Info on the Gaun Master type antenna's

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Re: Info on the Gaun Master type antenna's

Post by cjay » 20 May 2015, 14:33

The Vector 4000 being the Sirio clone of the Avanti Sigma IV?

I seem to remember reading a pretty damning write up on the Sigma IV from someone who had managed to model it and found it wasn't as great as it was made out to be so, personally, I'd take that write up with a pinch of salt until I had found the tech write up and considered why the GM seems as good as the Vector because it could just be that the GM is being compared to something for the wrong reasons.

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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 20 May 2015, 17:37

SgtBilko302 wrote:I use an I-Max 2k and do ok but the man above ^^^ has good mates and he does ok as well. LOL.
Sometimes :lol:
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 20 May 2015, 17:53

RadioDaze wrote:
108EH002 wrote:
RadioDaze wrote:I use the Gain Master and I like it. I am not sure about the performance claims yet and have had it about 3 months and being using it mobile static. For some reason I can only get a SWR of 1.5 or 1.6 : 1 whereas my 1/2 wave silver rod goes 1.1 : 1 with ease. I am going to try and test the Silver Rod out in similar conditions in weeks to come. As I change location it is more difficult to get a like for like impression against other verticals.

In saying this (and it might have happened with another antenna) my longest distant contact was to Indonesia and using the Gain Master.
I am trying to base performance considerations on long distance UK point to point line of sight / ground wave contacts. It is a work in progress.

Whatever it does the job well and in my mind is one of the top 3 performing vertical 5/8 length antennas in existence.

They work well but that will be a relatively small performance increase relative to other good 5/8 wave length antennas.

Some report 6dB differences (that is a lot for just an antenna change and much more bang for buck than going from 100W to around 500W which is what you need to get a similar gain increase) 1 S point.
So if the Gainmaster is in the top 3,what are the other 2 best antenna without radial's,maybe the Imax 2000 will be in your 3 ? I use a A.B.S. 1600 and it work's ok for me.
Hi man, it does not really matter what I think, we all know the big vertical ones, over and above the basic GPA's and Silver Rods (And sirio variations) in most peoples budget area.

Gain Master
Imax 2000
Antron 99 (copes and variants included Thunderpole etc.)

Are surely the most popular and all performing about the same in the wide range of situations people use them in.

I am 100pct sure the ABS 1600 does alright. For me the more informative tests regarding antenna performance is long distance in the UK. I can only compare my own 2 antennas really. One day I will compare the Gain Master against the humble silver rod on the same pole. Possibly this week if I can take the time and effort to do it.
It does matter what you think,have you seen how many test antenna's on switcher boxes,the antenna's are not even in the same position,at least you are going to test it properly :)
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

RadioDaze

Re: Info on the Gaun Master type antenna's

Post by RadioDaze » 21 May 2015, 09:08

I will do this for sure with some locals. I have actually found that my SWR meter has been lying thus the reason why the GM has been showing a higher SWR it is back to 1.2/1.3:1 now on another meter ! So sorry for crying wolf on it. Blooming meters. Must have took a knock sometime I cannot remember dropping but these thing do happen when mobile.

I had a new problem that many do not suffer yesterday... a stone in your PL-259 screw section !

Mud on me coax (I wash them down once every now and then) and soil up your Silver Rod SO-239 piece (that sound very dirty indeed)

Will try and sort a Silver Rod vs GM test with a few breakers on air sometime.

RadioDaze

Re: Info on the Gaun Master type antenna's

Post by RadioDaze » 21 May 2015, 12:07

I think the GM is an incredible feat of engineering. Sometimes it is the skill and knowledge and design you pay for. As long as the materials are up to the job, that is what counts. I appreciate some find the fibre glass poles fray and snap, that would be irritating and expensive. A few people tried to discourage me from using the GM mobile static but I pressed on with it. I did not want to compromise on not getting the best vertical that exists.

It is a bit of extra work to attach a 7m fibre glass margin pole to the lower section, gaffer tape that up and then put white insulating tape on every foot or so to hold the coax/capacitor/matching stub and upper copper radiating wire to the mast but not that hard and I get quicker at doing it each time. So far no breakages either, just have to be careful not to kink it in storage/handling. I am very pleased with it. :)

RadioDaze

Re: Info on the Gaun Master type antenna's

Post by RadioDaze » 21 May 2015, 12:59

This Shockwave guy seems to know a lot about the GM and it's design... this is about the choke, the choke apparently has to stop RF energy dead in it's tracks and physically determine that this is the end of the antenna, this way it keeps it's radiation pattern and stops the fed line radiating with all the unpredictable issues that causes. Makes you wonder if he was on the Sirio design team.

"CDX, I believe there are variables such as the spacing between wraps that will determine what the maximum impedance of the choke can be in terms of wraps. The choke on the GM has a serious task to accomplish when you consider the RF voltage at the base of this antenna.

Because the RF voltage is the same at the base as it is at the top of this balanced antenna, I think they used more wraps with spacing to provide near perfect RF isolation. I also think it will be difficult to modify this antenna to handle multiple kilowatts.

The radome simply does not have enough room to use the type of capacitor this power would require. I suppose you could stack a few smaller caps in series to handle the voltage. I suspect the coax will fail at some point but not because of the current or heat.

This failure would most likely occur between the wraps on the choke and arc across the braid because this is where the RF voltage drops on a coax choke. This also suggests changing the cable may not cure the problem. You need better insulation on the outside of the cable."

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Re: Info on the Gaun Master type antenna's

Post by Mudslinger » 21 May 2015, 18:18

The GM is a relatively simple design, made from relatively easy to obtain parts.

Makes you wonder why someone hasn't made something similar before...
Mudslinger - Simon
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26CT612

There is no such thing as a Fidelity 1000 which is too good to scrap.

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Re: Info on the Gaun Master type antenna's

Post by RadioDaze » 21 May 2015, 18:31

I can understand the train of thought Mudslinger...when you look at the parts it is simple I agree. Understanding what RF currents will be flowing and where and stopping the common mode currents that can, as I gather cause a lot of ambiguity on general performance (radiation elevation angle and polar response) seems like the hard bit. Actually getting a real physical antenna to provide an actual advantage over others is not easy (there are other good ones about) and no wonder the antenna has been designed by computer modelling. I reckon they dotted all the Rf i's so to speak, they had to otherwise they could have built something that did not provide the gain the computer models suggested.

All the parts need moulding, machining, wire cutting, fixing up properly, soldering, heat shrinking, testing and quality control. I would have guessed it is quite a labour intensive antenna to make compared to aluminium poles slotting into each other and a bit of wire wrapped round a former with SO239 popped on the end. And in Italy that labour cost will not be cheap, sometimes it is not just the parts. R&D and labour must be considered.

They are not really mass market consumer items. Sirio need a profit just like any other business, hat's off to them is what I say.

I would loved to have been a fly on the way as the engineers looked at plots and models.

I would buy another one if mine broke.

ian
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Re: Info on the Gaun Master type antenna's

Post by ian » 21 May 2015, 19:50

Me too, but I've read about the home brew ones on here and I would like to try the home brew against the original to see how good they are.
De Ian 108SD121 - 108ID121 - 108OP121.

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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 14 May 2018, 07:39

Swapped the abs 1600 for an 827 in 2015,tried a gainmaster and put the 827 back up,now use an Imax 2k,but would get another 827.Knights claim the 2k has 1-2db gain more than an 827/gm.
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

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Re: Info on the Gaun Master type antenna's

Post by Mudslinger » 14 May 2018, 20:57

108EH002 wrote:
14 May 2018, 07:39
Swapped the abs 1600 for an 827 in 2015,tried a gainmaster and put the 827 back up,now use an Imax 2k,but would get another 827.Knights claim the 2k has 1-2db gain more than an 827/gm.
I very much doubt that the 2k has any gain over an 827, in fact it is probably the other way around.


Unless they are relying on what is written on the box, and we know how true that tends to be...

Not saying that the Imax is bad mind you, but the 827 is just better still.
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There is no such thing as a Fidelity 1000 which is too good to scrap.

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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 14 May 2018, 22:20

Sgm was 1 s point worse on tx/rx at my location for locals upto 50 mile away,compared to 827/2k.All antennas tested at same height about 28ft up.Imax longer than 827 so might have a slight gain on rx,I was told the 827 worked better on tx out the 3 twigs,so can only go with what is reported back eh.Suffer from plenty noise at home from neighbours stupid security lights,and each antenna worth about £100 new was just the same for the chip pan noise......total sh1te :lol:
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

108EH002
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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 17 May 2018, 09:35

Mudslinger wrote:
14 May 2018, 20:57
108EH002 wrote:
14 May 2018, 07:39
Swapped the abs 1600 for an 827 in 2015,tried a gainmaster and put the 827 back up,now use an Imax 2k,but would get another 827.Knights claim the 2k has 1-2db gain more than an 827/gm.
I very much doubt that the 2k has any gain over an 827, in fact it is probably the other way around.


Unless they are relying on what is written on the box, and we know how true that tends to be...

Not saying that the Imax is bad mind you, but the 827 is just better still.
You doubt the bigger Imax 2k antenna works better than an 827 in anyway Simon,but say a mobile antenna should be better because it is bigger as you typed "I would guess that the modulator will work better as it is larger" = Imax bigger than 827 = ?
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

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Re: Info on the Gaun Master type antenna's

Post by Mudslinger » 17 May 2018, 09:59

The IMAX might be longer but it has no radials. The radials benefit the radiation pattern and recieve much more than an extra two foot in overall length.

What would work better, a modulator on a car roof or a tank whip on a biscuit tin?
Mudslinger - Simon
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There is no such thing as a Fidelity 1000 which is too good to scrap.

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Re: Info on the Gaun Master type antenna's

Post by 108EH002 » 17 May 2018, 10:46

Dunno = maybe work different if the biscuit tin has 4 groundplane wires like mine did in the attic Simon,when I used the said whip until I put a grinder through it for a mobile pmr twig.I use a Les Wallen modulator on a 3/8th dv mount drilled through the roof at present.Have had sirios/wilsons/1/4 wave whips/pal firestiks/dx27s and loads more,but I am happy enough with my L.W.

My homemade dipole can hear Scandinavia/Wales better than when I used an 827 15 ft higher up than the dipole,doesnt mean its better than an 827,it was just better positioning for the direction the signal was being rxed for my location.The 827 was new and still working fine at another 20 so nowt wrong with the 827 twig.

Not very much metal in the air on a homebrew dipole but it seems to work, = Op Trevor in Swansea said no fading on my dipole and was a constant 9+,but on the 827 to him,the needle was 1-9+ and back to 1 like a window wiper back and forth running 40w.I could be heard txing .4w out an old H407 into my dipole and a respectable S7 to Swansea from up here.Some folk are happy with 10w on 40m getting that far,I just prefer experimenting test free and being an IQ0 on CB radio ;)
You can talk worldwide on CB = not 10 - 15 miles,
some are too far up their own @rse to admit it = snobs,
but many freebanders just happen to know otherwise = test free.


27.781.25 Fm
27.555 Usb
27.385 Lsb
27.315 Fm
27.275 Usb
27.025 Am

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