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can anyone provide the BOM for the 4.1 board and possibly a link to a high res picture of the board? I can't find the old links. Jim n2go

After years of using exiter, I am trying myVNA for the first time. The installation went well and I followed the configuration setup without any issues. My setup is a win10 64bit machine, however at this time I have not completed assembling my USB to parallel port adapter board. I decided to purchase a Startech PCIe parallel card and use this in the meantime. (since my N2PK has a parallel port). The config went well and I am able to set and verify the frequency of the LO DDS. In addition when I run the vector volt meter, initial the ADC is blank, however after checking the "DDS Phase Init Test" box the numeric displays come to life and the readings makes sense for a non-calibrated VNA. However this issue I am having is that the buttons at the top to start a sweep do nothing. The expected scan time is reported at the bottom, but no progress on the scan and the DDS LOs do not get programmed to the starting frequency. They stay at the last frequency used in the vector volt meter test. So my conclusion is either there is an issue with win 10 64bit combined with parallel port, or there is some other issue with my setup that is preventing a sweep from starting. Since I have not used this before I'm not sure what to expect, however the calibration window that I think should popup when I hit calibration does not open. This leads me to think its a parallel port/win10/64 bit issue. Has any one used this combination with myVNA successfully? Is there something I need to do to start the calibration window besides hitting the button? Do other users find that the ADC readings in vector volt meter do not start without pushing the "DDS Phase Init check box? Sorry for the basic questions about this and any experience with myVNA is helpful in my debugging. My investigation of the archieved messages didn't help. Brian

Hopefully one of the experts can help me decide if I should dig farther. I built a dual (2 detector) version the the LTC2440 (faster) ADC converters at least a dozen years ago. I'm not really sure about the years because they just fly by. Well the VNA has been great for me for a number of projects (thanks Paul and others) and I have kept it alive my keeping an old win 2000 machine with the parallel port. In the last year with the combination of the more convenient nanoVNA and keeping a parallel port machine alive, I have retired my N2VNA to the ex-project pile. Recently I wanted to make a some low frequency power supply and PID control loop measurements and thought that the N2PK VNA could be adopted for this purpose. With the non-integrated source and detector ports (2) (external bridge) , I thought I could modify the bridge and make a specialized bridge for these measurements. As a reference you can look at the RIdleyEngineering software and injection measurements he makes with his low frequency analyzer (AP310). In order to make these measurements I think I would need to make the following adjustments, hopefully someone can provide me some feedback if this is possible. I've been using exciter which can measure both S21 and S11 but not simultaneously. In addition I still use the parallel port, but I purchased the USB adapter years ago but never completed the build. My question are: 1) Which of the more modern software interfaces supports measuring both S21 and S11 at the same time. This would be required to perform injection measurements. https://www.ridleyengineering.com/hardware/ap310-analyzer/ap300-application/ap300-loop-injection.html 2) Does any of the software support sweeping below 50kHz. This is the exciter low freq limitation and also the DDS transformer limit. I don't mind changing the hardware to make this a low freq only analyzer 3) Could I use my unfinished WB6DHW HSUSB_R1 interface to support the correct software? 4) Are there better/easier ways to make these low freq phase and amplitude measurements (100Hz - 2MHz) than the above concept. Thanks in advance for any suggestions Brian

Group - For many many years my N2PK/MyVNA combo has been great. Recently I have gotten it into a state and not found an exit. With a short cable from RF Out to Detector 1 and the M2PK ion transmission mode, the sweep looks perfect: flat with loss < .01 dB. With no cable, the trace is very noisy and loss is just a little more than .01 dB. The trace looks like the trace normally seen with no input, which normally is -85 to -90 dB. So the trace seems to be correct but the vertical axis labels were not updated. I tried clicking on AutoScale many times, restting the N2PK, and restarting MyVNA. I find nothing in Display Options nor in the window that appears after left clicking on the plot. So what have I done? Chuck

Hello, Has someone captured all of the messages from N2PK yahoo group? Thanks, Dave - wb9own

Hi all in myVNA the calibration standards are defined in terms of fringe capacitance, resistance, inductance ( load )etc etc. I purchase a calibration KIT with parts from Rosemberger , they define the standards in term of delay from the reference plan . How is possible to transform the value parameters between the two definitions ? The standard by default in myVNA are referred to which calibration KIT ? Thanks to all Regards IZ2ZNC Gianfranco

As WFH and sorting out stuff, I have also managed to go through some of the older projects I needed to complete from 2006 and found I have a V4.1 dual detector N2PK and an original N2PK to make up. Got the dicast enclosures as well as all the parts (phew). Lacking PSU and sma/Ntype chassis connectors though. Seem to have a USB to LPT control project as well for the N2PK control based on a Cyrus chipset? Hope to pop back as I melt solder on these and to find more destructions and ideas. I see the N2PK site was archived so grabbed copies of that too now. 73 Dom M1KTA

Hi Everyone, I hope you're well. Although I have some RF background, I don't do this for a day job, I'm very much a beginner so apologies if I'm asking something basic. I've never had to match such a filter before, but long story short, I have a 8-pole filter model "QMF 10725" which according to the PDF datasheet<https://www.hy-q.com.au/pdf/Filter%20Guide.PDF> looks like 910 ohm in parallel with 25 pF. I wish to match to 50 ohms input and output. According to calculators, that means that I can use a series capacitor of 72 pF and a parallel inductor of 2.4 uH. I didn't get good results when I tried it (not sure how precisely I need to trim the capacitance and inductance - I would say I had the inductance and capacitance to within a few percent since I measured them at 10.7 MHz). With the matching circuit attached to the QMF filter, on a Smith Chart I could not get the 10.7MHz point anywhere near the centre, I was just circling not far from the perimeter! So, I decided to measure the filter on its own (i.e. without any matching) using the RF-IV sensor, to confirm if it is 910 ohm//25pF or not, and I see Rp and Xp as shown in this screenshot: https://app.box.com/s/9706a84esjsi67lbwj6f5goh7g15peps I'm fairly confident I'm using the RF-IV sensor and MyVNA correctly (I tested with known resistances to confirm the OSL calibration), so I have confidence in the measurements. As can be seen, in the filter passband, Rp varies considerably. Xp also varies a lot, in some places inductive, and some capacitive. How can I match it do you think? Should a series C and parallel L be fine, and if so, what values would you suggest? The CSV file of the data is here: https://app.box.com/s/bm6y2g4t560v6hd1cebvaby4mmouci0s The Extended CSV is here: https://app.box.com/s/tq4z0r4ti1myfeofptqmjz9654f9gj6m Many thanks, Shabaz.

Hello All, I haven't posted in years but I need your help now. The hardware is a single detector board with Pauls original coupler board unmodified. The software I'm using is MyVNA version 1.0.0.54 on an XP machine. Problem. I think I'm having problem measuring the correct Q of good Caps and Inductors, I never seem to measure a Q greater than 200. Vacuum Cap or inductors wound on PVC forms. Why is that? Is this to be expected with the original coupler board? Should I be using the wider bandwidth RF-IV sensor PCB for measuring higher impedance parts? Thanks for your time, Dave - wb9own

Greetings Q can be derived for either L or C by measuring their complex impedance . In either case Q is a ratio of the real to imaginary values provided by the VNA. I have recently spent considerable hobby time using my N2PK VNA to derive equivalent series resistance (ESR) of high quality fixed capacitors. My bottom line is that accurate measurement becomes increasingly challenging for capacitors with values less than 100 pF and at frequencies below 10MHz or above 100MHz One academic study bluntly concluded that a VNA is unsuited to the task and several manufactures use other measurement instruments. I have a 6-page summary of my efforts, let me know if you would like a copy if anyone 73 Ron W6WO

Hello folks, After many years of great service my N2PK VNA has developed a problem, it acts like it's detectors both have poor sensitivity. Can anyone give me some guidance troubleshooting? Drop me a email and I will try to describe the problem a little better and the steps I have taken. Thanks I sure miss this thing!!

Hi I am wondering whether anyone might have a single detector PCB available. I am looking to update a rather old single detector N2PK VNA to a dual detector for use by a friend. Thanks. Bob, 5B4AGN

I've finished a v5.2 board and the VNA seems to be operating properly. However there was one odd observation that I was hoping someone in the group may have seen before, or have a theory about. The 3.3V regulator that feeds the CW master osc shows 3.3V **without** the CW MO connected. With the CW MO connected, the 3.3V terminal reads about 3.55V. Roughly 0.25V high. Notes: 1. The voltage tracks the 5V rail. If the 5V rail is set to 5.1V, the observed voltage is higher yet, about 3.6V. 2. The regulator is not oscillating. I have measured the voltage at the terminal with 2 HP lab DVM, a fluke, an oscilliscope and a SA. There is some level of the 156 Mhz present on the +3.3V line, but I'm not sure if that's just being picked up by the near proximity of the oscillator's ajacent output. I've replaced both the 0.1 & 10 uF caps ajacent the CW osc just for good measure. 3. The VNA seems to work fine with as-expected noise floor levels. 4. While the CW part is a 3.3V nominal, the abs max voltage is 5V so even if the circuit is truly running at 3.55V, the oscillator is probably not in mortal peril. 5. Checks of nearby points show nothing in the 3.55V or 0.25V range. 6. With the +3.3V feed from the regulator pulled, the voltages around the CW osc are all zero. 7. The CW oscillator output is clean and stable. I can see 2nd/3rd harmonic levels but it looks like it's working fine. 8. Current consumption of the oscillator is about 30 mA which I think is in line with the datasheet values. At the moment I have no explanation for this. Hoping someone would have a theory. Or be able to check their board and see if they have a similar observation on the MO voltage. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com

Hi all I have a problem. I calibrate in reflection mode, then I apply again the load used to calibrate and display the Xp. See enclosed the result, glitches ? Help IZ2ZNC Gianfranco

Hi All, Ivan has kindly added an archived copy of my now defunct website to his website here: <https://www.makarov.ca/n2pk_archive/index.html> I have also updated my QRZ page to reflect this. Stay safe, Paul

Hi I am using the myVNA 1.0.0.95 When I import a any configuration ( transmission, S-Parameters etc ) appears tick also " TDR mode only". I have to un tick it and everything works properly. Any explanation ? Thanks Regards IZ2ZNC Gianfranco

Hi Everyone, The HTML version of the paper is published, these three links below cover the 'part 1' PDF. I'm now working on the part 2 PDF, splitting that out too into multiple shorter pages too. Once they are all complete, I can add hyperlinks between them all. Here are the links to the first set: VNA Measurement Examples: https://www.element14.com/community/docs/DOC-94326/l/hf-vector-network-analyzer-some-measurement-examples VNA Theory of Operation: https://www.element14.com/community/docs/DOC-94327/l/hf-vector-network-analyzer-theory-of-operation VNA Performance: https://www.element14.com/community/docs/DOC-94338/l/hf-vector-network-analyzer-performance I think the Part 2 will be split into six sections: VNA Hardware Overview and Schematic VNA Construction Notes VNA Power Interface Board VNA Bridges and Calibration Standards VNA Master Oscillator VNA DDS Buffer and Detector Pre-Amplifier Many thanks, Shabaz.

Hello, This email message is a notification to let you know that the following files have been uploaded to the Files area of the [email protected] group. /N2PKwebsite.zip Uploaded By: David Feldman <wb0gaz@...> Description: N2PK web site archive captured January 1, 2020 from URL: http://n2pk.com/N2PKwebsite.zip Cheers, The Groups.io Team

Greetings I have been a keen user virtually from the beginning. Recently a very good friend passed away and prior to leaving us he donated the VNA Items which he built or purchased, He was an expert builder and his superior workmanship is clear. Unfortunately he died before final assembly and testing. Here are the items that I am offering for sale as a complete set. The case is typically used in N2PK VNA projects .The front panel has the 3 SMA connectors with a USB rear connector Main board rev 5.1 came from Ivan VE3IVM Semiflex cables with SMA connectors are used throughout HF reflection bridge has SMA sockets to match those on the front panel with male-male couplers VE3IVM RF-IV rev 2 board (not built) Two low noise power supplies with over-voltage and crow-bar protection were designed specifically for the N2PK VNA and made by OM3LZ, One is dual 12 and 5V version 4 is the other supplies 12, 9 and 5 v for use with transverters.I recommend studying the OM3LZ project description on his web site I will be pleased to respond to email questions and will provide pictures of all items to those interested As a sanity check I am expecting offers over $300