Alot of money? Maybe...but then again i hear that enough from my wife and you should have heard her when i told her 15 yrs ago how much I was paying for a amplifier that was killing a 25k slug in a bird 43...yeah
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Battle of the ground planes
- Thread starter 211inthamag
- Start date
If it were just wire and fiberglass, it would be a Big Stick, Antron or Imax and share all of the problems those antennas have with coax radiation and RFI. You're paying for what no other company has been able to bring to the market in 30 years.
Technology that provides a match to a center fed 5/8 wave radiator that is balanced and requires no radials. Covers 3 bands with no tuner or RFI and does it with a signal that matches antennas 8 feet longer.
Technology that provides a match to a center fed 5/8 wave radiator that is balanced and requires no radials. Covers 3 bands with no tuner or RFI and does it with a signal that matches antennas 8 feet longer.
What the manufacturer says or myself for that matter really doesn't make a difference. What matters is how the antenna performs and I was pleasantly surprised to find my results matched what the manufacturer claims. While it is just wire and fiberglass, no other combination of these materials has even come close to what this antenna does.
I am not questioning that the antenna works but even by the mfg's own admission it's a center feed dipole. I am just leery of some mfg's smoke and mirrors ad's.
I like my GM. Always had RFI with my Antron and Imax. I'm not about to get all technical about it, but the GM has noticeable signal improvement. The bandwidth is very welcomed. I wouldn't use any other vertical. I'd even pay double the cost, if I had to.
Very very pleased with it. Best performing vertical in all my years in the hobby.
Very very pleased with it. Best performing vertical in all my years in the hobby.
I've learned to be just as leery over the years too when I see impossible claims like the Solarcon 9 dbi and not a drop of sound technical theory behind the design to back even the slightest improvement.
Sirio on the other hand claimed 1 or 2 more db than a 5/8 wave groundplane. Having seen what the Sigma IV or Vector 4000 could do to a Penatrator over a 50 mile or more distance, I knew this type of gain in an omni was possible.
After reading how the antenna was cleverly designed to be center fed like a dipole but very clear about the Gain Master being a 5/8 wave and not a 1/2 wave dipole made me curious. Seeing this new style coaxial capacitor and tuning stub made me test the bandwidth claims.
After learning about how the design works it become obvious it would only work if complete isolation from the coax and mast were achieved. That created a huge improvement with any RFI issues including those pesky PC speakers.
Sirio on the other hand claimed 1 or 2 more db than a 5/8 wave groundplane. Having seen what the Sigma IV or Vector 4000 could do to a Penatrator over a 50 mile or more distance, I knew this type of gain in an omni was possible.
After reading how the antenna was cleverly designed to be center fed like a dipole but very clear about the Gain Master being a 5/8 wave and not a 1/2 wave dipole made me curious. Seeing this new style coaxial capacitor and tuning stub made me test the bandwidth claims.
After learning about how the design works it become obvious it would only work if complete isolation from the coax and mast were achieved. That created a huge improvement with any RFI issues including those pesky PC speakers.
So essentially its a center fed .64 (.62 according to them) that is isolated from the feed point. Sounds easy enough to build one. I am not being high hat here but I like building antennas and looking at the specs it does not look all that hard. I might throw one together this weekend and see how it works.
Just getting the coax capacitor cut to the precise length and soldered in place without screwing up its value proved to be more difficult than I thought at first. How you prune the braid back on this tiny value pf part makes a difference in VSWR.
Donald, you are right, according to the models below Sirio does show better gain at low angle if the model is done with no mast in Free Space. My models show it is 1.44 dbi better than my I-10K with no mast and in FS.
Over real Earth however, the I-10K shows a little better match, but IMO it is so close, as to be hardly worth a mention. IMO, the GM also as a physical height advantage with the feed point being in the center, so if i raised the I-10K's feed point up to match the GM's FP...then who knows, 11' feet more height is a lot.
I'm not suggesting, in this case, that raising the feed point is a fair comparison, but I tend to believe that the height of the feed point makes the difference and gives an advantage, for example, with the AstroPlane when the bottom is set as high as the bottom of a 5/8 wave the differences pretty much disappears.
View attachment Recap of GainMaster vs. I-10K.pdf
Personally I find the GM a superior antenna, simply because it is as streamline as you can get, it does things like eliminate RF on the feed line, and it shows great gain with a wildly large bandwidth. I do still think for this one there are particular heights where it preforms better, but I was never really able to test this idea before I got too ill.
I have some models however, that might help demonstrate these peculiar responses. I have already reported the physical responses I saw when I first installed this antenna, but that idea never seemed to interest anybody.
The GainMaster, bar none, is probably the best all around antenna that I have, for what it is, and like fine wine...it is not for everybody.
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I have a question for those who "OWN" a gain master antenna...what were yall seeing as far as SWR goes ?
Hey 211, I don't know if a dummy load is a good description, but SW's idea is on point.
Here are my bandwidth curves taken a couple of months after I bought mine and after I installed the antenna several times as well.
My results in testing my GM were a bit irregular at first, and this is where I got the idea that this one quite likely had some particular affinities at some particular heights, and with different feed line lengths. For me this is a sign of an antenna that works well to control the resistance using very good symmetry, and the state of the reactance over a broad range.
This is not something that anybody would be able to really notice just operating their radio, but I was able to duplicate my test with very similar results with the GM standing alone, and also with it side by side of my Starduster.
IMO the GM design does a great job of compromise matching in order to yield such a broad working bandwidth. You will notice that my VA1 readings suggest this antenna shows a complex value of Z impedance, with little to no dip. For me this may be at least one way that optimized bandwidths are achieved with minimal ill-effects on the gain and angle.
You might no be impressed with the matchers lack in handling big watts, but the design is impressive.
I think you will find what Shockwave suggested above is right in line with these results, and if you look at the Sirio Website you will also notice their bandwidth curve is uniquely similar to mine.
You can't make this stuff up.
View attachment GainMaster bandwidth reports.pdf
So in short term would you say that it performs better then the vector 4000 or SP500 as far as RX and Tx goes? The wattage part is my only concern but again ive never had to run more then 300 watts on SSb to do what I need it to do!! My BIGGEST thing im looking at is a antenna that has the lowest loss at the feed point and highest gain out and if icing the cake was being able to hold 2k watts that would be nice also, but can live without that because my beams will be up sooner or later and set up for Am Broadcasting 
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