Remote KAT500
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Again, thanks to all. To summarize for all who took the time to offer
information and suggestions: 1. From an Elecraft engineer [who I happen to know quite well]: The AUX cable is probably not a good choice to extend. In addition to voltage and RFI issues, there are timing constraints on those circuits. I can do what I need with RS-232. 2. I should be able to make RS-232 work. I personally know that many so-called RS-232 drivers use +/-5 V rather than +/-12 V. This is a problem I can solve. 3. Universal agreement on no connectors outside. Almost universal agreement on "no connectors penetrating the housing." Almost universal agreement on cable entrance glands of one type or another. 4. Condensate drain(s) are a must. There is universal agreement that water (and apparently other things) runs downhill. :-) I learned that changes in inside vs outside pressure over the day will also initiate condensation [did not understand how that works]. 5. Insectus Multileggus tend to be somewhat limited in our area due to hard winter freezes and reduced summer precipitation, but I will need to keep them out. We have small bunnies [not jack rabbits] that abound [and chew] around here, it appears that our backyard is immune right now but I will protect the cable drip loops anyway. I will personally congratulate any gopher or mole that can dig through our caliche. 6. Right now, I'm leaning toward a large enough PVC pipe, several inches long and open at the bottom [except for critter control] for cable entrance, condensate drain, and pressure equalization. I'll probably put a light bulb in the case. There is universal agreement that I need common-mode chokes at the ends and maybe along the cable runs inside the conduit. Fortunately, I know K9YC, I'll consult with him on those. Thanks to all for all the information, advice, ideas, and guidance. I'll post occasionally as this plan progresses. 73, Fred K6DGW - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Fred,
"Real" RS-232 drivers use +/- 15 volts rather than +/-5 or even +/- 12 volts - the maximum open circuit voltage is +/- 25 volts. The key is that at the receiver end, the levels must be +/-3 volts or greater. Both cable resistance and cable capacitance will reduce the levels at the end of a long run. 73, Don W3FPR On 1/21/2016 5:44 PM, Fred Jensen wrote: > > 2. I should be able to make RS-232 work. I personally know that many > so-called RS-232 drivers use +/-5 V rather than +/-12 V. This is a > problem I can solve. > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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On Thu,1/21/2016 3:11 PM, Don Wilhelm wrote:
> Both cable resistance and cable capacitance will reduce the levels at > the end of a long run. Cable capacitance rolls off the high end, which softens the rise and fall time of the pulses. The primary effect is to limit the baud rate. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k6dgw
On 1/21/2016 4:44 PM, Fred Jensen wrote: > 1. From an Elecraft engineer [who I happen to know quite well]: The > AUX cable is probably not a good choice to extend. In addition to > voltage and RFI issues, there are timing constraints on those > circuits. I can do what I need with RS-232. LOL! Yep, that's what I was thinking... Ethernet has voltage, RFI, and timing constraints, too. That just makes me want to test it to find out if I can make it work now... <diabolical grin and air-washing of hands> > 4. Condensate drain(s) are a must. There is universal agreement that > water (and apparently other things) runs downhill. :-) I learned that > changes in inside vs outside pressure over the day will also initiate > condensation [did not understand how that works]. Pressure AND temp changes, combined with sufficiently humidified air can act almost like a water pump... I learned the hard way before I taught myself how to put equipment on masts. ;) (Enclosures matter... choose the wrong one and it doesn't make much difference what doo-dads you attach, the "plastic" itself will allow moisture ingress. > 6. Right now, I'm leaning toward a large enough PVC pipe, several > inches long and open at the bottom [except for critter control] for > cable entrance, condensate drain, and pressure equalization. I'll > probably put a light bulb in the case. There is universal agreement > that I need common-mode chokes at the ends and maybe along the cable > runs inside the conduit. Fortunately, I know K9YC, I'll consult with > him on those. Are you putting your cable runs in the ground? That's a whole different discussion. ;) 73, Clay ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by k6dgw
Any need to optically isolate control lines et. Al., with simple
opto-couplers (6 pin DIP's)? Jim W6AIM -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of Fred Jensen Sent: Thursday, January 21, 2016 2:44 PM To: Elecraft Reflector Subject: [Elecraft] Remote KAT500 Again, thanks to all. To summarize for all who took the time to offer information and suggestions: 1. From an Elecraft engineer [who I happen to know quite well]: The AUX cable is probably not a good choice to extend. In addition to voltage and RFI issues, there are timing constraints on those circuits. I can do what I need with RS-232. 2. I should be able to make RS-232 work. I personally know that many so-called RS-232 drivers use +/-5 V rather than +/-12 V. This is a problem I can solve. 3. Universal agreement on no connectors outside. Almost universal agreement on "no connectors penetrating the housing." Almost universal agreement on cable entrance glands of one type or another. 4. Condensate drain(s) are a must. There is universal agreement that water (and apparently other things) runs downhill. :-) I learned that changes in inside vs outside pressure over the day will also initiate condensation [did not understand how that works]. 5. Insectus Multileggus tend to be somewhat limited in our area due to hard winter freezes and reduced summer precipitation, but I will need to keep them out. We have small bunnies [not jack rabbits] that abound [and chew] around here, it appears that our backyard is immune right now but I will protect the cable drip loops anyway. I will personally congratulate any gopher or mole that can dig through our caliche. 6. Right now, I'm leaning toward a large enough PVC pipe, several inches long and open at the bottom [except for critter control] for cable entrance, condensate drain, and pressure equalization. I'll probably put a light bulb in the case. There is universal agreement that I need common-mode chokes at the ends and maybe along the cable runs inside the conduit. Fortunately, I know K9YC, I'll consult with him on those. Thanks to all for all the information, advice, ideas, and guidance. I'll post occasionally as this plan progresses. 73, Fred K6DGW - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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