GD77, Fresh Battery, and Distorted Audio

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VE3RWJ
Posts: 25
Joined: Mon Jun 08, 2020 3:34 am

GD77, Fresh Battery, and Distorted Audio

Post by VE3RWJ » Thu Jun 25, 2020 3:42 pm

I'm just an end user, so I have no idea if this can be addressed or filtered in software somehow.

There seems to be quite a bit of distortion on the speaker audio, depending on the voltage of the battery. It seems to be at it's worst when the battery is fully charged until maybe around 7.5 volts, when it is less distorted. Then the distortion creeps back up as the voltage drops below that point. This is most noticeable the lower you have the volume. It almost sounds like... hmmm... the best way I can describe it is an 8-bit record, or maybe a wax kazoo.

Should I take this up with Radioddity as well, along with the rather pronounced bump in receive audio around 295Hz, and the distorted sibilant sounds (similar to Yaesu) on TX audio?
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de VE3RWJ (FN03af)

VE3RWJ
Posts: 25
Joined: Mon Jun 08, 2020 3:34 am

Re: GD77, Fresh Battery, and Distorted Audio

Post by VE3RWJ » Thu Jun 25, 2020 3:44 pm

Also, some GD77's have quite audible CPU noise on RX, and a constant clicking sound (about every 100ms) on analog TX.

Mine doesn't do this, but I have heard it on three others.

Again, I don't know if this can be addressed/filtered in firmware or not.
My referral link will get you a discount at Radioddity's Website:
http://radioddity.refr.cc/chrissmart?t=tw

and the podcast I help produce is at:
www.makingbetterpod.com

de VE3RWJ (FN03af)

VK3KYY
Posts: 2960
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia
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Re: GD77, Fresh Battery, and Distorted Audio

Post by VK3KYY » Thu Jun 25, 2020 9:55 pm

There is a known hardware bug with a whine on the audio when the battery gets fully charged.

Jason VK7ZJA has some stuff in his web pages about how to change some analog components in the radio to fix this.
Search for VK7ZJA GD77 Mods

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