Hi Bill, Just a general remark:
I think we need to divide protection into different topologies/ barriers/ zones. This is according to threat phenomena ( e.g. xxx kilo Amps to milli Amps and smaller ). Threat levels need to be reduced step by step and systematically. Surge Limiters / Filtering / Shielding / System Layout with minimizing coupling effects are part of this. Protection against any threat level ( EMI energy / current / voltage /EM field derivatives) can/should realistically and economically not be implemented just finally at the radio itself. Lightning is first of all a more external system problem (Tower / Station Single Entry Panel Point / Cable- Layout, loop, spark over voltage / conductor melting/welding...). While lower threat levels, like adverse subsystem (shack) coupling of transients / continuous waves etc. -EMI/ESD Immunity- are certainly part of the good EMC radio/design . Professional EMC Standards (EU-HAM Radio, EN ETSI 301783... https://www.etsi.org/deliver/etsi_en/301700_301799/301783/02.01.01_60/en_301 783v020101p.pdf and specific System Experience http://k9yc.com/publish.htm -also from big contest stations- tell you what to do in HAM Radio electronics. Tnx, Cu, vy 73 de Andy HB9CVQ, DK2VQ, AK4IG https://www.qrz.com/db/HB9CVQ -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of Bill Frantz Sent: Montag, 18. Januar 2021 04:34 To: Elecraft Reflector <elecraft@mailman.qth.net> Subject: [Elecraft] Automatic lightning protection for radios, an off the wall idea I've been thinking about some kind of automatic lightning protection for radios, specifically ones like the K3 and K4. The idea is that when you turn the radio off, all the things that are subject to damage are protected by disconnecting them from the external world and shorting their inputs to ground. This approach probably wouldn't protect against a direct hit to one of the wires coming into the radio, which are most likely on the antenna input and the power from a solar system. But I understand that the most significant part of the problem is voltage spikes introduced when the external wires act as antennas and pick up nearby lightning strikes. I'm not a hardware engineer, so I'm going to assume that relays are used in this device. Some of the things I see this device doing are: USB connection: Elecraft tells us that blown USB chips are one of the more common forms of lightning damage in the K3. There are 4 wires in the USB interface, two of which carry power from the external world. The relay(s) would float the USB wires and ground the connections to the internal USB chip. Since power from the external world is present when the radio is off, we can't ground the power leads, although we can ground the power input to the radio's USB chip. Note that currently a computer attached to the K3 can see its USB chip, even when the radio is turned off. This change would mean that the computer would no longer see the radio over USB, which might have annoying software effects. A similar thing could happen to the antenna inputs. Key/Paddle, microphone, headphones, RS232, etc. would be treated the same way. The AUXbus would be treated similarly, but anything that can be turned on via the AUXbus would need special handling. The 12V power input is needed to turn the radio on with the power button. I don't know how often radios are damaged through their 12V power input. This input may not need protection. Otherwise, the relay that protects power and the switch to the radio could be the only things powered when the radio is off. If it can't be protected, it could be made easily field replaceable. It would be neat if there's enough room inside a K4 to put this kind of protection "under the covers". 73 Bill AE6JV ----------------------------------------------------------------------- Bill Frantz | The race is not always to the swift, nor the | (408)348-7900 | battle to the strong, but that's the way to bet. | www.pwpconsult.com | - Damon Runyon | ______________________________________________________________ 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 hb9...@hispeed.ch ______________________________________________________________ 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
