Caveat : I know that DX is hugely dependent on atmospheric conditions and so therefore making hard and fast statements is clearly not possible. I am also aware that any individual antenna should be taken into account with the complete antenna system as a whole. Poles, chokes, isolation or not, grounding, QTH, heigth above ground, height above sea level, soil conditions (though at 27Mhz this is less of an issue for common ground types)
I have a Gain Master and have made some good contacts, however I am starting to wonder if it is really as good a DX antenna as Sirio and the reports I have read make it out to be in my specific situation.
I have learnt this antenna does like to be away from other objects and have found that under 6M high and low angle TOA performance might begin to suffer a bit. Whereas potentially ground plane types can operate quite well close to the ground and being bolted to a metallic object can actually be of benefit.
I keep hearing stories of people doing 10,000 mile multi hop skip with their mobile whip antenna and there is video evidence of this happening on Youtube. So it can be done.
My issue is I think I should be getting better DX score given my rather elaborate DX mobile base station. I do have an IMAX antenna and am considering giving that a go soon on a decent set of poles 6M + in the air. I have good height, decent power and a good antenna. I am starting to think that the GM may not be that good an antenna for DX compared to a good 5/8 wave ground plane type.
Thought that pop into my head:
Why do mobile static stations with a mobile whips - anecdotally at least - seem to do as well ? (In practice I take what people say on air at face value and believe their DX logs)
Am I asking too much of an omni directional antenna ?
Is my height above sea level (400-600ft usually) a detriment to DX ?
Am I comparing my performance and DX success against stations that also have beams.
(I know for a fact that many of my locals use beams and I do not know in what capacity they might be pointing them to gain an advantage, it would seem odd to own a beam that is permanently set up and not actually use it)
I know there is more to a good antenna than getting a signal to the end QTH. Relative noise/static pick up as well. What is the point of getting a signal there if you cannot hear them? etc.
I have what could be called dubious grounding of my radio system. I do not use batteries that are earthed to the vehicle and the car chassis is not earthed to the physical soil/earth either. My batteries sit in the passenger seat foot well. One normal car battery for the radio and a deep cycle leisure battery for the linear. This could potentially be a problem. I have apparently suffered a little scratchy audio from time to time but have remedied this by not over driving my linear. I am backing off the power drive by 20-30pct to keep the signal cleaner. I generally obtain good SWR of 1.2:1 being typical.
Maybe it is just conditions and maybe I am over thinking the set up. I am thinking of giving the IMAX a go in a basic config with no radials and no isolation and no chokes just to see what happens. The issue being is that I might go out and speak to nobody and then think the IMAX is a bad antenna.
I am trying to balance getting the fundamental set up right vs experimenting with other antennas to see if they perform better in my specific set up. Any advice or thoughts are welcome. Thanks.
I will add that when I DX and patch someone through or vice versa, on the same contacts, some days I am a little under signal wise compared to a friend and some days a little more. So maybe it is all about the moment and your exact whereabouts. i.e. pure chance.
I find this aspect of 11m band use a little frustrating and unsatisfying because it is subject to the vagueries of ionospheric charge. If your QTH is 40 miles from a friend and you have slightly different angles of TOA at your lowest elevation lobes then we could expect to see 100mile differences between where the energy from our antennas hits patches of randomly ionized gasses. And maybe 1 day I hit the strong bit and one day not and vice versa. (given that 100mile difference)
In saying that I just want to maximize my overall station performance and wondered if anyone can spot some glaringly obvious operational mistakes. I know this is more than IMAX vs Gain Master.
The Gian Master is the devil I know and I do not appear to be getting too much of a problem from RF in the shack and the GM is known as a fairly clean antenna and does not produce TVI too badly probably from lack of common mode on the coax. I also like the convenience of not having to set up ground radials.
I have a Gain Master and have made some good contacts, however I am starting to wonder if it is really as good a DX antenna as Sirio and the reports I have read make it out to be in my specific situation.
I have learnt this antenna does like to be away from other objects and have found that under 6M high and low angle TOA performance might begin to suffer a bit. Whereas potentially ground plane types can operate quite well close to the ground and being bolted to a metallic object can actually be of benefit.
I keep hearing stories of people doing 10,000 mile multi hop skip with their mobile whip antenna and there is video evidence of this happening on Youtube. So it can be done.
My issue is I think I should be getting better DX score given my rather elaborate DX mobile base station. I do have an IMAX antenna and am considering giving that a go soon on a decent set of poles 6M + in the air. I have good height, decent power and a good antenna. I am starting to think that the GM may not be that good an antenna for DX compared to a good 5/8 wave ground plane type.
Thought that pop into my head:
Why do mobile static stations with a mobile whips - anecdotally at least - seem to do as well ? (In practice I take what people say on air at face value and believe their DX logs)
Am I asking too much of an omni directional antenna ?
Is my height above sea level (400-600ft usually) a detriment to DX ?
Am I comparing my performance and DX success against stations that also have beams.
(I know for a fact that many of my locals use beams and I do not know in what capacity they might be pointing them to gain an advantage, it would seem odd to own a beam that is permanently set up and not actually use it)
I know there is more to a good antenna than getting a signal to the end QTH. Relative noise/static pick up as well. What is the point of getting a signal there if you cannot hear them? etc.
I have what could be called dubious grounding of my radio system. I do not use batteries that are earthed to the vehicle and the car chassis is not earthed to the physical soil/earth either. My batteries sit in the passenger seat foot well. One normal car battery for the radio and a deep cycle leisure battery for the linear. This could potentially be a problem. I have apparently suffered a little scratchy audio from time to time but have remedied this by not over driving my linear. I am backing off the power drive by 20-30pct to keep the signal cleaner. I generally obtain good SWR of 1.2:1 being typical.
Maybe it is just conditions and maybe I am over thinking the set up. I am thinking of giving the IMAX a go in a basic config with no radials and no isolation and no chokes just to see what happens. The issue being is that I might go out and speak to nobody and then think the IMAX is a bad antenna.
I am trying to balance getting the fundamental set up right vs experimenting with other antennas to see if they perform better in my specific set up. Any advice or thoughts are welcome. Thanks.
I will add that when I DX and patch someone through or vice versa, on the same contacts, some days I am a little under signal wise compared to a friend and some days a little more. So maybe it is all about the moment and your exact whereabouts. i.e. pure chance.
I find this aspect of 11m band use a little frustrating and unsatisfying because it is subject to the vagueries of ionospheric charge. If your QTH is 40 miles from a friend and you have slightly different angles of TOA at your lowest elevation lobes then we could expect to see 100mile differences between where the energy from our antennas hits patches of randomly ionized gasses. And maybe 1 day I hit the strong bit and one day not and vice versa. (given that 100mile difference)
In saying that I just want to maximize my overall station performance and wondered if anyone can spot some glaringly obvious operational mistakes. I know this is more than IMAX vs Gain Master.
The Gian Master is the devil I know and I do not appear to be getting too much of a problem from RF in the shack and the GM is known as a fairly clean antenna and does not produce TVI too badly probably from lack of common mode on the coax. I also like the convenience of not having to set up ground radials.
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