Skip to main content

uBITX Setting for Custmized(Hacked or Modified) LPF's

uBITX Setting for Extneded LPF's

I find it hard to find the right title for this posting.
Extneded LPF's, Hacked LPF, Improved LPF... and more

Anyway, I noticed a couple of months ago that the various ways to improve the Spur of uBITX were discussed by some OM's on how to replace the LPF.

This version is for users who want to modify the LPF, Users who use Stock Hardware do not necessarily have to upgrade this firmware.

1.LPF Structure of Stock Hardware 
The basic LPF of uBITX uses Arduino Nano's 5, 4, and 3 I / O.

[ubitx source code]

[ubitx source code]

Frequency >   21.000Mhz   : TXA Off, TXB Off, TXC Off
Frequency >= 14.000Mhz   : TXA  On, TXB Off, TXC Off
Frequency >=  7.000Mhz    : TXA  On, TXB On, TXC Off
Frequency >=       0Mhz    : TXA  On, TXB On, TXC On

2.Schematic for testing LPF of uBITX

In general, you may only use TXA, TXB, TXC such as stock hardware.
But if you use it in a way that controls one relay per I / O, three I / Os will be insufficient.

If you use I2C LCD or Nextion LCD, there will probably be plenty of extra I / O.
In CEC Firmware Version 1.11, you can use D10, D11, D12, D13 as you want.
You can control High / Low by frequency just by setting in uBITX Manager.
Maybe this could be used to control the external linear.

I connected TXA, TXB, TXC and D10~D13 to the breadboard for testing.
yellow lines is TXA~TXC, white lines is D10~D13.

Below is a picture of TXA, TXB, TXC, D10, D11, D12, and D13 lines in uBITX.

TXA, TXB, TXC, D10, D11, D12, and D13 can be viewed according to the frequency as shown below.

3.LPF Control Test for stock hardware





4.Customized LPF (Hacked LPF or Extended LPF)
You will find several ways to modify the LPF to improve uBITX.

- How to use 4 bands (LPF) using 3 relays like uBITX's basic
  (use 3 I/O)

- How to use 4-band to 7-band (LPF) with a combination of relays
  (use 2~3 I/O)

- How to use up to 8 bands (LPF) using Line Decoder such as 74LS138
  (use 3 I/O)

- Various other methods
  (use 3~7 I/O)

5.Compiling source code for using Customized LPF
First of all, the CEC Version allows customized LPF Filter to be configured as desired by the user.

To use your LPF, you need to change the compile options to compile.
I will not provide a precompiled HEX file using this option (To prevent misuse of genuine hardware users)
If you have trouble compiling, please contact me and I will compile it in the form you want.

Uncomment the line below in the ubitx.h file


When you compile with this option enabled, you may get the following error:
(Version 1.11 will only display the following message when using Nextion LCD or 16x02 Dual LCD)

If you see this message, you can remove one feature that you do not use.

If Nextion LCD is used, IF_Shift, ATT, CW Speed etc are all controlled on the LCD.
(If you do not use Text Mode frequently on Nextion LCD, you can make about 20% program space)

The following is a successful compilation after removing the IF_SHIFT function.

See Link below for more details on this.

6.Setting for Customized LPF Users
6.1 Before uploading any settings after uploading the firmware

As you can see in the picture above, the LPF does not do anything.

6.2 LPF structure similar to LPF installed in stock uBITX

As you can see in the pictures below, it works the same as before firmware update.

6.3 Relay Combination or Decode (such as 74LS138)
7 LPFs are available.
The frequency range can be set as desired by the user.









6.4 D10 ~ D13 Extended Mode
This mode is only available for I2C LCD (16x02, 20x04) or Nextion LCD (TJC LCD) users.







6.5 Clone mode using D10~D12 (for External Power Amplifier)
Perhaps this function can be applied not only to LPF but also to various applications.

This is done by running in Clone mode.







Source code and uBITX Manager can be downloaded from the link below.
Download File :


  1. By mistake of mine, I made the mistake of connecting the digital and analog cables backwards.
    The screen is illuminated white.
    Could you tell me if only the firmware was corrupted or maybe some component failed?
    Thank you

  2. If you need more space and dont want to loose any features you can try this.


Post a Comment

Popular posts from this blog

Release CEC Firmware v1.200 for uBITX All version(include V2, V3, V4, V5)

Release CEC Firmware v1.200 for uBITX All Version (include v2, v3, v4, v5) I did the firmware work for v5 when uBITX V5 was released, but I release it now.
I received the feedback from a thankful beta tester and tested it myself by converting my uBITX v3 to v5 but I was not sure.

I ordered the uBITX V5 and delivered the correct uBITX V5, so I made a little more fine-tuning.
If you use V2, V3, V4, you do not need to update this firmware.

uBITX with Nextion LCD (CEC Firmware) - Installation and Introduction

uBITX with Nextion LCD (CEC Firmware) - Installation and Introduction uBITX CEC Firmware supports various LCD since Version 1.08 (16x02 Parallel, 20x04 Parallel, 16x02  I2C, 20x04 I2C, 16x02 Dual LCD with I2C).
Supports Nextion LCD (Graphic LCD) from Version 1.09, Version 1.09x is primarily aimed at Nextion LCD support. Also 1.09x will continue to be Beta version. If you want a stable version, please use 1.08 or 1.1 version to be released in the future.

Release EU1KY AA Firmware CEC Version 1.01 and 1.0a

Release EU1KY AA Firmware CEC Version 1.01 and 1.0a
It is the stabilized final version of EU1KY AA. Updates starting with Version 0.1 continue to add features. Please refer to the link below for added features.

I have separated the Version to 1.01 and 1.0A for users who want to use AA only for instrumentation purposes.

*  If you want to use all the features added up to Version 0.71, please use Version 1.0A.
*  If you want to use it only for instrument use, please use Version 1.01

Version V1.0A

Version V1.01

1.Download Firmware Version 1.01 and 1.0a
Version 1.01 (Version with only antenna analyzer function)
Version 1.0A (Version with all features added up to Version 0.71)
ConvertRXP (Converters for using AA measurement data in other tools such as Matlab)…