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Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia


Post by VK3KYY » Fri Mar 27, 2020 9:54 pm

The newer versions of the OpenGD77/OpenDM1801 use unified calibration data memory.

If your radio has corrupt calibration data you will see the message


To fix this you either need to either

1. downgrade to the previous version of firmware which you were using.


2. You fix the calibration data

What you need to do to fix the corrupt calibration data depends on how corrupt the data is.
Possibly only the calibration data "signature" byes are corrupt, but potentially the entire calibration table is corrupt.

Using the OpenGD77CPS in the Extras->OpenGD77Support backup your existing calibration data

Download a hex editor, e.g. Hxd, and compare the first 2 bytes of your calibration table, and they should be 0xA0 0x0F
For the GD77 the first 8 bytes should be these

Code: Select all

Offset(h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

00000000  A0 0F C0 12 A0 0F C0 12 E4                        .À. .À.ä
Note. On the Baofeng DM-1801 only the first 2 bytes are guaranteed to be 0xA0 0x0F

Use Hxd to change the first 2 bytes to the correct values, and resave the calibration file with a different name.

Then use the CPS to restore the calibration into the radio

The radio should not start normally.

You should also use the Calibration screen in the Extras menu of the OpenGD77 to check the other values in your calibration data

These are screengrabs of the VHF and UHF calibration data in one of my radios.

All radios will have slightly different values for most of the settings, but the Reference Oscillator Tuning value should be in the range 980 to 1020 and the Tx I & Q values should be similar to my values.

My power values have been calibrated for my radio, and are likely to be significantly different from a radio where the owner has not done their own power calibration, because the factory power calibration seemed extremely inaccurate
vhf_calibration.png (31.44 KiB) Viewed 1493 times
uhf_calibration.png (31.18 KiB) Viewed 1493 times
(352 Bytes) Downloaded 142 times

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