[Drakelist] T-4X Stability: EPILOGUE
Hi All, Well, this morning I essentially duplicated my previous stability tests with the Drake T-4X here, only with a minor change: as was suggested to me earlier, this time I let the umpire rig---my ICOM 751A transceiver---warm-up, alone, for a full hour... Before getting to the results, I should add here that the T-4X has a small cooling fan mounted above the amplifier cage, extracting air from inside it to the outside: it ran continuously whenever the rig was on during the course of both evaluations. Ambient room temperature in my basement was 59F, as before. Again, I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test. The actual PTO frequency itself was monitored with the 751A in general coverage mode... Here are the results this time: (1) 5455.0-KHz (cold start); (2) 5454.8-KHz (downward drift of 200-Hz from cold start); (3) 5454..4-KHz (downward drift of 600-Hz from cold start); (4) 5454.0 KHz (downward drift of 1-KHz from cold start); (5) 5453.7-KHz (downward drift of 1.3-KHz from cold start), and, (6) 5453.7-KHz (unchanged). The end result in terms of drift was actually 100-Hz MORE than was observed the first time, i.e. 1.2-KHz with both rigs running from cold starts, to 1.3-KHz with the ICOM warmed-up for an hour! No matter---after an hour's warm-up the signal remains essentially unchanged, and I'm happy with that. I'm especially pleased to note that the warbble effect / jumpiness previously afflicting my PTO has apparently disappeared, in the aftermath of all of my resistor swapping in it...and the dial correction that I have to do on the T-4X after the resistor swaps is pretty much in line with what I had to do before the re-build. My conclusions after all this stuff? Well, #1, it was most interesting gratifying, both...and #2, if I take the quoted manual warm-up period time to be, in fact, one full hour minimum, then my transmitter actually EXCEEDS the quoted Drake specs for drift of :...less than 100 cycles after warm up considerably: in fact, mine doesn't drift at all after that time...! And THAT, as Martha Stewart is wont to say, ...Is a GOOD thing. Hi Hi Now---how about all those other T-4X rigs that are out there in general circulation...? Are the results of YOUR stability tests similar to mine here...? ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Nice work Eddy. I do my tests a little differently, I look at overall stability by zero beating WWV. Regardless, my early T-4X (5KHz markings) is also just about 1.2KHz. But my slightly newer R-4A (13 tube, but 25KHz markings and vernier Preselector) is worse at just about 1.5KHz. IIRC, there is a drift spec. somewhere of... 1.5KHz, if so, WE are in spec :) And, like you, after a GOOD warmup, they are pretty darn stable!! I have also noted that the drift seems worse at the high end of the dial. 73, Gary WB6OGD - Original Message - From: Eddy Swynar deswy...@xplornet.ca Now---how about all those other T-4X rigs that are out there in general circulation...? Are the results of YOUR stability tests similar to mine here...? ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Hi Eddy - Would you be up for one more test run?? I wonder what would happen WITHOUT the fan. Certainly the interior would warm up faster. A trade-off would 'perhaps' be a larger delta t from transmit to receive. Especially without an ambient air of 59F constantly being pulled through the cabinet. As this is a T-4X, it is a bipolar PTO. The T-4XB and C had a FET PTO, for better stability. The receiver PTOs switched from bipolar to FET early in the 'B' series. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Eddy Swynar wrote: Hi All, Before getting to the results, I should add here that the T-4X has a small cooling fan mounted above the amplifier cage, extracting air from inside it to the outside: it ran continuously whenever the rig was on during the course of both evaluations. Ambient room temperature in my basement was 59F, as before. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Hi Eddy: Excellent! Now, you might also learn something worthwhile by doing the same test, but measuring the drift of actual output after mixing at say 7 or 14Mhz. If the crystal Osc goes the other direction, it might get somewhat better...then again if it goes the other way...well...! :) I'll see if I can measure my B twins here but will not guarantee my room temp to start at 59.. It is usually about 62 upstairs in the AM now. Curt KU8L On 11/29/2011 8:30 AM, Eddy Swynar wrote: Hi All, Well, this morning I essentially duplicated my previous stability tests with the Drake T-4X here, only with a minor change: as was suggested to me earlier, this time I let the umpire rig---my ICOM 751A transceiver---warm-up, alone, for a full hour... Before getting to the results, I should add here that the T-4X has a small cooling fan mounted above the amplifier cage, extracting air from inside it to the outside: it ran continuously whenever the rig was on during the course of both evaluations. Ambient room temperature in my basement was 59F, as before. Again, I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test. The actual PTO frequency itself was monitored with the 751A in general coverage mode... Here are the results this time: (1) 5455.0-KHz (cold start); (2) 5454.8-KHz (downward drift of 200-Hz from cold start); (3) 5454..4-KHz (downward drift of 600-Hz from cold start); (4) 5454.0 KHz (downward drift of 1-KHz from cold start); (5) 5453.7-KHz (downward drift of 1.3-KHz from cold start), and, (6) 5453.7-KHz (unchanged). The end result in terms of drift was actually 100-Hz MORE than was observed the first time, i.e. 1.2-KHz with both rigs running from cold starts, to 1.3-KHz with the ICOM warmed-up for an hour! No matter---after an hour's warm-up the signal remains essentially unchanged, and I'm happy with that. I'm especially pleased to note that the warbble effect / jumpiness previously afflicting my PTO has apparently disappeared, in the aftermath of all of my resistor swapping in it...and the dial correction that I have to do on the T-4X after the resistor swaps is pretty much in line with what I had to do before the re-build. My conclusions after all this stuff? Well, #1, it was most interesting gratifying, both...and #2, if I take the quoted manual warm-up period time to be, in fact, one full hour minimum, then my transmitter actually EXCEEDS the quoted Drake specs for drift of :...less than 100 cycles after warm up considerably: in fact, mine doesn't drift at all after that time...! And THAT, as Martha Stewart is wont to say, ...Is a GOOD thing. Hi Hi Now---how about all those other T-4X rigs that are out there in general circulation...? Are the results of YOUR stability tests similar to mine here...? ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Hi Garey, An EXCELLENT idea...! I'm doing exactly that, even as I type this... Stay tuned! ~73~ de Eddy VE3CUI - VE3XZ ** On 2011-11-29, at 9:26 AM, Garey Barrell wrote: Hi Eddy - Would you be up for one more test run?? I wonder what would happen WITHOUT the fan. Certainly the interior would warm up faster. A trade-off would 'perhaps' be a larger delta t from transmit to receive. Especially without an ambient air of 59F constantly being pulled through the cabinet. As this is a T-4X, it is a bipolar PTO. The T-4XB and C had a FET PTO, for better stability. The receiver PTOs switched from bipolar to FET early in the 'B' series. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Eddy Swynar wrote: Hi All, Before getting to the results, I should add here that the T-4X has a small cooling fan mounted above the amplifier cage, extracting air from inside it to the outside: it ran continuously whenever the rig was on during the course of both evaluations. Ambient room temperature in my basement was 59F, as before. ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Hi Curt, A sort of an elaborate ...temperature-compensating-oscillator-heterodyning scheme...! Hi Hi We could call it The Rube Golberg method of frequency stabilization!: ) ~73~ de Eddy VE3CUI - VE3XZ ** On 2011-11-29, at 9:42 AM, Curt wrote: Now, you might also learn something worthwhile by doing the same test, but measuring the drift of actual output after mixing at say 7 or 14Mhz. If the crystal Osc goes the other direction, it might get somewhat better...then again if it goes the other way...well...! :) ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Which brings us to an interesting point: isn't the spec for the stability of the rig overall? I don't have the manual with me, so I'm just asking. Steve, W1ES/4 PS - nice work, Eddy! -Original Message- From: Eddy Swynar <deswy...@xplornet.ca>Sent: Nov 29, 2011 10:57 AM To: Curt <cptc...@flash.net>Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability: EPILOGUE Hi Curt, A sort of an elaborate "...temperature-compensating-oscillator-heterodyning" scheme...! Hi Hi We could call it "The Rube Golberg" method of frequency stabilization! : ) ~73~ de Eddy VE3CUI - VE3XZ ** On 2011-11-29, at 9:42 AM, Curt wrote: Now, you might also learn something worthwhile by doing the same test, but measuring the drift of actual output after mixing at say 7 or 14Mhz. If the crystal Osc goes the other direction, it might get somewhat better...then again if it goes the other way...well...! :) ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE
Yes it is for output or input frequency. The other oscillator is crystal controlled, so not likely to move even 10 Hz over this restricted range. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: Which brings us to an interesting point: isn't the spec for the stability of the rig overall? I don't have the manual with me, so I'm just asking. Steve, W1ES/4 PS - nice work, Eddy! -Original Message- From: Eddy Swynar Sent: Nov 29, 2011 10:57 AM To: Curt Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability: EPILOGUE */Hi Curt,/* A sort of an elaborate .../temperature-compensating-oscillator-heterodyning/ scheme...! Hi Hi We could call it */The Rube Golberg/* method of frequency stabilization! * : )* */~73~ de Eddy VE3CUI - VE3XZ/* ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] T-4X Stability: EPILOGUE (Almost!)
Hi Again All, At the specific suggestion of Garey, I went ahead completed a 3rd stability test on my Drake T-4X transmitter PTO... I essentially repeated everything that I did in the very first test, i.e. I used the ICOM 751A as an umpire, both it and the T-4X were started at the same time (i.e. cold), and the ambient basement temperature was 59F---but this time I LEFT THE AIR EXTRACTING COOLING FAN ATOP THE FINAL AMPLIFIER OF THE T-4X CAGE TURNED OFF. Again, I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test. The actual PTO frequency itself was monitored with the 751A in general coverage mode... The results with this third (and final---I promise!) test were most interesting (NOTE: for comparative purposes, I have square-bracketed---[ ]---the changes observed at the very same time intervals in the FIRST test, at the end of each observation line). Here goes: (1) 5455.0-KHz (cold start)---[0.0-Khz]; (2) 5455.0-KHz (unchanged)---[0.0-KHz]; (3) 5454.3-KHz (downward drift of 700-Hz from cold start)---[500-Hz]; (4) 5453.7 KHz (downward drift of 1.3-KHz from cold start)---[1.0-KHz]; (5) 5453.2-KHz (downward drift of 1.8-KHz from cold start)---[1.2-KHz], and, (6) 5453.2-KHz (unchanged)---[0.0-KHz0 The end result in terms of PTO drift with the fan off was 1.8-KHz, versus 1.2-KHz with the fan on. Interesting! That's a difference of 600-Hz, or HALF of the drift experienced with the fan running! It's obvious that proponents of utilizing cooling fans for their Drake transmitters are on to something, alright---but the benefits are NOT restricted merely to prolonged tube life: PTO drift is reduced by one third, as well. My guess is that the cooler environment afforded by the fan to the entire works of the transmitter hastens the PTO in achieving its ambient operating temperature. Because its environment is more directly controlled with the fan, the PTO has less opportunity to diverge in as great a frequency swing as it normally might, as may be evidenced by the results when no fan is used. Anyway, I'm still attempting to wrap my head around all of this, and I certainly do welcome any all feedback comments from the readership. One final point that bears repeating, as was mentioned to me by no less than two subscribers to the Reflector: the Drake manual specs for stability are quoted for THE TRANSMITTER AS AN OPERATING WHOLE, and NOT just for the PTO alone. The final transmitted frequency is a mix of many different frequencies, from self-excited oscillators, from crystal control. As the TV advertisements state, RESULTS AT HOME MAY VARY, Hi Hi. This has all been a most interesting exercise, nonetheless---I only hope that my ramblings herein have NOT inspired readers to unsubscribe from the list..! ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE (Almost!)
Eddy - Great info. Actually this confirms what I would expect to happen. What you do with the fan is provide a constant temperature, whatever it is, much better for short-term stability. The other oscillators involved in the output frequency are the Carrier Oscillator and the Band Oscillator. Both are crystal controlled, and probably stay within 10 Hz or less over the limited temperature range involved. One more run on 40M?? Transmitter keyed, minimum GAIN control. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Eddy Swynar wrote: Hi Again All, At the specific suggestion of Garey, I went ahead completed a 3rd stability test on my Drake T-4X transmitter PTO... I essentially repeated everything that I did in the very first test, i.e. I used the ICOM 751A as an umpire, both it and the T-4X were started at the same time (i.e. cold), and the ambient basement temperature was 59F---but this time I LEFT THE AIR EXTRACTING COOLING FAN ATOP THE FINAL AMPLIFIER OF THE T-4X CAGE TURNED OFF. Again, I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test. The actual PTO frequency itself was monitored with the 751A in general coverage mode... The results with this third (and final---I promise!) test were most interesting (NOTE: for comparative purposes, I have square-bracketed---[ ]---the changes observed at the very same time intervals in the FIRST test, at the end of each observation line). Here goes: (1) 5455.0-KHz (cold start)---[0.0-Khz]; (2) 5455.0-KHz (unchanged)---[0.0-KHz]; (3) 5454.3-KHz (downward drift of 700-Hz from cold start)---[500-Hz]; (4) 5453.7 KHz (downward drift of 1.3-KHz from cold start)---[1.0-KHz]; (5) 5453.2-KHz (downward drift of 1.8-KHz from cold start)---[1.2-KHz], and, (6) 5453.2-KHz (unchanged)---[0.0-KHz0 The end result in terms of PTO drift with the fan off was 1.8-KHz, versus 1.2-KHz with the fan on. Interesting! That's a difference of 600-Hz, or HALF of the drift experienced with the fan running! It's obvious that proponents of utilizing cooling fans for their Drake transmitters are on to something, alright---but the benefits are NOT restricted merely to prolonged tube life: PTO drift is reduced by one third, as well. My guess is that the cooler environment afforded by the fan to the entire works of the transmitter hastens the PTO in achieving its ambient operating temperature. Because its environment is more directly controlled with the fan, the PTO has less opportunity to diverge in as great a frequency swing as it normally might, as may be evidenced by the results when no fan is used. Anyway, I'm still attempting to wrap my head around all of this, and I certainly do welcome any all feedback comments from the readership. One final point that bears repeating, as was mentioned to me by no less than two subscribers to the Reflector: the Drake manual specs for stability are quoted for THE TRANSMITTER AS AN OPERATING WHOLE, and NOT just for the PTO alone. The final transmitted frequency is a mix of many different frequencies, from self-excited oscillators, from crystal control. As the TV advertisements state, RESULTS AT HOME MAY VARY, Hi Hi. This has all been a most interesting exercise, nonetheless---I only hope that my ramblings herein have NOT inspired readers to unsubscribe from the list..! ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE (Almost!)
This has all been a most interesting exercise, nonetheless---I only hope that my ramblings herein have NOT inspired readers to unsubscribe from the list..! On the contrary, Eddy. I find this stuff fascinating. The most productive learning environments always have people who say things like, I wonder what would happen if we.? I hope you keep sharing the results of your experiments with us. 73, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE (Almost!)
I'll second that... it's epics like these that make this and other lists worth riding along with. Thanks for taking the time, and thanks for the info. I always knew fans were a good idea :-) John K5MO At 01:47 PM 11/29/2011, Robert Fish wrote: This has all been a most interesting exercise, nonetheless---I only hope that my ramblings herein have NOT inspired readers to unsubscribe from the list..! On the contrary, Eddy. I find this stuff fascinating. The most productive learning environments always have people who say things like, I wonder what would happen if we.? I hope you keep sharing the results of your experiments with us. 73, Bob K6GGO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability: EPILOGUE (Almost!)
On Tue, 29 Nov 2011 13:25:27 -0500, Eddy Swynar wrote: It's obvious that proponents of utilizing cooling fans for their Drake transmitters are on to something, alright---but the benefits are NOT restricted merely to prolonged tube life: PTO drift is reduced by one third, as well. This, I have been saying :) 73 -Jim NU0C -- Questionable management practices at the 146760.net web site? http://radiojim.exofire.net/pages/Questions.html ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Hi Steve, Be that as it may, I'm still gonna re-run my test here, but only AFTER allowing the ICOM to warm-up for an hour---could be interesting... ~73~ de Eddy VE3CUI - VE3XZ * On 2011-11-26, at 5:45 PM, Steve Wedge wrote: I should have commented that what Eddy reported doesn't seem unusual given the temperatures involved. The fact that everything seems to have settled down after an hour obviously empirically shows what time was needed for the 59F ambient warmup from cold. Even an ovenized counter will drift when turned on from cold. If you've left the oven running, you just won't get any drift from the crystal. Steve Wedge, W1ES/4 I swear by my life, and my love of it, that I will never live for the sake of another man, nor ask another man to live for mine. -Ayn Rand. All my computers have my signature with various pearls of wisdom appended thereto. From: Eddy Swynar Sent: Saturday, November 26, 2011 8:13 AM To: captc...@flash.net Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability Hi Curt, Wow...! What I really wanted to do here, primarily, was to validate my fix of the Drake PTO that's been practically driving me to drink here lo these past many months! Hi Hi. What I'll do, then, is warm-up the 751A separately for one full hour, before initiating a repeat of the test that I did the other day. Any major divurgence in the apparent drifting of the PTO in the new test (as compared to yesterday's) can then be reasonably assumed to be the fault of the ICOM rather than the T-4X, all things remaining the same... Stay tuned---this just gets more more interesting all the time, I must say... ~73!~ de Eddy VE3CUI - VE3XZ * On 2011-11-26, at 8:02 AM, Curt Nixon wrote: GM Eddy: Even the 100Kc calibrator is going to suffer from start-up drift. At the very least--and surely acceptable for a tens-of-Hz startup measurement, just leaving the 751A on for some period of time before doing the start-up test on the Drake should suffice. I settled my 751 down an amazing amount by simply surrounding the primary crystal with an improvised styrofoam box and some cotton. Its all as stable as a crystal can be without some PLL or temp compensation done on it. I guess the main thing is to use a standard that is already settled in and warmed up when making the turn-on drift measurement. If you haven't been involved in an FMT, (Frequency Measurement Test) the level of effort will shock you!. But we're talking a few hundredths (yes, .01) Hz. Small enough so the variations seen in the over-the-air WWV broadcasts become non-useable when multi-path is present. What you find out real fast is that if you can control the temperature, the frequency of most equipment follows along. Current state of the art is GPS-disciplined rubidium reference oscillators. It makes my military oven-ized HP reference osc seem flaky! Any way, thanks for sharing your results. I will be interested to see how much different they are with a pre-stabilized 751A as the reference. BTW, if you use a PC in the shack, a program like FlDigi, or Spectran, (or Spectrum Lab if you are really into it) can help you plot very good reference information using WWV at 2.5, 5, or the CHU frequency infor. They plot using an audio reference from your rig. pretty simple really and easy millihertz accuracy right out of the gate. Have fun. Curt KU8L On 11/26/2011 7:37 AM, Eddy Swynar wrote: Hi Curt, When I get the chance this weekend I'm gonna run some stability tests on the 751A here, using a 100-KHz crystal calibrator / oscillator as its umpire... You've got me thinking: maybe there really WAS a reason that ICOM offered for sale an optional high-standard / ultra-stable crystal oscillator as option for the 751A back-in-the-day...! ~73~ de Eddy VE3CUI - VE3XZ *** On 2011-11-25, at 9:05 PM, Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot
Re: [Drakelist] T-4X Stability
Hi Curt, When I get the chance this weekend I'm gonna run some stability tests on the 751A here, using a 100-KHz crystal calibrator / oscillator as its umpire... You've got me thinking: maybe there really WAS a reason that ICOM offered for sale an optional high-standard / ultra-stable crystal oscillator as option for the 751A back-in-the-day...! ~73~ de Eddy VE3CUI - VE3XZ *** On 2011-11-25, at 9:05 PM, Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
GM Eddy: Even the 100Kc calibrator is going to suffer from start-up drift. At the very least--and surely acceptable for a tens-of-Hz startup measurement, just leaving the 751A on for some period of time before doing the start-up test on the Drake should suffice. I settled my 751 down an amazing amount by simply surrounding the primary crystal with an improvised styrofoam box and some cotton. Its all as stable as a crystal can be without some PLL or temp compensation done on it. I guess the main thing is to use a standard that is already settled in and warmed up when making the turn-on drift measurement. If you haven't been involved in an FMT, (Frequency Measurement Test) the level of effort will shock you!. But we're talking a few hundredths (yes, .01) Hz. Small enough so the variations seen in the over-the-air WWV broadcasts become non-useable when multi-path is present. What you find out real fast is that if you can control the temperature, the frequency of most equipment follows along. Current state of the art is GPS-disciplined rubidium reference oscillators. It makes my military oven-ized HP reference osc seem flaky! Any way, thanks for sharing your results. I will be interested to see how much different they are with a pre-stabilized 751A as the reference. BTW, if you use a PC in the shack, a program like FlDigi, or Spectran, (or Spectrum Lab if you are really into it) can help you plot very good reference information using WWV at 2.5, 5, or the CHU frequency infor. They plot using an audio reference from your rig. pretty simple really and easy millihertz accuracy right out of the gate. Have fun. Curt KU8L On 11/26/2011 7:37 AM, Eddy Swynar wrote: Hi Curt, When I get the chance this weekend I'm gonna run some stability tests on the 751A here, using a 100-KHz crystal calibrator / oscillator as its umpire... You've got me thinking: maybe there really WAS a reason that ICOM offered for sale an optional high-standard / ultra-stable crystal oscillator as option for the 751A back-in-the-day...! ~73~ de Eddy VE3CUI - VE3XZ *** On 2011-11-25, at 9:05 PM, Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynardeswy...@xplornet.ca To:drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire
Re: [Drakelist] T-4X Stability
Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynardeswy...@xplornet.ca To:drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Something I haven't seen discussed and I have noticed on my R-4A is: One end of the PTO range drifts A LOT more than the other end. IIRC it is the high end of the dial (where the PTO slug is inside). 73, Gary WB6OGD - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: captc...@flash.net Cc: drakelist@zerobeat.net Sent: Sat, 26 Nov 2011 13:13:18 - (UTC) Subject: Re: [Drakelist] T-4X Stability Hi Curt, Wow...! What I really wanted to do here, primarily, was to validate my fix of the Drake PTO that's been practically driving me to drink here lo these past many months! Hi Hi. What I'll do, then, is warm-up the 751Aseparately for one full hour, before initiating a repeat of the test that I did the other day. Any major divurgence in the apparent drifting of the PTO in the new test (as compared to yesterday's) can then be reasonably assumed to be the fault of the ICOM rather than the T-4X, all things remaining the same... Stay tuned---this just gets more more interesting all the time, I must say... ~73!~ de Eddy VE3CUI - VE3XZ * On 2011-11-26, at 8:02 AM, Curt Nixon wrote: GM Eddy: Even the 100Kc calibrator is going to suffer from start-up drift. At the very least--and surely acceptable for a tens-of-Hz startup measurement, just leaving the 751A on for some period of time before doing the start-up test on the Drake should suffice. I settled my 751 down an amazing amount by simply surrounding the primary crystal with an improvised styrofoam box and some cotton. Its all as stable as a crystal can be without some PLL or temp compensation done on it. I guess the main thing is to use a standard that is already settled in and warmed up when making the turn-on drift measurement. If you haven't been involved in an FMT, (Frequency Measurement Test) the level of effort will shock you!. But we're talking a few hundredths (yes, .01) Hz. Small enough so the variations seen in the over-the-air WWV broadcasts become non-useable when multi-path is present. What you find out real fast is that if you can control the temperature, the frequency of most equipment follows along. Current state of the art is GPS-disciplined rubidium reference oscillators. It makes my military oven-ized HP reference osc seem flaky! Any way, thanks for sharing your results. I will be interested to see how much different they are with a pre-stabilized 751A as the reference. BTW, if you use a PC in the shack, a program like FlDigi, or Spectran, (or Spectrum Lab if you are really into it) can help you plot very good reference information using WWV at 2.5, 5, or the CHU frequency infor. They plot using an audio reference from your rig. pretty simple really and easy millihertz accuracy right out of the gate. Have fun. Curt KU8L On 11/26/2011 7:37 AM, Eddy Swynar wrote: Hi Curt, When I get the chance this weekend I'm gonna run some stability tests on the 751A here, using a 100-KHz crystal calibrator / oscillator as its umpire... You've got me thinking: maybe there really WAS a reason that ICOM offered for sale an optional high-standard / ultra-stable crystal oscillator as option for the 751A back-in-the-day...! ~73~ de Eddy VE3CUI - VE3XZ *** On 2011-11-25, at 9:05 PM, Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc
Re: [Drakelist] T-4X Stability
I didn't mean to imply that 59 was room temp - it's been a long time since I lived in New England ;-) I did used to have my shack down cellar when I lived up there, and 59 would be warm in some instances before the baseboard heat came up to heat the place. Obviously, you must allow for more. I suspect I took the question more as what is the defined warm-up time rather than trying to figure the extra time needed for a cellar warm-up. I do miss my cellah here in NC, but have adapted. With the kids gone, the den on the first floor has become my shack. My XYL is extremely tolerant these days with all the Drake rigs in various states of disassembly strewn across the floor behind my operating position, and that I have to use the island in the kitchen as my rework station :) The B-line is getting a break for the rest of the weekend as I dabble in CQWWCW with my K3. I had thought of putting the Drakes on, but I sold my W1WEF keying interface when I got the K3 - thinking I didn't need it. I'll be taking a break for the contest and other stuff tomorrow at 4 to try and check in to the net. Steve Wedge, W1ES/4 I swear by my life, and my love of it, that I will never live for the sake of another man, nor ask another man to live for mine. -Ayn Rand. All my computers have my signature with various pearls of wisdom appended thereto. -- From: Garey Barrell k4...@mindspring.com Sent: Friday, November 25, 2011 5:57 PM To: Steve Wedge w1es1...@earthlink.net Cc: Eddy Swynar deswy...@xplornet.ca; drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
I like warming up the counter for a while if not possessing an oven. Can't remember if a Fluke 1911A has one, or not. Steve Wedge, W1ES/4 I swear by my life, and my love of it, that I will never live for the sake of another man, nor ask another man to live for mine. -Ayn Rand. All my computers have my signature with various pearls of wisdom appended thereto. -- From: Garey Barrell k4...@mindspring.com Sent: Friday, November 25, 2011 10:07 PM To: captc...@flash.net Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability Curt - Excellent point. I missed the 'standard' in the first read of Eddy's message. I always use an 'ovenized' counter and just well, you know.. :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ
Re: [Drakelist] T-4X Stability
I should have commented that what Eddy reported doesn't seem unusual given the temperatures involved. The fact that everything seems to have settled down after an hour obviously empirically shows what time was needed for the 59F ambient warmup from cold. Even an ovenized counter will drift when turned on from cold. If you've left the oven running, you just won't get any drift from the crystal. Steve Wedge, W1ES/4 I swear by my life, and my love of it, that I will never live for the sake of another man, nor ask another man to live for mine. -Ayn Rand. All my computers have my signature with various pearls of wisdom appended thereto. From: Eddy Swynar Sent: Saturday, November 26, 2011 8:13 AM To: captc...@flash.net Cc: drakelist@zerobeat.net Subject: Re: [Drakelist] T-4X Stability Hi Curt, Wow...! What I really wanted to do here, primarily, was to validate my fix of the Drake PTO that's been practically driving me to drink here lo these past many months! Hi Hi. What I'll do, then, is warm-up the 751A separately for one full hour, before initiating a repeat of the test that I did the other day. Any major divurgence in the apparent drifting of the PTO in the new test (as compared to yesterday's) can then be reasonably assumed to be the fault of the ICOM rather than the T-4X, all things remaining the same... Stay tuned---this just gets more more interesting all the time, I must say... ~73!~ de Eddy VE3CUI - VE3XZ * On 2011-11-26, at 8:02 AM, Curt Nixon wrote: GM Eddy: Even the 100Kc calibrator is going to suffer from start-up drift. At the very least--and surely acceptable for a tens-of-Hz startup measurement, just leaving the 751A on for some period of time before doing the start-up test on the Drake should suffice. I settled my 751 down an amazing amount by simply surrounding the primary crystal with an improvised styrofoam box and some cotton. Its all as stable as a crystal can be without some PLL or temp compensation done on it. I guess the main thing is to use a standard that is already settled in and warmed up when making the turn-on drift measurement. If you haven't been involved in an FMT, (Frequency Measurement Test) the level of effort will shock you!. But we're talking a few hundredths (yes, .01) Hz. Small enough so the variations seen in the over-the-air WWV broadcasts become non-useable when multi-path is present. What you find out real fast is that if you can control the temperature, the frequency of most equipment follows along. Current state of the art is GPS-disciplined rubidium reference oscillators. It makes my military oven-ized HP reference osc seem flaky! Any way, thanks for sharing your results. I will be interested to see how much different they are with a pre-stabilized 751A as the reference. BTW, if you use a PC in the shack, a program like FlDigi, or Spectran, (or Spectrum Lab if you are really into it) can help you plot very good reference information using WWV at 2.5, 5, or the CHU frequency infor. They plot using an audio reference from your rig. pretty simple really and easy millihertz accuracy right out of the gate. Have fun. Curt KU8L On 11/26/2011 7:37 AM, Eddy Swynar wrote: Hi Curt, When I get the chance this weekend I'm gonna run some stability tests on the 751A here, using a 100-KHz crystal calibrator / oscillator as its umpire... You've got me thinking: maybe there really WAS a reason that ICOM offered for sale an optional high-standard / ultra-stable crystal oscillator as option for the 751A back-in-the-day...! ~73~ de Eddy VE3CUI - VE3XZ *** On 2011-11-25, at 9:05 PM, Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm
[Drakelist] T-4X Stability
Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
- Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 11:32 AM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ I suspect this is normal. An hour for all parts to reach some sort of thermal equilibrium is not very long. Some equipment takes a lot longer, for instance, somewhere in the TMC literature its stated that the stabilization time for the GPR-90 receiver is 48 hours! I think this is probably typical for a lot of equipment. OTOH perhaps the temperature compensation in your TX is not quite on. The fact that it drifts in the same direction is IMO a good sign. Some compensation results in drift that varies in direction as the temp changes. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Eddy, Well, it depends. One thing that will add to the drift rate is how often and to what degree the final amplifier is exercised. A fan pulling the hot air out helps if it is located above or behind the final amplifier cage. Because of this, the R4C is often used for primary frequency control with a C line. My experience with the B line, C line, and 7 line, is that there are classes of drift due to either production line variations, component lots, or luck of the draw. For example, I've had TR-7s that drift well under 50 hz per hour while others have drifted over 200 hz per hour and needed 18-24 hours to stabilize; too, some never stabilized. Enjoy those Drakes. And don't forget the Drake nets... 73, Evan, K9SQG -Original Message- From: Eddy Swynar deswy...@xplornet.ca To: drakelist drakelist@zerobeat.net Sent: Fri, Nov 25, 2011 9:33 am Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
At 02:32 PM 11/25/2011, Eddy Swynar wrote: although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. Good God man, close the windows when you're measuring drift! :-) John K5MO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
I wish my HQ-140X was this stable ... and has been said ... 59 degrees ... yikes ... hell even I don't function well at 59 degrees..!! Bill, W0LPQ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] T-4X Stability
Curt - Excellent point. I missed the 'standard' in the first read of Eddy's message. I always use an 'ovenized' counter and just well, you know.. :-) 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Curt Nixon wrote: Not sure anyone asked this, and I didn't see it in your initial post, but was the 751A already warmed up when you tested the drake? What is the frequency reference in the 751A? I recently used a 751 which is essentially the same frequency determining set-up for a freq measurement test and I can tell you, it isn't all that stable either...and, it goes up and down with small temperature differences over a span of only several minutes. Even when it had been running in Rx only for over 24 hours. So..keep in mind that the data you recorded is the net difference from a moving reference. After warm-up, I'm not so sure that the 751A is any better than the Drake. They are a lot better if they have the TCXO module added, but I didn't see that mentioned. Anyway, just curious what the reference conditions were. Thanks Curt KU8L On 11/25/2011 5:57 PM, Garey Barrell wrote: Steve - I think 30 minutes is a reasonable 'warm-up' time. IF the radio is in a controlled environment.!! Take one out of the garage in winter and plug it in, it's gonna take considerably longer before everything reaches equilibrium. You have some sizable chunks of iron and steel in there that can absorb quite a bit of heat. From 60 degrees to a 'nominal' 75 degree ambient on top of normal internal heating would take a while, perhaps an hour?!? :-) Plus as Evan said there will be a delta from transmitting as well. A fan makes a BIG difference in this if you are into long transmissions or TTY, etc. This is one reason why the TR-7 fan is used to exhaust hot air from the PA right out the back rather than blow it in all over the radio, including the PTO, with each transmission. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs www.k4oah.com Steve Wedge wrote: I always assumed it was a 30 minute warmup, because I seem to remember the alignment procedures spec 30 minutes warmup before doing an alignment. Steve Wedge, W1ES/4 I can't complain, but sometimes I still do. - Joe Walsh If the above message appears, it came from Steve's Son of Laptop! - Original Message - From: Eddy Swynar deswy...@xplornet.ca To: drakelist@zerobeat.net Sent: Friday, November 25, 2011 2:32 PM Subject: [Drakelist] T-4X Stability Hi All, The manual for my T-4X states that stability is LESS THAN 100 CYCLES AFTER WARM-UP. My question is simply this: how long, exactly, is an accepted period of warm-up...? After all of the hoops that I've jumped through in stabilizing the PTO in my rig (re-buiding it almost, actually!), I decided this morning to actually measure its drift. I used my ICOM 751A transceiver (in general coverage mode) as the frequency umpire, and tuned it directly to the Drake PTO's output frequency of 5454.0-KHz. Both rigs were in the basement overnight, where the ambient room temperature was 59F. I measured the frequency a total of SIX times, i.e. (1) immediately at the start of the test, (2) 3 minutes into the test, (3) 15 minutes into the test, (4) 30 minutes into the test, (5) 1 hour into the test, and finally (6) two hours into the test... Here are my results: (1) 5454.0-KHz (cold start); (2) 5454.0-KHz (unchanged from cold start); (3) 5453.5-KHz (downward drift of 500-Hz from cold start); (4) 5453.0 KHz (downward drift of 1-KHz from cold start); (5) 5452.8-KHz (downward drift of 1.2-KHz from cold start), and, (6) 5452.8-KHz (unchanged). So---it looks like the rascal that I have here stabilizes after a good hour of steady warm-up, which leads me to suspect that maybe warm-up to the writer of the manual was, in fact, just that, i.e. one hour...? No matter, it was a most interesting exercise---and I sure would be curious if my rig's performance might match that of some of the other T-4Xs that are out there...although I dare say, probably not everyone has as thick a hide as I do in being able to withstand a 59F ambient room temperature...! Hi Hi. ~73~ de Eddy VE3CUI - VE3XZ ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
