The third "SAW" filter..

[flight checker]

Hi Glyn. it's me, Karl!
Hope you're doing well.

AirNav might know more:

There are other antennas which explicity say they have an anti static design as well which are also perfect for the job.

I'm only aware of this vendor that explicitly states an antenna to be "DC grounded" saying:

To greatly reduce noise caused by atmospheric discharges-lightening, etc., all metal parts are DC - Grounded with the antenna showing a DC - Short Across the "N"Coaxial Socket. This also greatly reduces problems with RF-Pre-amp, Input Stages!!

Check here:
http://www.ssejim.co.uk/26-sseads1090sj.htm

Kind regards

Karl

[Speedbird London]

Malc41 asked me to keep you informed so here we are: After using the repaired ‘box for the weekend on and off, the reception range, after it’s third repair, didn’t increase to what it had been when at it’s best but, was better than it had been after it had, (presumably), been zapped by static.

(After it’s first “Repair” I had to send it back immediately because, in spite of having a new SAW filter, the reception was rubbish – It was returned to me with a note saying that dry joints had been to blame)

Rather than majorly get the hump and send it back yet again, Last evening I decided to try the co-linear aerial that I got from a guy called Dave in the US; The range improved of course, it having several times the gain of the supplied “twig” aerial. And quite honestly, I’ve had a belly-full of waiting in a lunchtime central London post office queue, so, I’m going to give it a few days before I decide what to do next.

After seeing Airnav support’s post, below, I felt I had to comment further.

“Speedbird,
The supplied antenna is a essentially an indoor antenna. While it can be used on mobile trips its is not meant to be placed externally for a long period of time.

It will end up being damaged by the elements as well as static on the antenna will build up after a few days in conditions and damage your SAW filter.

We strongly advice if you purchase an external antenna or an antenna which has an anti static design or you will face the same issues again.”

Now, it’s fine for you to point out the above and for most of it I have to agree, in fact it wouldn’t have occurred to me to use it as a permanent installation but rather a get-you-up-and-running measure.

Your other comments are also fine and I can accept them now though it seems you are bringing them up a little late in the day! – I quote from the 2008 RadarBox manual:

“In order to achieve
maximum performance and to ensure good range and coverage, the following points should be noted:
•The RadarBox antenna is not an internal antenna.
•The antenna should ideally be positioned outdoors and clear of obstructions.
•The higher the antenna, the better the performance.
•The longer the feed cable, the poorer the performance.
Whilst RadarBox can work perfectly acceptably with the antenna sitting on a window
ledge, you should always try to find the highest and clearest position.”….

Sorry to throw this into the fray but I don’t want anyone to get the mistaken idea that I’ve used the gear incorrectly.  I've said this before but just to reiterate; I have, and have had, a lot of radio gear that has never suffered from static down the aerial, in spite of being left connected to various verticals, dipoles and long high wires I’ve just assumed the front-end was suitably equipped to deal with that environment while at the same time sensibly disconnecting/earthing them if a storm threatened - No thunderstorms in N.London for months.

So, here we are – what to do now? I accept your claim that the percentage of returns due to static damage is statistically very small but, knowing THAT is no comfort to ME when I realise it's dead again and that I'm going to have to send it away, again....  How about, support, you point us in the direction of some device or other that we can put in the aerial lead to bleed the static off? without degrading the incoming signal - I’d certainly consider buying such a thing myself though shouldn’t really have to – like I’ve said, I just want it to work -- all the time -- then I’d feel content.

Cheers

Ed

Email: justmovingyou@aol.com

[AirNav Support]

Yes as mentioned in few posts back there is a mistake in the forum and its being changed.

As advised, if you looking for a permanent setup which is external:

- Either our antenna Kit online
- attach a mast amp which should bleed any excess static away
- dc block (bleed away excess static)
- purchase an antenna with an anti static design

Those items above will reduce your chances of any damage by static to the max. Obviously you need take precautions during electrical storms to disconnect your antenna.

[AirNav Support]

Further to the above, we are only going add this to FAQ as we are getting a lot of posts surrounding this and we have said the above a fair few times.

[CoastGuardJon]

Yes as mentioned in few posts back there is a mistake in the forum and its being changed.

As advised, if you looking for a permanent setup which is external:

- Either our antenna Kit online
- attach a mast amp which should bleed any excess static away
- dc block (bleed away excess static)
- purchase an antenna with an anti static design

Those items above will reduce your chances of any damage by static to the max. Obviously you need take precautions during electrical storms to disconnect your antenna.

Further to the above, we are only going add this to FAQ as we are getting a lot of posts surrounding this and we have said the above a fair few times.

Sorry ANSupport, you need to get your act together and sort this problem out now.    You're selling a product, with what is now known and acknowledged by yourselves to be a faulty design - you need to remedy this design defect (whether it's in the RB or antenna) in mighty short time, or it's going to cost you a lot more than a few RTB repairs.    In my opinion, your name is on the line now (I've not been in there lately but I bet there's 2 other sites that won't be slow to climb on the slagging off wagon).    The fact that the RB is supplied with a magmount is indicative that the antenna is designed and should be suitable to use on moving vehicle, a very easy way to generate static, especially in the current weather conditions.

[AirNav Support]

It is NOT a design fault and we have never ever said it was design fault and we have explained a that a few times now and getting annoyed at these false accusations.

The level of the return rate was NOT at a level where you can determine this as fault. If you don't believe us, even our past main dealership who we left due to other reasons don't believe in it being a fault either.

We acted in a good will, in producing the second batch with an increased level of protection.  There are still 97%+ of the first batch happily working fine.

To act again in the favour of the customer we said any static issues in the first batch we would repair for free regardless of whether it was in warranty.

The actual cases of those affected overall is less than 0.5% of the total boxes sold but due to close knit community this rare issue is being highlighted.

This has now been added to FAQ, any further repetitions which simply can be answered by the FAQ, we will point the customer to FAQ and then delete the post as its not helping anything other than to bring up the same details again and again which have already been answered and dealt with.

[CoastGuardJon]

If users choose to ignore the advice, that the supplied magmount is not designed/intended to be used or for prolonged exposure to the elements is one thing, and that's fair enough.    You are now advising that this antenna can cause static problems, if used externally - if that is not a design fault, are you saying it's intentional - I'm sure not???    

:( as you would say!!!

[AirNav Support]

No of course not. We have said in the FAQ that you can use the antenna indoors perfectly and you can use it outdoors on mobile trips to the airports.

The problem arises when its permanently used externally. Its simply not an external antenna, it will deteriorate under the weather for start and there is increased risk of the static albeit it is still rare after prolonged usage in externally as static will build up.

Thats why we are saying to reduce your risk purchase an external antenna which is anti static design.

The simple matter the antenna supplied is not an external one.

[CoastGuardJon]

Thanks for that ANSupport, I still think you've opened up Pandora's Box...........

[daveg4otu]

My opinion is that rather than there being a " design fault "as such...there may be a good case for stating that there have been  some boxes  from the second batch  that have either been supplied with the original  static-damage-prone SAW filter....or there are a (small?) number of SAW filters  fitted that are not up to standard from the word go.


Take the example of my  box ...second batch no. 105xx  died after a week...repaired ("Dry joints on SAW filter & USB")... worked as before for 5  days  then deaf again ...returned for repair...this time "SAW filter replaced".

Box returns  with greatly enhanced performance!....better than when new by a factor of probably 40%

So - was it really working properly when originally supplied ? - maybe - but certainly not as good as when a  new Filter was fitted.

How many more like that ?  I know I'm not the only one. Not large numbers I hope - but far more than should be allowed to happen.

New users have no yardstick to measure performance against....

So ANS - I would suggest to you that it may be more a question of quality control  both in assembly and component manufacture  than the "static" question....which, if you'll pardon me...still sounds  very unlikely   under normal  conditions.(If this is really such a risk - I have other equipment here which should have died years ago).

[bratters]

My opinion is that rather than there being a " design fault "as such...there may be a good case for stating that there have been  some boxes  from the second batch  that have either been supplied with the original  static-damage-prone SAW filter....or there are a (small?) number of SAW filters  fitted that are not up to standard from the word go.


Take the example of my  box ...second batch no. 105xx  died after a week...repaired ("Dry joints on SAW filter & USB")... worked as before for 5  days  then deaf again ...returned for repair...this time "SAW filter replaced".

Box returns  with greatly enhanced performance!....better than when new by a factor of probably 40%

So - was it really working properly when originally supplied ? - maybe - but certainly not as good as when a  new Filter was fitted.

How many more like that ?  I know I'm not the only one. Not large numbers I hope - but far more than should be allowed to happen.

New users have no yardstick to measure performance against....

So ANS - I would suggest to you that it may be more a question of quality control  both in assembly and component manufacture  than the "static" question....which, if you'll pardon me...still sounds  very unlikely   under normal  conditions.(If this is really such a risk - I have other equipment here which should have died years ago).

That is a very sensible and well-reasoned post. It clearly reflects my own experiences and I would agree with the conclusions.
Lack of consistent quality both in components and assembly would go a long way to explaining some of the odd, albeit apparently few, problems that seem to afflict some boxes, whether it be filters, aerial sockets, USB leads etc.
I don't know where and by whom the boxes are assembled but I would hope that quality control is under constant scrutiny.

[CoastGuardJon]

Hi all, what this is making me wonder is just how many RBs are there out there, which are "deaf", but people aren't aware of it, because there is no way to compare the performance of individual boxes, unless 2 or 3 owners can get together.     I may pick up 2-300 in 24 hours, a less deaf box might make 12-1300, I'm not saying this is a fact because I don't know, how can I or anyone else know - buy a second RB so a direct on-site comparison can be done (or to run one as a spare when t'other's down).      In my 50 years of tinkering with radios and electronics, I've never come across alleged "static" problems such as being suggested here by AN - this is could well be that it's because we're dealing with digital signals - again I don't know the answer.    I've never even bothered disconnecting aerials during thunderstorms, because the equipment all actually is connected to earth, not just a +ve and -ve supply provided by a sm power supply within a computer that is not earthed (RF or electrically).     I have been quite disappointed with the performance of my RB (and Support, can you explain just what security risks are raised by publishing the RB's actual Serial Number in here - other than the fact that we can all compare our numbers?) and can score as low as 10 an hour even in the middle of the day.

[daveg4otu]

and can score as low as 10 an hour even in the middle of the day

Given your location I would have thought that to be a bit   on the low side- I would have expected you to have  a fair number of oceanic  flights in view at any time during the day(out to maximum range as you have a clear view)

(...plus presumably activity from Culdrose -tho' not tracked).

[AirNav Support]

Again there is a lot of false theories flying around.

Firstly let me make this clear that you guys are very lucky to be in this situation to even bring up these "theories" and get a response. How many other companies would let you get away with customer saying a certain product has a defect on that products website without any proof. Most companies would have deleted the post and warned the member. Further please remember any prospective customer will read this and even though the actual box affected is less than 0.5% the customer will be scared off. Please bare that in mind before you post something which has no backing.

In regarding to the questions posted above. Of your course QC takes place on the RadarBoxes, I think many of you are not aware of what percentage of items are actually returned for minor faults for various products from electronic goods to cars.

Regarding if you get low aircraft count. You are confusing things here, if the SAW filter fails there will be dramatic change in reception down to 10% what you got before so the customer will know there is something wrong. It is extremely unlikely that a RB will arrive with a failure already to that part (this has not happened) and in that case as with any other product with a reciever it would be hard for the customer to determine the fault.

To carry on the from the first paragraph for those intrested in return rates and to put this in perspective, have a read of:

http://www.1up.com/do/newsStory?cId=3166259

We are extremely sorry for those customers who have been experienced issues but to imply anything about it being faulty of bad QC proceadures is totally incorrect.

I hope that explains things.

[flight checker]

Again there is a lot of false theories flying around

Agree AirNav, but how about your own (theories) ?:

Thought I might know quite  a bit of RF amplifier properties, I NEVER heard about this one:

attach a mast amp which should bleed any excess static away

A  (mast) amp might survive static discharge if its input is well protected against. Otherwise it will of course be destroyed too.
You might even find what is called "sacrifice amplifiers", to protect sensitive (and high value) equipment. They are "victimized" in order to anticipate harm from the equipment "behind" them. Static may "BLEED to a GROUND" if supplied, I agree, but the amplifier itself cannot "bleed" it. Where should it bleed it to ? No need for a mastamp of course, if the equipment itself is protected against "ESD"sufficiently. Maybe you've

lost in translation

as I did according to your opinion a couple of postings before, AirNav ?


                               -----------------------------------------

dc block (bleed away excess static)

NO, it wont do, no matter how often you are going to repeat:

A „DC Block“ (finally a “capacitor”, sometimes mounted in a coaxial [discrete] housing, sometimes directly found on an electronic component board as its integral part) by definition is supposed to serve as  a “DC barrier” between  electronic circuits, -instruments, -amplifiers etc etc. that carry a DC  (a bias- / supplyvoltage in most cases) beside of an AC (signal) component on an output, that is supposed to be connected to another electronic circuit,  -instrument -amplifier etc.etc. input, that happens to be sensitive to DC., which, depending on its magnitude, might destroy components of the follow up devices’s input circuitry.
A typical example would be a RF “spectrum analyzer”, whose input attenuator circuitry is  situated almost directly behind its front- / input- connector. Care must be taken to not only prevent the attenuator from “seeing” higher RF power levels than it is spec’ed for, (+30 dbm appearing a typical value) but also to keep away any DC component, (that the RF possibly might be “riding” on) as long, as the analyzers input itself  is not set “AC coupled”. The latter then assuring, that a DC Block, (!) e.e. capacitor as mentioned before, already is taking care of the “barrier function”, that has been described previously.

While a “DC Block”, among other applications, is well known in the one described above, it is NOT supposed to be a measure against ESD hits, if introduced between an external antenna, and a receivers input behind such an antenna.
I honestly agree with AirNav, that “ESD” (to their words) has been discussed “in a lenght”. Nevertheless, AirNav keeps on claiming a “DC Block” to be a solution to the phenomenon it is about, which it is NOT at all.
There have been other “voices” in this discussion, trying to correct AirNavs “opinion”. No
success so far. AirNav saying, no ESD problems until now occuring to those RBs, making use of a DC Block. Are there really any users who do? I doubt! Would be interested to hear from about, show up, please !

Maybe to try the “other way round” for those who are concerned: just “google” for “DC Block”. No need to check all of those thousands of answers to find out that a lot of  “well known manufactorers” (and distributors) not only specify their DC Blocks, but are also describing typical applications. NOT ONE OF THEM mentioning ESD countermeasures as such an application. Why even should they?
One more aspect: Electrostatic Discharge must be “given its way”. Remember your “wrist grounding” via “earth lead” to a heater plumbing (f.i.) before mounting a “static sensitive device” to your PC, or the aircraft, whose static charge (if there still is once ground) is “depleted to ground” by the fuel truck driver, providing a connection between the aircrafts body and a “static point” prior to refueling.
In case of the DC Block sitting in front of a receiver, static charge, if no further measure provided to “find its way to ground”, might cause a capacitor / DC Block to “break through” above a “threshhold”,  depending on its specifications, then hitting the receivers sensitive input by its intension finding a way to bleed off via the component board – powersupply – mains.
There are better and usefull measures too that have been discussed “in a lenght before”, and might be looked for if there is interest.

                                     ----------------------------

purchase an antenna with an anti static design

Fully agreed. Waiting for your answers on alternatives as Glyn has been asking for. The only one that I know has been mentioned before.
Regards

Karl