sirio 827 5/8 vs gainmaster

[Marconi]

an old radio friend about 20 miles atcf from me was using his sirio 827, sirio's best performing and by far strongest 5/8wave groundplane,
he told me he'd bought a gainmaster and wanted to know what i thought about them,
been a 827 devotee he was not expecting better performance just a lighter neater antenna, something he could safely handle without assistance,

the antenna sits on a 20ft scaffold pole fixed to a shed in a small field on flat ground.

i asked him to do an impromptu test swapping antennas on the same ( pole /coax/ ft857@ full power ) before he bought new coax for the gainmaster,

his signal to me was between s-4 and s-5
he swapped to the gainmaster, his signal has increased to a solid s-6,
some of my other radio friends who usually struggle to hear what he's saying when im talking to him now receive him with increased signal and perfectly readable modulation,
the happy owner reports similar improvement in his receive.

as always your mileage may vary

Bob, thanks for opening this thread up again. When I read you recent post, I remembered that I wanted to address and issue, and I missed the chance and then forgot about the thread.

You note here, that the signals you recorded from your friend's 827, 20 miles away, on a 20' mast...showed between S4 - S5. I checked my last signal reports after I got my GM, and I find I didn't have any contacts noted there that were less than 25 miles away. However, none of those contacts shown as farther away showed me less that S6, and most of those were closer to 30 miles and or more. The recap of my signal reports, which shows all contacts averaged over the 6 months to rank 9 antenna I tested, shows not one with a signal less than 6.9 Sunits. See below:

View attachment Signal Reports Recap 051411.pdf

Now, some of these guys run power, some have beams, and all of them lie a lot, and that is why I stopped talking on my radio. But kidding aside, they are all farther away, and many are twice or three times as far, and they show me signals that are better than your friend, just 20 miles from you.

Granted that we're on pretty flat land here and you probably aren't, so what do you think causes these result compared to your results?

Is it my radios? At times I have compared my TS-570D, TS-50, Galaxy 2547, Cobra 148 GTL, Teaberry Stalker XV, SBE SSBIV, and a Sonar FS something, and they are all somewhat similar. How am I so unlucky to have such radios with meters that don't show a difference in signals?

I might miss some things at time, and until I got into considering antennas, I took very little notice of the signals for my contacts, but I'm sure I would have noticed something as significant as the range of difference we hear mentioned all the time such as you reported above. This is not a new phenomenon with me, I've been aware of such a signal difference in my observations compared to others for a long long time. I know we've discussed this before without resolve, but here it is again.

another local swapped his 5/8wave sirio 827 for a gainmaster today, same 20ft pole / coax, the antenna is just above gutter height near the roof, i saw just over 1/4 s-unit improvement @15 miles with the gainmaster, the least increase i have seen so far, he saw a healthy increase on his icom s-meter.

In this case did you ask about reflections since you noted his GM was close to the gutter? I know folks don't believe me, but I am sure my GM shows attenuation to a point of showing responses on my bandwidth curves that are irregular, and that happens when it about 20' feet and less to the ground, or it's too close to other stuff or another antenna, radiating or not.

I figure this, because of the choke that is doing so much work to stop the common mode currents (CMC) dead in their tracks, where necessary and useful, depends on being well in the open in order for this particular antenna to work as a center fed 5/8 wave dipole. I can't prove any of this, and it's too much to ask anybody else to check it out too, but this is my thinking.

Maybe both of his antennas are just too close to his roof. Maybe he is experiencing more of a difference due to his recording your signal and the reflections from his roof are not affected the same on hia receive as when he is transmitting to you.

 

[bob85]

im not sure why i did not see the result we have seen in other comparisons eddie,
the other tests were done on poles not fixed to the house,
first impressions are they don't like things close to the bottom of the antenna but we would have to do more tests with gainmasters close to the house roof to see if there was a common trend,

im starting to wonder if the gm would beat my i-10k if i raised them up a little higher.

 

[Needle Bender]

Being a balanced antenna, anything near the Gainmaster which reflects RF will tend to unbalance it and skew the pattern, leaving a crap-shoot as to what pattern is left.

The Gainmaster is definitely not the best antenna for all installations. The Imax would be a better choice when close to nearby roofs, antennas, trees, etc. when radials aren't welcome, otherwise; I-10k or Penetrator for a better performing, quieter antenna than the Imax, in a cluttered environment.

I'm still hoping someone will figure out this one-wavelength-high issue where the GM seems to not outperform an Imax. :glare:

 

[Marconi]

im not sure why i did not see the result we have seen in other comparisons eddie,
the other tests were done on poles not fixed to the house,
first impressions are they don't like things close to the bottom of the antenna but we would have to do more tests with gainmasters close to the house roof to see if there was a common trend,

im starting to wonder if the gm would beat my i-10k if i raised them up a little higher.

Bob, I am sure not one to be hashing out the workings of a coil, but most seem very sensitive while doing their work. I assume that unless they're setup in some specific situation, and/or free and clear of stuff around them...stuff will happen that can possibly counteract that function. Then they may suffer to do the work.

Some designs even have additional parts associated with their function, that is adjustable, and somehow that allows the magical work they do to be adjusted. Stopping current from flowing may be physically easy, but to do it as completely as I see happening with the GM, I figure it needs the best install it can get, and that being high and clear with plenty of free space around it, and for sure away from stuff on the same plane with the choking coil. Without that choke working like it should, that antenna would just be a random long wire...all the way back to the transmitter.

If you do raise you stuff up, be sure and keep us posted.

 

[Marconi]

Being a balanced antenna, anything near the Gainmaster which reflects RF will tend to unbalance it and skew the pattern, leaving a crap-shoot as to what pattern is left.

The Gainmaster is definitely not the best antenna for all installations. The Imax would be a better choice when close to nearby roofs, antennas, trees, etc. when radials aren't welcome, otherwise; I-10k or Penetrator for a better performing, quieter antenna than the Imax, in a cluttered environment.

I'm still hoping someone will figure out this one-wavelength-high issue where the GM seems to not outperform an Imax. :glare:

NB, I think my GM is within 1.5' feet of that height right now. If the wind lays down a bit, I might go out there and lower mine to 36' feet. The problem is I hear no regular traffic that would allow me some chances for comparisons.

The only thing I could do is do a VA1 analyzer bandwidth scan along with a SWR scan...and compare before and after, and that might not show anything.

Tell me again exactly what you experienced other than the Imax besting the GM. Was this just a one time check with just one contact, or what?

 

[bob85]

eddie,
when i saw less of an improvement today i quizzed the guys at the other end about the exact install situation looking for differences between our tests,
the only thing i could come up with is the proximity to the roof / house but one test to a few stations is far from conclusive,

with more tests we may see a trend that agrees with what you shockwave and 007 claim.

 

[nav2010]

The GM's a rate pile Bob. lol op:

 

[Needle Bender]

NB, I think my GM is within 1.5' feet of that height right now. If the wind lays down a bit, I might go out there and lower mine to 36' feet. The problem is I hear no regular traffic that would allow me some chances for comparisons.

The only thing I could do is do a VA1 analyzer bandwidth scan along with a SWR scan...and compare before and after, and that might not show anything.

Tell me again exactly what you experienced other than the Imax besting the GM. Was this just a one time check with just one contact, or what?

No, not a one-time occurrence, consistently the Imax kept up with the GM and even bested it to a couple guys about 35 miles away. He hears no improvement with the GM, which I was expecting to be a full s-unit better than his old Imax. He's planning to put the Imax back up and sell the GM. I'm disappointed he didn't see improvement like I did.

 

[Marconi]

No, not a one-time occurrence, consistently the Imax kept up with the GM and even bested it to a couple guys about 35 miles away. He hears no improvement with the GM, which I was expecting to be a full s-unit better than his old Imax. He's planning to put the Imax back up and sell the GM. I'm disappointed he didn't see improvement like I did.

Well I've see worst cases of disbelief, but I know it's possible the Imax can perform better than the GM in some cases. I don't like my Imax, and never have, but it is not a bad antenna.

My Startduster most of the time is quieter than my GM, and on occasion shows a little better signal, but as usual with me...the difference is never much. For sure my GM doesn't show as much improvement as most of the happy CB'rs I hear describe it all too often, but that doesn't change the fact that I think it is one of the best CB antennas out there.

 

[BOOTY MONSTER]

any idea why you don't see/hear the differences in antennas that others claim to marconi ? do you think its due to your soil ? nearby structures ? terrain ? or that you're more meticulous in your measuring ?

but , at least your not seeing 4 to 15 s-units of difference between antennas

 

[gamegetter]

Being a balanced antenna, anything near the Gainmaster which reflects RF will tend to unbalance it and skew the pattern, leaving a crap-shoot as to what pattern is left.

The Gainmaster is definitely not the best antenna for all installations. The Imax would be a better choice when close to nearby roofs, antennas, trees, etc. when radials aren't welcome, otherwise; I-10k or Penetrator for a better performing, quieter antenna than the Imax, in a cluttered environment.

I'm still hoping someone will figure out this one-wavelength-high issue where the GM seems to not outperform an Imax. :glare:

I would think that all omni antennas would be affected equally by objects in their near field or by ground absorption. Can you explain other wise?

 

[Needle Bender]

I would think that all omni antennas would be affected equally by objects in their near field or by ground absorption. Can you explain other wise?

I haven't experienced much in the way of interaction with any other 5/8 until the Gainmaster, then I found it came on strong only when it was the only antenna up there.

 

[Marconi]

any idea why you don't see/hear the differences in antennas that others claim to marconi ? do you think its due to your soil ? nearby structures ? terrain ? or that you're more meticulous in your measuring ?

but , at least your not seeing 4 to 15 s-units of difference between antennas

I've had a lot of ideas about why I might not see more differences here, but it has always been sort of that way since I first started comparing signals when I heard guys making wild claims about many of these same antennas we talk about all the time.

The first antenna I ever bought just to test was Jay's I-10K, and if it had been as good as I heard...that would be the only one I ever needed. I wasn't convinced, even after I used it. It is a great antenna, but I don't see the advantages I hear about, except maybe its construction.

In my opinion, the best way to judge an antenna is to use one, and compare it to the others, as fairly as you can and one radio signal report won't cut it.

 

[Marconi]

I haven't experienced much in the way of interaction with any other 5/8 until the Gainmaster, then I found it came on strong only when it was the only antenna up there.

Well first off NB I'm with you. I've never experienced the use of a choke that preformed as flawlessly as the one on the GM.

I figure this choke has a lot of work to do to stop dead the common mode currents that have to be flowing on the bottom section. So, it does not surprise me that the GM is probably, just as I have experienced, sensitive to stuff around the bottom. Since we can't visually see what is going on, we somehow have to use our God given senses and try to be observant in what we do.

That said, I think most guys over in Europe have to have their GM down sort of low, because of the devil in their wheel house. So they suffer the consequences with total disregard.

Does it make any difference if your GM is too low or close to stuff, I have no idea, but I saw it revealed here on my bandwidth curves, and that's not just a lot of hot air or words.

View attachment Gain Master Bandwidth curves.pdf

 

[The Man from Uncle]

as you all already know ...... the fiberglass is just viagra to hold the copper wire inside that is actually the antenna . i think i remember some comments about the matching network used in the 99/2K doesn't make efficient use of ground elements added to them . i know the GM doesn't use ground elements and its said to not need them ....... but i wounder how it would react to having four 9 footers added to its feed-point horizontally or sloped ?? has anyone thought of trying it on theirs ?

The Fiberglass used for these antennas i.e. A-99, Imax 2000, the Solarcon and Gainmaster as you stated "Does support" the internal wire, but the Fiberglass also helps in reducing spurious radiation, EMI, and static build up (skin effect)