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Author Topic: Supplied antenna mystery  (Read 15240 times)

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bratters

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Re: Supplied antenna mystery
« Reply #15 on: March 25, 2010, 01:45:35 PM »
VK2GEL both types  use the disc for groundplane, I found the antenna with the three "nibs" moulded to have much better quality (especially the screen) co-ax, which is what I think makes the difference.   It would appear that these better quality antennas were supplied with the Portugese PrimeTech earlier boxes.

I concur and that explains the mystery of a 50% difference in performances.

QUESTION FOR AIRNAV - can we please have access to the old three knib aerial again - even if we have to buy it from W&S? It is surely in your interest to get the very best results from the equipment.

AirNav Support

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Re: Supplied antenna mystery
« Reply #16 on: March 25, 2010, 01:48:49 PM »
We will look into this. We did conduct testing and found very little difference between the two but we will look into it again.
Contact Customer/Technical support via:
http://www.airnavsystems.com/contact.html
[email protected]

bratters

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Re: Supplied antenna mystery
« Reply #17 on: March 25, 2010, 01:50:42 PM »
Thanks for that Airnav. Obviously if an improved aerial can make what appears to be such a substantial difference, it will be well worth the effort.

radarspotter10

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Re: Supplied antenna mystery
« Reply #18 on: March 25, 2010, 01:54:25 PM »
VK2GEL both types  use the disc for groundplane, I found the antenna with the three "nibs" moulded to have much better quality (especially the screen) co-ax, which is what I think makes the difference.   It would appear that these better quality antennas were supplied with the Portugese PrimeTech earlier boxes.

I concur and that explains the mystery of a 50% difference in performances.

QUESTION FOR AIRNAV - can we please have access to the old three knib aerial again - even if we have to buy it from W&S? It is surely in your interest to get the very best results from the equipment.

Hi all
Very interesting posts,  i would buy it as well bratters.
from pat

CoastGuardJon

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Re: Supplied antenna mystery
« Reply #19 on: March 25, 2010, 07:42:47 PM »
Hi AN Support, the quality of the connections in the antenna base can also be suspect, but (and I'm sorry to be requesting this again) can you please get some whips made up in stainless steel, I'll buy 2 for sure, and the cost would surely be minimal over a mild steel one!
ANRB :  AOR AR8000 : Icom R-7000 : Icom IC-R9000 : JRC NRD-545 : OptoElectronics Digital Scout and OptoLinx Interface; Realistic Pro-2005 : UBC 800XLT - listed in alphabetical order, not cost, preference, performance or entertainment value!

Southwest

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Re: Supplied antenna mystery
« Reply #20 on: March 26, 2010, 11:06:59 AM »
If the better antenna is the one with the disc at the bottom, then this groundplane could be making the difference.

A bikky/sweets tin lid will help, something about 12-18 cm diameter. Some of them can be soldered.


My aerial is on top of a wooden wardrobe.

If I put tin foil on the top of the wardrobe and then put the base on top of that do you think it would make any difference?

bratters

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Re: Supplied antenna mystery
« Reply #21 on: March 26, 2010, 01:20:06 PM »
If the better antenna is the one with the disc at the bottom, then this groundplane could be making the difference.

A bikky/sweets tin lid will help, something about 12-18 cm diameter. Some of them can be soldered.


My aerial is on top of a wooden wardrobe.

If I put tin foil on the top of the wardrobe and then put the base on top of that do you think it would make any difference?

Doubt it. Stick to the supplied base or a decent sized biscuit tin. The wooden wardrobe makes no difference.

CoastGuardJon

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Re: Supplied antenna mystery
« Reply #22 on: March 26, 2010, 09:39:01 PM »
Hi SW, I use an old brake disc off a Peugeot 405, which won't blow off our flat roof.    We get very strong winds straight off the Atlantic, I agree with Bratters, either the supplied CD size disc or a Roses/Quality Street tin lid, but for my location, it has to be heavier than those!    The size doesn't seem to make the slightest difference, and there is no direct connect to the ground plane, so, Iwould assume it is capacitively coupled, like some car mobile phone twigs.
ANRB :  AOR AR8000 : Icom R-7000 : Icom IC-R9000 : JRC NRD-545 : OptoElectronics Digital Scout and OptoLinx Interface; Realistic Pro-2005 : UBC 800XLT - listed in alphabetical order, not cost, preference, performance or entertainment value!

g0seg

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Re: Supplied antenna mystery
« Reply #23 on: March 29, 2010, 05:28:52 AM »
Just a quick observation about groundplanes. Yes, the old sweet tin lid is a good standby but rusts quickly. I`ve found that a cheap teflon covered steel round baking tin is a good option - had mine up for months now and no signs of rust. As for the size of groundplane required, i agree that size doesn`t appear to matter at all. Regarding coax, the heavier screen the better and it`s a critical point - equal to the antenna used plus its height and location. Roger

Jeremy

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Re: Supplied antenna mystery
« Reply #24 on: March 29, 2010, 10:59:08 AM »
Think about your radio ham theory. A groundplane must be more than a quarter wavelength. It also depends on the antenna. If it is a half wave then it actually doesn't need a groundplane at all. Most of these whips are a combination of halfwaves and quarter waves, i.e. coliniears.
J.
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QRZ.com

bratters

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Re: Supplied antenna mystery
« Reply #25 on: March 29, 2010, 11:51:34 AM »
This has been a useful thread that has wandered this way and that.

I would draw two conclusions:  firstly whilst everyone is constantly seeking the best possible reception, many of us are (and always will be) stuck with the supplied aerial and its inherent limitations regarding outside use.

Secondly, since there already appear to be significant variations in the quality of the supplied aerials, it seems likely that these can be improved. A large number of us would benefit greatly from what should be a relatively simple and inexpensive operation to produce a MK 3 high quality indoors antenna.

Fingers crossed.

CoastGuardJon

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Re: Supplied antenna mystery
« Reply #26 on: March 29, 2010, 01:35:04 PM »
Hi John, or better still, one that can be used inside or out...............AN?
ANRB :  AOR AR8000 : Icom R-7000 : Icom IC-R9000 : JRC NRD-545 : OptoElectronics Digital Scout and OptoLinx Interface; Realistic Pro-2005 : UBC 800XLT - listed in alphabetical order, not cost, preference, performance or entertainment value!

Southwest

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Re: Supplied antenna mystery
« Reply #27 on: March 29, 2010, 02:34:23 PM »
Hi John, or better still, one that can be used inside or out...............AN?

Radical or what!

CoastGuardJon

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Re: Supplied antenna mystery
« Reply #28 on: March 29, 2010, 06:06:30 PM »
Well, it has to be said most magmounts are intended for outdoor use, as in on a mobile tin box with wheels - even more radical?
ANRB :  AOR AR8000 : Icom R-7000 : Icom IC-R9000 : JRC NRD-545 : OptoElectronics Digital Scout and OptoLinx Interface; Realistic Pro-2005 : UBC 800XLT - listed in alphabetical order, not cost, preference, performance or entertainment value!

bratters

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Re: Supplied antenna mystery
« Reply #29 on: March 29, 2010, 06:36:15 PM »
Well, it has to be said most magmounts are intended for outdoor use, as in on a mobile tin box with wheels - even more radical?

Hi Jon - I bought the MD1105 on that principle but unfortunately in all my tests the performance has not been not as good as the RB supplied aerial. It is of course a much more substantial product. It uses better quality (heavier) cable but unfortunately there's an awful lot of it - presumably for higher siting or use on top of a Luton van ;). This means some signal loss, not helped by the necessity for an additional connector/adaptor.

I must admit I very much like the lightweight twig for indoor use as it fits into the tightest areas.
I just want it tweaked up a bit.