The thread on whiskers could use a little clarification.
The question about lead (Pb) in Europe is an issue over health concerns, not
electrical sort circuits.
Whiskers are an issue in reliability of (usually space) components and
circuits. The culprits are Tin >97% pure, 100% pure cadmium and 100% pure
zinc. If these metals are NOT pure, there is little problem.
It is only 100% pure that cause the problems. Many users of hi rel
components and anything that is plated with pure metals are requiring legal
certs that they are NOT using the prohibited materials. There are new
instruments now on the market just to test for compliance with the rules
against these prohibited materials. It is a real big deal right now.
They just hate to have mission hardware fail due to whiskers...
Al
N6TA
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Bob Lombardi
> Sent: Friday, April 01, 2005 2:21 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] TowerTalk Digest, Vol 28, Issue 2
>
> At 10:53 AM 4/1/2005 , you wrote:
> >----------------------------------------------------------------------
> >
> >Message: 1
> >Date: Thu, 31 Mar 2005 17:44:37 -0800
> >From: "Pat Barthelow" <aa6eg@hotmail.com>
> >Subject: [TowerTalk] Relay Specs -Coax Switch
> >To: w8ji@contesting.com, keith@dutson.net, TowerTalk@contesting.com
> >Message-ID: <BAY106-F28BF0ADC546629AE971C02FB380@phx.gbl>
> >Content-Type: text/plain; format=flowed
> >
> >Hello Tom, Keith, and group.
> >
> >I went searching for some relay images to post and have some experts view
> >them and comment on the plusses and minuses relative to High Power RF
> use,
> >of the various designs. I found quite a few pictures, on the web, which I
> >may post for viewing and feedback from the experts.
> >
> >I also remember in the W6AM Biography book by Jan Perkins, that Don
> Wallace,
> >W6AM had humongous numbers of big antenna relays for his Rhombic Farm
> >that he had to modify to make less lossy at HF...Very interesting book...
> >
> >BUT what I also found is mind boggling and I think of interest to many of
> >us, especially in this time of (apparent) change towards no-lead solders.
> >Check out these NASA and related sites and what they document with
> respect
> >to tin whiskers and the damage they do, esp to high rel (space) systems.
> >
> >http://nepp.nasa.gov/whisker/photos/
> >http://nepp.nasa.gov/whisker/photos/relay/ng/relay-armature2.jpg
> >http://nepp.nasa.gov/whisker/photos/relay/ng/relay-armature1.jpg
> >http://nepp.nasa.gov/whisker/photos/relay/gsfc/whisker2.html
> >http://nepp.nasa.gov/whisker/photos/relay/gsfc/whisker3.html
> >http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-
> whiskers01
> >.jpg
> >http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-
> whiskers05
> >.jpg
> >http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-
> whiskers02
> >.jpg
> >http://nepp.nasa.gov/whisker/photos/waveguide/2004-waveguide-tin-
> whiskers02
> >.jpg
> >http://nepp.nasa.gov/whisker/anecdote/20year/index.html
> >http://nepp.nasa.gov/whisker/failures/index.htm
> >
> >There are also Ziinc whiskers that did damage, that came from: Floor
> tiles,
> >of all things...
> >A paper within these listings documents quite a few million dollar plus
> >satellites destroyed by these teeny tiny tin whiskers...
> >Fascinating, and scary if you are in the space electronics industry...
> >
> >73, DX, de Pat Barthelow AA6EG aa6eg@hotmail.com
> >
>
>
> This is a looming problem in the electonics industry. The European Union
> started the RoHS laws (reduction of hazardous substances) after some alarm
> about the amount of solder in the landfills over there. They set a date
> for phasing out lead, and I think it's in a few years. Unfortunately,
> there is no substitute that is just as good. While they specifically
> excluded military and high-rel applications (there are comparatively few
> of
> them), that's silly. Everyone buys parts from the same manufacturers and
> if the part sources go lead-free, everyone gets lead-free parts! (The
> Analog Devices guys told me they use the term "Pb-Free" because non-
> English
> speakers get mixed up between short "e" lead (pronounced "led" - Pb) and
> long "e" lead ("leed" - the things that hang out of a component that you
> solder to).
>
> Maybe people don't mind if their cellphone shorts out and dies in a couple
> of years, and they toss it, but nobody wants to toss out a $30,000
> aircraft
> radio - let alone a multi-million dollar satellite. I don't know about
> you, but I sure don't want to lose my Icom to a tin whisker!
>
> From what I gather, nobody really knows how to deal with the
> problem. I've heard that a solder coating, a high lead solder, or gold
> plating may prevent it. But no hard data.
>
> I'm dealing with this issue at work right now, so sorry if I seem a little
> "worked up" about it.
>
>
>
> 73,
> Bob
> W4ATM
>
>
>
> _______________________________________________
>
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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