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Author Topic: ESD and Sawfilter problems  (Read 8549 times)

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73TORANA!

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ESD and Sawfilter problems
« on: August 19, 2010, 02:18:04 AM »
Hi all, as I look through old postings one thing that keeps popping up is poor receive performance and the amount of people that have returned there radar box to have the front end Saw filter replaced. As I stated in my post on 9Db antennas this is a great product but the front end has very poor ESD protection. Due to there tiny size I would doubt that these saw filters  would even handle a 50 volt ESD. Wind on a hot dry dusty day will easily cause a static build up of more one hundred times that , may be not in the damp UK ,sorry guys. In my 30 years of aviation radio engineering I have only had 2 problems like this and they were due to direct hits of lightning, but planes get hit every day so its not a common fault with them due to simple protection.
Most high quality Radio's and Aviation equipment have a low impedance (resistance) paths to ground on the antenna input for any DC or a non RF type potential to be shunted to ground, the DC input impedance of the radar box is very high allowing even the slightest ESD to build up and when flash over occurs its to late for the tiny ESD device that Airnav fitted to the later units to do its job. Note ESD in my experience can be a DC , low frequency AC or a pulse (technically AC) nasty stuff and you don't need a storm to get it. Have a look at carrier based planes returning to the deck and see the ESD on the arrester hook as they touch down and Helicopter rotors at night with night vision camera footage and when the plane hit the world trade centre I bet the flash was an ESD. On my unit i have fitted an Inductor to the antenna connector inside the unit.
1.5 turns on a 1/8th drill bit using a wire leg of a 1/4 watt resistor (see photo),it provides a low impedance to any low frequency signal I.E ESD or DC and the inductance is high enough not to interfere with the input tuned circuits of the saw filter. the sensitivity of the unit has not been affected in any way , range is as good as it has always been.
NOTE : THIS WILL VOID YOUR WARRANTY SHOULD YOU DO THIS . YOU MUST ALWAYS USE A GROUNDED TIP SOLDERING IRON AND USE GOOD ESD PRACTISES WHEN SOLDERING.  if you have any doubts about anything DON'T do it. This will not stop a direct hit but it will give you massive protection improvement.
If you don't want do this I would suggest that you disconnect your antenna when not in use .
Regards ,Geoff Arnold.  
« Last Edit: August 19, 2010, 05:55:41 AM by 73TORANA! »

RobinB

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Re: ESD and Sawfilter problems
« Reply #1 on: August 22, 2010, 08:40:33 AM »
I am just beginning to wonder if I need to return my unit as its performance is not what it used to be.

We did have a lightening storm a week ago.

bratters

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Re: ESD and Sawfilter problems
« Reply #2 on: August 22, 2010, 11:35:18 AM »
I am just beginning to wonder if I need to return my unit as its performance is not what it used to be.

We did have a lightening storm a week ago.

In my case the performance fell off a cliff - a drop in range from 160 miles down to 20 miles at best.  No question about something being amiss.

RobinB

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Re: ESD and Sawfilter problems
« Reply #3 on: August 22, 2010, 04:46:00 PM »
Something is not right, I have rechecked connections and still only getting around 50% range.

I am going to take box and mobile antenna with laptop out later to do a check with that just to make double sure.

73TORANA!

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Re: ESD and Sawfilter problems
« Reply #4 on: August 23, 2010, 12:32:39 AM »
I have had a look at the spec sheets on these devices and they will not handle any dc voltage at the input so even a small pulse of ESD will damage them .
Does Airnav have any thing to input.? It may pay to send the units for repair ,I would be curios to see the outcome.
Geoff.

AirNav Development

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Re: ESD and Sawfilter problems
« Reply #5 on: August 23, 2010, 03:08:01 AM »
Regarding teh SAW filter "problem": as explained many times in the past it was an hardware issue that could happen to the very first batch of RadarBox units. It has been corrected years ago and cannot be consider an issue at this time. - several thousand units later

At the same time it is well known that the "SAW filter problem" was something constantly repeated by our competitors/ML&S/SBS to try to halt RadarBox reputation: there are constant rumours that SBS is about to be discontinued by Kinetic which clearly shows how the quality of RadarBox is so high that it is taking its competitor out of the market.

RobinB: are you on an hidden agenda here?
Most of your 34 posts on this forum focus on negative and most of them false facts. There is a forum on the internet well known for this kind of games and maintained in background by our competitors so please avoid continuing them on this forum.
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73TORANA!

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Re: ESD and Sawfilter problems
« Reply #6 on: August 23, 2010, 06:39:59 AM »
Airnav Thanks for the update please be advised that this post was not intended to degrade the reputation of this product as I am extremely happy with it as I'm sure everyone else is. It was just to bring to the attention of a potential problem but if your sure that It has been rectified thanks for doing so ,I have a later unit with the new ESD device fitted . I guess only time will tell .I would still disconnect an outside antenna anyway when not in use as you don't want to come home to a pile of ash. 

HH

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Re: ESD and Sawfilter problems
« Reply #7 on: August 23, 2010, 06:53:36 AM »
AirNav Development:

could you pls specify which units ("very first batch") are affected and are they exchanged? I think I might have one of those and I'm planning to connect an outside antenna in the near future. After reading this thread, this might be not the best idea?

Markus

AirNav Support

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Re: ESD and Sawfilter problems
« Reply #8 on: August 23, 2010, 09:37:20 AM »
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lambertw

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Re: ESD and Sawfilter problems
« Reply #9 on: August 23, 2010, 10:05:30 AM »
I have one of those ("very first batch"),going mobile to various locations and playing about with antenna locations with my anrb I am very reluctant to do so,I think that a recall of these units should have had taken place,I'm shaw that I am not alone on this one.

AirNav Support

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Re: ESD and Sawfilter problems
« Reply #10 on: August 23, 2010, 10:09:38 AM »
lambertw,

It should be ok for that. The cases where it as failed is where customers have placed it externaly for a continued period of time which has allowed the static to build up.

As mentioned the return rate for those and cases are rare so there is no reason for a recall.
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air7677

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Re: ESD and Sawfilter problems
« Reply #11 on: August 23, 2010, 10:32:47 AM »
Hi 73TORANA!
I would agree with you always follow the basic safety rules when lighting is about.
Disconnect your aerials TV, CB, ham radio, airnav, i always do, and all my aerial are grounded,  i take no chances i know what static electricity can do.
Also remember there is a two year warranty if a problem does arise.

S.F
« Last Edit: August 23, 2010, 12:44:10 PM by air7677 »

AirNav Development

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Re: ESD and Sawfilter problems
« Reply #12 on: August 23, 2010, 05:36:57 PM »
Less than 5% of the first batch units were repaired so this saw filter probelm is a non-problem.
For those following the RadarBox project since the beggining and when we had MLS as our distributor (they are the distributors of SBS) they used to say how impressive RadarBox was since it was a totally new project with a much lower return rate than SBS.

So and in resume there is nothing to fear regarding first batch units. These problems are extremelly rare and if they occur we have lifetime guarantee for them.
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RobinB

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Re: ESD and Sawfilter problems
« Reply #13 on: August 24, 2010, 05:29:12 PM »
RobinB: are you on an hidden agenda here?
Most of your 34 posts on this forum focus on negative and most of them false facts. There is a forum on the internet well known for this kind of games and maintained in background by our competitors so please avoid continuing them on this forum.

NOT AT ALL.

I AM having problems with reception for the last hence this post.

Please take time to see what I have written :-

-----

I am just beginning to wonder if I need to return my unit as its performance is not what it used to be.

We did have a lightening storm a week ago.
Something is not right, I have rechecked connections and still only getting around 50% range.

I am going to take box and mobile antenna with laptop out later to do a check with that just to make double sure.

------

I want to get it resolved.

And to say I am having a problem is not being negative at all but I am having a problem !


What false facts are you referring to ?


.
« Last Edit: August 24, 2010, 05:32:37 PM by RobinB »

air7677

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Re: ESD and Sawfilter problems
« Reply #14 on: August 24, 2010, 08:01:29 PM »
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