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Release Firmware CEC Version 0.21 for Antenna Analyzer(EU1KY)

Release Firmware CEC Version 0.21 for Antenna Analyzer(EU1KY)

Version 0.2 has been added with some improvements and some simple features.
A brief introduction is given below. This document contains a description of how to use the LC meter included in 0.21.
The LC meter is portable and easy to use, or fun to use when working with antennas.

The CEC Firmware V0.21 Linke is at the bottom of this article.

1.Introduction -
5.Principle of Antenna Analyzer
6.Antenna Analyzer Firmware Improvement -
7.Release Firmware CEC Version 0.21 for Antenna Analyzer (EU1KY) - this article

1.Improvements or Changed
-  Tracking scope name changed  S21 Gain.

 - Remove% from battery indicator
 -  Fixed a delay in battery check when I went to another menu

 - Added continuous measurement function in S21 Gain (before name is tracking scope)

 - Memory-Related Optimization : Reducing memory usage, fixing misused memory jobs, etc.
 - etc: Correct spelling, correct beeps and more

 -  Added LC Meter function

  The EU1KY Antenna Analyzer already measures L and C values. I just worked a little bit.
  Low-cost LC meters sold on eBay or AliExpress can only measure very high capacitors or Inductors. I also have a handheld meter that can measure LC, but the measurement range is quite high. so, It is generally available, but it is not usable when we make an antenna or make a filter.
Fortunately, the EU1KY Antenna Analyzer was able to measure the capacitance in pF and the Inductor in uH units.
  (The added function can measure 300pF or less for a capacitor and 20uH or less for an inductor)

Simply create a probe and use it for just fun. The better the probe, the better the measurement. You can easily make a probe with a coaxial cable and a connector.
This should not be used for precision purposes. It is just a hobby or just for fun.

Below is a simple probe I made for testing.

It can be used conveniently if you make a probe for each use purpose.

2.1 Calibration for LC-Meter
LC-Meter Probe Calibration is performed independently for other calibration data and quickly, so you can do it at any time. If you have several types of probes, you can calibrate each probe individually.
LC-Meter Probe Calibration is very simple and quickly. To create an LC-Meter Calibration Kit, you need one 50-ohm resistor.

The calibration video is at the bottom of this chapter. You can see the entire calibration process in the video.

Connected LC-Meter Probe

Short the two lines of probe. then touch the 'SET SHORT' button on Antenna Analyzer

Probe Connect a 50 ohm resistor between two wires. then touch 'the 'SET LOAD' button on Antenna Analyzer

Do not connect anything to the probe. then touch the 'SET OPEN'
(If you want to get a little more accuracy, I recommend making short, load, and open calibration kits of the same length for accurate probe calibration.)

Finally, Touch the 'Apply & Save' button. The calibrated probe will be stored the name LC-Probe A.

When the save is complete, the color of the button changes to blue. Probe-A means calibrated.

I touched the 'Probe Next' button to register another probe with AA. On the screen, 'LC-Probe A' has been changed to 'LC-Probe B'.
The buttons Color changed back to yellow. This means that LC Probe B has not yet been calibrated.

Perform the calibration procedure in the same way as Probe-A.

Probe-B is registered to AA

Calibration Video

2.2.How to LC-Meter
The LC-Meter should be used for hobby and fun purposes only because of the error.
(Capacitors of 300pF or less, Inductor of 50uH or less)

Touch the 'L/C Meter' button on AA

Connect the probe to AA.
Use the 'Probe Next', 'Probe Prior' buttons to select a name for the probe.AA remembers the last used probe, so you do not have to choose if you have not changed the probe.

Use the 'Mode L / C' button to select a function. (Inductor or Capacitor)
Connect the part to be measured to the probe.

Below is an example of measurement. All parts used in the experiment are of the common lead type with a 5% or 10% error rate.

Inductor 0.22 uH connected.

Inductor 0.1 uH connected.

Inductor 0.15 uH connected.

Mode Change (L -> C), (Touch the 'Mode L/C' button on AA)

Capacitor 56pF connected.

Capacitor 22pF connected.

Capacitor 10pF connected.

Capacitor 100pF connected.

I removed Probe-A and installed Probe-B. My Probe-B was included when I purchased the Signal Generator. (I do not recommend it. If you look at the video, you can see that the frequency is lowered because it is not precise measurement)

Connected 0.22uH Inductor to Probe-B

The error rate is too high. The error rate is displayed as 'E:' at the bottom of the screen. If the error rate is too high, the measurement result will be displayed in red.
The smaller the error rate, the better.

Decrease the frequency one by one. Touch the frequency on the screen.

The value is output when measuring at 15Mhz. The error rate is about 16

Connected 0.15uH Inductor to Probe-B

Connected variable capacitor to Probe-B.

Watch videos related to measurement below.

If the error rate is too high, 'Out of Range' error will be displayed on the screen.

The guess values for L and C are displayed in small letters at the bottom of the screen. If you want to ignore the high error rate and see the result, you can look at the guess value.

Download Link

Stabilized version V0.35 has been released, and stabilized version is posted separately.
Please download the latest stable version from the link below.

How to update the Firmware -

I simply added the L / C meter to the AA. This may be of some help when creating antennas and filters. But please use this for hobby and fun.

I had a low-cost portable L / C meter, but it was impossible to measure the small value I needed. Because of this, it could not be used when fabricating antennas and filters.

This feature is may be useful to us because we can measure a range that can not be measured on a low cost LC meter.

Again, this feature is only available for hobby and fun because of the error rate.

Antenna analyzers made by EU1KY and improved by DH1AKF are already excellent as antenna analyzers. Firmware updates are not required unless absolutely necessary. Just update those who need it.

Thanks for reading

73, Ian KD8CEC


  1. Good evening, Ian
    Launched your version with L / C measurement. Calibrated as shown on video. But it turned out really bad. The same happened with LY3BD Alexander. Calibrated seems to be normal, but the measurement reading is very far from the truth.
    Made pictures of measurements:
    This photo is C=15pF in 15MHz
    in 20 MHz:
    in 10 MHz:

    This is L=10 mikroH 10 MHz
    in 15 mHz:
    in 20 MHz:

    What could be the reason for such an incorrectly shown device?

    With respect Justas LY2BOK , Aleksandr LY3BD.

    1. Justas, Aleksandr
      This is much more error than I thought. What about the measurement results at 25Mhz?
      This is a method of measuring L and C by the phase change as in the case of measuring the antenna.

      After calibrating, the capacitor seems to have increased. This is a function that can not be used at all.

      Make the probe a coaxial cable. Please make the length of general wire(not coxial cable parts) as short as possible. Can you test again after that?

      Thanks for your testing

      Ian KD8CEC

  2. Jan, good afternoon.
    The probe I have a cable, so here everything is OK.
    It turns out this way: the lower the frequency, the larger the measured value. So it is with condensers. So it is with inductance. ??????? Not at all clear.In your video is all very beautiful.
    Pay attention that we have levels of the Magnitude,V-MiliVolt and H-MiliVolt, more than you.
    We have "DSP Mag " about 5400. Increased to make the device work better at high harmonics. Maybe this is the reason...?
    Justas LY2BOK

    1. Maybe that is the reason. The lower the original frequency, the greater the error. Therefore, measurements should be made mainly in the 25 MHz range.
      V-miliVolt and I-Milivolt were not used to measure L / C. Only the phase difference is judged from the result of FFT.

      I plan to create a program that will analyze the calibration file. If I create the program, let's analyze your calibration file together.

  3. Thank you very much! I finally got a device that can correctly measure small inductances. I checked my inductances on 15 nano and the device showed them perfectly. But I could not figure out the measurement of the length of the coaxial cable. 30 cm piece of cable the device identifies as 38 cm.

    1. A few days ago I made a simple LPF using L / C meter. It seems to be portable.
      Coaxial cable length measurement using TDR may have some errors.
      We'll test it together and find a way to improve it.

      Thanks for information.
      Ian KD8CEC

  4. "Hello Ian,
    after fiddeling with three memories for storing the 401 complex measured data, I made a new version of my software. Now the window "Frequency Sweep" is enhanced.
    Here is the source:

    It would be very interesting, to build a conglomerate of our different versions.
    But I imagine, that this is a lot of work...
    73's Wolfgang (DH1AKF)"

    I have moved here a letter from Wolfgang
    Justas LY2BOK

    1. Justas

      There is a lot of effort to communicate. My source did some cleanup, but there are too many Debug Codes, so I'm going to release it to Wolfgang for the time being, but I'll also show it on this link.

      AA_Src_CEC Verson v0.21 based DH1AKF
      code Link :

      I have completed most of the experiments I want to implement today.
      If I have some time, I will create version 0.3

      Ian KD8CEC

  5. Hello Mr. Lee

    I am hobbist and try to understand your programm.
    In some parts I smiled because I saw some comments
    which are written in to me famliiar character.

    best regards


    1. Min
      Thank you for your interest.
      In fact, the source code is not perfect. There was a lot of Debug related code in my code. I have temporarily removed Debug code to deliver the source code to DH1AKF OM. But you still have something you have not erased yet. lol.

      I will release a 0.25 source that improves on memory. And I will put the debug code again to add some features and I will release source code again after version 1.0

      Thank you again
      Ian KD8CEC

  6. Hello Ian
    Your work is great and I appreciate it. In your presentation I noticed the measurement of inductors of 0.1uH and 0.15uH and AA indicates 0.974 and 1.495 respectively. It's the difference of a size order. I also tested the VNA side. It is very good (the error measured by me was below 0.8dB -in my measurement conditions), maybe the AUTO button to be bigger and not in the corner.

    best regards
    Augustin - YO7LJJ

    1. Thank you for your testing.
      I am preparing to work on the next version again.
      In the next version I will try to put a little fun.
      Let's think together about how to do the 'Auto' button. lol

      Ian KD8CEC

  7. Hi Ian. Great job. What is missed for me is wider span ranges up to 500MHz like in testing software from DH1AKF. Or maybe it should be set manually like I need now 115MHz span and set it manually to 115MHz instead if fixed values. What do you think ?

    1. Lucjan

      Great Idea.
      It was too uncomfortable for me.
      I will apply your opinion until Version 1.0 is over. It will probably be modified not to be too difficult.
      I will register on Todo List.

      Ian KD8CEC

  8. Hi, Ian! I ran into the problem that the device does not remember the OSL settings or remembers them with errors. If you turn off and turn on the device, the OSL settings disappear. sometimes after turning off the device, SD is unreadable and must be reformatted. I downloaded a program from a German radio amateur into the device and this problem disappeared, but I like your program more. What could be the problem?

    1. I have had that experience some times.
      It was mostly SD card issue. I installed a new SD card and the problem was solved.
      I recommend replacing it with another SD card.
      I will also test the part that can protect the SD card

      Ian KD8CEC

    2. Yes, Ian. I change SD card and the problem disappeared! Before that, I used an expensive Sandisk Ultra and now I put the cheapest nameless one and everything worked fine. :D

    3. I was similar.
      I was using some SD-Cards that were pretty fast because I had to compile in Raspberry Pi. I put one of them in AA and in a few days I got a similar symptom.

      I'm using a $ 4 SD card now and it works very well. :D

      Ian KD8CEC

  9. Hi Ian. I would like to ask the source menu.

    Janos HA8NJ

    1. Janos
      What source menu are you talking about? I'll give you an answer whenever you ask.

      Ian KD8CEC

    2. Hi Ian,

      I would be interested in the GUI code. The start menu.
      73, Janos HA8NJ


  10. Hi Ian,
    thanks for sharing your source code! Tomorrow I shall have a first look at it.
    73, Wolfgang (DH1AKF)

    1. I've got a better frequency range measurement thanks to your efforts.
      I love this feature.

      Ian KD8CEC

  11. One more question Ian. Which pins are used for measure voltage of battery, buzzer and DS3231 clock?

    1. Lucjan
      See below for a description of Buzzer-D8, Bat-A8 and Wolfgang's description.
      The DS3231 uses the I2C port of the RF board.

      Ian KD8CEC

  12. Hi Lucjan,
    please have a look at
    (page 6, 11)
    Realtime clock: page12

    Hello Ian,
    I have some questions, better discussed in private.
    My email:
    Wolfgang, DH1AKF

    1. Wolfgang
      Thank you for your kind guidance.
      I will send you an email now.

      Ian KD8CEC

  13. This comment has been removed by the author.

    1. Hi Ian,

      I like the main menu and I want to ask the main menu source (GUI).

      73, Janos HA8NJ

  14. Hi Janos,
    the complete source CEC V0.21 is here:

  15. Hi Wolfgang,

    Thanks for the information.
    73, Janos

  16. Hi Ian,

    Please send me the mainimg_bmp and imgbuttons_bmp files.

    73, Janos HA8NJ

  17. Hi Ian. More than anything, I was waiting for S21 feature you have added and glad that your finally released the Firmware.
    But alas!! even after tapping the CLK02 from Si5351 and calibrating the VNA's new S21 option, I am not getting any proper graph.

    1. After Calibration, when I connect the VNA and S21 port to the output-Input of my LPF (and later direct the VNA- S21 port direct like for Calibration), I get plot like this :

    2. When I leave both the Port open (not connected) I get the below plot :

    3. When I connect the S21 port to my Scope while "Scanning" is in progress (that is , the CLK signal from Si5351 is coming out to port ):

    Any hint what may be wrong ?

  18. Your blog is always improved on how you share this wonderful and helpful blog.


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