Differences between radio hardware revisions

Discussion related to the exprimental TYT MD-9600 / Retevis RT-90 version
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VK3KYY
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Differences between radio hardware revisions

Post by VK3KYY » Mon Jan 03, 2022 12:25 am

The MD-9600 / RT-90 have 3 major hardware verions, which use different ICs and also other modifications

V2 and V3 radios use the same PLL and IF chips
V4 radios use a different PLL chip to V2/V3 but use the same IF chip
V5 (aka V4A) radios use a different PLL chip to the older radios and also use a different IF chip. Hence the V5 radios are quite different from the previous versions


The main difference between the V2 and V3 hardware are improvements to the PA to fix DMR BER problems. There is also a fix for the speaker click problem


Both the V4 and V5 have the PA fix, but don't seem to have the fix for the speaker click.

We think that possibly the fix for the speaker click caused other problems, possibly the loss in some audio at the start of Rx, but can't be sure.

It may be possible to partially fix the speaker click by changes to the firmware, specifically by using PWM modulation of the amplifier control signal, but I have not had time to investigate whether this is possible or whether it would cause other problems

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