[time-nuts] HP5065a cfield issue
Bob kb8tq
kb8tq at n1k.org
Wed Dec 2 14:27:13 UTC 2020
Hi
Ok, if the synth is off the “suspect” list …. *and* it’s a good solid lock.
Back to the C field.
If it jumped 4x10^-11, that’s a very different thing than jumping 2x10^-9. Finding
the “source” of a 0.04 ppb shift is going to be a lot harder than finding a 2 ppb
gotcha. Best to nail down the shift first …
Suspects for a small shift:
There are a *lot* of parts (like electrolytic caps) in the voltage regulator circuit.
That feeds the C field current source and the rest of the system. A quick check
of the 20V supply might help narrow that a bit.
Suspects for a large shift:
Just like the heater windings, it is at least possible that the mag field winding
shorts out in some way. An ohm meter check with both sides of the winding
disconnected ( so floating winding to ground / case ) would be the first step
in that investigation …
Yes, there are a lot of other things that could go on that list …
Bob
> On Dec 2, 2020, at 9:14 AM, paul swed <paulswedb at gmail.com> wrote:
>
> Hello to the group.
> Last night I dug further into the 5065 along with a lot of reading.
> The synth is producing the correct frequency according to the charts here and in the manual.
> I also now see that any logic I may have assumed about the thumbwheel switches is completely wrong.
> The test tonight will actually use some different numbers. As an example the switch should be 8714 the next increment is actually 8333 according to the manual. So want to see what that actually does.Likewise there is a number on the other side of 8714.
> But none of this explains why the system jumped at least 4 X E-11 (Or is that 40?) after years of only very small minor division changes.
> Regards
> Paul
> WB8TSL
>
> On Tue, Dec 1, 2020 at 5:34 PM Poul-Henning Kamp <phk at phk.freebsd.dk <mailto:phk at phk.freebsd.dk>> wrote:
> > To make any sense at all out of the synthesizer settings, you need the magic table in
> > the manual. They are very random and not all settings actually work ( = produce a
> > stable output).
>
> A few of the entries have very much longer moduli than the rest,
> and those will probably be less stable for that reason.
>
> I suspect the published list was tweaked to ensure even-ish coverage.
>
> I once hacked a small python script (attached) to reproduce the table
> from the manual, here is the output from it:
>
> +---------------------------+-----------------------------+
> | Thumb Offset Freq | Thumb Offset Freq |
> +---------------------------+-----------------------------+
> | 0001 -213.719 5314955.00 | 9348 -1000.603 5314417.19 |
> | 0002 -199.087 5314965.00 | 7885 -995.309 5314420.81 |
> | 0003 -923.334 5314470.00 | 9189 -986.777 5314426.64 |
> | 0004 -616.078 5314680.00 | 9030 -977.471 5314433.00 |
> | 0005 -602.910 5314689.00 | 8871 -970.785 5314437.57 |
> | 5691 -940.723 5314458.12 | 8712 -965.767 5314441.00 |
> | 5726 -596.318 5314693.51 | 8394 -958.686 5314445.84 |
> | 5952 -191.236 5314970.37 | 7758 -950.566 5314451.39 |
> | 5980 -621.015 5314676.63 | 5691 -940.723 5314458.12 |
> | 6301 -221.040 5314950.00 | 9841 -930.036 5314465.42 |
> | 6518 -916.829 5314474.45 | 0003 -923.334 5314470.00 |
> | 6519 -784.650 5314564.79 | 6518 -916.829 5314474.45 |
> | 7013 -591.165 5314697.03 | 7472 -911.838 5314477.86 |
> | 7207 -40.474 5315073.41 | 8267 -903.497 5314483.56 |
> | 7318 -55.120 5315063.40 | 8744 -893.401 5314490.46 |
> | 7443 -408.216 5314822.07 | 8903 -888.104 5314494.08 |
> | 7472 -911.838 5314477.86 | 9062 -880.993 5314498.94 |
> | 7603 -181.446 5314977.06 | 9221 -870.970 5314505.79 |
> | 7696 -630.493 5314670.15 | 8601 -864.270 5314510.37 |
> | 7697 -430.586 5314806.78 | 9380 -855.827 5314516.14 |
> | 7698 -230.489 5314943.54 | 8919 -844.913 5314523.60 |
> | 7743 -766.959 5314576.88 | 8458 -840.524 5314526.60 |
> | 7758 -950.566 5314451.39 | 9539 -830.236 5314533.63 |
> | 7777 -309.118 5314889.80 | 7854 -822.836 5314538.69 |
> | 7792 -492.447 5314764.50 | 8776 -817.274 5314542.49 |
> | 7854 -822.836 5314538.69 | 9237 -809.431 5314547.85 |
> | 7885 -995.309 5314420.81 | 8935 -800.433 5314554.00 |
> | 7888 -341.848 5314867.43 | 8029 -789.973 5314561.15 |
> | 7918 -731.156 5314601.35 | 6519 -784.650 5314564.79 |
> | 7919 -509.961 5314752.53 | 9698 -777.681 5314569.55 |
> | 8014 -582.532 5314702.93 | 7743 -766.959 5314576.88 |
> | 8029 -789.973 5314561.15 | 8347 -763.037 5314579.56 |
> | 8031 -322.490 5314880.66 | 8951 -754.594 5314585.33 |
> | 8142 -360.488 5314854.69 | 9253 -745.259 5314591.71 |
> | 8238 -172.783 5314982.98 | 8808 -737.036 5314597.33 |
> | 8253 -403.313 5314825.42 | 7918 -731.156 5314601.35 |
> | 8267 -903.497 5314483.56 | 9555 -723.253 5314606.75 |
> | 8333 -240.028 5314937.02 | 8522 -712.134 5314614.35 |
> | 8347 -763.037 5314579.56 | 8967 -707.335 5314617.63 |
> | 8379 -702.976 5314620.61 | 8379 -702.976 5314620.61 |
> | 8394 -958.686 5314445.84 | 9412 -695.293 5314625.86 |
> | 8397 -97.666 5315034.32 | 8681 -685.857 5314632.31 |
> | 8411 -640.485 5314663.32 | 9269 -678.277 5314637.49 |
> | 8413 -60.283 5315059.87 | 9126 -666.821 5314645.32 |
> | 8429 -22.139 5315085.94 | 8983 -658.598 5314650.94 |
> | 8458 -840.524 5314526.60 | 8697 -647.552 5314658.49 |
> | 8459 -541.900 5314730.70 | 8411 -640.485 5314663.32 |
> | 8491 -472.679 5314778.01 | 7696 -630.493 5314670.15 |
> | 8522 -712.134 5314614.35 | 5980 -621.015 5314676.63 |
> | 8556 -6.016 5315096.96 | 0004 -616.078 5314680.00 |
> | 8571 -286.087 5314905.54 | 9857 -608.295 5314685.32 |
> | 8586 -572.113 5314710.05 | 0005 -602.910 5314689.00 |
> | 8601 -864.270 5314510.37 | 5726 -596.318 5314693.51 |
> | 8618 -497.231 5314761.23 | 7013 -591.165 5314697.03 |
> | 8619 -163.755 5314989.15 | 8014 -582.532 5314702.93 |
> | 8635 -121.061 5315018.33 | 8586 -572.113 5314710.05 |
> | 8651 -77.372 5315048.19 | 8872 -562.939 5314716.32 |
> | 8667 -32.615 5315078.78 | 9015 -556.355 5314720.82 |
> | 8681 -685.857 5314632.31 | 9158 -547.532 5314726.85 |
> | 8682 -336.579 5314871.03 | 8459 -541.900 5314730.70 |
> | 8697 -647.552 5314658.49 | 9301 -535.095 5314735.35 |
> | 8712 -965.767 5314441.00 | 8745 -526.756 5314741.05 |
> | 8714 -250.255 5314930.03 | 9444 -516.279 5314748.21 |
> | 8744 -893.401 5314490.46 | 7919 -509.961 5314752.53 |
> | 8745 -526.756 5314741.05 | 9031 -502.702 5314757.49 |
> | 8776 -817.274 5314542.49 | 8618 -497.231 5314761.23 |
> | 8777 -440.973 5314799.68 | 7792 -492.447 5314764.50 |
> | 8793 -396.362 5314830.17 | 9587 -484.412 5314769.99 |
> | 8808 -737.036 5314597.33 | 8491 -472.679 5314778.01 |
> | 8825 -303.512 5314893.63 | 8904 -468.260 5314781.03 |
> | 8841 -255.171 5314926.67 | 9317 -458.486 5314787.71 |
> | 8871 -970.785 5314437.57 | 9047 -447.250 5314795.39 |
> | 8872 -562.939 5314716.32 | 8777 -440.973 5314799.68 |
> | 8873 -154.361 5314995.57 | 7697 -430.586 5314806.78 |
> | 8889 -101.777 5315031.51 | 9730 -418.820 5314814.82 |
> | 8903 -888.104 5314494.08 | 7443 -408.216 5314822.07 |
> | 8904 -468.260 5314781.03 | 8253 -403.313 5314825.42 |
> | 8919 -844.913 5314523.60 | 8793 -396.362 5314830.17 |
> | 8935 -800.433 5314554.00 | 9063 -389.895 5314834.59 |
> | 8936 -367.890 5314849.63 | 9333 -378.190 5314842.59 |
> | 8951 -754.594 5314585.33 | 8936 -367.890 5314849.63 |
> | 8967 -707.335 5314617.63 | 8142 -360.488 5314854.69 |
> | 8968 -261.286 5314922.49 | 9603 -350.565 5314861.47 |
> | 8983 -658.598 5314650.94 | 7888 -341.848 5314867.43 |
> | 9000 -147.865 5315000.01 | 8682 -336.579 5314871.03 |
> | 9015 -556.355 5314720.82 | 9079 -330.551 5314875.15 |
> | 9030 -977.471 5314433.00 | 8031 -322.490 5314880.66 |
> | 9031 -502.702 5314757.49 | 9476 -315.392 5314885.51 |
> | 9032 -26.952 5315082.65 | 7777 -309.118 5314889.80 |
> | 9047 -447.250 5314795.39 | 8825 -303.512 5314893.63 |
> | 9062 -880.993 5314498.94 | 9349 -293.957 5314900.16 |
> | 9063 -389.895 5314834.59 | 8571 -286.087 5314905.54 |
> | 9079 -330.551 5314875.15 | 9222 -279.502 5314910.04 |
> | 9095 -269.114 5314917.14 | 9095 -269.114 5314917.14 |
> | 9126 -666.821 5314645.32 | 8968 -261.286 5314922.49 |
> | 9127 -139.481 5315005.74 | 8841 -255.171 5314926.67 |
> | 9143 -71.036 5315052.52 | 8714 -250.255 5314930.03 |
> | 9158 -547.532 5314726.85 | 8333 -240.028 5314937.02 |
> | 9159 0.013 5315101.08 | 7698 -230.489 5314943.54 |
> | 9189 -986.777 5314426.64 | 6301 -221.040 5314950.00 |
> | 9221 -870.970 5314505.79 | 0001 -213.719 5314955.00 |
> | 9222 -279.502 5314910.04 | 9873 -205.467 5314960.64 |
> | 9237 -809.431 5314547.85 | 0002 -199.087 5314965.00 |
> | 9253 -745.259 5314591.71 | 5952 -191.236 5314970.37 |
> | 9254 -128.259 5315013.41 | 7603 -181.446 5314977.06 |
> | 9269 -678.277 5314637.49 | 8238 -172.783 5314982.98 |
> | 9301 -535.095 5314735.35 | 8619 -163.755 5314989.15 |
> | 9317 -458.486 5314787.71 | 8873 -154.361 5314995.57 |
> | 9333 -378.190 5314842.59 | 9000 -147.865 5315000.01 |
> | 9348 -1000.603 5314417.19 | 9127 -139.481 5315005.74 |
> | 9349 -293.957 5314900.16 | 9254 -128.259 5315013.41 |
> | 9380 -855.827 5314516.14 | 8635 -121.061 5315018.33 |
> | 9381 -112.413 5315024.24 | 9381 -112.413 5315024.24 |
> | 9397 -14.413 5315091.22 | 8889 -101.777 5315031.51 |
> | 9412 -695.293 5314625.86 | 8397 -97.666 5315034.32 |
> | 9444 -516.279 5314748.21 | 9508 -88.388 5315040.66 |
> | 9476 -315.392 5314885.51 | 8651 -77.372 5315048.19 |
> | 9508 -88.388 5315040.66 | 9143 -71.036 5315052.52 |
> | 9539 -830.236 5314533.63 | 8413 -60.283 5315059.87 |
> | 9555 -723.253 5314606.75 | 7318 -55.120 5315063.40 |
> | 9587 -484.412 5314769.99 | 9635 -47.655 5315068.50 |
> | 9603 -350.565 5314861.47 | 7207 -40.474 5315073.41 |
> | 9635 -47.655 5315068.50 | 8667 -32.615 5315078.78 |
> | 9698 -777.681 5314569.55 | 9032 -26.952 5315082.65 |
> | 9730 -418.820 5314814.82 | 8429 -22.139 5315085.94 |
> | 9841 -930.036 5314465.42 | 9397 -14.413 5315091.22 |
> | 9857 -608.295 5314685.32 | 8556 -6.016 5315096.96 |
> | 9873 -205.467 5314960.64 | 9159 0.013 5315101.08 |
> +---------------------------+-----------------------------+
>
> --
> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG | TCP/IP since RFC 956
> FreeBSD committer | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
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