[time-nuts] neon/nixie clock
Can't recall this clock been mentioned on timenuts before: http://wwwhome.cs.utwente.nl/~ptdeboer/ham/neonclock/ -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] neon/nixie clock
Poul-Henning Kamp- Can't recall this clock been mentioned on timenuts before: http://wwwhome.cs.utwente.nl/~ptdeboer/ham/neonclock/; __ Actually the idea isn't that unique and anyone who remembers the decatron tubes have seen the entire decade built into a single tube that performed both counting and display functions. Here is a link to a clock project using decatron tubes. http://www.dos4ever.com/decatron/decatronweb.html#decatron -Arthur ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] GPS antenna distribution from a DTV multi switch
Have been using a sat passive splitter and most of my cables are using F connectors so I'm thinking of modifying a DTV multi switch to provide 5 volts instead of 13 volts on the LNB/antenna port. Antenna is a Trimble bullet II 5 volt antenna. The switch is active and I would ignore the 22Khz and 18V inputs, just need the extra outputs and amplification. I've opened it up and it ( a eagle aspen DTV4X8 ) has two lm317's maybe for 18 and 13 volts as well as a ua78m06 for the amps and volt/22Khz switches. options: 1) add a 78m05 for the GPS antenna between the 13 volt supply and the RF choke (my first choice) 2) adjust the 13 volt lm317 regulator to 5 volts by adding a resistor in parallel with the existing resistor 3) cut the 13 volt feed and add a diode .7 volt drop from the 6 volt supply Please let me know what you think. I have read the 50 ohm vs 75 ohm cable discussions and due to cost and ease of using f-connectors will live with the mismatches for now. Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 11729C versus 11848A
Thanks to Rick's great hint, I'm now awaiting some AM123 amps to arrive. Why is it that I just don't get better than -165...-170 dBc/Hz? Let me try some simple math: At L and R levels of +7.5 dBm (that's what come out of my 10811's), subtract some 7.5 dB mixer conversion loss to see that 0 dBc would be exactly 0 dBm at the mixer output. (The calibration is performed with the R signal decreased by 40 db. At the 40 dB LNA output, I'm measuring pretty exactly 0 dBm.) At room temperature, the thermal noise is -174 dBm/Hz. Add some 4 dB for the LNA noise figure and LPF insertion loss, so the system noise floor is at -170 dBm/Hz. Give or take a dB, but that's pretty much about it. Now, with the calibrated carrier level of 0 dBm at the LNA input, the residual noise floor is -170 dBm/Hz -(+0 dBm) = -170 dBc/Hz A modern RF spectrum anylyzer has a noise figure in the 15 dB range, add 10 dB of 'safety' attenuation, so the analyzer noise floor is -174 dBm/Hz -(+25 dB) = -149 dBm/Hz. Remember that the mixer output / LNA input of -170 dBm/Hz is amplified by the LNA by 40 dB, so the analyzer input 'noise signal' from the test set is -170 dBm/Hz + 40 dB = -130 dBm/Hz, which is 19 dB above the analyzer's noise. If we increase the L and R levels by 15 dB, we need a +23 dBm mixer, but we will add 15 dB to the system dynamic range. The mixer conversion loss, LNA noise figure and thermal noise floor haven't changed, so the noise floor in dBm is still the same -170 dBm/Hz, but we're now refering to a carrier level of +22.5 dBm instead of the above +7.5 dBm (+15 dBm versus 0 dBm at the mixer output). That's why we can now measure down to -170 dBm/Hz -(+15 dBm) = -185 dBc/Hz. Adrian John Miles schrieb: That sounds about right to me. I was guessing you meant 40 dB and not 30 dB in the previous message, or there was something else causing about 10 dB of loss. Lots of things to go wrong in this process! -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Adrian Sent: Friday, May 07, 2010 10:38 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 11729C versus 11848A Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor at the input don't make that filter such a great solution ;-) So, I brewed something better together... The 10 kHz beat note is now near 0 dBm when the R input signal is decreased by 40 dB, which makes a lot more sense than before... And, I have a noise floor of some -165 to -169 dBc/Hz at +7.5 dBm input, and I'm seeing the 10811A's some 5 dB above that. Adrian John Miles schrieb: John, I'd say you nailed it. After some more testing, I can confirm that the limiter amp and the LPF are the culprit. I opened the box and plugged directly into the mixer LO port. And, for the LPF, as a quick 'n dirty solution, I connected the 1 MHz front panel output with the LNA input. Now, at 10 dBm each into the mixer ports, I'm getting a noise floor of -145 dBc/Hz at 100 Hz and about -170 dBc/Hz at 10 kHz and above. That's pretty aggressive for 10811s. The floor on those is usually around -165 dBc/Hz. How's your calibration process -- are you accounting for the 600 ohm output Z of the 1 MHz output port? It'll lose a few dB if you try to drive 50 ohms with it, and/or the filter response won't be correct. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 11729C versus 11848A
Minus the 6 dB L(f) conversion factor, so we get theoretical L(f) noise floors of -176 dBc/Hz and -191 dBc/Hz. Adrian Adrian schrieb: Thanks to Rick's great hint, I'm now awaiting some AM123 amps to arrive. Why is it that I just don't get better than -165...-170 dBc/Hz? Let me try some simple math: At L and R levels of +7.5 dBm (that's what come out of my 10811's), subtract some 7.5 dB mixer conversion loss to see that 0 dBc would be exactly 0 dBm at the mixer output. (The calibration is performed with the R signal decreased by 40 db. At the 40 dB LNA output, I'm measuring pretty exactly 0 dBm.) At room temperature, the thermal noise is -174 dBm/Hz. Add some 4 dB for the LNA noise figure and LPF insertion loss, so the system noise floor is at -170 dBm/Hz. Give or take a dB, but that's pretty much about it. Now, with the calibrated carrier level of 0 dBm at the LNA input, the residual noise floor is -170 dBm/Hz -(+0 dBm) = -170 dBc/Hz A modern RF spectrum anylyzer has a noise figure in the 15 dB range, add 10 dB of 'safety' attenuation, so the analyzer noise floor is -174 dBm/Hz -(+25 dB) = -149 dBm/Hz. Remember that the mixer output / LNA input of -170 dBm/Hz is amplified by the LNA by 40 dB, so the analyzer input 'noise signal' from the test set is -170 dBm/Hz + 40 dB = -130 dBm/Hz, which is 19 dB above the analyzer's noise. If we increase the L and R levels by 15 dB, we need a +23 dBm mixer, but we will add 15 dB to the system dynamic range. The mixer conversion loss, LNA noise figure and thermal noise floor haven't changed, so the noise floor in dBm is still the same -170 dBm/Hz, but we're now refering to a carrier level of +22.5 dBm instead of the above +7.5 dBm (+15 dBm versus 0 dBm at the mixer output). That's why we can now measure down to -170 dBm/Hz -(+15 dBm) = -185 dBc/Hz. Adrian John Miles schrieb: That sounds about right to me. I was guessing you meant 40 dB and not 30 dB in the previous message, or there was something else causing about 10 dB of loss. Lots of things to go wrong in this process! -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Adrian Sent: Friday, May 07, 2010 10:38 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 11729C versus 11848A Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor at the input don't make that filter such a great solution ;-) So, I brewed something better together... The 10 kHz beat note is now near 0 dBm when the R input signal is decreased by 40 dB, which makes a lot more sense than before... And, I have a noise floor of some -165 to -169 dBc/Hz at +7.5 dBm input, and I'm seeing the 10811A's some 5 dB above that. Adrian John Miles schrieb: John, I'd say you nailed it. After some more testing, I can confirm that the limiter amp and the LPF are the culprit. I opened the box and plugged directly into the mixer LO port. And, for the LPF, as a quick 'n dirty solution, I connected the 1 MHz front panel output with the LNA input. Now, at 10 dBm each into the mixer ports, I'm getting a noise floor of -145 dBc/Hz at 100 Hz and about -170 dBc/Hz at 10 kHz and above. That's pretty aggressive for 10811s. The floor on those is usually around -165 dBc/Hz. How's your calibration process -- are you accounting for the 600 ohm output Z of the 1 MHz output port? It'll lose a few dB if you try to drive 50 ohms with it, and/or the filter response won't be correct. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP 53132A VFD
All, I know this question comes up occasionally but has anyone discovered a source for replacement Vacuum Florescent Displays (VFT) for the 53132A counter? As I understand, these are HP/Agilent p/n 5040-0023, Samsung p/n INB-12MM53T. Rick W2GPS ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP 11729C versus 11848A
Hi Just to be picky: You get 6 db for SSB to DSB when you are looking at a modulation effect (correlated sidebands) and 3 db when you are looking at random noise (un-correlated sidebands). If both oscillators contribute equally, you get a 3 db factor. The total can be anywhere from 3 db to 9 db depending on the situation. I'm sure glad I'm out of rock throwing range Bob On May 8, 2010, at 5:33 PM, Adrian wrote: Minus the 6 dB L(f) conversion factor, so we get theoretical L(f) noise floors of -176 dBc/Hz and -191 dBc/Hz. Adrian Adrian schrieb: Thanks to Rick's great hint, I'm now awaiting some AM123 amps to arrive. Why is it that I just don't get better than -165...-170 dBc/Hz? Let me try some simple math: At L and R levels of +7.5 dBm (that's what come out of my 10811's), subtract some 7.5 dB mixer conversion loss to see that 0 dBc would be exactly 0 dBm at the mixer output. (The calibration is performed with the R signal decreased by 40 db. At the 40 dB LNA output, I'm measuring pretty exactly 0 dBm.) At room temperature, the thermal noise is -174 dBm/Hz. Add some 4 dB for the LNA noise figure and LPF insertion loss, so the system noise floor is at -170 dBm/Hz. Give or take a dB, but that's pretty much about it. Now, with the calibrated carrier level of 0 dBm at the LNA input, the residual noise floor is -170 dBm/Hz -(+0 dBm) = -170 dBc/Hz A modern RF spectrum anylyzer has a noise figure in the 15 dB range, add 10 dB of 'safety' attenuation, so the analyzer noise floor is -174 dBm/Hz -(+25 dB) = -149 dBm/Hz. Remember that the mixer output / LNA input of -170 dBm/Hz is amplified by the LNA by 40 dB, so the analyzer input 'noise signal' from the test set is -170 dBm/Hz + 40 dB = -130 dBm/Hz, which is 19 dB above the analyzer's noise. If we increase the L and R levels by 15 dB, we need a +23 dBm mixer, but we will add 15 dB to the system dynamic range. The mixer conversion loss, LNA noise figure and thermal noise floor haven't changed, so the noise floor in dBm is still the same -170 dBm/Hz, but we're now refering to a carrier level of +22.5 dBm instead of the above +7.5 dBm (+15 dBm versus 0 dBm at the mixer output). That's why we can now measure down to -170 dBm/Hz -(+15 dBm) = -185 dBc/Hz. Adrian John Miles schrieb: That sounds about right to me. I was guessing you meant 40 dB and not 30 dB in the previous message, or there was something else causing about 10 dB of loss. Lots of things to go wrong in this process! -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Adrian Sent: Friday, May 07, 2010 10:38 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP 11729C versus 11848A Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor at the input don't make that filter such a great solution ;-) So, I brewed something better together... The 10 kHz beat note is now near 0 dBm when the R input signal is decreased by 40 dB, which makes a lot more sense than before... And, I have a noise floor of some -165 to -169 dBc/Hz at +7.5 dBm input, and I'm seeing the 10811A's some 5 dB above that. Adrian John Miles schrieb: John, I'd say you nailed it. After some more testing, I can confirm that the limiter amp and the LPF are the culprit. I opened the box and plugged directly into the mixer LO port. And, for the LPF, as a quick 'n dirty solution, I connected the 1 MHz front panel output with the LNA input. Now, at 10 dBm each into the mixer ports, I'm getting a noise floor of -145 dBc/Hz at 100 Hz and about -170 dBc/Hz at 10 kHz and above. That's pretty aggressive for 10811s. The floor on those is usually around -165 dBc/Hz. How's your calibration process -- are you accounting for the 600 ohm output Z of the 1 MHz output port? It'll lose a few dB if you try to drive 50 ohms with it, and/or the filter response won't be correct. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna distribution from a DTV multi switch
I've opened it up and it ( a eagle aspen DTV4X8 ) has two lm317's maybe for 18 and 13 volts as well as a ua78m06 for the amps and volt/22Khz switches. Pictures here : www.n4iqt.com/dtv4x8 Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna distribution from a DTV multi switch
Hi There's a *lot* ore in there than in a normal GPS splitter. Bob On May 8, 2010, at 8:24 PM, Stanley Reynolds wrote: I've opened it up and it ( a eagle aspen DTV4X8 ) has two lm317's maybe for 18 and 13 volts as well as a ua78m06 for the amps and volt/22Khz switches. Pictures here : www.n4iqt.com/dtv4x8 Stanley ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS antenna distribution from a DTV multi switch
Yes, not using most of it. Has a 22khz tone and voltage level detector for all 8 outputs I don't need, but my cost with power brick was $10, ebay has them under $20 now. Stanley - Original Message From: Bob Camp li...@rtty.us To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Sat, May 8, 2010 7:53:02 PM Subject: Re: [time-nuts] GPS antenna distribution from a DTV multi switch Hi There's a *lot* ore in there than in a normal GPS splitter. Bob snip ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
