Re: [Elecraft] XV50 cooling
Don, I do not like to add to your workload, but I would be interested to know if the heat generated by the Mitsubishi power module has any negative effect on the transverter's noise figure (receive mode) if you have the time to measure it. If I understand the layout of the XV50 correctly, the input circuitry of its receive path is placed quite close to the power module. My reason for asking is that I have been considering the option of buying a XV50 for use in a set up dedicated only to 6m EME, rather than building a transverter from scratch 73, Geoff GM4ESD Don Wilhelm wrote on Sunday, June 06, 2010 at 3:59 AM: Gentleman, My promised temperature rise measurements will have to be delayed a bit. This XV50 has a bad power output module and I will have to wait for one to be sent from Watsonville. Later next week, I will have the data. BTW - Mitsubishi in their notes at the end of the data sheet suggest that the module case temperature should be limited to 60 deg/C - but that is too hot to touch (140 deg/F), so the excessively hot criteria may actually be well within the limits of tolerance - I would not want to hold my hand very long on a surface that is at 60 deg/C. Also, I do agree that other components can be affected by the temperature rise, but most are spec-ed at 60 deg/C, so in reality, there may be no problem, just a discomfort zone - details after the new module arrives. 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
Re: [Elecraft] XV50 cooling
Geoff, I do not have proper equipment to do a true noise figure measurement, but my signal generator will go down to -140 dBm, and I can give the number of dB above the receive noise floor for that signal strength - I can do that at various temperatures during the other tests. I doubt the temperature rise will affect the active devices, but a change in temperature *could* alter the inductors a bit which could detune the input circuits slightly. At this point, that is all speculation. 73, Don W3FPR Geoffrey Mackenzie-Kennedy wrote: Don, I do not like to add to your workload, but I would be interested to know if the heat generated by the Mitsubishi power module has any negative effect on the transverter's noise figure (receive mode) if you have the time to measure it. If I understand the layout of the XV50 correctly, the input circuitry of its receive path is placed quite close to the power module. My reason for asking is that I have been considering the option of buying a XV50 for use in a set up dedicated only to 6m EME, rather than building a transverter from scratch 73, Geoff GM4ESD Don Wilhelm wrote on Sunday, June 06, 2010 at 3:59 AM: Gentleman, My promised temperature rise measurements will have to be delayed a bit. This XV50 has a bad power output module and I will have to wait for one to be sent from Watsonville. Later next week, I will have the data. BTW - Mitsubishi in their notes at the end of the data sheet suggest that the module case temperature should be limited to 60 deg/C - but that is too hot to touch (140 deg/F), so the excessively hot criteria may actually be well within the limits of tolerance - I would not want to hold my hand very long on a surface that is at 60 deg/C. Also, I do agree that other components can be affected by the temperature rise, but most are spec-ed at 60 deg/C, so in reality, there may be no problem, just a discomfort zone - details after the new module arrives. 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 __ 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
Re: [Elecraft] XV50 cooling
Don, Thank you. Yes it is the possible effect on the input L-C circuit that is my main concern. 73, Geoff GM4ESD Don Wilhelm wrote: Geoff, I do not have proper equipment to do a true noise figure measurement, but my signal generator will go down to -140 dBm, and I can give the number of dB above the receive noise floor for that signal strength - I can do that at various temperatures during the other tests. I doubt the temperature rise will affect the active devices, but a change in temperature *could* alter the inductors a bit which could detune the input circuits slightly. At this point, that is all speculation. 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
Re: [Elecraft] XV50 cooling
Yes it is the possible effect on the input L-C circuit that is my main concern. 73, Geoff GM4ESD I would think the major concern would be elevated noise or change in the first stage's semiconductor device parameters from the receiver's input device temperature increase, not from tuned circuit drift or PA noise. I can't imagine a tuned circuit wide enough to pass six meters drifting so far as to change sensitivity, or really any meaningful change on a band like six meters. 73 Tom __ 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
Re: [Elecraft] XV50 cooling
Would that not depend on whether or not the source impedance presented to the input device has been optimised for lowest noise figure or for optimum power transfer? If the former then the question arises how rapidly does the noise figure change with small deviations from an optimum noise match, even if the effective loaded Q of the input circuitry is suitable to pass the six metre band. I agree that the noise figure need not be very low for terrestrial 6m, but 6m EME requires much lower noise figures when looking away from manmade noise sources. 73, Geoff. Tom W8JI wrote: I would think the major concern would be elevated noise or change in the first stage's semiconductor device parameters from the receiver's input device temperature increase, not from tuned circuit drift or PA noise. I can't imagine a tuned circuit wide enough to pass six meters drifting so far as to change sensitivity, or really any meaningful change on a band like six meters. 73 Tom __ 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
Re: [Elecraft] XV50 cooling
Would that not depend on whether or not the source impedance presented to the input device has been optimised for lowest noise figure or for optimum power transfer? If the former then the question arises how rapidly does the noise figure change with small deviations from an optimum noise match, even if the effective loaded Q of the input circuitry is suitable to pass the six metre band. The two primary sources of noise are from current flow in the input device and thermal noise. I'm not sure what portion of the two exist in the XV50, but almost certainly the semiconductor characteristics would change far more rapidly than the impedance of relatively broadly tuned matching circuits. __ 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
Re: [Elecraft] XV50 cooling
Gentleman, My promised temperature rise measurements will have to be delayed a bit. This XV50 has a bad power output module and I will have to wait for one to be sent from Watsonville. Later next week, I will have the data. BTW - Mitsubishi in their notes at the end of the data sheet suggest that the module case temperature should be limited to 60 deg/C - but that is too hot to touch (140 deg/F), so the excessively hot criteria may actually be well within the limits of tolerance - I would not want to hold my hand very long on a surface that is at 60 deg/C. Also, I do agree that other components can be affected by the temperature rise, but most are spec-ed at 60 deg/C, so in reality, there may be no problem, just a discomfort zone - details after the new module arrives. 73, Don W3FPR Don Wilhelm wrote: Eric, Have you actually measured the temperature rise? I am interested in just how much is excessively hot. While it does get warm, I have always found the temperatures to be well within spec for the output module. I have an XV50 here for repair right now. It is next in line for work, and I intend to get to it this weekend. After it is repaired, I will measure the temperature rise on the bottom panel right under the heat spreader. I have a Fluke 279 with a temperature probe available. Report on Monday. 73, Don W3FPR Eric wrote: I have a late-model xv144 with holes in both top and bottom panels, connected to k3 with milliwatt drive. It runs excessively hot at 10w out in digital mode EME when used one minute on one minute off, so i dont think just getting new panels will help you. I use a small muffin fan blowing air underneath with the xv-144 up on the optional tilt stand and this simple solution works great. I also use an xv-432 for eme at 10w but its internal fan keeps it cool. Perhaps if enough people request a retrofit kit with an internal fan for the xv-50 and xv-144 Elecraft would consider it. I'd pony up. The fan could attach inside the top panel. 73 Eric WD6DBM __ 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 __ 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
[Elecraft] XV50 cooling
I have a late-model xv144 with holes in both top and bottom panels, connected to k3 with milliwatt drive. It runs excessively hot at 10w out in digital mode EME when used one minute on one minute off, so i dont think just getting new panels will help you. I use a small muffin fan blowing air underneath with the xv-144 up on the optional tilt stand and this simple solution works great. I also use an xv-432 for eme at 10w but its internal fan keeps it cool. Perhaps if enough people request a retrofit kit with an internal fan for the xv-50 and xv-144 Elecraft would consider it. I'd pony up. The fan could attach inside the top panel. 73 Eric WD6DBM Sent from my ePhone (I wish) __ 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
Re: [Elecraft] XV50 cooling
Eric, Have you actually measured the temperature rise? I am interested in just how much is excessively hot. While it does get warm, I have always found the temperatures to be well within spec for the output module. I have an XV50 here for repair right now. It is next in line for work, and I intend to get to it this weekend. After it is repaired, I will measure the temperature rise on the bottom panel right under the heat spreader. I have a Fluke 279 with a temperature probe available. Report on Monday. 73, Don W3FPR Eric wrote: I have a late-model xv144 with holes in both top and bottom panels, connected to k3 with milliwatt drive. It runs excessively hot at 10w out in digital mode EME when used one minute on one minute off, so i dont think just getting new panels will help you. I use a small muffin fan blowing air underneath with the xv-144 up on the optional tilt stand and this simple solution works great. I also use an xv-432 for eme at 10w but its internal fan keeps it cool. Perhaps if enough people request a retrofit kit with an internal fan for the xv-50 and xv-144 Elecraft would consider it. I'd pony up. The fan could attach inside the top panel. 73 Eric WD6DBM __ 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
Re: [Elecraft] XV50 cooling
Evening gang: Just got home from work and reading my male.I looked at the manual for the XV432 to see how the internal fan is mounted and how it was hooked up. It really doesn't look like much of a task to modify my XV50 and install such a fan. I contacted sales and was told the vented panels are not available. As much as I hate drilling my own panels ( don't like messing up the paint ) I see very little challenge in copying what Elecraft did with the 432 version. I will wait Don, to hear the results of your tests before doing anything. 73 to all; Jerry N0JRN On 6/3/2010 1:18:45 PM, Eric (gliderboy1...@yahoo.com) wrote: I have a late-model xv144 with holes in both top and bottom panels, connected to k3 with milliwatt drive. It runs excessively hot at 10w out __ 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
Re: [Elecraft] XV50 cooling
Well, as I recall I could not hold my hand on it, but i only ran it without a fan once when I first built it and my memory is hazy. Remember digital EME is one minute on, one minute off for hours. I have run four hours at a time that way without a break, and I'm sure others run longer. Maybe it was still in spec, but why push it? All that extra heat can't possibly make the XV more stable or less prone to failure than if it were running at room temp. Mine does have the xtal oven if that makes a difference. I don't know how much heat that adds to the system. 73, Eric WD6DBM Sent from my iPhone On Jun 3, 2010, at 4:18 PM, Don Wilhelm w3...@embarqmail.com wrote: Eric, Have you actually measured the temperature rise? I am interested in just how much is excessively hot. While it does get warm, I have always found the temperatures to be well within spec for the output module. I have an XV50 here for repair right now. It is next in line for work, and I intend to get to it this weekend. After it is repaired, I will measure the temperature rise on the bottom panel right under the heat spreader. I have a Fluke 279 with a temperature probe available. Report on Monday. 73, Don W3FPR Eric wrote: I have a late-model xv144 with holes in both top and bottom panels, connected to k3 with milliwatt drive. It runs excessively hot at 10w out in digital mode EME when used one minute on one minute off, so i dont think just getting new panels will help you. I use a small muffin fan blowing air underneath with the xv-144 up on the optional tilt stand and this simple solution works great. I also use an xv-432 for eme at 10w but its internal fan keeps it cool. Perhaps if enough people request a retrofit kit with an internal fan for the xv-50 and xv-144 Elecraft would consider it. I'd pony up. The fan could attach inside the top panel. 73 Eric WD6DBM __ 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
[Elecraft] XV50 Cooling
OK gang: I've seen a number of posts in the archive about drilling holes in the panels to cool a transverter. None of those posts are very specific about where your drilling the holes. Can some of you who have done this, tell me where you did that ??? ORdoes Elecraft make panels available that are pre-drilled ?? ( I don't see then in the products list ) Just curious ! 73 JerryN0JRN __ 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
Re: [Elecraft] XV50 Cooling
Jerry, There are holes in the top cover that are supposed to be positioned above the attenuator resistors, and the new transverters have holes on the bottom on either side of the power module. I am looking at a rather new XV50 right now that has come in to me for repair. The builder did not position the top cover holes over the attenuator resistors, but the holes are in the cover. If you are driving the transverter from the low power outputs, the attenuator resistors are not used, so that source of heat is a no-op, but the resistors will heat up if higher power is used to drive the transverter. I do not believe additional ventilation holes are needed in most cases. If air flow below the transverter is available (do not operate it without the feet), the cooling is adequate. It seems to me that some operators get concerned with any heat generation, but in reality, if it is cool enough you can place your hand on it for more than 30 seconds, it is not hot enough for concern. Earlier transverters did not have the holes in the bottom panel, and some very early ones did not have the vent holes in the top cover. Yes, these may need additional vent holes, especially over the attenuator resistors. 73, Don W3FPR n0jrn wrote: OK gang: I've seen a number of posts in the archive about drilling holes in the panels to cool a transverter. None of those posts are very specific about where your drilling the holes. Can some of you who have done this, tell me where you did that ??? ORdoes Elecraft make panels available that are pre-drilled ?? ( I don't see then in the products list ) Just curious ! 73 JerryN0JRN __ 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 __ 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
Re: [Elecraft] XV50 Cooling
Thanks Don: I bought this unit unbuilt from another list member and it is a very early model. It has no vent holes at all ! I am driving with low power and therefore have the attenuator resistors bypassed. So not worried about heat from that area. I do have the feet on the transverter so air flow under it is good. My concern stems from a reduction of output power after using the unit non stop for a period of time. My fear is the power module is getting hot and falling off some. Module was installed using the heat transfer pads correctly located.I did not use heat sink compound. This unit has the old style power module in it ( M57735 ) This predates requirement of setting the PA bias in the XV50. Just thought I would give it a little more air to help my PA live a little longer. :-) Guess I'll drop Gary a note and see if he has a spare set of panels. Thanks again Don and have a great day. 73 Jerry N0JRN On 6/2/2010 10:36:44 AM, Don Wilhelm (w3...@embarqmail.com) wrote: Jerry, There are holes in the top cover that are supposed to be positioned above the attenuator resistors, and the new transverters have holes on the bottom on either side of the power module. I am looking at a rather new XV50 right now that has come in to me for repair. The builder did not position the top cover holes over the attenuator resistors, but the holes are in the cover. If you are driving the transverter from the low power outputs, the attenuator resistors are not used, so that source of heat is a no-op, but the resistors will heat up if higher power is used to drive the transverter. I do not believe additional ventilation holes are needed in most cases. If air flow below the transverter is available (do not operate it without the feet), the cooling is adequate. It seems to me that some operators get concerned with any heat generation, but in reality, if it is cool enough you can place your hand on it for more than 30 seconds, it is not hot enough for concern. Earlier transverters did not have the holes in the bottom panel, and some very early ones did not have the vent holes in the top cover. Yes, these may need additional vent holes, especially over the __ 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
