Greetings from a white-haired Italian

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Nat
Posts: 21
Joined: Fri Nov 27, 2020 11:09 pm
Location: Italy

Greetings from a white-haired Italian

Post by Nat » Wed Mar 10, 2021 11:15 pm

Hi all,
my name is Nat, I am not "a radio-amateur" but, better said, I am a man who "loves radio".
I got a few low cost radios. Ofcourse I just use them as receivers.
I loaded the opengd77 firmware on my DM1801 and I keep it updated with both stable or beta versions.
Many tanks to Roger and to the people who is dedicating their time writing and testing this great firmware.

If I can I would like to report a couple of bugs found on openDM1801.

1. Noise from screen backlight appears to be back. I noticed it from version 2021.03.06.01, never heard it before on my DM1801 with previous versions. It is surely related to the display backlight as it disappears with backlight at 100% or at 0%. Noise change “tone/volume” according to the backlight setting with more noise on medium values. Let say very noisy from 20% to 80%.
Noise is present only when audio is open. Tested with original battery and external power supply, same result.

2. From version 2021.02.13.01 reaching the "Zone" menu using the "Quick Key" function, display appears OK but scrolling beyond the first top line or beyond the last bottom line I got corrupted lines with strange symbols or blank lines. Sometime, if I select a corrupted line then the "Zone" menu will be corrupted even when I reach it through the MENU button.
To fix the issue I must scroll through zone or switch the radio Off/On.
No issue using the MENU button to reach the Zone menu.

Thanks again

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Greetings from a white-haired Italian

Post by VK3KYY » Thu Mar 11, 2021 1:50 am

Hi Nat

Re: Backlight noise

I don't think all DM1801 have this bug.
The official firmware does not have this feature.
However if your radio has this problem, it is not possible to fix in firmware, because the problem is caused by the PWM / dimming control of the backlight LED.
You must use 100% or 0%.

Re: Bug 2

OK. I have not see this bug.

I will add this to the bugs list, and it will be investigated

https://github.com/rogerclarkmelbourne/ ... issues/926

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Greetings from a white-haired Italian

Post by VK3KYY » Thu Mar 11, 2021 9:17 am


Nat
Posts: 21
Joined: Fri Nov 27, 2020 11:09 pm
Location: Italy

Re: Greetings from a white-haired Italian

Post by Nat » Thu Mar 11, 2021 2:01 pm

Hi Roger,

I tested the version you posted to fix the issue 926, it works. Now it is possible to use the quick Key to reach the zone menu and scroll through it without any problem. ; )

About the backlight/noise issue. It's just a really little flaw, I can live with it.

But, as I was pretty sure it was related to last beta version, I decided to double check all the versions from stable D2021.01.19.01 to beta D2021.03.06.01. If this can be useful to you to trace the "guilty" I can confirm you that the issue has been introduced from beta version D2021.03.06.01.

The noise is only present on version D2021.03.06.01.

Not present on previous version D2021.02.16.01 and the older ones.

Thanks to ;) you all. You are doing a great job.

All the best.

Ciao

Nat

W9YA
Posts: 56
Joined: Sun Sep 06, 2020 4:16 am
Location: DM65pd38
Contact:

Re: Greetings from a white-haired Italian

Post by W9YA » Thu Mar 11, 2021 8:36 pm

VK3KYY wrote:
Thu Mar 11, 2021 9:17 am
Daniel has fixed the bug

See

https://github.com/rogerclarkmelbourne/ ... ug_926.zip
FIX WORKS FB.

MNY TNXS OM DE "baab" w9ya

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Greetings from a white-haired Italian

Post by VK3KYY » Thu Mar 11, 2021 9:01 pm

Nat wrote:
Thu Mar 11, 2021 2:01 pm
About the backlight/noise issue. It's just a really little flaw, I can live with it.

But, as I was pretty sure it was related to last beta version, I decided to double check all the versions from stable D2021.01.19.01 to beta D2021.03.06.01. If this can be useful to you to trace the "guilty" I can confirm you that the issue has been introduced from beta version D2021.03.06.01.

The noise is only present on version D2021.03.06.01.

Not present on previous version D2021.02.16.01 and the older ones.
That is strange

Nat
Posts: 21
Joined: Fri Nov 27, 2020 11:09 pm
Location: Italy

Re: Greetings from a white-haired Italian

Post by Nat » Fri Mar 12, 2021 1:38 pm

Hi Roger,

FYI
I've done more tests onte subjet, I got this results:

Radio setting is: Backlight On set to 70%, audio open, volume set to 0.

Noise is only noticeable on external earpiece (I used the original one).
Not audible at all with internal speaker. That could be due to the different way the internl speaker is connected respect to the earpiece.

Strangely the noise is not present on previous versions using the same setting.

Any idea?

Ciao.

Nat

VK3KYY
Posts: 7478
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: Greetings from a white-haired Italian

Post by VK3KYY » Fri Mar 12, 2021 8:59 pm

The GD77 uses a differential / push-pull connection to the internal speaker but a single connection to the external speaker.

The DM1801 uses a different audio amplifier chip but may also connect via a differential output to the internal speaker, which would explain the noise, if it is on the supply voltage.

However the PWM is a hardware function in the CPU chip and I use a 10kHz time base for the PWM, so it will not be audible.
Originally I used 1kHz but I found that on the DM1801 that the PWM could be heard through the speaker.

The voltage supply regulation and smoothing is not as good in the DM1801 as the GD77.

Possibly the reason you hear the noise is mixing / summing or the normal supply noise because of the CPU and the other chips, and the PWM for the backlight dimming

Nat
Posts: 21
Joined: Fri Nov 27, 2020 11:09 pm
Location: Italy

Re: Greetings from a white-haired Italian

Post by Nat » Fri Mar 12, 2021 10:59 pm

I tried to see the frequency with an oscilloscope with no success. But, now you said 1KHz, the sound I ear looks like a 1KHz tone indeed.
Is it possible that, for any reason, the PWM frequency is back to 1KHz?

Nat
Posts: 21
Joined: Fri Nov 27, 2020 11:09 pm
Location: Italy

Re: Greetings from a white-haired Italian

Post by Nat » Fri Mar 12, 2021 11:04 pm

Or maybe PWM is 10KHz but, for some reason, is chopped or iterrupted at lower rate.

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