Static Damage Prevention/Protection

[AllanK]

I have just had my radarbox returned after suffering, what I assume was, static damage.  Although the repair was lightening (no pun intended) quick - 3 days - I am not keen to suffer the damage again.  The relevent FAQ says, to prevent this damage,:
- Purchase an antenna with an anti-static design
- Either attach a Mast amp which should bleed any excess static away and improve your reception.
- Either add a dc block (to bleed away excess static)
So, my questions are......
1. What antennas are of an anti-static design? What sort of designs are these? ( ie colinear, j-pole)
2. What is a good (and economical) mast amp - for protection, where the received signal is alread good? (my current 1/4 wave dipole receives good signals at the hieght it is at, but clearly (I presume) is not of a good anti-static design.
3. Where can I get a dc-block in the UK? - googling seems to return nothong of local asistance!
4. Can a high value resisitor be placed across the co-ax socket to bleed static to earth?
5.  Should the radar box be earthed?


your replies will be read with interest.  Thank you

--
Allan

[Cumulus]

Hi Allan,

I can recommend the SSE antenna and Kuhne preamp.

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

http://www.kuhne-electronic.de/en/shop/143_Vorverstaerker/article:342_KU_LNA_1090_A_TM

Regards,

Peter

[juangelb]

Hi Allank

I live in a country (Brazil) thath is from far the mosr hitted with thunderstorms.
I have one RB with a homebriew antenna at the top of a 16 floor building and never disconnect anything even when a thunderstorm is overhead.
A second RadarBox (remote ...5 NM away) with homebriew antenna at the top of a 15 floor biulding...
As I do not have phisical access to it ....Also never is disconnecter from atenna no matther the wheather is..
I deal with RBs since lauched on market... have 4 at this time.... Never got one dameged, even when I did with RBs a lor of testings and also wrongly feeded one of them with 8 VDC... It is still working well here.
Detail : Both antennae are not grouded !!!!!!!!!!!!!!!!!

I do not beliene in goog or bad luck.... Maybe there are some other factors "destroying" your RB.

But if You suspect that some static is damagin your rb (I do not think it is the case), why not to try to use a lighting arrestot like those used in Wireless systems ?

Like this one :http://www.snappernet.co.nz/Packages/FernShopUni/FernShopUni/Pub.Shop.Product/PID/10BEE54F/LINK/Pub.Shop.Product_BTN_DETAILS10BEE54F/TYPE/details/ROOT/SNAPPER

Cheers from Brazil

[bratters]

Hi AllanK - if you search through forum you will find chapter and verse on this subject.

A great deal of the discussion centres round the "static" theory however there is considerable contrary evidence such as juangelb's brazilian account (above) and my own and other's experiences where aerials have been not been exposed to outside use together with other cases where the supplied aerial was in use in fact and indoors at that.

There is I suppose the possibilty of "human" produced static from nylon carpets etc. but in the absence of a clearly defined pattern one wonders whether we are seeing the occasional and totally random failure of a part fitted within the box? ie nothing to do with static?

Whatever the cause, I think I'm right in saying that Airnav have re-assured us that repaired boxes are subsequently failure-proof.

[malc41]

bratters the thought of 'human static' is interesting, but like yourself i am sceptic on the cause of this problem.

it is good to see Airnav response and their support for all users over the deaf boxes

[Fenris]

Could I ask Airnav to confirm the S/N at which the enhanced protection is fitted in production?

The post I found in the original thread about this states 101500. That seems to have one digit extra. I couldn't decide whether it means 10150 or 11500.

[AirNav Support]

Hi Fenris,

Sorry reason for the confusion as the login codes and RB serial codes are similar but the login codes are slightly longer.

It might make it easier if we said the login codes as they are linked to the serial.
If you enter anything above PGANRB101500 then it will be the new boxes.

[AllanK]

Thanks for the replies so far.  I am confused/concerned that even though my box is PGANRB1104xx, ie higher than the 101500, that it has still suffered damage.  The fix was 'replaced SAW' so I assume it was static damage as there was no lightening around.

So do I need extra protection (dc block) or not - I am still not sure. Is the current 'fix' more robust than even the 110000+ units and therefore not needing any further protection?

--
Allan

[bratters]

Glad you're back in business Allan. Only Airnav themselves can answer your questions - the rest of us, like you, are guessing.

[AirNav Support]

Allank,

Please read:

http://www.airnavsystems.com/forum/index.php?topic=2759.0

[AllanK]

Please read:
http://www.airnavsystems.com/forum/index.php?topic=2759.0

Thanks for the link. I think that I need to provide some extra protection to my investment if it is to remain on 24/7 with an outdoor antenna.

Therefore I welcome any information on UK sources of dc-block, masthead amp that will be good for 1090Mhz.  Better safe than sorry

--
Allan

[velcrohead]

Please read:
http://www.airnavsystems.com/forum/index.php?topic=2759.0

Thanks for the link. I think that I need to provide some extra protection to my investment if it is to remain on 24/7 with an outdoor antenna.

Therefore I welcome any information on UK sources of dc-block, masthead amp that will be good for 1090Mhz.  Better safe than sorry

--
Allan

Me too, I would prefer the block though as I am not pulling my mast down again.

[flightchecker]

But if You suspect that some static is damagin your rb (I do not think it is the case)

What then do YOU think it is, juangelb, any idea? There is no known “voodoo” in electronics.

why not to try to use a lighting arrestot like those used in Wireless systems ?
Like this one :http://www.snappernet.co.nz/Packages/FernShopUni/FernShopUni/Pub.Shop.Product/PI
D/10BEE54F/LINK/Pub.Shop.Product_BTN_DETAILS10BEE54F/TYPE/details/ROOT/SNAPPER

"Lightning Protection" may not be mistaken with "Static Protection" juangelb. The “lightning arrestor”  your link is pointing at, has (what is called ) a "breakdown voltage" of 90 ! Volts DC, (there are others available with other “breakdown- / threshhold- levels”) and only in case this "threshold” is overriden. it "fires", thus shortening (for instance) a receivers input to ground / earth (assuming of course “ground” has been provided to the "arrestors” terminal respectively) to prevent “ligtning energy” from destroying the (receivers) input circuitry.

ESD (Electro Static discharges) well below this "threshold" might even be harmful, though
not always “instantaniously”, but due to known  “long term effects”, that degrade a receivers performance (sensitivity) "over time". (*)

DC Blocks, as well not a measure against the subject to talk about, and (among many other threads in this forum) discussed here:  http://www.airnavsystems.com/forum/index.php?topic=2746.0 in Reply # 29.

The antenna mentioned by Cumulus (Excellent suggestion!) above is the only one I know to have a “DC grounding design”. It must be grounded / connected to earth of course to comply with its design, and an almost cost intensive (“protecting only”) preamp with its accociated components may then not even be required.

All of the above discussed “in a lenght”, (as AirNavs uses to say) and  pointing at professional sources covering the subject, stating that SAW filters in a receivers input are suspective to ESD (Electrostatic discharge) as are other solid state devices in other applications, and carefull protecting measures must be applied to prevent harm to them.

AirNav said they have done so for the latest batches of RBs and will “modify” earlier receivers if their input SAW device have suffered from ESD strokes:
http://www.airnavsystems.com/forum/index.php?topic=2675.msg23352#msg23352
Reply #3


Regards
Karl

(* edited 29.07.09 / 17:45)
Filter manufacturers will typically specify DC voltages between 0 and about 20 Volt DC ! allowed to be applied to their SAW devices as a maximum.

K.

[juangelb]

OK flight checker

Thanks for all the info.

Cheers

[radarspotter10]

Glad you're back in business Allan. Only Airnav themselves can answer your questions - the rest of us, like you, are guessing.

hi all
I think people are to quick to jump on airnav on this static problem, did your ever think
carpet in your room is good starter for static, and a lot more things,
i have had my arinav 7 months now outdoor aerial no static damage,
if everyone was coming down with static problems yes its the airnav box fault.
The vultures from another forum prey heavily on this subject, to take airnav down.
But its only a very small few boxes that have the problem, so you have to say its something else that is causing the static build up, but what i do not know, well that is my thoughts for today
from pat