ESD Risk vs Relative Humidity
Locked
 
|
What is considered a 'normal' ESD safety limit?
Today in Hong Kong we have relative humidity (RH) of 55% (temp a 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ These past two days my daughter and xyl have mentioned several 'static shocks' when they play with our cats, all 6 of them. I remember my school kid days of cats tail static generators, but there's a serious question behind this. Under what conditions of RH do most builders of Elecraft rigs operate? My K2 and XV144 were constructed in spring/summer (90%+H) and autumn (70% RH+) with no apparent probs. Cats kept well away. I used a ESD earthed triple layer safety mat for the XV144. 73 Wyn, VR2AX _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: ESD Risk vs Relative Humidity
|
|
Wyn,
Congratulations on your moderate weather - enjoy it while you can. It would take a large ESD surge to cause any problem with assembled electronics, including the K2 and the XV144 - all the sensitive devices are connected in circuit to their normal termination. The problem during assembly IS severe - handling devices that are not mounted can cause ESD damage to the part. That is why one should work on a bench with an anti-static mat and use a wrist strap when inserting active devices into the boards. Once mounted, the devices are not as suceptable to static damage. You may occasionally cause a some malfunction by a static 'zap' to the case of the K2, but the effect would usually be transient. In the very worst case, one might have to do a Master Reset to recover, but that is rare and extreme. Even though such an occurrance is rare, it is wise to record all your menu parameters and filter settings just in case something like that ever happens. 73, Don W3FPR > -----Original Message----- > > What is considered a 'normal' ESD safety limit? > > Today in Hong Kong we have relative humidity (RH) of 55% (temp a > 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ > > These past two days my daughter and xyl have mentioned several > 'static shocks' when they play with our cats, all 6 of them. > > I remember my school kid days of cats tail static generators, but > there's a serious question behind this. Under what conditions of > RH do most builders of Elecraft rigs operate? > > My K2 and XV144 were constructed in spring/summer (90%+H) and > autumn (70% RH+) with no apparent probs. Cats kept well away. > > I used a ESD earthed triple layer safety mat for the XV144. > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.15.22/590 - Release Date: 12/16/2006 5:39 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: ESD Risk vs Relative Humidity
|
|
In reply to this post by Wyn Hughes
G'day,
<snip> Today in Hong Kong we have relative humidity (RH) of 55% (temp a 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ <snip> I assume the 16C was outside not inside. <snip These past two days my daughter and xyl have mentioned several 'static shocks' when they play with our cats, all 6 of them. I remember my school kid days of cats tail static generators, but there's a serious question behind this. Under what conditions of RH do most builders of Elecraft rigs operate? <snip> RH in the house is of the order 40-60% temp 20-22C most of the time. No cats, no ESD countermeasures besides touching an earthed object before picking up sensitive devices. Not killed one yet. Regards, Mike VP8NO _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Mike and Don,
Thanks for your input. I suspect that ESD damage occurs more often than one realises. Don's report confirms. I read reports that quite a few of the NATO IC-781s went down in the last gulf conflict for no apparent reason, other than microprocessor failure suspected due to the extreme low humidity. I have experienced some strange and otherwise wholly inexplicable PC failures due to early working without a wrist strap in the past. For safety sake I will stick with the new mat amd its combined wrist strap. Then at least I will eliminate one possibility from my shopping list of problem causes. Best 73 Wyn, VR2AX ----- Original Message ----- From: "Mike Harris" <[hidden email]> To: "Wyn Hughes" <[hidden email]>; <[hidden email]> Sent: Tuesday, December 19, 2006 5:42 AM Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > G'day, > > <snip> > Today in Hong Kong we have relative humidity (RH) of 55% (temp a > 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ > <snip> > > I assume the 16C was outside not inside. > > <snip > These past two days my daughter and xyl have mentioned several 'static > shocks' when they play with our cats, all 6 of them. > > I remember my school kid days of cats tail static generators, but there's > a serious question behind this. Under what conditions of RH do most > builders of Elecraft rigs operate? > <snip> > > RH in the house is of the order 40-60% temp 20-22C most of the time. No > cats, no ESD countermeasures besides touching an earthed object before > picking up sensitive devices. Not killed one yet. > > Regards, > > Mike VP8NO > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
ESD damage does not always show up immediately. ESD can "stunt" the life of
components. Instead of lasting 5 or 10 years, you may only get a few years out of them. I have had a lot of training in the military on ESD, and they spend big bucks on equipment And training. The avionics building I worked in in Germany had ESD tile on the floors, as well as grounded benches, mats And straps, etc. Mike AI4NS -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Wyn Hughes Sent: Tuesday, December 19, 2006 7:20 AM To: Mike Harris; [hidden email] Subject: Re: [Elecraft] ESD Risk vs Relative Humidity Mike and Don, Thanks for your input. I suspect that ESD damage occurs more often than one realises. Don's report confirms. I read reports that quite a few of the NATO IC-781s went down in the last gulf conflict for no apparent reason, other than microprocessor failure suspected due to the extreme low humidity. I have experienced some strange and otherwise wholly inexplicable PC failures due to early working without a wrist strap in the past. For safety sake I will stick with the new mat amd its combined wrist strap. Then at least I will eliminate one possibility from my shopping list of problem causes. Best 73 Wyn, VR2AX ----- Original Message ----- From: "Mike Harris" <[hidden email]> To: "Wyn Hughes" <[hidden email]>; <[hidden email]> Sent: Tuesday, December 19, 2006 5:42 AM Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > G'day, > > <snip> > Today in Hong Kong we have relative humidity (RH) of 55% (temp a > 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ > <snip> > > I assume the 16C was outside not inside. > > <snip > These past two days my daughter and xyl have mentioned several 'static > shocks' when they play with our cats, all 6 of them. > > I remember my school kid days of cats tail static generators, but there's > a serious question behind this. Under what conditions of RH do most > builders of Elecraft rigs operate? > <snip> > > RH in the house is of the order 40-60% temp 20-22C most of the time. No > cats, no ESD countermeasures besides touching an earthed object before > picking up sensitive devices. Not killed one yet. > > Regards, > > Mike VP8NO > > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: RE: ESD Risk vs Relative Humidity
|
|
In reply to this post by Wyn Hughes
In some manufacturing you cannot get through the security doors into the assembly area unless your boots and body strap pass the ESD test at the entry point.
David G3UNA > > From: "Mike Short" <[hidden email]> > Date: 2006/12/20 Wed PM 12:24:56 GMT > To: <[hidden email]> > Subject: RE: [Elecraft] ESD Risk vs Relative Humidity > > ESD damage does not always show up immediately. ESD can "stunt" the life of > components. > Instead of lasting 5 or 10 years, you may only get a few years out of them. > I have had a lot of training in the military on ESD, and they spend big > bucks on equipment > And training. The avionics building I worked in in Germany had ESD tile on > the floors, as well as grounded benches, mats > And straps, etc. > > Mike > AI4NS > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Wyn Hughes > Sent: Tuesday, December 19, 2006 7:20 AM > To: Mike Harris; [hidden email] > Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > > Mike and Don, > > Thanks for your input. I suspect that ESD damage occurs more often than one > realises. Don's report confirms. I read reports that quite a few of the > NATO IC-781s went down in the last gulf conflict for no apparent reason, > other than microprocessor failure suspected due to the extreme low humidity. > I have experienced some strange and otherwise wholly inexplicable PC > failures due to early working without a wrist strap in the past. For safety > sake I will stick with the new mat amd its combined wrist strap. Then at > least I will eliminate one possibility from my shopping list of problem > causes. > > Best 73 > Wyn, VR2AX > > > > > ----- Original Message ----- > From: "Mike Harris" <[hidden email]> > To: "Wyn Hughes" <[hidden email]>; <[hidden email]> > Sent: Tuesday, December 19, 2006 5:42 AM > Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > > > > G'day, > > > > <snip> > > Today in Hong Kong we have relative humidity (RH) of 55% (temp a > > 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ > > <snip> > > > > I assume the 16C was outside not inside. > > > > <snip > > These past two days my daughter and xyl have mentioned several 'static > > shocks' when they play with our cats, all 6 of them. > > > > I remember my school kid days of cats tail static generators, but there's > > a serious question behind this. Under what conditions of RH do most > > builders of Elecraft rigs operate? > > <snip> > > > > RH in the house is of the order 40-60% temp 20-22C most of the time. No > > cats, no ESD countermeasures besides touching an earthed object before > > picking up sensitive devices. Not killed one yet. > > > > Regards, > > > > Mike VP8NO > > > > > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > ----------------------------------------- Email sent from www.ntlworld.com Virus-checked using McAfee(R) Software Visit www.ntlworld.com/security for more information _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Re: ESD Risk vs Relative Humidity
|
|
In reply to this post by Mike Short
My 2c worth. I have posted on this reflector before my experiences with ESD
and my K2 as I was building it. First, understand that I live in the mountains of Colorado at about 8200' ASL. It is extremely dry here all year round and especially in the winter months when the RH rarely gets above 60 % To make matters worse, we are remote enough so that our home is 100% electric which is expensive so we supplement the heat with two wood burning stoves up and down. There isn't much more we can do to put humidity in our air than to keep fancy water pots filled on top of each stove. I have read many comments here before on the ability of the K2 to withstand ESD discharges but I can attest to having to do a complete reset of the K2 and reload all parameters on two occasions this season. Both of these instances occurred during the later stages of construction and alignment. These ESD related issues occurred while I was wearing a ESD wrist strap tied to the ground/neutral buss of the house supply. ESD is real and the K2 is definitely NOT immune. Since completion, and while the radio was fully buttoned up with all panels, the K2 has suffered ESD shutdowns of audio and other functions but was quickly remedied by cycling the power. It seems at times that I cannot move around in my chair without zapping the little rig. So my recommendation is to utilize ESD protection at all times when constructing or working on the interior of the rig. Again, your mileage may vary but these are my experiences. /joe k8fc ----- Original Message ----- From: "Mike Short" <[hidden email]> To: <[hidden email]> Sent: Wednesday, December 20, 2006 5:24 AM Subject: RE: [Elecraft] ESD Risk vs Relative Humidity > ESD damage does not always show up immediately. ESD can "stunt" the life > of > components. > Instead of lasting 5 or 10 years, you may only get a few years out of > them. > I have had a lot of training in the military on ESD, and they spend big > bucks on equipment > And training. The avionics building I worked in in Germany had ESD tile on > the floors, as well as grounded benches, mats > And straps, etc. > > Mike > AI4NS > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Wyn Hughes > Sent: Tuesday, December 19, 2006 7:20 AM > To: Mike Harris; [hidden email] > Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > > Mike and Don, > > Thanks for your input. I suspect that ESD damage occurs more often than > one > realises. Don's report confirms. I read reports that quite a few of the > NATO IC-781s went down in the last gulf conflict for no apparent reason, > other than microprocessor failure suspected due to the extreme low > humidity. > I have experienced some strange and otherwise wholly inexplicable PC > failures due to early working without a wrist strap in the past. For > safety > sake I will stick with the new mat amd its combined wrist strap. Then at > least I will eliminate one possibility from my shopping list of problem > causes. > > Best 73 > Wyn, VR2AX > > > > > ----- Original Message ----- > From: "Mike Harris" <[hidden email]> > To: "Wyn Hughes" <[hidden email]>; <[hidden email]> > Sent: Tuesday, December 19, 2006 5:42 AM > Subject: Re: [Elecraft] ESD Risk vs Relative Humidity > > >> G'day, >> >> <snip> >> Today in Hong Kong we have relative humidity (RH) of 55% (temp a >> 'freezing' 16 C), compared to our norm of 90 - 100% RH and temp 30 C+ >> <snip> >> >> I assume the 16C was outside not inside. >> >> <snip >> These past two days my daughter and xyl have mentioned several 'static >> shocks' when they play with our cats, all 6 of them. >> >> I remember my school kid days of cats tail static generators, but there's >> a serious question behind this. Under what conditions of RH do most >> builders of Elecraft rigs operate? >> <snip> >> >> RH in the house is of the order 40-60% temp 20-22C most of the time. No >> cats, no ESD countermeasures besides touching an earthed object before >> picking up sensitive devices. Not killed one yet. >> >> Regards, >> >> Mike VP8NO >> >> > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
RE: ESD Risk vs Relative Humidity
|
|
I recall as a kid reading stories (in the science books) of static
electricity with cats' tails, and of combs picking up bits of paper. Could never duplicate those occurrences, and hadn't the faintest (demonstrated) idea of what people were talking about. Just accepted what I read as fact somewhere in the world. This was growing up in Belize (then British Honduras), south of what is now Cancun on the Yucatan Peninsula. Temperatures generally in the thirties (Celsius), and relative humidity at least 80%. Built Heathkits, operated many radios, went to college in Jamaica, travelled all over the place (always going to warm places, or to cold places at warm times of the year), never an ESD event (still could not get the comb to pick up paper). Then, in the late 1990s (all of 50+ years of age), I spent three years in Rockville, MD. Autumn and winter the first year. Fully carpeted house. Every doorknob was a problem. The little screw holding the plate over the 120v wall power socket was a problem. The car door handle was a problem. Tingles, and lots of little sparks. And then it hit me: Back home in the tropics the humidity is generally so high that electrical charges leak off into the relatively damp air before they have time to accumulate to any appreciable extent. Now living in Barbados: air-conditioned bedroom with a rug on the floor. Cool the room way down, and relative humidity declines. Walk on the rug, touch an internal doorknob: you could see the spark jump! The hamshack is air-cooled. A big electric fan. Relatively high humidity. No ESD issues. Cheers, and Season's Greetings. Alan 8P9BM -----Original Message----- From: [hidden email] [mailto:[hidden email]] On Behalf Of Joe Wilkowski Sent: Wednesday, December 20, 2006 17:32 To: Mike Short Cc: [hidden email] Subject: Re: [Elecraft] ESD Risk vs Relative Humidity My 2c worth. I have posted on this reflector before my experiences with ESD and my K2 as I was building it. First, understand that I live in the mountains of Colorado at about 8200' ASL. It is extremely dry here all year round and especially in the winter months when the RH rarely gets above 60 % To make matters worse, we are remote enough so that our home is 100% electric which is expensive so we supplement the heat with two wood burning stoves up and down. There isn't much more we can do to put humidity in our air than to keep fancy water pots filled on top of each stove. I have read many comments here before on the ability of the K2 to withstand ESD discharges but I can attest to having to do a complete reset of the K2 and reload all parameters on two occasions this season. Both of these instances occurred during the later stages of construction and alignment. These ESD related issues occurred while I was wearing a ESD wrist strap tied to the ground/neutral buss of the house supply. ESD is real and the K2 is definitely NOT immune. Since completion, and while the radio was fully buttoned up with all panels, the K2 has suffered ESD shutdowns of audio and other functions but was quickly remedied by cycling the power. It seems at times that I cannot move around in my chair without zapping the little rig. So my recommendation is to utilize ESD protection at all times when constructing or working on the interior of the rig. Again, your mileage may vary but these are my experiences. /joe k8fc _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |