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Author Topic: Static - earthing antennas - specifically earthing Magmount types.  (Read 25874 times)

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TedLoon

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #15 on: May 17, 2009, 10:14:29 AM »
I can't help you daveg but i'm also waiting for the answer

 Colin

daveg4otu

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #16 on: May 17, 2009, 10:28:17 AM »
Yes - nobody seems to  want to risk their necks with  a constructive answer....

I have my own ideas - but  just wondered what anyone else might offer.
5 Miles N of BHD at 50.28.28 N/3.30.43W...400ft amsl.

Hampshire, Devon, Dorset and Isle of Wight  Airfields Websites.....
http://devonairfields.tripod.com/index.htm

lambertw

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #17 on: May 17, 2009, 11:35:13 AM »
I am a liitle concerned about the static problem as I appear to have a unit that is not protected ANRBXXX,it is mounted in the loft but if I want to go mobile I am a bit worried that static could damage it, is there any divice tha can be put in-line from anntena to box that can protect it.(apart from earth cable)
Also now we have an idea of the batches that are not protected could it not make the resale of these very difficult,not that I am going to sell my beloved box.
« Last Edit: May 17, 2009, 11:43:22 AM by AirNav Support »

CoastGuardJon

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #18 on: May 17, 2009, 12:58:38 PM »
Yours is the later batch which has the increased protection. It should be 001750 not 01750.

Simpler way if it 1 after ANRB, its the newer batch.

Many thanks for the prompt and individual response AND, re-assuring.

Hi Dave, as far as I've ever been aware, there is no effective way of grounding a magmount on a car, and these are the most likely to build up a friction induced static charge, especially in very dry conditions - moving vehicles on insulating tyres, often with plastic body panels - we've all experienced the zaps on getting out of a car.     It seems to me that AN are trying to get us chasing shadows - a thought on the practical side of things, are these plastic/epoxy paint coatings on the whips causing static build ups that wouldn't occur with exposed metal - who remembers creating huge static charges in the physics lab. by rubbing one material (usually synthetics) with something else - the nylon slips (petticoats) that produced their own mini Aurora displays..............
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!

AirNav Support

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #19 on: May 17, 2009, 02:55:07 PM »
Please do not post your serials online (it is a risk). You can work out from the above posts by us and Development what batch it is.

To again reiterate we are talking about minority of people who have been affected.

Regardless what batch you are in, you should take steps to limit static build up.
There are few threads about this on the forum at the moment and a lot of questions are being repeated, to save us repeaing ourselves have a quick of read of them.
Contact Customer/Technical support via:
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WAL 2T

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #20 on: May 17, 2009, 03:14:11 PM »
Yes - nobody seems to  want to risk their necks with  a constructive answer....

I have my own ideas - but  just wondered what anyone else might offer.

Dave, is there absolutely no chance of knocking a couple of thin grounding stakes into the floor around the walls of your house - the 1m B&Q earthing rods are ok or are you in a difficult situation such as an upper floor apartment?
Chris

Under the EGGP 27 Centreline & 15nm from EGCC

flightchecker

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #21 on: May 17, 2009, 04:15:54 PM »
Just “the other way round“ John and Dave : It is YOU that “gathers static charge” and “discharges” to earth” by touching the car’s metal frame (Zap!), the latter beeing “tightened to ground” via the car’s tires, that are not “insulators” anymore  as compared to earlier times, when a “ conducting strap” sometimes had been attached to the car frame in order to deplete its static build up to ground as one or the other might remember. 
Nowadays, “conductive additives” as part of  the tire’s building materials prevent a car itself to charge up.

A solution for grounding a Magmount might be a wire, attached to the (metal) outer connector (just at the input of the ANRB) by means of an alligator clip or similar. The lead then attached to a metal part of the car’s frame by another clip. (“Intuition” requested).

I have been involved in endless discussions regarding static problems with ANRB, getting tired finally, to be honest. Now feeling  at least somewhat satisfied, that AirNav approaches it
in a serious manner, (beside of “DC Blocks” and other useless “solutions”) even resulting in a modifications of the receiver, that will solve the issue most hopefully.

Regards

Karl

daveg4otu

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #22 on: May 17, 2009, 04:39:27 PM »
Checker- I was thinking along those lines -  I have the  MD1105  Magmount   feeding the  box via a BNC/SMA adaptor- nice metal  surface -  and a  clip  with cable from there seems the obvious and hopefully efficient way....take the cable to an earth rod outside the house.

Wal2T - yes I can  whack an earth rod in  about six feet away  from the  box-  and bolt the earth  cable  to it no problems - just will have to  cut a groove in the concrete path to  drop the cable into(to stop Mrs G4OTU  falling over it ).

There is a  discussion on someone with similar problems on another site  where it has been suggested  hooking the earth wire (from coax shield) directly to the domestic earth - this I think may not be a  safe idea.

Moving from the coax  to the ground plane (Metal tin)...does anyone see  any point in earthing that ?- after all there is no direct electrical connection to the antenna as the magmount itself is encased ina  rubber "boot"...the only  connection  is capacative.


Opinions on the back of a £10 note please!
5 Miles N of BHD at 50.28.28 N/3.30.43W...400ft amsl.

Hampshire, Devon, Dorset and Isle of Wight  Airfields Websites.....
http://devonairfields.tripod.com/index.htm

CoastGuardJon

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #23 on: May 17, 2009, 05:26:27 PM »
Hi Dave, using the mains earth for radio and similar equipment is always said to be an absolute No No - PME and interference problems, similarly, how many houses now have a mains water supply using metal pipes, not very many.    That used to be a very good and effective earth.    As I referred to in another post (by Dave, I think) the current issue of Radio User mag. features a "water drill" type of technique using copper water pipe to form a permanent earth, may well be worth exploring.
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!

flightchecker

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #24 on: May 17, 2009, 05:29:21 PM »
Quote
Checker- I was thinking along those lines -  I have the  MD1105  Magmount   feeding the  box via a BNC/SMA adaptor- nice metal  surface -  and a  clip  with cable from there seems the obvious and hopefully efficient way....take the cable to an earth rod outside the house.
Excellent !!!

Karl

flightchecker

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #25 on: May 17, 2009, 05:46:54 PM »
Quote
Moving from the coax  to the ground plane (Metal tin)...does anyone see  any point in earthing that ?- after all there is no direct electrical connection to the antenna as the magmount itself is encased ina  rubber "boot"...the only  connection  is capacative.

Is the coax fixed to the magmount, or attached by a connector? Unfortunately I'm not familiar with the supplied magmount.

If a "fixed coax": No chance! Why then not purchase an external antenna ?


Karl


daveg4otu

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #26 on: May 17, 2009, 06:01:56 PM »
No the  coax is seperate- but the  outer end is nicety encased in a weatherproof  rubber shield so the obvious  point to use  is the inner(box) end .

Jon...yes -  in this instanceI was thinking of   high voltage spikes that can occur on an earth in the event of failure of some other piece of household equipment.

With   Transmitters or TX/RX I have  never connected them to the domestic earth in any way - using the domestic earth is one good way  of generating RFI.
5 Miles N of BHD at 50.28.28 N/3.30.43W...400ft amsl.

Hampshire, Devon, Dorset and Isle of Wight  Airfields Websites.....
http://devonairfields.tripod.com/index.htm

malc41

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #27 on: May 17, 2009, 07:27:29 PM »
aren't the cold water and gas pipes in most houses is earth tied. I don't suggest that everybody uses the rb in the bathroom etc but it saves driving a stake into you property
15 Miles East of EGNJ

CoastGuardJon

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #28 on: May 17, 2009, 07:40:43 PM »
aren't the cold water and gas pipes in most houses is earth tied. I don't suggest that everybody uses the rb in the bathroom etc but it saves driving a stake into you property

Hi Malc, no, the water pipes and CH radiators are electrically connected to the common mains electric earth - this is done for safety and prevention of mains electric shock, the mains water for most houses arrives through black or blue polyurethane pipes, water boards are now (AFAIK) only using blue plastic pipe to lay/reline new mains.    When the mains water was in cast iron, steel or lead pipes, these formed a very effective earth mats
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!

CoastGuardJon

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Re: Static - earthing antennas - specifically earthing Magmount types.
« Reply #29 on: May 17, 2009, 08:56:25 PM »
It is YOU that “gathers static charge” and “discharges” to earth” by touching the car’s metal frame (Zap!),

Yes Karl, I would agree to the extent, that the body is carrying a different potential to the car's metal bodywork, but this happens with synthetic cloth seats and clothing mainly


the latter beeing “tightened to ground” via the car’s tires, that are not “insulators” anymore  as compared to earlier times, when a “ conducting strap” sometimes had been attached to the car frame in order to deplete its static build up to ground as one or the other might remember. 
Nowadays, “conductive additives” as part of  the tire’s building materials prevent a car itself to charge up.

The black in car tyre rubber used to be high carbon content, which did act as a bit of a conductor to earth, but some tyres today have virtually 0% rubber or carbon, but are long chain polymers derived from oil products (ie plastics/synthetics, as is also used in a crap road surface material SMA - Synthetic Mastic Asphalt - which is causing problems of its own!).    Try putting a multimeter across a tyre, that's such one heck of a conductor, I'm surprised it isn't used instead of copper! - overhead high voltage cables are usually high aluminium content - much lighter than copper, a lot less stretchy and almost as efficient a conductor.    Anyway, back to the post, in wet weather, you don't get these static build up and violent discharges on cars.    You will more often than not notice a zp when it's very dry weather, especially when having driven across a field of dry earth and grass - had one last year at the Great Dorset Steam Fair!    Long before plastic static discharge straps were thought up (around the same time as velour and synthetic cloth materials took over the car upholstery world from rexine and leathercloth - I tend to only buy cars with leather seats to avoid the static problems - I remember when a length of drain plug chain would be attached to the exhaust or the vehicle's chassis or bodywork to "earth" it, to prevent car/travel sickness![/quote]


A solution for grounding a Magmount might be a wire, attached to the (metal) outer connector (just at the input of the ANRB) by means of an alligator clip or similar. The lead then attached to a metal part of the car’s frame by another clip. (“Intuition” requested).

This problem doesn't exhibit itself with car radios, so actually maintaining the "earth" side of an RB at the vehicle's potential could well be an effective solution.

I have been involved in endless discussions regarding static problems with ANRB, getting tired finally, to be honest. Now feeling  at least somewhat satisfied, that AirNav approaches it
in a serious manner, (beside of “DC Blocks” and other useless “solutions”) even resulting in a modifications of the receiver, that will solve the issue most hopefully.

No-one is twisting your arm to join in this thread, you but must find it of some interest or you wouldn't have!   

Following from my comment above,  in a domestic house, a proper RF earth would seem to be a good answer, these boxes are being run off totally isolated power supplies, and are not earthed in any way as they come - they have -ve and +ve supplied by the computer, totally isolated electrically, I know I've repeated myself, but it's only just sinking into my dense brain!    AN themselves have been putting forward this "static" damage problem - I'd venture to suggest that it is the isolated potential nature of the RB which is causing the trouble and agree that a properly earthed wire to the case will prove to be the solution, be it to an RF ground earth or vehicle's bodywork.    Sorry if this seems like wading through treacle,but I've spent the afternoon thinking about it, and the electrically insulated nature of the box (and PCs for that matter) has only just struck me, desktop PC metal cases are earthed to prevent shock (and provide RFI screening), but the power supplies within have no connection to earth.
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!