Re: Digest for sark110@googlegroups.com - 10 updates in 2 topics

[Edward Mccann]

My experience with noisy signals has in every case ended up with a connector failure, Coax issue , or poor connection to ground. Nothing has led to the Sark-110.

Run those items thru the mill and see what happens.

Ed McCann

AG6CX

Sent from my iPhone

On Apr 28, 2020, at 1:56 AM, sar...@googlegroups.com wrote:

sar...@googlegroups.com

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• Noisy Input Problem - 9 Updates
• L and C measurements - 1 Update

Noisy Input Problem

k3gau Dave <k3g...@gmail.com>: Apr 27 09:25AM -0700 GM,   I had noticed what seemed to be "a noisy input" problem even before I had Steve repair my SARK 110. So his repair had NOTHING to do with the problem.   It doesn't seem to act right then it is looking at an the open circuit. It does seem to read a short, 50 ohm, 100 ohm and 200 ohm loads across its bandwidth just fine. But looking at an open, it sometimes reads out some negative resistances, etc. when measuring 'RS' and plots them on the screen as well. The problem seems worse at the higher end of the spectrum when scanning the full 230 MHz range. As I recall, when I first got my unit, open circuit 'RS' was always full scale, a high value (in the kOhms) and never a negative. I have gone through the detector check and calibration procedures. They seemed to be about normal.   Any idea what could be causing the problem? Bad component, bad solder joint?   Dave

<melchor...@gmail.com>: Apr 27 06:33PM +0200 Hello Dave,     Could you please save a scan for the open circuit condition (connecting the same open load as the used for calibration) and send to me for analysis? Also, it will be helpful if you send me the calibration files.     Thanks,   Melchor EA4FRB     De: sar...@googlegroups.com <sar...@googlegroups.com> En nombre de k3gau Dave Enviado el: lunes, 27 de abril de 2020 18:25 Para: sark110 <sar...@googlegroups.com> Asunto: Noisy Input Problem     GM,     I had noticed what seemed to be "a noisy input" problem even before I had Steve repair my SARK 110. So his repair had NOTHING to do with the problem.     It doesn't seem to act right then it is looking at an the open circuit. It does seem to read a short, 50 ohm, 100 ohm and 200 ohm loads across its bandwidth just fine. But looking at an open, it sometimes reads out some negative resistances, etc. when measuring 'RS' and plots them on the screen as well. The problem seems worse at the higher end of the spectrum when scanning the full 230 MHz range. As I recall, when I first got my unit, open circuit 'RS' was always full scale, a high value (in the kOhms) and never a negative. I have gone through the detector check and calibration procedures. They seemed to be about normal.     Any idea what could be causing the problem? Bad component, bad solder joint?     Dave   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sark110+u...@googlegroups.com <mailto:sark110+u...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/1eda21ed-7150-417d-91a1-7739a5253e53%40googlegroups.com <https://groups.google.com/d/msgid/sark110/1eda21ed-7150-417d-91a1-7739a5253e53%40googlegroups.com?utm_medium=email&utm_source=footer> .

k3gau Dave <k3g...@gmail.com>: Apr 27 10:24AM -0700 Melcor, What files are looking for? (name) Dave   On Monday, April 27, 2020 at 12:33:41 PM UTC-4, EA4FRB wrote:

<melchor...@gmail.com>: Apr 27 07:29PM +0200 The calibration .dat files, e.g. detcalib.dat, oslcalib.dat, oslprof1.dat; and a saved .csv file for the sweep scan with the open load (select <File> <Save Data File> after completing the scan).     Thanks,   Melchor     De: sar...@googlegroups.com <sar...@googlegroups.com> En nombre de k3gau Dave Enviado el: lunes, 27 de abril de 2020 19:25 Para: sark110 <sar...@googlegroups.com> Asunto: Re: Noisy Input Problem     Melcor,   What files are looking for? (name)   Dave   On Monday, April 27, 2020 at 12:33:41 PM UTC-4, EA4FRB wrote:   Hello Dave,     Could you please save a scan for the open circuit condition (connecting the same open load as the used for calibration) and send to me for analysis? Also, it will be helpful if you send me the calibration files.     Thanks,   Melchor EA4FRB     De: sar...@googlegroups.com <javascript:> <sar...@googlegroups.com <javascript:> > En nombre de k3gau Dave Enviado el: lunes, 27 de abril de 2020 18:25 Para: sark110 <sar...@googlegroups.com <javascript:> > Asunto: Noisy Input Problem     GM,     I had noticed what seemed to be "a noisy input" problem even before I had Steve repair my SARK 110. So his repair had NOTHING to do with the problem.     It doesn't seem to act right then it is looking at an the open circuit. It does seem to read a short, 50 ohm, 100 ohm and 200 ohm loads across its bandwidth just fine. But looking at an open, it sometimes reads out some negative resistances, etc. when measuring 'RS' and plots them on the screen as well. The problem seems worse at the higher end of the spectrum when scanning the full 230 MHz range. As I recall, when I first got my unit, open circuit 'RS' was always full scale, a high value (in the kOhms) and never a negative. I have gone through the detector check and calibration procedures. They seemed to be about normal.     Any idea what could be causing the problem? Bad component, bad solder joint?     Dave   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sar...@googlegroups.com <javascript:> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/1eda21ed-7150-417d-91a1-7739a5253e53%40googlegroups.com <https://groups.google.com/d/msgid/sark110/1eda21ed-7150-417d-91a1-7739a5253e53%40googlegroups.com?utm_medium=email&utm_source=footer> .   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sark110+u...@googlegroups.com <mailto:sark110+u...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/b9940772-5794-4697-a133-b87d1a8a1649%40googlegroups.com <https://groups.google.com/d/msgid/sark110/b9940772-5794-4697-a133-b87d1a8a1649%40googlegroups.com?utm_medium=email&utm_source=footer> .

k3gau Dave <k3g...@gmail.com>: Apr 27 10:35AM -0700 On Monday, April 27, 2020 at 12:33:41 PM UTC-4, EA4FRB wrote:

k3gau Dave <k3g...@gmail.com>: Apr 27 10:40AM -0700 Melchor,   I think I sent all files you ask for and probably a couple you don't need. SARK 1, SARK 2 and SARK 3 are three different shots of my screen taken within a few minutes.   Dave   On Monday, April 27, 2020 at 12:25:06 PM UTC-4, k3gau Dave wrote:

<melchor...@gmail.com>: Apr 27 09:44PM +0200 Thank you for the files. I don’t see a problem with these readings and the cal files. When there is no load connected, it is possible to get negative Rs readings influenced by noise because the error is high when the load is close to the infinity. Also, there is the influence of the used open load for the OSL calibration.     Best regards,   Melchor EA4FRB     De: sar...@googlegroups.com <sar...@googlegroups.com> En nombre de k3gau Dave Enviado el: lunes, 27 de abril de 2020 19:40 Para: sark110 <sar...@googlegroups.com> Asunto: Re: Noisy Input Problem     Melchor,     I think I sent all files you ask for and probably a couple you don't need. SARK 1, SARK 2 and SARK 3 are three different shots of my screen taken within a few minutes.     Dave   On Monday, April 27, 2020 at 12:25:06 PM UTC-4, k3gau Dave wrote:   GM,     I had noticed what seemed to be "a noisy input" problem even before I had Steve repair my SARK 110. So his repair had NOTHING to do with the problem.     It doesn't seem to act right then it is looking at an the open circuit. It does seem to read a short, 50 ohm, 100 ohm and 200 ohm loads across its bandwidth just fine. But looking at an open, it sometimes reads out some negative resistances, etc. when measuring 'RS' and plots them on the screen as well. The problem seems worse at the higher end of the spectrum when scanning the full 230 MHz range. As I recall, when I first got my unit, open circuit 'RS' was always full scale, a high value (in the kOhms) and never a negative. I have gone through the detector check and calibration procedures. They seemed to be about normal.     Any idea what could be causing the problem? Bad component, bad solder joint?     Dave   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sark110+u...@googlegroups.com <mailto:sark110+u...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/3eeb8866-8bca-4938-a40b-ced41b7dea9b%40googlegroups.com <https://groups.google.com/d/msgid/sark110/3eeb8866-8bca-4938-a40b-ced41b7dea9b%40googlegroups.com?utm_medium=email&utm_source=footer> .

k3gau Dave <k3g...@gmail.com>: Apr 27 04:16PM -0700 GE Melchor,   Have you plotted those Sark files? I would like to send you a picture of the SARK screen but my cellphone is not working. Maybe I can use my other camera. I can save a file with the 'open' removed and just the open connector on the input.   In any case, I don't remember my screen looking that when it was new.   I got them with my other camera. Does that look normal for an 'OPEN' condition?   Dave K3GAU   On Monday, April 27, 2020 at 3:45:04 PM UTC-4, EA4FRB wrote:

<melchor...@gmail.com>: Apr 28 08:13AM +0200 Hello Dave,     Yes, I have plotted those files. Note that the ripples are more or less visible depending on the selected scale: fixed or automatic; or logarithmic (default) or linear. Please find below some pics for comparing.     The fact is that for the open condition it is possible to get negative readings of Rs due to the increased error close to infinity and influenced by the noise. This effect can be reduced by using averaging and/or double sampling, and calibrating w/o a computer connected.         Figure 1, sark__01.csv, logarithmic scale, auto-scale         Figure 2, sark__01.csv, linear scale, auto-scale         Figure 3, sark__01.csv, linear scale, auto-scale (SARK_Plots)       Figure 4, sark__01.csv, smith chart   Best regards,   Melchor EA4FRB     De: sar...@googlegroups.com <sar...@googlegroups.com> En nombre de k3gau Dave Enviado el: martes, 28 de abril de 2020 1:17 Para: sark110 <sar...@googlegroups.com> Asunto: Re: Noisy Input Problem     GE Melchor,     Have you plotted those Sark files? I would like to send you a picture of the SARK screen but my cellphone is not working. Maybe I can use my other camera. I can save a file with the 'open' removed and just the open connector on the input.     In any case, I don't remember my screen looking that when it was new.     I got them with my other camera. Does that look normal for an 'OPEN' condition?     Dave K3GAU     On Monday, April 27, 2020 at 3:45:04 PM UTC-4, EA4FRB wrote:   Thank you for the files. I don’t see a problem with these readings and the cal files. When there is no load connected, it is possible to get negative Rs readings influenced by noise because the error is high when the load is close to the infinity. Also, there is the influence of the used open load for the OSL calibration.     Best regards,   Melchor EA4FRB     De: sar...@googlegroups.com <javascript:> <sar...@googlegroups.com <javascript:> > En nombre de k3gau Dave Enviado el: lunes, 27 de abril de 2020 19:40 Para: sark110 <sar...@googlegroups.com <javascript:> > Asunto: Re: Noisy Input Problem     Melchor,     I think I sent all files you ask for and probably a couple you don't need. SARK 1, SARK 2 and SARK 3 are three different shots of my screen taken within a few minutes.     Dave   On Monday, April 27, 2020 at 12:25:06 PM UTC-4, k3gau Dave wrote:   GM,     I had noticed what seemed to be "a noisy input" problem even before I had Steve repair my SARK 110. So his repair had NOTHING to do with the problem.     It doesn't seem to act right then it is looking at an the open circuit. It does seem to read a short, 50 ohm, 100 ohm and 200 ohm loads across its bandwidth just fine. But looking at an open, it sometimes reads out some negative resistances, etc. when measuring 'RS' and plots them on the screen as well. The problem seems worse at the higher end of the spectrum when scanning the full 230 MHz range. As I recall, when I first got my unit, open circuit 'RS' was always full scale, a high value (in the kOhms) and never a negative. I have gone through the detector check and calibration procedures. They seemed to be about normal.     Any idea what could be causing the problem? Bad component, bad solder joint?     Dave   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sar...@googlegroups.com <javascript:> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/3eeb8866-8bca-4938-a40b-ced41b7dea9b%40googlegroups.com <https://groups.google.com/d/msgid/sark110/3eeb8866-8bca-4938-a40b-ced41b7dea9b%40googlegroups.com?utm_medium=email&utm_source=footer> .   -- You received this message because you are subscribed to the Google Groups "sark110" group. To unsubscribe from this group and stop receiving emails from it, send an email to sark110+u...@googlegroups.com <mailto:sark110+u...@googlegroups.com> . To view this discussion on the web visit https://groups.google.com/d/msgid/sark110/8efc52e0-673c-4f7d-b853-729814e04e1c%40googlegroups.com <https://groups.google.com/d/msgid/sark110/8efc52e0-673c-4f7d-b853-729814e04e1c%40googlegroups.com?utm_medium=email&utm_source=footer> .

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L and C measurements

Steven Andros <andro...@gmail.com>: Apr 27 02:10PM -0700 Hello everyone,   Since I seem to have a bit more free time available than I usually do, I've decided to experiment with low pass filter circuits for use with my home brew water cooled LDMOS amp. Since the SARK-110 can measure L and C values at a specified frequency, it seems like a better instrument to use that my trusty L/C Meter 2B from Almost All Digital Electronics.   I have a MCX to Type N female cable. With adapters to temporary convert it to BNC, I performed an OSL calibration, then tested the SARK-110 using a 1000pF cap I had on hand. With the unit set to test at 7 MHZ. It read as expected.   Next, I tried a torroid inductor I had wound. The AADE meter read what I expected - about .48uH, but to my surprise the SARK-110 read almost twice that (.802uH). Given the success with the cap, I was quite surprised at the results with the inductor.   I also need to construct a fixture that will allow convenient testing of not only torroids, but SMD caps. Anyone have a setup they've made that works to their satisfaction? If so, how did you facilitate OSL calibration?   All the best from Bradenton Fl,   Steve KG4LJB

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