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Sirio Gainmaster

Discussion in 'Amateur Radio Antennas' started by ahh, Mar 5, 2012.

  1. ahh

    ahh Member

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    :confused: Hi, everybody. I was wondering if any of you ten meter and cb radio operators have used/use this antenna? For those of you that have no idea what this antenna is, it is a 5/8 wave vertical that is quite broadbanded, and its frequency range is from 25.5-30 Mhz with a 2.0 SWR in that entire range. In the past, I have had good luck with various verticals for ten meters...the Cushcraft AR-10, and the MaCO V58 for CB use. However, at least in my experience and without using a tuner, I was never able to use either antenna on BOTH 10 meter band AND the Citizen's Band. The best I got was around a 1 Mhz bandwidth at 2.0 SWR or less.



    --I realize the antenna is not cheap, but if it can cover 26.965-27.405 Mhz, and also 28-29.700Mhz with just one antenna, it just might be worth it (then I can use my antenna tuner for various wire antennas, etc.). So, has anyone on this forum used one yet? Are the broadbanded claims I see on YouTube true? Thanks for your help.
     
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  2. unit511

    unit511 Member

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    I use a gm on cb and it works great. I have it attached to my radio with 50ft of times microwave lmr 400 coax. The antenna is up about 45ft with no obstructions. The mast is grounded to a home depot ground rod buried with just 1ft showing. My swr is extremely low in that it barely moves the needle. I am pleased with it so far. My .02
     
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  3. ahh

    ahh Member

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    --Have you tested the antenna in the 12 meter band (24.890-24.990)? I know it's not rated down that low, but was just curious. Too bad they didn't make the antenna to xmit from 24.890-29.700, but I guess that's just nit-picky, as it could probably be tuned with little problem by the radios internal antenna tuner (assuming your radio has one built in)
     
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  4. Robb

    Robb Yup

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    The A99 and the Imax 2000 can be used all of the way up to and including the 20m band for almost half the price of the SGM.
    Talked to Japan and Ireland on that Imax on 17m.

    While the SGM uses an innovative design, I've always felt that it was a little too expensive and couldn't handle 500 watts without popping the capacitor . . .
     
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  5. Highlander_821

    Highlander_821 Amour d'Ecosse

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    I use one for both 10 and 11 meters. I had an Imax2000 that broke.

    I have no empirical evidence that this antenna is better than the Imax, but it seems to hear better than the Imax did, so therefore would also likely have a slight improvement in TX over the Imax as well. It is pricey. I have no issue with power, as I rarelly go over 100 watts on either band. I'm sure with a tuner it can cover anywhere the Imax can.
     
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  6. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    There is nothing special or magical about the A99 or the Imax 200 that "allows" it to operate from 20m up to 10m. Pretty much anything including a junk piece of scrap wire strung out for 18-20 feet will do the same with an antenna tuner. I just cannot understand everyone always talking about them in that fashion. I used to work 20m-6m with a 9 1/2 foot antenna on the mobile and an auto tuner at the feedpoint. To me, and most others, an antenna is useable on a band if it presents a decent SWR without an antenna tuner and radiates somewhat efficiently. I tend to differentiate between "it's useable on 20m" and " I use it on 20m". I have "used" some pretty "unusable" antennas especially on 80 and 160m. ;)
     
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  7. Robb

    Robb Yup

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    Where did I say 'magical'? Must be assuming. I merely pointed out - as you did - that for the money spent (yes; I am cheap!), that an A99 or an Imax offers much the same thing that a SGM does at half the price.
     
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  8. ahh

    ahh Member

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    --While I understand the Gain Master has approximately 4.5Mhz of bandwidth with 2.0 SWR, but what about the IMAX2000 and the Solarcon A99 (without an antenna tuner, that is)? I was thinking that both the IMAX and the A99 "only" had about 1 Mhz of bandwidth (which I am probably wrong). I have never heard of a CB antenna with as much bandwidth as the Gainmaster. Makes me want to look inside one to see what gives it that edge of that extra bandwidth. I have no idea what kind of "item" that could be added to the antenna to give it more bandwidth, but I would sure want to add it to my MaCO V58, which I love.
     
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  9. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    Nope, not assuming anything just stating facts. You did not even so much as mention the words "magical" or "special" or even "mystical". Nope one slight utterance of the word(s). However as I said many people seem to think that just because an antenna tuner will allow a decent SWR on any given antenna then it is therefore a good antenna on that band while I pointed out that a scrap piece of wire will accomplish the same thing for mere pennies. How`s that for being cheap? :laugh:
     
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  10. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    The problem with your idea is that an antenna can only be optimized for one thing due to the laws of physics. If you broaden the bandwidth of an antenna then you will reduce the gain and in the case of a directional antenna you will reduce the rejection. If you want the gain to be increased and thus the beamwidth narrowed then the gain will be reduced. There are antennas that have a very wide useable bandwidth but the efficiency and thus the gain is very poor.As for adding anything to your Maco V58, it will generally narrow up the bandwidth. If it was configured to broaden the bandwidth then the gain will drop and you will no longer love it at much. Welcome to the world of antenna optimization.
     
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  11. much is written about the gainmaster having a wide usable bandwidth , and , as good or better TX , and , quieter RX than most antennas used before it . it seems to be all give and no take ..... since it can't change the laws of physics , does that mean the gain master could be optimized to have more gain or even better/cleaner ears by reducing its bandwidth ?
     
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  12. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    No, but increasing the gain will reduce the bandwidth. You do not set out to reduce the bandwidth of an antenna. If you design an antenna for a wider bandwidth it will have a lower gain than if it were designed for higher gain which would result in it also having a narrower bandwidth. Good examples of this are yagis. Look at the REAL specs of yagis and you will see that the higher gain models have much narrower bandwidths.
     
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  13. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    Talking to some of the locals today while they were driving home from work.

    OP out West gets in there also when conditions permit.

    I was using the IMAX2000 and then decided to switch to the Lazy H wire antenna fed with ladder line.

    OP out West said he could not tell any difference in signal strength from the wire compared to the IMAX. The lazy H is oriented to shoot a lobe to his area of the country.

    Basically if any antenna has a broadband width it is low gain due to the low Q of the matching circuit.

    If an antenna is narrow banded as CK said it will have good gain. Example the four element cubical quad, narrow banded but it sure does work at the freq of design.

    The imax works 15 through 10 meters with no tuner, it has a low gain lossy matching network but it does work. I have made contacts into japan on 15 meters and a 100 watts on the imax, I also have done the same thing off a piece of wire, ladder line and a tuner.
     
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    Last edited: Mar 6, 2012
  14. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

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    Lazy H hey? I suspect it is horizontal so therefore despite it's gain the polarity difference may have been the cause of there being no difference in signal strength.
     
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  15. wavrider

    wavrider W9WDX Amateur Radio Club Member

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    (y) you are correct, but the contact was DX not local so the polarity of the antenna should not make much difference.
    Of course if I used the lazy H for local talking there would be an 18 to 20 db difference in signal strength as the other ops are vertical.
     
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    Last edited: Mar 6, 2012

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