

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    I figured that possibly the magnet mount may be the cause.
     
  5. M0GVZ

    M0GVZ Sr. Member

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    I'm running a Siro 5000 here which must be at least a decade old or more now. Its mounted with a fixed SO239 mount in the roof of the car so yes that means drilling a hole. I've also bonded the hood and trunk lids to the main vehicle body too. Like all the CB antennas I put on my car mounted via this method I had to get the dremel out and cut a few inches off the whip, 4 inches in this case because it was resonant at just below 26MHz. Antenna whip lengths are usually selected to work with the lowest common denominator installation and as you improve the RF ground you need to shorten the antenna. The same issue happens with Hustler BTV antennas for amateur radio base stations which if you have a good RF ground and not just a ground rod you find you have to move the traps.

    With the car running driving down the road out of town I get S0 on the S meter and can hear stations who are S0 too. Fixed mounts and bonding is definitely worth the time and money to do.

    In regards to the grounding, all grounding for RF needs to be take care of where the braid of the coax ends at the antenna end. "Grounding" a radio bracket doesn't fix the problem, merely masks it. Common mode RFI is the cause of the noise and thats a result of a poor RF ground.

    www.k0bg.com and the sections on mounting, grounding and bonding are worth a read.
     
  6. Supspt454

    Supspt454 Member

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    I wonder why it makes a difference with my radio if the mounting bracket is touching a metal surface or plastic. When it touches a metal surface the radio doesn't act right.
     
  7. tecnicoloco

    tecnicoloco Tweaknician in Training

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    change radios and touch the metal surface with the mounting bracket to see what happen?
     
  8. Tallman

    Tallman W9WDX Amateur Radio Member, KW4YJ EXTRA class

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    I have one of those and have been happy with it and it's performance. I run it on ten meters and have no problem getting out and the receive is pretty decent as well.
    I will say it is the best magnet mount antenna I have ever used.

    If your power and ground are not the best you can't blame that on a magnet mount. All power and ground connections need to be the best you can make regardless of the antenna you use.
     
  9. Supspt454

    Supspt454 Member

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    I ran #8 awg electrolytic grade copper direct to the battery, then soldered to the radio harness. I've confirmed that the noise is not coming in from the power supply. All connections are stereo grade terminals.
     
  10. Supspt454

    Supspt454 Member

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    I have used three radios. All with the same results. My latest radio is the most sensitive.
     
  11. Supspt454

    Supspt454 Member

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    I will say that this antenna has given the best noticeable TX and RX results of any mobile I've ran before. This is testing to a base station located a very good distance away. He has confirmed on several occasions that it has the strongest signal against a Wilson 5000, K40, Wilson 1000 (all mag mounts) on my same vehicle. However the Sirio picks up a lot more noticeable static and engine noise then the others.
     
  12. Supspt454

    Supspt454 Member

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    I'm wondering about the bonding RF issue that M0GVZ mentioned
     
  13. 222DBFL

    222DBFL Sr. Member

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    Yes bonding will help. Drilling a hole and making it a hard mount antenna would help a lot as well!! You have to maintain a magnet mount if you are going to use one for long term. Keep the moisture out. Keeping the area where the mag mount attaches to the roof clean and free of any moisture is a daily task almost where I am. But maybe not so with yohr area. Also change out the coax and get some good stuff that will handle the elements for long periods of time. I recommend some Thur like LMR240UF, made by some of the more quality companies. But for all that, you could just drill a hole and add a good hard mount. Breedlove makes a nice mount that works well with this antenna. And it really does make a difference. Also bonding is crucial. It takes time to get it right. But once done you'll reap the benefits of a good antenna system. JMHO's. Have a good day and hope some of this helps. Listen to the others they are correct with what they say!!
     
    Mudduckmobile likes this.
  14. Mudduckmobile

    Mudduckmobile Well-Known Member

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    Love the Sirio 5000. I use the "trucker" mounted with the Breadlove 4 1/2in. hard mount. (there are some photos on one of the threads some place here).
    The big thing is you really need to BOND, and if your running an amp it's very important to bond. Bond your exhaust system to your frame, and body to frame...Every thing hood, doors it all "looks" to youa antenna as something good or bad...Bond it and it will look "good" to your antenna. I really learned. BOND it all.
     
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  15. Big Kahuna

    Big Kahuna Well-Known Member

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    My Sirio 5000 mag outperforms my Wilson 5000 mag. I prefer the lower profile of the Wilson 5000 though. Sirio is a great antenna - just wish the mag mount came with a longer run of coax.
     
    Bundy likes this.

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