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Author Topic: Static Damage Prevention/Protection  (Read 24001 times)

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velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #15 on: July 28, 2009, 06:33:40 PM »
I now have a DC block, Just need to check its ok on the Radarbox, When I get it back.

AllanK

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  • Posts: 21
Re: Static Damage Prevention/Protection
« Reply #16 on: July 29, 2009, 06:56:23 PM »
I now have a DC block, Just need to check its ok on the Radarbox, When I get it back.
Where did you get it ?

malc41

  • RadarBox Beta Testers
  • Hero Member
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  • Posts: 586
Re: Static Damage Prevention/Protection
« Reply #17 on: July 29, 2009, 07:43:41 PM »
Sounds interesting
15 Miles East of EGNJ

velcrohead

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Re: Static Damage Prevention/Protection
« Reply #18 on: July 30, 2009, 05:42:49 AM »
I now have a DC block, Just need to check its ok on the Radarbox, When I get it back.
Where did you get it ?
After looking online for inline SMA blocks, a) I could only find them in the US and b) They are VERY expensive at that, I decided to make one at work, It has BNC connectors so I will be using adapters, I should have my RB back from repair today so will try it with and without to see how if at all it is affected, My scanner is not affected at all with any signal loss, But I don't listen to anything at 1090MHz.

AllanK

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  • Posts: 21
Re: Static Damage Prevention/Protection
« Reply #19 on: July 30, 2009, 07:16:28 AM »
After looking online for inline SMA blocks, a) I could only find them in the US and b) They are VERY expensive at that, I decided to make one at work, It has BNC connectors so I will be using adapters, I should have my RB back from repair today so will try it with and without to see how if at all it is affected, My scanner is not affected at all with any signal loss, But I don't listen to anything at 1090MHz.
That's the problem I had looking.  I look forward to your tests and then perhaps you can share construction details?

flightchecker

  • Guest
Re: Static Damage Prevention/Protection
« Reply #20 on: July 30, 2009, 09:31:12 AM »
Hi velcrohead and AllanK

A DC Block inserted into your receivers input will not of course noticeable degrade the performance of the latter, PROVIDED its design specifications meet the receivers frequency operating range and input impedance.
A “homemade” realization of such a device must be considered very carefullly, as the frequency it is supposed to handle is almost 1090MHz ! The capacitors “RF behavior”, as well as its housing (“to behave strictly coaxial” of course) must be in accordance with the RF rules that are indispensable at the frequency it is about. Otherwise, and among others, impedance mismatch might occur, resulting in an increased SWR (Standing Wave Ratio), all of those finally degrading / attenuating the signal “seen” by the receiver.

Following my posting that I’ve been mentioning in reply #12 you will be given an answer, what a DC Block is supposed to be, and really supposed to be for. To repeat myself once more: if in doubt, “google for DC Blocks”, and you may find out about the above yourself. You’ll not find one ! manufacturer, that claims his DC Block to be a ESD protection measure. (He might get into trouble otherwise)  You will even find  the “blocks” specified for typical “max Input voltages” of 100V DC only, a “nothing” as compared to the potential, ESD voltages may rise up.

Regards

Karl
« Last Edit: July 30, 2009, 09:35:27 AM by flight checker »

velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #21 on: July 30, 2009, 11:46:11 AM »
After looking online for inline SMA blocks, a) I could only find them in the US and b) They are VERY expensive at that, I decided to make one at work, It has BNC connectors so I will be using adapters, I should have my RB back from repair today so will try it with and without to see how if at all it is affected, My scanner is not affected at all with any signal loss, But I don't listen to anything at 1090MHz.
That's the problem I had looking.  I look forward to your tests and then perhaps you can share construction details?

If all is ok, I certainly will, although it is nothing complicated.

velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #22 on: July 30, 2009, 11:50:20 AM »
Hi velcrohead and AllanK

A DC Block inserted into your receivers input will not of course noticeable degrade the performance of the latter, PROVIDED its design specifications meet the receivers frequency operating range and input impedance.
A “homemade” realization of such a device must be considered very carefullly, as the frequency it is supposed to handle is almost 1090MHz ! The capacitors “RF behavior”, as well as its housing (“to behave strictly coaxial” of course) must be in accordance with the RF rules that are indispensable at the frequency it is about. Otherwise, and among others, impedance mismatch might occur, resulting in an increased SWR (Standing Wave Ratio), all of those finally degrading / attenuating the signal “seen” by the receiver.

Following my posting that I’ve been mentioning in reply #12 you will be given an answer, what a DC Block is supposed to be, and really supposed to be for. To repeat myself once more: if in doubt, “google for DC Blocks”, and you may find out about the above yourself. You’ll not find one ! manufacturer, that claims his DC Block to be a ESD protection measure. (He might get into trouble otherwise)  You will even find  the “blocks” specified for typical “max Input voltages” of 100V DC only, a “nothing” as compared to the potential, ESD voltages may rise up.

Regards

Karl

Hi Karl, good advice, I do of course already know all of this, being in electronics test for quite some time, and a fully licenced radio ham, I am merely trying to reduce any future problem, I cannot test my box unfortunately as the test gear we had to do it has been moved to France.
My Radarbox has not shown up either rather worryingly.

flightchecker

  • Guest
Re: Static Damage Prevention/Protection
« Reply #23 on: July 30, 2009, 12:05:38 PM »
Appreciating your comments, velcrohead

Karl

velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #24 on: July 30, 2009, 03:22:27 PM »
Appreciating your comments, velcrohead

Karl

I hope my reply wasn't taken the wrong way Karl, I know sometimes they can be on forums/email etc.
Cheers.

flightchecker

  • Guest
Re: Static Damage Prevention/Protection
« Reply #25 on: July 30, 2009, 04:00:49 PM »
NEVER EVER !!! velcrohead

cheers, and have a nice weekend,
Karl

velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #26 on: July 30, 2009, 04:02:39 PM »
NEVER EVER !!! velcrohead

cheers, and have a nice weekend,
Karl

Ok, good, I still cannot test my little box of tricks as I don't have my RB back yet.

flightchecker

  • Guest
Re: Static Damage Prevention/Protection
« Reply #27 on: July 30, 2009, 04:08:06 PM »
For those among us, that even always wanted to know what a “SAW Filter” physically looks like check here:

http://www.cts-kenwood.cz/kv/Klinovec/
(parent directory / overwiew)

http://www.cts-kenwood.cz/kv/Klinovec/airnavuvnitr.jpg
ANRB (inside „ black box“)

http://www.cts-kenwood.cz/kv/Klinovec/uvnitr1024c.jpg
&
http://www.cts-kenwood.cz/kv/Klinovec/airnavvstup.jpg
SAW devices "in detail" (> F1 / F2 / F3)

http://www.cts-kenwood.cz/kv/Klinovec/panorama1024.jpgpanorama1024.jpg
WISH I WAS HERE……………………………………………………………..
(And explaining of course the [parent directories] excellent ANRB  screenshots, that most of us probably will keep on dreaming for the rest of our life......it's a shame, isn't it..........

Karl







« Last Edit: July 30, 2009, 04:27:13 PM by flight checker »

velcrohead

  • Guest
Re: Static Damage Prevention/Protection
« Reply #28 on: July 30, 2009, 04:15:14 PM »
Some nice pictures there Karl, Thanks.

flightchecker

  • Guest
Re: Static Damage Prevention/Protection
« Reply #29 on: July 30, 2009, 04:23:09 PM »
Quote
Ok, good, I still cannot test my little box of tricks as I don't have my RB back yet.
Rather interested in some more details on that if you've finally realized your testing, velcrohead.

If interested in my "provision against ESD harm" contact me via e-mail. Should be easy to realize for you, knowing you're a HAM, but may at least  be matter of interest.

Karl.