Re: [Elecraft] Anti-static Pads
G=1/R as I remember it. Yes, I wanted to reply to Alan's method, but I have been away. I wanted to re-read it to see if he allowed time to determine if a cap was leaky first. It was a clever idea. I have two Simpson's so I should be able to duplicate the test, if I can round up exposed metal pans. I bought my anti-static mat online. I'm at a loss concerning specs. I file everything, but after doing so for more than 50 years, things aren't found quickly. I don't remember receiving specs, either. Static discharge is an on-going concern for me. I humidify in the winter, and try to stay around 40%. I keep a grounded wrist-band around a tin breath mint container on the table beside my recliner for watching TV. When I stand up, I touch the tin to discharge myself. Otherwise, I zap my video equipment. Humidifying helps, but it's no guarantee. At my workbench, I have a four outlet metal box that is grounded so that I can touch it regularly to bleed off any static build-up. I can be 'sure' that it is grounded, but I have to 'trust' that my wrist strap and anti-static mat are. Maybe I'm a 'belt and suspenders' type of guy. Dick, n0ce On 9/20/2016 12:41 PM, Fred Jensen wrote: > Simplest way I know: Conductivity = 1 / Resistance. All you need is a > slide rule. :-) But seriously, > > Alan's method ... charge a capacitor to a known voltage, discharge it > through the mat to a lower voltage measuring how long it takes, and > use the RC time constant to calculate the resistance ... is about the > simplest and maybe the most ingenious. > > 73, > > Fred K6DGW > - Sparks NV DM09dn __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Simplest way I know: Conductivity = 1 / Resistance. All you need is a slide rule. :-) But seriously, Alan's method ... charge a capacitor to a known voltage, discharge it through the mat to a lower voltage measuring how long it takes, and use the RC time constant to calculate the resistance ... is about the simplest and maybe the most ingenious. 73, Fred K6DGW - Sparks NV DM09dn - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org On 9/19/2016 8:32 PM, Richard Fjeld wrote: I stand corrected. I didn't realize the resistance was that great. I need to think of a simple way to determine conductivity rather than measuring the resistance. Thanks for the answers. Dick, n0ce __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
The person who needs a piece of you mind is the Electrical Inspector who didn't do his job Fred On 9/20/16 10:37 AM, Terry Schieler wrote: > Don wrote, > > your house. You can use a banana plug in the round pin of an electrical > receptacle, but before you trust it, get one of the receptacle testers and > make sure that green wire ground is intact - some are not.> > > I built a new home in 1996. After living there a few years I noticed an > intermittent issue with an outlet on the first floor. Upon opening up the > outlet box I discovered the green "safety ground" coiled up, disconnected in > the back of the box. I fixed that. Then I used a receptacle tester to > confirm the other outlets. All the outlets but three on the first floor had > the disconnected green wire stuffed into the back of the box. I spent a > weekend making them safe again. All outlets in the rest of the house were > fine. > Hearing my experience, most people say "man I hope you gave your builder a > piece of your mind". I was unable to do that as he was in federal prison at > the time... for fraud. Every dog has his day. > > Check your receptacles. > > Terry, WØFM > > > > -Original Message- > From: Don Wilhelm [mailto:donw...@embarqmail.com] > Sent: Monday, September 19, 2016 3:59 PM > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] Anti-static Pads > > Hi all, > > While I can state that Ron's comment about the K2 is typically true, the > static tolerance of thru-hole ICs and transistors is lower than it was back > in 1998 or even 2006 (OK, I picked those years as a guess). Many DIP mounted > devices are really SMD devices with DIP leads and can be as static sensitive > as the devices in the K3 and KX3. > Despite the "touch grounded metal" instruction in the K2 manual, I do see > some repairs come in with failed firmware ICs, and rarely, but not zero, some > 'normal' ICs on a new build. > My best guess is that those parts were damaged due to a static charge. > Whether the builder did not follow the "touch a metal ground" or not I cannot > tell, all I know is that it failed. > > When possible, use an anti-static mat and wrist strap when handling ICs and > transistors, especially during periods of low humidity. Do not work on > carpet without them and do not wear nylon clothing - and don't shuffle your > feet on the floor while working. > The minimum should be a wrist strap connected to the green-wire ground in > your house. You can use a banana plug in the round pin of an electrical > receptacle, but before you trust it, get one of the receptacle testers and > make sure that green wire ground is intact - some are not. > > > __ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to f...@fmeco.com -- Fred Moore email: f...@fmeco.com f...@safes.com phone: 321-217-8699 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Don wrote, I built a new home in 1996. After living there a few years I noticed an intermittent issue with an outlet on the first floor. Upon opening up the outlet box I discovered the green "safety ground" coiled up, disconnected in the back of the box. I fixed that. Then I used a receptacle tester to confirm the other outlets. All the outlets but three on the first floor had the disconnected green wire stuffed into the back of the box. I spent a weekend making them safe again. All outlets in the rest of the house were fine. Hearing my experience, most people say "man I hope you gave your builder a piece of your mind". I was unable to do that as he was in federal prison at the time... for fraud. Every dog has his day. Check your receptacles. Terry, WØFM -Original Message- From: Don Wilhelm [mailto:donw...@embarqmail.com] Sent: Monday, September 19, 2016 3:59 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Anti-static Pads Hi all, While I can state that Ron's comment about the K2 is typically true, the static tolerance of thru-hole ICs and transistors is lower than it was back in 1998 or even 2006 (OK, I picked those years as a guess). Many DIP mounted devices are really SMD devices with DIP leads and can be as static sensitive as the devices in the K3 and KX3. Despite the "touch grounded metal" instruction in the K2 manual, I do see some repairs come in with failed firmware ICs, and rarely, but not zero, some 'normal' ICs on a new build. My best guess is that those parts were damaged due to a static charge. Whether the builder did not follow the "touch a metal ground" or not I cannot tell, all I know is that it failed. When possible, use an anti-static mat and wrist strap when handling ICs and transistors, especially during periods of low humidity. Do not work on carpet without them and do not wear nylon clothing - and don't shuffle your feet on the floor while working. The minimum should be a wrist strap connected to the green-wire ground in your house. You can use a banana plug in the round pin of an electrical receptacle, but before you trust it, get one of the receptacle testers and make sure that green wire ground is intact - some are not. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
On 09/19/2016 08:32 PM, Richard Fjeld wrote: I stand corrected. I didn't realize the resistance was that great. I need to think of a simple way to determine conductivity rather than measuring the resistance. Here are the results of some anti-static mat testing that I did a few years ago. If you scroll down to the bottom, there is a description of the test procedure. http://www.mail-archive.com/elecraft%40mailman.qth.net/msg94407.html Alan N1AL __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
I stand corrected. I didn't realize the resistance was that great. I need to think of a simple way to determine conductivity rather than measuring the resistance. Thanks for the answers. Dick, n0ce __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
The test procedure involves both the contact area and measuring a very high resistance - in the Gigaohm range. That requires very specialized equipment that few (if any) Hams have on hand. Useful "probes" for connecting to the mat run from $150 to almost $400. For example: https://www.amazon.com/PRS-801-W-Conductive-Surface-Resistance-Electrode/dp/ B017V3RO2A/ref=pd_day0_328_6?ie=UTF8=1=9VFF4V66Y9VFB0F7Z4E9 I believe you will need two probes, plus a meter that can measure in the Gigaohm range . The price of one probe would convince me to simply buy a new mat, Hi! 73 Ron AC7AC P.S. Us K2 owners are rather quiet these days. I suspect few are still monitoring the reflector. I miss the many questions about soldering, testing, setting up an antenna, etc. But time, and products, moves on.. -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Richard Fjeld Sent: Monday, September 19, 2016 7:34 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Anti-static Pads At this point; A Question about how to properly test an anti-static mat? I bought one last winter that appears to be totally non-conductive. I don't think it is my error. If others have mats like this, and are trusting them, I can see the possibility for failures. Dick, n0ce P.S. I like reading the comments about the K2's. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
10^9+ ohms [1,000 megohms or more] is pretty much "non-conductive" for anything we ordinary hams have to measure it. My Heath MM-1 just doesn't register at that. :-) Whether or not your mat is any good for ESD protection, and whether or not you can believe the specs if it has them, depends a lot on where it comes from. 73, Fred K6DGW - Sparks NV DM09dn - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org On 9/19/2016 7:34 PM, Richard Fjeld wrote: At this point; A Question about how to properly test an anti-static mat? I bought one last winter that appears to be totally non-conductive. I don't think it is my error. If others have mats like this, and are trusting them, I can see the possibility for failures. Dick, n0ce __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Well, the resistance of a good one is probably higher than what a normal VOM could measure. A merger might measure it, but having never had access to one I couldn't be sure. On Sep 19, 2016 8:35 PM, "Richard Fjeld"wrote: At this point; A Question about how to properly test an anti-static mat? I bought one last winter that appears to be totally non-conductive. I don't think it is my error. If others have mats like this, and are trusting them, I can see the possibility for failures. Dick, n0ce P.S. I like reading the comments about the K2's. On 9/19/2016 4:12 PM, Don Wilhelm wrote: > Hi all, > > A point I failed to make in my comments below is that the goal of > anti-static measures is to keep everything at the same potential (and > not necessarily to 'ground things'). > For instance, all my tools touch my anti-static mat before I use them, > and when I remove a device which is shipped in anti-static bags or the > black foam from its anti-static material, I place the bag or foam on > my anti-static mat first, then remove the device and place its leads > on the mat. That assures that anything originating beyond the bounds > of my mat will be equalized to whatever potential exists on the mat - > there should be no static potential difference between items that > reside on my mat. > > 73, > Don W3FPR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to jimk...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
At this point; A Question about how to properly test an anti-static mat? I bought one last winter that appears to be totally non-conductive. I don't think it is my error. If others have mats like this, and are trusting them, I can see the possibility for failures. Dick, n0ce P.S. I like reading the comments about the K2's. On 9/19/2016 4:12 PM, Don Wilhelm wrote: > Hi all, > > A point I failed to make in my comments below is that the goal of > anti-static measures is to keep everything at the same potential (and > not necessarily to 'ground things'). > For instance, all my tools touch my anti-static mat before I use them, > and when I remove a device which is shipped in anti-static bags or the > black foam from its anti-static material, I place the bag or foam on > my anti-static mat first, then remove the device and place its leads > on the mat. That assures that anything originating beyond the bounds > of my mat will be equalized to whatever potential exists on the mat - > there should be no static potential difference between items that > reside on my mat. > > 73, > Don W3FPR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
As I observed to Dick, n0ce: It's been a long, long road from the early low-impedance bipolar transistors to the modern ultra low power FETs. There was a time we worried about getting hurt: knocked on our keister by accidentally touching high voltage or burning our fingers on a hot vacuum tube. Now the tables are turned and we have to worry more about the equipment. 73, Ron AC7AC -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Don Wilhelm Sent: Monday, September 19, 2016 1:59 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] Anti-static Pads Hi all, While I can state that Ron's comment about the K2 is typically true, the static tolerance of thru-hole ICs and transistors is lower than it was back in 1998 or even 2006 (OK, I picked those years as a guess). Many DIP mounted devices are really SMD devices with DIP leads and can be as static sensitive as the devices in the K3 and KX3. Despite the "touch grounded metal" instruction in the K2 manual, I do see some repairs come in with failed firmware ICs, and rarely, but not zero, some 'normal' ICs on a new build. My best guess is that those parts were damaged due to a static charge. Whether the builder did not follow the "touch a metal ground" or not I cannot tell, all I know is that it failed. When possible, use an anti-static mat and wrist strap when handling ICs and transistors, especially during periods of low humidity. Do not work on carpet without them and do not wear nylon clothing - and don't shuffle your feet on the floor while working. The minimum should be a wrist strap connected to the green-wire ground in your house. You can use a banana plug in the round pin of an electrical receptacle, but before you trust it, get one of the receptacle testers and make sure that green wire ground is intact - some are not. Whether your anti-static precautions are 'overkill' for the task to be accomplished will never be known. Take whatever precautions make you feel comfortable with the risk factor involved. Doing nothing or ignoring the static damage probability is not acceptable unless you are willing to accept the risk. I suggest that you do not connect the wrist strap to a separate ground rod that you have for your hamshack unless that ground rod is also bonded to the utility entrance ground rod. It is off this topic, but if your ground rods are not connected to the utility entrance ground, it is a safety hazard should something in the house *or* your shack develop a fault. In addition, it is a violation of the NEC (those codes are written for your safety). 73, Don W3FPR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Hi all, While I can state that Ron's comment about the K2 is typically true, the static tolerance of thru-hole ICs and transistors is lower than it was back in 1998 or even 2006 (OK, I picked those years as a guess). Many DIP mounted devices are really SMD devices with DIP leads and can be as static sensitive as the devices in the K3 and KX3. Despite the "touch grounded metal" instruction in the K2 manual, I do see some repairs come in with failed firmware ICs, and rarely, but not zero, some 'normal' ICs on a new build. My best guess is that those parts were damaged due to a static charge. Whether the builder did not follow the "touch a metal ground" or not I cannot tell, all I know is that it failed. When possible, use an anti-static mat and wrist strap when handling ICs and transistors, especially during periods of low humidity. Do not work on carpet without them and do not wear nylon clothing - and don't shuffle your feet on the floor while working. The minimum should be a wrist strap connected to the green-wire ground in your house. You can use a banana plug in the round pin of an electrical receptacle, but before you trust it, get one of the receptacle testers and make sure that green wire ground is intact - some are not. Whether your anti-static precautions are 'overkill' for the task to be accomplished will never be known. Take whatever precautions make you feel comfortable with the risk factor involved. Doing nothing or ignoring the static damage probability is not acceptable unless you are willing to accept the risk. I suggest that you do not connect the wrist strap to a separate ground rod that you have for your hamshack unless that ground rod is also bonded to the utility entrance ground rod. It is off this topic, but if your ground rods are not connected to the utility entrance ground, it is a safety hazard should something in the house *or* your shack develop a fault. In addition, it is a violation of the NEC (those codes are written for your safety). 73, Don W3FPR On 9/19/2016 4:12 PM, Ron D'Eau Claire wrote: Note that the K2 manual does not make much of an issue about an anti-static mat. It's on the bottom of the anti-static priority list Wayne compiled. In the interest of full disclosure, I built my K2 while most of my stuff was in storage, working solely on a small wooden drawing board using my ESD-Safe iron. I simply did the recommended "touch a ground" before each time I reached for a transistor, i.c. or pc board and experienced no problems whatsoever. Sixteen years later the K2 is still going strong. 73, Ron AC7AC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Hi all, A point I failed to make in my comments below is that the goal of anti-static measures is to keep everything at the same potential (and not necessarily to 'ground things'). For instance, all my tools touch my anti-static mat before I use them, and when I remove a device which is shipped in anti-static bags or the black foam from its anti-static material, I place the bag or foam on my anti-static mat first, then remove the device and place its leads on the mat. That assures that anything originating beyond the bounds of my mat will be equalized to whatever potential exists on the mat - there should be no static potential difference between items that reside on my mat. 73, Don W3FPR Hi all, While I can state that Ron's comment about the K2 is typically true, the static tolerance of thru-hole ICs and transistors is lower than it was back in 1998 or even 2006 (OK, I picked those years as a guess). Many current DIP mounted devices are really SMD devices with DIP leads and can be as static sensitive as the devices in the K3 and KX3. Despite the "touch grounded metal" instruction in the K2 manual, I do see some repairs come in with failed firmware ICs, and rarely, but not zero, some 'normal' ICs on a new build. My best guess is that those parts were damaged due to a static charge. Whether the builder did not follow the "touch a metal ground" or not I cannot tell, all I know is that it failed. When possible, use an anti-static mat and wrist strap when handling ICs and transistors, especially during periods of low humidity. Do not work on carpet without them and do not wear nylon clothing - and don't shuffle your feet on the floor while working. The minimum should be a wrist strap connected to the green-wire ground in your house. You can use a banana plug in the round pin of an electrical receptacle, but before you trust it, get one of the receptacle testers and make sure that green wire ground is intact - some are not. Whether your anti-static precautions are 'overkill' for the task to be accomplished will never be known. Take whatever precautions make you feel comfortable with the risk factor involved. Doing nothing or ignoring the static damage probability is not acceptable unless you are willing to accept the risk. I suggest that you do not connect the wrist strap to a separate ground rod that you have for your hamshack unless that ground rod is also bonded to the utility entrance ground rod. It is off this topic, but if your ground rods are not connected to the utility entrance ground, it is a safety hazard should something in the house *or* your shack develop a fault. In addition, it is a violation of the NEC (those codes are written for your safety). 73, Don W3FPR On 9/19/2016 4:12 PM, Ron D'Eau Claire wrote: Note that the K2 manual does not make much of an issue about an anti-static mat. It's on the bottom of the anti-static priority list Wayne compiled. In the interest of full disclosure, I built my K2 while most of my stuff was in storage, working solely on a small wooden drawing board using my ESD-Safe iron. I simply did the recommended "touch a ground" before each time I reached for a transistor, i.c. or pc board and experienced no problems whatsoever. Sixteen years later the K2 is still going strong. 73, Ron AC7AC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
I built K2 S/N 4398 the same as Ron, on a desktop with a Formica top in a room with a carpet. I kept all semiconductor parts in their anti-static bags and/or conductive foam, and touched ground before picking them up. My soldering station is static-safe. I tried not to shuffle my feet on the carpet and wore sneakers with rubber soles. I did ban the vacuum from the room until I was done and the K2 was working. :-) Don did an alignment for me when he replaced an intermittent component, other than that, it's been completely fine. 73, Fred K6DGW Sparks NV USA Washoe County DM09dn On 9/19/2016 1:12 PM, Ron D'Eau Claire wrote: Note that the K2 manual does not make much of an issue about an anti-static mat. It's on the bottom of the anti-static priority list Wayne compiled. In the interest of full disclosure, I built my K2 while most of my stuff was in storage, working solely on a small wooden drawing board using my ESD-Safe iron. I simply did the recommended "touch a ground" before each time I reached for a transistor, i.c. or pc board and experienced no problems whatsoever. Sixteen years later the K2 is still going strong. 73, Ron AC7AC __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] Anti-static Pads
Hello Ed: I don't have any experience with mat cleaners. Perhaps some of the other list members do. If your old mat did not come with a resistance value specified, I suggest replacing it. The Elecraft engineer testing a variety of mats found that the resistance of a mat without a spec was always far too high to be of practical value. I checked to see if the products suggested are still available. These all have resistances in the Gigaohm (1X10^9 ohm) range. The U-Line mat can be purchased here: https://www.uline.com/BL_7403/Anti-Static-Table-Mats The Desco 66164 is available here: http://www.testequipmentdepot.com/desco/floor-worksurface-mats/worksurface-mats/vinyl/66164.htm The 3M mats seem to have been replaced by this one: http://www.isconline.com/product/8214/3M-Blue-2%27x4%27-Table-Mat.html?cid=14 Note that the K2 manual does not make much of an issue about an anti-static mat. It's on the bottom of the anti-static priority list Wayne compiled. In the interest of full disclosure, I built my K2 while most of my stuff was in storage, working solely on a small wooden drawing board using my ESD-Safe iron. I simply did the recommended "touch a ground" before each time I reached for a transistor, i.c. or pc board and experienced no problems whatsoever. Sixteen years later the K2 is still going strong. 73, Ron AC7AC -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Dauer, Edward Sent: Monday, September 19, 2016 12:10 PM To: elecraft@mailman.qth.net Subject: [Elecraft] Anti-static Pads Ron – Your post (below) came at the right moment. I am about to begin building another K2 and wondered whether my anti-static pad, now more than five years and ten Elecraft kits old, needs some sort of cleaning to maintain its properties; and, if so, what to clean it with – or maybe to replace it. I have looked and found no brand name on it anywhere, though maybe there was one that disappeared when I cut the mat to fit my workspace. I believe it was one of those recommended by Elecraft, but I have no record of it. Is there a generic cleaner, or would it be safer to begin with a new one? Forgive my asking this on the reflector rather than by private e-mail; but I suspect there may be some other old mats like me out there . . . Thanks, Ted, KN1CBR __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com