Electrostatic ground
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When I built my K2 (#337) I used a wrist strap electrostatic ground connected to my station ground which went a short distance out the window and to a ground rod. Now, in a different house, my station is on the second floor and I have no easy access to a ground. I guess I should have my K2 grounded, but I haven't worried about it since I'm running a balanced antenna. However, I'm now building a K1 and I'm worried about handling the electrostatic sensitive components. What would you guys recommend for this? Can I safely ground my wrist strap to the AC ground? Or should I bite the bullet and run a ground out the window (about 12' from my radio desk) and down 2 stories to a ground rod? Or what else???
73, Randy, KS4L -- Randy Moore, KS4L Huntsville, ALcom _______________________________________________ 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 |
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Randy,
ESD ground is really only needed between you and the radio/PCBA. When you move you generate static. You and the radio could be both up at 1000V and still be safe. Just make sure there is no potential between you and the PCBA. Ground your soldering iron to your ESD matt and your wrist strap to your ESD Matt. You really need an ESD work station matt. Go to www.esda.org for ESD Training. Paul w0rw _______________________________________________ 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 |
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In reply to this post by wrmoore
Randy, KS4L asked:
When I built my K2 (#337) I used a wrist strap electrostatic ground connected to my station ground which went a short distance out the window and to a ground rod. Now, in a different house, my station is on the second floor and I have no easy access to a ground. I guess I should have my K2 grounded, but I haven't worried about it since I'm running a balanced antenna. However, I'm now building a K1 and I'm worried about handling the electrostatic sensitive components. What would you guys recommend for this? Can I safely ground my wrist strap to the AC ground? Or should I bite the bullet and run a ground out the window (about 12' from my radio desk) and down 2 stories to a ground rod? Or what else??? ------------------------------------------------------------ The mains ground is just fine, providing it IS grounded!! In any case, be sure your wrist strap has at least 1 megohm of resistance in it to avoid a dangerous shock hazard should you accidentally touch a lead carrying significant voltage. An inexpensive outlet tester is available at almost any hardware or home improvement store that can confirm your grounds. It's good to know about the outlets in a "new" home anyway. Even new construction often has outlets that are ungrounded or which are wired backwards. As others here have pointed out here in the past, if you have a station ground rod it's a good idea to tie it to the mains ground rod anyway. There's usually a ground rod right under the panel where power somes into the house. The reason for tying them together is this: If the power lines suffer a surge from a near-miss lightning strike, tens or hundreds of amperes of current may flow into the ground at the mains box. No ground rod makes a really low-resistance ground connection, not even the exotic attempts by Hams in years past who buried copper rods in earth treated with salt. So the current flowing through that resistance to ground will cause the house "grounds" to suddenly be several hundred volts, or more, above actual ground for the duration of the pulse. If you have more than one ground system, one for the shack and one for the mains, you may find that during a surge there is a lethal potential difference between the phones on your head or the front panel of your rig and something else close at hand that isn't tied to the station ground. It's not such a big deal for an antenna ground for lightening protection, since there is usually no low-resistance d-c path between that ground and your equipment. It will only come into play if there's a surge big enough to cause an arc across the lightning arrestor from the antenna system to that ground. Ron AC7AC _______________________________________________ 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 |
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Hi Folks,
#3641 with KBT2 battery option is still for sale. New price $475.00 U.S. including shipping to U.S. or Canada. Paypal is preferred. Some details: I have checked the power out on all bands and it's fine. There is a small scratch on the top cover. I find the audio somewhat low for my tastes. However, when you disable the AGC it's very loud! Please reply off list and if you could, please remove the [Elecraft] subject tag as my Elecraft mail goes into a separate folder. Thanks and 73 Chris -- Chris VA7CAB _______________________________________________ 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 |
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In reply to this post by Ron D'Eau Claire-2
To adequately "ground" for electrostatic charges does not require a
connection to physical earth at all. In fact whether to use a strap at all depends on your local temperature and humidity at the work station. Dry cold winter weather is more risk than a wet spring unless you have a cold air conditioned lab in which you are working, that has dry air. You establish a ground plane or conductive pad under the chassis or board you are working on. To this is attached a wrist strap thru a coiled cord. There is a current limiting resistor in the commercial cord/ strap set ups to limit any surge to the human. The idea is to have the human and the board or chassis at the same voltage, (potential) before you touch the board with your hands or tools. Once you pick up the part or tool, your wrist strap discharges anything on the part/ tool. When you insert the part in the chassis or board that is "grounded" to the conductive pad, you have removed the danger of a spark. Check the web sites of some of the manufacturers by Googling "static discharge tools". There should be some application notes to further discuss precautions. 73, Stuart K5KVH _______________________________________________ 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 |
Grounded or Not? (WAS:] Electrostatic ground)
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In reply to this post by Ron D'Eau Claire-2
Both Paul and Sandy pointed out that the real issue is the potential
difference between you, your tools and the ESD-sensitive components, so a completely "floating" system in which everything on the work area is at the same potential is perfectly safe for the components involved even if no ground is present. That's true in theory, but I'm personally not comfortable counting on that being the case. For example, my soldering station, along with all of my of my AC powered test equipment, is grounded through the AC mains ground system. So if I, my wrist strap and the components I'm working with are all carrying an electrostatic charge and I pick up my soldering iron by its insulated handle and touch it to a pin of the ESD-sensitive part, that charge will be drained to ground through the iron and sensitive part. The whole system is immediately defeated. My approach is to ensure that the outlet that serves my bench is truly grounded to the AC mains ground and that everything on that bench is connected in parallel to the same ground, including myself through a wrist strap and a 1-megohm resistor. An anti-static pad is nice too. If used it should be connected to the common ground through a 1 megohm resistor as well. The important point about the work surface is to avoid those that collect static charges easily. AVOID such bench coverings as rubber or a piece of carpet! While a wrist strap is a very good investment, its major benefit is to protect you if you forget to ground yourself frequently by touching an unpainted metal ground. Keep in mind that simply squirming around on your chair can produce a destructive charge, so if you don't use a wrist strap, have that ground within easy reach, remember to touch it regularly as you work, use a grounded-tip soldering iron and you'll have no problems with ESD damage. Ron AC7AC _______________________________________________ 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: Grounded or Not? (WAS:] Electrostatic ground)
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On Thu, 2006-02-16 at 13:51 -0800, Ron D'Eau Claire wrote:
> a completely "floating" system in which everything on the work area is at the > same potential > For example, my soldering station, along with all of my of > my AC powered test equipment, is grounded through the AC mains ground > system. In that case you do not have a "completely floating system". The tip of your iron is not floating with the rest of the system. > That's true in theory, but I'm personally not comfortable counting on that > being the case. The entire concept of "ground" is nothing but notation to make life easier for us. There's no such thing as some point ("ground") which has zero voltage. Since voltage is a potential difference *between two points*, it makes no sense to talk about the voltage of any single point (including "ground"). When we talk about a point having a certain voltage, what we are really saying is that it has a certain voltage "relative to an arbitrary point which we have labelled ground and will use as a reference for all voltage measurements." If it makes you feel more comfortable, designate your floating work area as "ground", and make sure everything has a small enough potential relative to it - including your iron! _______________________________________________ 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 |
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In reply to this post by wrmoore
Thanks to everyone. I picked up a mat today and plugged it, with the wrist
band also connected to it, into the AC ground. Seems to be working fine. 73, Randy, KS4L _______________________________________________ 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 |
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In reply to this post by Chris Brougham
Sold! Thanks!
Chris Brougham wrote: > Hi Folks, > > #3641 with KBT2 battery option is still for sale. New price $475.00 > U.S. including shipping to U.S. or Canada. > > Paypal is preferred. > > Some details: > > I have checked the power out on all bands and it's fine. There is a > small scratch on the top cover. I find the audio somewhat low for my > tastes. However, when you disable the AGC it's very loud! > > Please reply off list and if you could, please remove the [Elecraft] > subject tag as my Elecraft mail goes into a separate folder. > > Thanks and 73 Chris > -- Chris VA7CAB _______________________________________________ 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 |
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