I'm just as amazed as you are Scott, and I don’t understand why either. I just posted my most recent Signal Reports #’s 17-21 in my album
Edit: sorry I can't add any more albums to my profile. Maybe I'll delete some of my albums if I can still do that. I think this happended once before, but I don't recall what the solution was.
If you look back at my first report #17 dated 12/03/10, for my new GM vs. Top One...you'll notice that my recorded average difference in Sunits was a modest 0.6su in favor of the GM. The GM was about 11' feet higher at the tip. The bottom of the GM and the bottom hoop on the TO were at the same 33' foot height.
GM @ 55' feet = average 7.9su ------ 0.7su advantage for the Gain Master.
TO @ 44' feet = average 7.2su
On my report #18 dated 12/05/10, I put both antennas at the same tip height of 44' feet which lowered the GM 11' feet. This was a test over just a few hours. I recorded some signals from a few contacts that were not included in my previous tests, so I noted these with a "*" in the margin. I excluded them in my averaging for Sunits difference.
GM @ 44' feet = average 6.9su
TO @ 44' feet = average 7.4su ------ 0.5su advantage for the Top One.
On my report # 19 dated 12/10/10, I centered both antennas at 38' feet.This effectively raised the Gain Master about 5' feet higher than the previous test.
GM @ 49' feet = average 7.3su ------ 0.4su advantage for Gain Master.
TO @ 44' feet = average 6.9su
On my report #20 dated 12/12/10, at the recommendation of others I removed the Top One from its mount and tested the GM alone with the tip @ 55’ feet. This is about as high as I can get my new mount 33.5' feet and that limits what I can do here.
GM @ 55' feet = average 7.2su
A day later on the same report # 20 dated 12/12/10, I removed the GM and installed my A99 without a GPK and tested it.
A99 @ 51.5’ feet = average 7.4su
On my report #21 dated 12/15/10, I installed 3 x 72” radials on the A99 in the horizontal position and tested the A99 again.
A99 @ 51’ feet = average 7.3su
On 12/17/10, on the recommendations of other’s I mounted the GM @ 50’ feet to the tip on the mount that my AstroPlane (Top One) was originally mounted on. This was to try and compare any possible differences between the two mounts. I made a mistake while setting the guying bracket position and the GM ended up 5’ feet lower than my previous test using the TO on that mount. I will have to fix this error, raise 5’ and retest.
GM @ 50’ feet = average 7.6su
Some of these numbers may have changed a bit since I first posted information from these reports. That is because I went back and made all report averages…using the same 7 stations from test to test. I (-)'ed out all other stations that did not appear in all reports just to make the reports more balanced.
You could be right 007, but over the years my experience has seldom shown nearly as much differences among the CB vertical antennas I have compared to what other guys indicate. I will admit that I often use height to compare antennas just to see what the antenna is capable of, but I do realize that is not considered a fair way of comparing them. That said however, most guys never consider, or discuss height even when talking about their comparison ideas. This idea of height is truly not that important to the average CB’er wanting to simply install his antenna and talk on it. What really got me started was being intrigued by the inaccurate comments that the AstroPlane antenna had to be installed low to the ground for it to work well and that it was designed that way. Height was surely the issue in the design idea, but IMO it had nothing to do with having to be low to the ground in order to work as intended.
Additionally, I’ve made the argument that the soil in my area of the Texas Gulf Coast is noted to be very conductive compared to most other areas of the country. I do not have a good understanding of the technical affects, but IMO the Earth probably has the greatest affect of any single characteristic in antenna performance, next is polarity, and then height. To prove how the ground beneath the antenna can affect the performance of an antenna all you have to do is experience your antenna over salt water. The differences on land may not be that dramatic, but in a technical sense it can have a considerable affect and without close study it may be hard to realize.
I also consider symmetry to be a very important aspect that is most often overlooked when considering antenna performance and design. I think you might agree when considering your P500 and its well balanced design along with the Gain Master. I think we both appreciate that balanced quality in design.
I think that is also why we both consider it important to get the GM well out into the clear as best possible…for best performance.
I have all kinds of stuff around my location that can affect the GM’s performance, to say nothing about how my radios handle signals through their AGC circuits. I use only one radio to do my reports, but they all seem to display about the same readings when I take the time to compare them. If a station hits me with an S9 on my Galaxy DX2547, the same shows up on my TS570D, and my TS50. I can back the RF gain down sometimes and see more of a difference between different antennas, but more often it makes little to no difference.
Let’s not even mention conditions, and ground clutter affecting line of sight signals. I’m not doing rocket science here.
Again, I can’t really explain it either. I find it just as hard to accept seeing a GM produce a 1-3 su better signal compared to any other antenna. That said however, I’m not ready to consider the GM a give-away antenna.
Scott you know doing this comparison stuff is a lot of work, but I encourage others to do their own and show me their results…instead of just making claims they can’t support. I don’t disbelieve guys either, but I do know how complicated testing can get, and I figure most are not going to take the time or energy to do it, record and produce results, fuss and discuss, when making wide-eyed claims is so easy.
Well, I don’t have a solution for your dilemma, but for the next few days I will have both the A99 and the GM up. I don’t typically believe there is much to be learned in DX contacts, because combinations of various RF angles and such has so much affect on signals between two points, but if you hear Texas in your radio on 27.385 lsb, give me a holler. We’ve talked before and I’m sure we can do it again.
Soon, I want to get one of my 5/8 wave or my Sigma4 up and compare it to the GM. How do you think is best to mount them for a fair comparison, mount to mount height equal on the same pole? If my past experiences were correct, the GM does not stand a chance against my Sigma 4 in such a scenario. I could be surprised however. How are your comparisons coming along?