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Is the Sirio Gain Master really a good DX vertical ?

Discussion in 'CB Antennas' started by RadioDaze, Oct 2, 2015.

  1. RadioDaze

    RadioDaze Antenna enquirer

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    Caveat : I know that DX is hugely dependent on atmospheric conditions and so therefore making hard and fast statements is clearly not possible. I am also aware that any individual antenna should be taken into account with the complete antenna system as a whole. Poles, chokes, isolation or not, grounding, QTH, heigth above ground, height above sea level, soil conditions (though at 27Mhz this is less of an issue for common ground types)

    I have a Gain Master and have made some good contacts, however I am starting to wonder if it is really as good a DX antenna as Sirio and the reports I have read make it out to be in my specific situation.

    I have learnt this antenna does like to be away from other objects and have found that under 6M high and low angle TOA performance might begin to suffer a bit. Whereas potentially ground plane types can operate quite well close to the ground and being bolted to a metallic object can actually be of benefit.

    I keep hearing stories of people doing 10,000 mile multi hop skip with their mobile whip antenna and there is video evidence of this happening on Youtube. So it can be done.

    My issue is I think I should be getting better DX score given my rather elaborate DX mobile base station. I do have an IMAX antenna and am considering giving that a go soon on a decent set of poles 6M + in the air. I have good height, decent power and a good antenna. I am starting to think that the GM may not be that good an antenna for DX compared to a good 5/8 wave ground plane type.

    Thought that pop into my head:

    Why do mobile static stations with a mobile whips - anecdotally at least - seem to do as well ? (In practice I take what people say on air at face value and believe their DX logs)

    Am I asking too much of an omni directional antenna ?

    Is my height above sea level (400-600ft usually) a detriment to DX ?

    Am I comparing my performance and DX success against stations that also have beams.
    (I know for a fact that many of my locals use beams and I do not know in what capacity they might be pointing them to gain an advantage, it would seem odd to own a beam that is permanently set up and not actually use it)

    I know there is more to a good antenna than getting a signal to the end QTH. Relative noise/static pick up as well. What is the point of getting a signal there if you cannot hear them? etc.

    I have what could be called dubious grounding of my radio system. I do not use batteries that are earthed to the vehicle and the car chassis is not earthed to the physical soil/earth either. My batteries sit in the passenger seat foot well. One normal car battery for the radio and a deep cycle leisure battery for the linear. This could potentially be a problem. I have apparently suffered a little scratchy audio from time to time but have remedied this by not over driving my linear. I am backing off the power drive by 20-30pct to keep the signal cleaner. I generally obtain good SWR of 1.2:1 being typical.

    Maybe it is just conditions and maybe I am over thinking the set up. I am thinking of giving the IMAX a go in a basic config with no radials and no isolation and no chokes just to see what happens. The issue being is that I might go out and speak to nobody and then think the IMAX is a bad antenna.

    I am trying to balance getting the fundamental set up right vs experimenting with other antennas to see if they perform better in my specific set up. Any advice or thoughts are welcome. Thanks.



    I will add that when I DX and patch someone through or vice versa, on the same contacts, some days I am a little under signal wise compared to a friend and some days a little more. So maybe it is all about the moment and your exact whereabouts. i.e. pure chance.

    I find this aspect of 11m band use a little frustrating and unsatisfying because it is subject to the vagueries of ionospheric charge. If your QTH is 40 miles from a friend and you have slightly different angles of TOA at your lowest elevation lobes then we could expect to see 100mile differences between where the energy from our antennas hits patches of randomly ionized gasses. And maybe 1 day I hit the strong bit and one day not and vice versa. (given that 100mile difference)

    In saying that I just want to maximize my overall station performance and wondered if anyone can spot some glaringly obvious operational mistakes. I know this is more than IMAX vs Gain Master.

    The Gian Master is the devil I know and I do not appear to be getting too much of a problem from RF in the shack and the GM is known as a fairly clean antenna and does not produce TVI too badly probably from lack of common mode on the coax. I also like the convenience of not having to set up ground radials.
     
    #1 RadioDaze, Oct 2, 2015
    Last edited: Oct 2, 2015

  2. gamegetter

    gamegetter Well-Known Member

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    a lot of solar magnetic disturbances popping up from day to day...

    when i have time, i sit by radio and take advantage of any conditions that may occurr other wise, i'm waiting for a better day or time in the cycle.

    no offense meant, but try not to over think it too much
     
    RadioDaze likes this.
  3. RadioDaze

    RadioDaze Antenna enquirer

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    None taken. I do think sometimes I am trying to analyze the un-analzye-able.

    Once I am out I have commited to the day with a mobile set up. I can only get out there when I can do. Would be great to sit with radio on and jump to it when it picks up. I have to take what I am given with my way of operation.
     
    gamegetter likes this.
  4. BigKahuna

    BigKahuna Active Member

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    gain master is one of, if not best vertical ive used for DX. Better than my a99 and imax 2000 and maco. Only one I've heard is better is sirio vector 4000 but havent tried one.

    Your antenna is better than a mobile don't worry about that. DX goes where it wants to who it wants.

    I run a wilson 5000 in my mobile and I talked to Australia yesterday. Some locals on base ants couldn't ger through to them. Is my mobile better than their base stations, no. It was just luckly. DX conditions are super picky right now too. We had 100 mile local skip the day before and then 3000 mile skip the day after, then nothing.

    As winter comes the DX will get better and your gain master will work some good contacts. As other guy said, don;t overthink it.
     
    222DBFL and RadioDaze like this.
  5. vkrules

    vkrules Sr. Member

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    What I like about the gm compared to the imax is there is no CMC evident . With the imax CMC can be a bit of an issue.Like you said the gm is a very clean antenna. Also found the GM has less noise, in my case up to 2s points better. Also found the GM easier to use portable SWR remained the same no mater at what height I mounted it. 5ft or 30ft swr remained flat.

    Tested a imax side by side with the GM for about 2 months. Both antennas 10 meters above the ground and both fed with rg213 cable of the same length.
    Most cases there was no difference in signal strength.However I did find the GM better with the long haul to UK (10,000 miles or so)

    With replacing one 5/8th with another I don't think you will see much difference ,if any in a portable situation .
     
    Mudfoot and RadioDaze like this.
  6. RadioDaze

    RadioDaze Antenna enquirer

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    Thanks Big K and VK Rules, both good perspectives to have.
     
  7. 543_Dallas

    543_Dallas Sr. Member

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    People shoot skip mobile all the time. Ive keyed on alot of base antennas but that doesn't mean those guys had crummy antennas. I was just in the right place at the right time with just enough power.

    The gainmaster is overpriced for what you get and but they are aren't bad antennas. I agree they are a better design than an a99 or imax but I'd take a 5/8 ground plane over a gainmaster any day.

    The vector 4000 will outperform the 5/8 but the guys around here that have one have to worry more about wind than I do. To be fair I will say their antennas are home brew copies of the vector. They seem to be well built but catch a lot of wind.
     
    RadioDaze likes this.
  8. M0GVZ

    M0GVZ Sr. Member

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    Having done 9,000+ miles on 10m mobile myself and busting through a pileup with 50W mobile to VP8LP I can answer this....

    1) Good solar conditions so a nice high SFI and a nice low K index

    2) The most important - being in the right place at the right time or in other words being lucky to be in the right position for a good path to the other station.

    Operating a lot mobile you learn that its as much about where you are as anything else. Driving on a long run listening to DX a lot of the time their signal will go up and down. Sometimes it'll be really strong, sometimes it'll almost disappear. And its not QSB because when you stop their signal remains constant.

    DXing is like fishing. You throw the hook in and hope to get a bite. Of course you can guarantee a catch by using a hand grenade instead of a hook with bait on just as you can with radio by using a kW amp and five stacked 5 ele yagis on a 120ft tower but neither offers a challenge and in my opinion are no fun.

    Probably and having both an Imax 2000 up and a Moxon beam both at 32ft I can tell you there's simply no contest. The Moxon will hear stuff at S5 that the Imax isn't even aware is there. Differences in gain for vertical monopole antennas are next to nought and no matter what vertical antenna you use you're not going to get a result that'll match a yagi.
     
    #8 M0GVZ, Oct 2, 2015
    Last edited: Oct 2, 2015
  9. gamegetter

    gamegetter Well-Known Member

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    i understand totally....i work so much some weeks and months, that when I do get some time off for the hobby, i want to be able to have some quality time and enjoy contacts.

    but that is the nature of the beast. take what mother nature gives you and enjoy.

    good day my friend.
     
    RadioDaze likes this.
  10. vkrules

    vkrules Sr. Member

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    Here is a portable vertical 3 el Skypper beam that I built on a 10m fishing pole

    [​IMG]
     
  11. vkrules

    vkrules Sr. Member

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    Needle Bender and RadioDaze like this.
  12. Mudfoot

    Mudfoot Sr. Member

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    I really like my GM.
     
    RadioDaze likes this.
  13. DJboutit

    DJboutit Active Member

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    GM max wattage is like 400w or 500w really low to me should be more like 1.2kw to 1.5wk
     
  14. M0GVZ

    M0GVZ Sr. Member

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    Difference between 400W and 1.5kW isn't even a S point to the other end but the amount of work you need to do with a 1.5kW install and how much grief you cause locals on adjacent channels even with a perfect install is considerably more. "Only" having a maximum power rating of 400/500W isn't the handicap people think it is.

    A yagi, quad, hexbeam or moxon 30+ feet off the floor would give you the same or higher signal strength with 400W going into it to the DX station as any vertical CB antenna with 1.5kW going into it no matter what the height.
     
    RadioDaze likes this.
  15. AudioShockwav

    AudioShockwav Extraterrestrial Admin
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    How often do you run 1.2 to 1.5K?
    I find it interesting that many people say this about the gain master, yet I would guess that less than 80% run more than 500 watts.

    73
    Jeff
     
    undertaker and 222DBFL like this.

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