Re: [time-nuts] OT: Power level reference
In message c793a5fe0912012031k12893065w2682c6e74c920...@mail.gmail.com, Josep h Gray writes: I also found lots of Google hits for the AD8307. Within its limitations, this chip seems to be very popular. Please notice that most of these chips are intended for AGC purposes for transmitters, they very seldom have a frequency-flatness spec worth anything. -- 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.
Re: [time-nuts] OT: Power level reference
In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! I think you may find the option was best pulse response OR an increased 3dB frequency of 275 MHz. The difference is just an matter of adjusting the compensation in the vertical amp. The best pulse response in terms of least overshoot etc, also gives a flatter response in the pass band (which it should as this is effectively adjusting to give a pure Bessel response). The higher 3dB frequency version gave considerable overshoot on the pulse response, and a bumpier pass band. I was quite surprised to find quite HOW bumpy the pass band can be the first time I did a check on my 7904 using an SG504. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: 02 December 2009 01:31 To: Mike S Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: Power level reference I do. Very well, in fact. Unless you have swept a scope with a very well leveled sine generator, you are only guessing it is flat. That's WHY Tektronix sells BOTH fast rise Pulse Generators and Leveled Sine Generators. In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! -John At 07:00 PM 12/1/2009, J. Forster wrote... Scopes tend to have non-flat frequency response. I'd consider a precision load and something like an HP 3400A True RMS meter for up to a hunderd MHz or so. You have to know your equipment. I have a Tek 485 350 MHz analog scope, so I'm confident it's flat into VHF (at least beyond 100 MHz). I've verified it exceeds the 350 MHz spec (i.e. 3 db down @ 350 MHz) with a tunnel diode pulser. ___ 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] OT: Power level reference
Since a levelled generator requires a detector with a flat frequency response, calibrating a scope so that it can in turn be used to measure power is a somewhat circular process. In the 1970's NBS used a matched pair of schottky diode detectors mounted in the same temperature controlled heatsink to compare RF and dc signals. David C. Partridge wrote: In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! I think you may find the option was best pulse response OR an increased 3dB frequency of 275 MHz. The difference is just an matter of adjusting the compensation in the vertical amp. The best pulse response in terms of least overshoot etc, also gives a flatter response in the pass band (which it should as this is effectively adjusting to give a pure Bessel response). The higher 3dB frequency version gave considerable overshoot on the pulse response, and a bumpier pass band. I was quite surprised to find quite HOW bumpy the pass band can be the first time I did a check on my 7904 using an SG504. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: 02 December 2009 01:31 To: Mike S Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: Power level reference I do. Very well, in fact. Unless you have swept a scope with a very well leveled sine generator, you are only guessing it is flat. That's WHY Tektronix sells BOTH fast rise Pulse Generators and Leveled Sine Generators. In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! -John At 07:00 PM 12/1/2009, J. Forster wrote... Scopes tend to have non-flat frequency response. I'd consider a precision load and something like an HP 3400A True RMS meter for up to a hunderd MHz or so. You have to know your equipment. I have a Tek 485 350 MHz analog scope, so I'm confident it's flat into VHF (at least beyond 100 MHz). I've verified it exceeds the 350 MHz spec (i.e. 3 db down @ 350 MHz) with a tunnel diode pulser. ___ 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] OT: Power level reference
In message 4b163ca2.7090...@xtra.co.nz, Bruce Griffiths writes: Since a levelled generator requires a detector with a flat frequency response, [...] This is usually done with a built in thermal converter, like in the HP3335 and HP3336 products. -- 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.
Re: [time-nuts] Jupiter GPS Question
Talking of which, I have been wondering if our beloved Thunderbolts could handle WAAS/EGNOS. I can't see any way to configure the current software - doubtless an upgrade would be required, but does the hardware have the capability? Does anybody have any thoughts? TTFN, Peter 2009/12/1 Magnus Danielson mag...@rubidium.dyndns.org: David Pritchard wrote: Hi, I am trying to add DGPS capability to an older Rockwell Jupiter GPS module. I have a known good DGPS receiver and have tried to interface it to the Jupiter via Serial Port 2 (pin #15). So far, I have had no luck making it work. I'm wondering whether I need to tell the Jupiter that I have a DGPS unit attached, using the binary commands (which I have no clue how to do since I normally use the NMEA mode). Any help would be greatly appreciated. You should have this document in your hands anyway: http://gpsd.berlios.de/vendor-docs/jupiter/MN002000A_JupiterReceiver_DesignerGuide_print.pdf Digital protocol, DGPS... well most things. Cheers, Magnus ___ 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. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ 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] Jupiter GPS Question
SBAS (WAAS/EGNOS/etc) use L1 carrier frequency and compatible PRN codes, but the datamessage goes at a higher rate (200bps (?)) than the normal GPS which uses 50 bits per second. This means that most receiver will have added dedicated/modified hardware for SBAS signals reception. -- Björn Talking of which, I have been wondering if our beloved Thunderbolts could handle WAAS/EGNOS. I can't see any way to configure the current software - doubtless an upgrade would be required, but does the hardware have the capability? Does anybody have any thoughts? TTFN, Peter 2009/12/1 Magnus Danielson mag...@rubidium.dyndns.org: David Pritchard wrote: Hi, I am trying to add DGPS capability to an older Rockwell Jupiter GPS module. I have a known good DGPS receiver and have tried to interface it to the Jupiter via Serial Port 2 (pin #15). So far, I have had no luck making it work. I'm wondering whether I need to tell the Jupiter that I have a DGPS unit attached, using the binary commands (which I have no clue how to do since I normally use the NMEA mode). Any help would be greatly appreciated. You should have this document in your hands anyway: http://gpsd.berlios.de/vendor-docs/jupiter/MN002000A_JupiterReceiver_DesignerGuide_print.pdf Digital protocol, DGPS... well most things. Cheers, Magnus ___ 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. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ 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] OT: Power level reference
Hi The accuracy / flatness of the detector is only one part of the problem. In an RF system, the match to the detector can be a significant part of the error. If some of the power is reflected it messes up the reading Bob On Dec 2, 2009, at 5:12 AM, Poul-Henning Kamp wrote: In message 4b163ca2.7090...@xtra.co.nz, Bruce Griffiths writes: Since a levelled generator requires a detector with a flat frequency response, [...] This is usually done with a built in thermal converter, like in the HP3335 and HP3336 products. -- 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 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] OT: Power level reference
In message ba422cf5-53f0-443c-8ad1-edc91a584...@cq.nu, Bob Camp writes: The accuracy / flatness of the detector is only one part of the problem. In an RF system, the match to the detector can be a significant part of the error. If some of the power is reflected it messes up the reading No disagreement from here on that. What I played with, was a 50 Ohm termination a rotating mechanical shutter and a IR sensor to see if it would be possible to level three different frequencies to the same power-level, for calibration of a HP3458A. For this particular _relative_ power measurement, I think the method has merits, it it may be possible to use it to calibrate relative to DC as well, thus making the calibration absolute, but I need to work on the mechanical setup some more. -- 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.
Re: [time-nuts] OT: Power level reference
At 12:30 AM 12/2/2009, J. Forster wrote... [re: tek 7704] Really? The most successful 'scope in history. Odd, since Tek themselves has called the 2200 series the most successful oscilloscopes in the world. And, they were contemporaneous with the 7704A. Sure, you can buy an uncalibrated 3400A (good to ~150W), and get some unknown amount worse than 5% accuracy. Apparently, you don't know what an HP 3400A is. Apparently, neither does HP, since you appear to also disagree with the specifications given in HP's datasheet (Meter accuracy 5% @3-10 MHz)? (I'll admit I made an err with the watts - I looked at the dbm spec) http://www.teknetelectronics.com/DataSheet/HP_AGILENT/HP__3400A.pdf Stick to political blogs. You amaze yourself. But, I won't get in a pissing match with someone who makes things up, gives snide and vague rebuttals, provides no references, and feels a need to make personal attacks. Buh-bye! ___ 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] OT: Power level reference
At 02:00 AM 12/2/2009, J. Forster wrote... Yeah... I got the model number wrong. I meant the 3403. Digtal, true RMS. Oh, well, in that case - 10% accuracy @ 100 MHz, max 1 V RMS (20 mW @ 50 Ohm). Or, you could measure 200W @ 1%, if the frequency is 1MHz. ___ 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] OT: Power level reference
On 12/2/09 12:01 AM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message c793a5fe0912012031k12893065w2682c6e74c920...@mail.gmail.com, Josep h Gray writes: I also found lots of Google hits for the AD8307. Within its limitations, this chip seems to be very popular. Please notice that most of these chips are intended for AGC purposes for transmitters, they very seldom have a frequency-flatness spec worth anything The 8307 and it's ilk are actually quite flat over frequency. Real broadband amplifiers in the log chain. Is it 0.1dB flat? I don't think so, and in an case, layout might give you more ripple than that. But certainly better than 0.5dB practically. The 8307 datasheet says 0.3dB typical for the middle 80dB range for frequencies less than 100MHz, and I'd believe that, based on the ones I've seen hooked up. That's about 1/10th of the -3dB frequency for the logamps in the chain, so they're quite flat. Specs on a logamp are tricky to evaluate against a square law or linear detector because it's tough to know if it's the log function or the basic detection that's at issue. For the thermistor mount, you're lucky to get 30dB dynamic range AND the accuracy will be worse at the bottom end, because a good portion of the measurement uncertainty is fixed, not a fraction of the input. For a diode detector, the newer meters know the cal curve of the diode, so they're not depending on the squarelaw characteristic, and you get maybe 50dB dynamic range, but again, the accuracy at the low end is worse than the high end. I wonder (just haven't looked til now) what they're using inside those USB power heads (e.g. MiniCircuits)... Is it a AD8307 type widget or a diode? ___ 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] OT: Power level reference
Not me. I've repaired and calibrated a lot of 7000 stuff for my lab. That was the point of my earlier posts, where it was asserted that a good pulse response indicated frequency flatness for power measurement. It does NOT! -John == In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! I think you may find the option was best pulse response OR an increased 3dB frequency of 275 MHz. The difference is just an matter of adjusting the compensation in the vertical amp. The best pulse response in terms of least overshoot etc, also gives a flatter response in the pass band (which it should as this is effectively adjusting to give a pure Bessel response). The higher 3dB frequency version gave considerable overshoot on the pulse response, and a bumpier pass band. I was quite surprised to find quite HOW bumpy the pass band can be the first time I did a check on my 7904 using an SG504. Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster Sent: 02 December 2009 01:31 To: Mike S Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: Power level reference I do. Very well, in fact. Unless you have swept a scope with a very well leveled sine generator, you are only guessing it is flat. That's WHY Tektronix sells BOTH fast rise Pulse Generators and Leveled Sine Generators. In fact, on the Tek 7704 or 7704A (I forget which) there were No Cost options of maximally flat frequency response OR best pulse response. OR! -John At 07:00 PM 12/1/2009, J. Forster wrote... Scopes tend to have non-flat frequency response. I'd consider a precision load and something like an HP 3400A True RMS meter for up to a hunderd MHz or so. You have to know your equipment. I have a Tek 485 350 MHz analog scope, so I'm confident it's flat into VHF (at least beyond 100 MHz). I've verified it exceeds the 350 MHz spec (i.e. 3 db down @ 350 MHz) with a tunnel diode pulser. ___ 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] OT: Power level reference
Have you looked at a Dickie (?sp) Switch? -John === In message ba422cf5-53f0-443c-8ad1-edc91a584...@cq.nu, Bob Camp writes: The accuracy / flatness of the detector is only one part of the problem. In an RF system, the match to the detector can be a significant part of the error. If some of the power is reflected it messes up the reading No disagreement from here on that. What I played with, was a 50 Ohm termination a rotating mechanical shutter and a IR sensor to see if it would be possible to level three different frequencies to the same power-level, for calibration of a HP3458A. For this particular _relative_ power measurement, I think the method has merits, it it may be possible to use it to calibrate relative to DC as well, thus making the calibration absolute, but I need to work on the mechanical setup some more. -- 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 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] Jupiter GPS Question
Thanks Bjorn - I was afraid of that! TTFN, Peter 2009/12/2 b...@lysator.liu.se: SBAS (WAAS/EGNOS/etc) use L1 carrier frequency and compatible PRN codes, but the datamessage goes at a higher rate (200bps (?)) than the normal GPS which uses 50 bits per second. This means that most receiver will have added dedicated/modified hardware for SBAS signals reception. -- Björn Talking of which, I have been wondering if our beloved Thunderbolts could handle WAAS/EGNOS. I can't see any way to configure the current software - doubtless an upgrade would be required, but does the hardware have the capability? Does anybody have any thoughts? TTFN, Peter 2009/12/1 Magnus Danielson mag...@rubidium.dyndns.org: David Pritchard wrote: Hi, I am trying to add DGPS capability to an older Rockwell Jupiter GPS module. I have a known good DGPS receiver and have tried to interface it to the Jupiter via Serial Port 2 (pin #15). So far, I have had no luck making it work. I'm wondering whether I need to tell the Jupiter that I have a DGPS unit attached, using the binary commands (which I have no clue how to do since I normally use the NMEA mode). Any help would be greatly appreciated. You should have this document in your hands anyway: http://gpsd.berlios.de/vendor-docs/jupiter/MN002000A_JupiterReceiver_DesignerGuide_print.pdf Digital protocol, DGPS... well most things. Cheers, Magnus ___ 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. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ 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. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ 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] Jupiter GPS Question
b...@lysator.liu.se wrote: SBAS (WAAS/EGNOS/etc) use L1 carrier frequency and compatible PRN codes, but the datamessage goes at a higher rate (200bps (?)) than the normal GPS which uses 50 bits per second. This means that most receiver will have added dedicated/modified hardware for SBAS signals reception. SBAS uses a 500 symbol rate signal which uses the standard JPL 1/2 rate Convolution Encoder (actually not using the output inverter of the JPL convolution encode) for a 250 b/s stream. This requires a Viterbi decoder. However, it requires no extra hardware, but just a normal digital frontend, it just needs to support the SBAS C/A codes which many if not most frontends support. Dumping each milisecond works well enought. No, all it takes is additional software for SBAS symbol alignment, symbol-pair-alignment, viterbi-decoding, and the SBAS frame-structure decoding etc. Very similar to normal L1 C/A processing. Then comes the SBAS processing which hooks into the normal processing. It's not trivial, but not that complex either. A viterbi-decoder takes about 100-200 lines of C code. The SBAS processing takes up more. Cheers, Magnus ___ 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] OT: Power level reference
Hi I think that spending some time with a *good* reflection bridge at the specific frequencies of interest would be time well spent. Of course that heads us of to the subject OT: 50 ohm Standard Reference. I have some nice HP cal kits running around, but none of them really agree with each other without going back to the calibration data. For low frequencies you can do pretty well with a set of precision thin film SMT resistors. They fall apart as frequency heads up past a few hundred MHZ. Bob On Dec 2, 2009, at 7:47 AM, Poul-Henning Kamp wrote: In message ba422cf5-53f0-443c-8ad1-edc91a584...@cq.nu, Bob Camp writes: The accuracy / flatness of the detector is only one part of the problem. In an RF system, the match to the detector can be a significant part of the error. If some of the power is reflected it messes up the reading No disagreement from here on that. What I played with, was a 50 Ohm termination a rotating mechanical shutter and a IR sensor to see if it would be possible to level three different frequencies to the same power-level, for calibration of a HP3458A. For this particular _relative_ power measurement, I think the method has merits, it it may be possible to use it to calibrate relative to DC as well, thus making the calibration absolute, but I need to work on the mechanical setup some more. -- 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 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] OT: Power level reference
Bob Camp wrote: Hi I think that spending some time with a *good* reflection bridge at the specific frequencies of interest would be time well spent. Of course that heads us of to the subject OT: 50 ohm Standard Reference. I have some nice HP cal kits running around, but none of them really agree with each other without going back to the calibration data. For low frequencies you can do pretty well with a set of precision thin film SMT resistors. They fall apart as frequency heads up past a few hundred MHZ. An even more hairpulling aspect is 75 Ohm BNC kits into several GHz. Doing networks analysis under those conditions isn't as safe ground as the 50 Ohm would be. Oh... yes, I do need to measure RL on BNC and over several GHz for 75 Ohm systems. Luckilly that isn't in my private lab. Cheers, Magnus ___ 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] z3801a gps signal reflection and EFC woes
Hi guys, I wonder if anyone has ever replaced the 1PPS output of the oncore with an external 1PPS from say an M12M receiver. I would suspect all else being the same that the Z3801A would work much better, and not have the problems Mike is seeing? bye, Said In a message dated 12/2/2009 04:46:58 Pacific Standard Time, michael.c...@wanadoo.fr writes: You can see that the EFC immediately tries to follow the value calculated during the incident, regardless of any historical data the box is holding, if any. I haven't yet checked to see how much the violent swing in EFC effects the 10MHz output, but I suppose there must be some. I have tried 2 different VPs , but they appear to be suffering the same issue. Both have different firmware levels. Anyone seen this and know of a way of limiting the effect? I have thought about moving the Z3801A to my south balcony, where I shouldn't see so many reflections, or better, to the appartment roof, but that needs permission from the management. Mike ___ 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.
