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Re: SX-110 Crystal Instability
开云体育Don, ? The frequency will jump suddenly from A to B and then settle on that for a bit.? The changes aren’t slow. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of don Root <drootofallevil@...> ? I’m still curious; does the frequency jump suddenly from A to B, or does it ?settle for a bit on a variety of frequencies? or is it a slow change? Don VA3DRL ? From: [email protected] [mailto:[email protected]] On Behalf Of KW4H via groups.io
Sent: Thursday, November 3, 2022 4:42 PM To: [email protected] Subject: Re: [HallicraftersRadios] SX-110 Crystal Instability ? An update.? I just did another crystal alignment and yet again found the right spot and re-confirmed the crystal oscillator frequency null is at 453.410 KHz.? However, there is no doubt that merely tapping on the crystal – even a tiny bit – causes the null point to noticeably change when the crystal is in use.? Now – to be realistic – that’s what the crystal phasing control is for, and it won’t end up in exactly the same place every time.? If it shifts a little, the phasing control ends up in a different position when you adjust it.? So, for a receiver this old – meh – and probably no one cared back then at this price point.? Nevertheless, I’m going to try replacing the crystal with one that doesn’t jiggle.? Just because. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of Dan <pitfit@...> ? Perfect. ? Woulda thunk it? ? Thanks. ? Dan WB4GRA ?
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Re: SX-110 Crystal Instability
开云体育FWIW i opened the filter compartment of my HQ 129 X? the crystal is in a holder similar to the one pictured in the SX110.? Itried tapping it.? Did not change frequency or have any effect on the phasing control.? as mentioned before the same ki d of holder is used in the RCA AR 88 . I have tapped that one too and found it made a slight noise but didn't seem to change its frequency. I think it's possible the electrodes may be a little loose.? The change in capacitance word affect the phasing control. -------- Original message -------- From: don Root <drootofallevil@...> Date: 11/3/22 5:31 PM (GMT-08:00) Subject: Re: [HallicraftersRadios] SX-110 Crystal Instability I’m still curious; does the frequency jump suddenly from A to B, or does it ?settle for a bit on a variety of frequencies? or is it a slow change? Don VA3DRL ? From: [email protected] [mailto:[email protected]] On Behalf Of KW4H via groups.io ? An update.? I just did another crystal alignment and yet again found the right spot and re-confirmed the crystal oscillator frequency null is at 453.410 KHz.? However, there is no doubt that merely tapping on the crystal – even a tiny bit – causes the null point to noticeably change when the crystal is in use.? Now – to be realistic – that’s what the crystal phasing control is for, and it won’t end up in exactly the same place every time.? If it shifts a little, the phasing control ends up in a different position when you adjust it.? So, for a receiver this old – meh – and probably no one cared back then at this price point.? Nevertheless, I’m going to try replacing the crystal with one that doesn’t jiggle.? Just because. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of Dan <pitfit@...> ? Perfect. ? Woulda thunk it? ? Thanks. ? Dan WB4GRA ?
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Re: SX-110 Crystal Instability
开云体育I’m still curious; does the frequency jump suddenly from A to B, or does it ?settle for a bit on a variety of frequencies? or is it a slow change? Don VA3DRL ? From: [email protected] [mailto:[email protected]] On Behalf Of KW4H via groups.io
Sent: Thursday, November 3, 2022 4:42 PM To: [email protected] Subject: Re: [HallicraftersRadios] SX-110 Crystal Instability ? An update.? I just did another crystal alignment and yet again found the right spot and re-confirmed the crystal oscillator frequency null is at 453.410 KHz.? However, there is no doubt that merely tapping on the crystal – even a tiny bit – causes the null point to noticeably change when the crystal is in use.? Now – to be realistic – that’s what the crystal phasing control is for, and it won’t end up in exactly the same place every time.? If it shifts a little, the phasing control ends up in a different position when you adjust it.? So, for a receiver this old – meh – and probably no one cared back then at this price point.? Nevertheless, I’m going to try replacing the crystal with one that doesn’t jiggle.? Just because. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of Dan <pitfit@...> ? Perfect. ? Woulda thunk it? ? Thanks. ? Dan WB4GRA ?
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Re: What's Old, is New Again - Hallicrafters SX-17 & FT8
开云体育Steve ?it Took a bit of work for the old gray matter to digest your last comment, and i will ditto your first line. 73? Don VA3DRL ? From: [email protected] [mailto:[email protected]] On Behalf Of KW4H via groups.io
Sent: Thursday, November 3, 2022 7:51 PM To: [email protected] Subject: Re: [HallicraftersRadios] What's Old, is New Again - Hallicrafters SX-17 & FT8 ? Good luck to you both, please keep us posted! ? And by the way, Bill, whenever I see your callsign I get a bad case of dyslexia.? ? ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of "Bill (Group Owner)" <k2wh@...> ? Good luck again and your enthusiasm is contagious. |
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Re: What's Old, is New Again - Hallicrafters SX-17 & FT8
开云体育Good luck to you both, please keep us posted! ? And by the way, Bill, whenever I see your callsign I get a bad case of dyslexia.? ? ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of "Bill (Group Owner)" <k2wh@...> ? Good luck again and your enthusiasm is contagious. |
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Re: What's Old, is New Again - Hallicrafters SX-17 & FT8
That's really interesting, Bill. I'd never even thought about that, but what a brilliant way to check on local oscillator drift! I really must get on with my SX16 restoration but it's going to be a long process. I've got capacitors from Hayseed, all the tubes, decals from RadioDaze - just need to find the time (and transformers!) and make some space in the shack/workshop to get started... 73 de Peter, G4ADJ ? |
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Re: SX-110 IF Alignment Question
开云体育??Hmmm... a few more comments, Steve -? You align the IF's, peaking each at the frequency you've determined the crystal best "sings" at. For example, at least using a SA, for a 455 kHz crystal inject a sweep generated signal of, say, 450 to 460 kHz (not super critical +/-) into the mixer grid (loosely coupled) and look at the response at the detector at your widest filter setting. Your crystal is the tuning fork and whatever it rings at is the key it's in. It will almost never be 455.00 kHz. Make sure you have the phasing control adjusted such that no null appears on either side of your peak. You're hoping to see a perfect upside down ice cream cone on your scope - maybe just a scoop of mashed potatoes at the widest setting - ?with the top tip somewhere near 455 kHz. Whatever frequency your curve peaks at is the actual in-circuit resonance of your IF crystal. It will never be 455.000 in an old radio. No matter. Go about your IF alignment with your sig gen at your new "actual" crystal frequency. Your phasing control is best set with the knob at 12 o'clock and no null anywhere on the curve. Turning it clockwise or counterclockwise should initiate a sharp null going up or down one side or the other. Hammarlund goes into quite some discussion of this in their HQ-120/129/140/150 models. Halli may do the same, I don't know. Hammarlund was strangely very tight-fisted about using a spectrum analyzer back when almost nobody had one. Opinions vary. Many don't have or use any instrument and just twist the IF cores to their loudest. I do know the design, function, and schematics of these single crystal filters with switch settings are remarkably alike. Aligning a single conversion HQ Hammarlund "by the book" with a spec. an. for "symmetry, amplitude, and coincidence" on all settings of the bandwidth knob is like playing three dimensional chess through a German Enigma machine with the settings changing on each pass through. Dan WB4GRA On Nov 3, 2022, at 2:26 PM, KW4H via groups.io <reedsteve@...> wrote:
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Re: SX-110 Crystal Instability
开云体育The crystal in my old super pro is rather large . It is in a bakelite holder with removable electrodes.? It's been a while since I've been into it but I don't remember it's being spring loaded or tight.? The crystal is a mechanical resonator and I think must not be restrained too much.? Later crystals are plated,? the coating acting as the electrodes but I think being elastically mounted.? I am not sure I remember all the details. The crystal in my AR 88 looks much like the posted pix bot I've never opened it. Tapping it does make a noise but it's pretty broad in its narrowest setting so I have never noticed any shifting.? -------- Original message -------- From: Jacques_VE2JFE <jacques.f@...> Date: 11/3/22 12:48 PM (GMT-08:00) Subject: Re: [HallicraftersRadios] SX-110 Crystal Instability Hi Dan, You wrote: But a loose mounted crystal wafer rattling about and being OK isn't an intuitive conclusion. Like to learn more about that. There is several examples of old radios using a “loose resonator crystal”. The old models of HRO use a plug-in crystal that “rattle” when you shake the holder. Another fairly well explained case is here: Go half-way down the page. ? 73, Jacques, VE2JFE in Montreal |
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Re: SX-110 IF Alignment Question
开云体育FYI – I stumbled across this video, which helped answer some of my questions.? The focus was the SX62, but the principles and circuitry are nearly the same.? It was some of the best 30 minutes of crystal filter theory and alignment training I’ve ever run across.? Highly recommend. ? ? 73 – Steve, KW4H From: <[email protected]> on behalf of "KW4H via groups.io" <reedsteve@...> ? So – this is something I’ve gone over and over again in the alignment instructions and I can’t find an answer.? Hallicrafters wants the IF aligned to the frequency of the crystal (which is almost certainly not going to be on exactly 455 KHz).? To identify the crystal frequency, you slowly sweep the signal generator above or below 455 KHz until you discover a sharp notch.? I’ve done that – no problem.? But, here’s the catch:? the location of that notch can vary rather signficantly with the position of the crystal phasing control, and there’s nothing in the alignment instructions about the correct position for the phasing control.? Been scratching my head over this, and so far I haven’t found any information about it online.? Anyone here run into this before and have an answer? ? 73 – Steve, KW4H |
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Re: SX-110 Crystal Instability
开云体育An update.? I just did another crystal alignment and yet again found the right spot and re-confirmed the crystal oscillator frequency null is at 453.410 KHz.? However, there is no doubt that merely tapping on the crystal – even a tiny bit – causes the null point to noticeably change when the crystal is in use.? Now – to be realistic – that’s what the crystal phasing control is for, and it won’t end up in exactly the same place every time.? If it shifts a little, the phasing control ends up in a different position when you adjust it.? So, for a receiver this old – meh – and probably no one cared back then at this price point.? Nevertheless, I’m going to try replacing the crystal with one that doesn’t jiggle.? Just because. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of Dan <pitfit@...> ? Perfect. ? Woulda thunk it? ? Thanks. ? Dan WB4GRA
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Re: SX-110 Crystal Instability
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On Nov 3, 2022, at 3:46 PM, Jacques_VE2JFE <jacques.f@...> wrote:
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Re: SX-110 Crystal Instability
开云体育Hi Dan, You wrote: But a loose mounted crystal wafer rattling about and being OK isn't an intuitive conclusion. Like to learn more about that. There is several examples of old radios using a “loose resonator crystal”. The old models of HRO use a plug-in crystal that “rattle” when you shake the holder. Another fairly well explained case is here: Go half-way down the page. ? 73, Jacques, VE2JFE in Montreal |
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Re: SX-110 IF Alignment Question
开云体育Scott.?You are trying to set the signal generator and the pitch control to the xtal frequency simultaneously.? The remarks column gives the procedure. The sig gen will peak at ?xtal freq, the pitch will dip to minimum. The correct spot is when they coincide. The pitch will attenuate the sig gen giving the “lowest peak” / “maximum dip”. 1. Adjust pitch to min.? 2. Adjust gen to peak.? 3. Repeat until 1and 2coincide.? Start at one end of pitch range and slowly move toward the other end. Do not reverse the pitch control.? 73 Dick. K9FFK Sent from my iThing which often corrects my typing and what I say.? On Nov 3, 2022, at 1:36 PM, Scott Petersen <s-petersen@...> wrote:
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Re: SX-110 Crystal Instability
开云体育Yeah, thanks for the reply.I am really interested in your ongoing experience here. I've measured actual IF crystal resonances of crystals both in and out of the radio - usually by sweeping them with a SA. A scope in x/y mode is also useful Most of my experience is with the single conversion Hammarlund HQ-series filters but Halli and others all use a similar switching design with crystal phasing that dates back into the 1930's. I look forward to your continued adventures that we can all learn from. Please keep posting! Dan WB4GRA On Nov 3, 2022, at 2:16 PM, KW4H via groups.io <reedsteve@...> wrote:
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Re: SX-110 IF Alignment Question
开云体育
I'm a little foggy on this, but I believe you are supposed to set it for highest output I think
From: [email protected] <[email protected]> on behalf of KW4H via groups.io <reedsteve@...>
Sent: Thursday, November 3, 2022 2:26 PM To: [email protected] <[email protected]> Subject: [HallicraftersRadios] SX-110 IF Alignment Question ?
So – this is something I’ve gone over and over again in the alignment instructions and I can’t find an answer.? Hallicrafters wants the IF aligned to the frequency of the crystal (which is almost certainly not going to be on exactly 455 KHz).? To identify the crystal frequency, you slowly sweep the signal generator above or below 455 KHz until you discover a sharp notch.? I’ve done that – no problem.? But, here’s the catch:? the location of that notch can vary rather signficantly with the position of the crystal phasing control, and there’s nothing in the alignment instructions about the correct position for the phasing control.? Been scratching my head over this, and so far I haven’t found any information about it online.? Anyone here run into this before and have an answer? ? 73 – Steve, KW4H |
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SX-110 IF Alignment Question
开云体育So – this is something I’ve gone over and over again in the alignment instructions and I can’t find an answer.? Hallicrafters wants the IF aligned to the frequency of the crystal (which is almost certainly not going to be on exactly 455 KHz).? To identify the crystal frequency, you slowly sweep the signal generator above or below 455 KHz until you discover a sharp notch.? I’ve done that – no problem.? But, here’s the catch:? the location of that notch can vary rather signficantly with the position of the crystal phasing control, and there’s nothing in the alignment instructions about the correct position for the phasing control.? Been scratching my head over this, and so far I haven’t found any information about it online.? Anyone here run into this before and have an answer? ? 73 – Steve, KW4H |
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Re: SX-110 Crystal Instability
开云体育My perspective is somewhat odd – every boat anchor I restore is a learning experience.? I tend to fuss around with things not because I’m unsatisfied, but because I’m curious. ? On the crystal – after much more research, the crystal is loose in the chamber inside the holder because that’s the way it was.? I also discovered that the IN-circuit resonant frequency is going to be somewhat different than the OUT-of-circuit resonance; therefore, there’s no significant value in testing the crystal outside of the radio unless a bad crystal is suspected.? And, as you’ve pointed out, the potential difference in resonant frequency from repositioning the radio is rather minimal.? I’m still going to test with a replacement 455 KHz crystal anyway – because, well, I’m curious. ? Next I have a question about the IF alignment, but will post that under a different subject so this doesn’t go on forever. ? 73 – Steve, KW4H ? From: <[email protected]> on behalf of Dan <pitfit@...> ? ? ??Is it just me (always a possibility!) or have we lost some perspective here? ? ? If you're getting +/- 50 hertz out of a 61 year old single crystal filter in a $160 radio made when Eisenhower might have been President, just align the radio at 453.750 and you'll be fine. ? Like you, I >am< a little circumspect about anything rattling around loose in the crystal case when shaking it. That's curious. I've removed, handled, and measured several crystal cases like yours from the single conversion HQ Hammarlunds and they don't rattle. What inside the case assembly makes you think the crystal was intended to be mounted loosely when you took it apart? Maybe it should be? I've never opened such a case. Could be, I guess. But a loose mounted crystal wafer rattling about and being OK isn't an intuitive conclusion. Like to learn more about that. ? Please continue posting since this is of interest to us. I'm especially curious how you intend to remount the new 455 crystal you have coming. ? Summarizing, I'm suspicious of the rattling sound you report when shaking your crystal case - seems a red flag to me - but +/- 50 hertz?? ? You'll never hear it or know it. Align it at 453.750 and go shortwave listening! ? Dan WB4GRA
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Re: SX-110 Crystal Instability
开云体育? ??Is it just me (always a possibility!) or have we lost some perspective here? ? If you're getting +/- 50 hertz out of a 61 year old single crystal filter in a $160 radio made when Eisenhower might have been President, just align the radio at 453.750 and you'll be fine. Like you, I >am< a little circumspect about anything rattling around loose in the crystal case when shaking it. That's curious. I've removed, handled, and measured several crystal cases like yours from the single conversion HQ Hammarlunds and they don't rattle. What inside the case assembly makes you think the crystal was intended to be mounted loosely when you took it apart? Maybe it should be? I've never opened such a case. Could be, I guess. But a loose mounted crystal wafer rattling about and being OK isn't an intuitive conclusion. Like to learn more about that. Please continue posting since this is of interest to us. I'm especially curious how you intend to remount the new 455 crystal you have coming. Summarizing, I'm suspicious of the rattling sound you report when shaking your crystal case - seems a red flag to me - but +/- 50 hertz?? You'll never hear it or know it. Align it at 453.750 and go shortwave listening! Dan WB4GRA On Nov 2, 2022, at 5:01 PM, KW4H via groups.io <reedsteve@...> wrote:
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don Root
Bill (Group Owner)
Jacques_VE2JFE
Paul Christensen