DM-5R: bad audio/motorboating

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W7ML
Posts: 83
Joined: Sat Jul 17, 2021 12:48 am
Location: Los Angeles, CA USA

DM-5R: bad audio/motorboating

Post by W7ML » Thu Jun 01, 2023 6:20 pm

Now with the OpenRD5R installed I am getting reports of "motorboating" on my audio.

He was kind enough to record my countdown from 10 to 1 and play the tape back for me, so I could hear what he was describing. Another user reported the same problem.

AND, I now realize how poor the audio is when I am receiving DMR.

I went back and connected my "other" RD-5R with the manufacturer's firmware to my external antenna (to duplicate the situation) and not only was the audio I was receiving 100% better quality, but he reported that the motorboating was gone.

Any fix for this?

W7ML
Posts: 83
Joined: Sat Jul 17, 2021 12:48 am
Location: Los Angeles, CA USA

Re: DM-5R: bad audio/motorboating

Post by W7ML » Fri Jun 02, 2023 2:23 am

That's interesting:

I first searched for motor boating before I posted and nothing came up.

Then for "motor" up came a Motorola comment.

Now I see 11 comments including motor boating. I will read these when I return home later, but if there is a specific fix I would appreciate being directed to it.

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DG1GMY
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Location: Southern Germany

Re: DM-5R: bad audio/motorboating

Post by DG1GMY » Fri Jun 02, 2023 3:19 pm

Indeed, the older threads have a lot of valuable information on this subject.

I have a bunch of OpenGD HTs from the various brands/makes including two RD-5R bought in 2020. Depending on settings (i.e. Eco level, display ON/OFF/brightness, DMR mic, PWR etc.) and/or external microphone and/or antenna setup (antenna distance to microphone cable...) I can still reproduce some "motorboating" on these.

The quality of the various TRX (and cheap speaker-microphones) varies greately. Apart from other "deep dive" technical solutions a simple option to avoid or at least minimize motorboating is an external antenna and a well-shielded speaker-microphone - combined with adequat menu settings. If there is motorboating even without a speaker-microphone you may still try an external antenna to see if this fully removes the motorboating (these devices may also send "nice" spurious emissions and therefore induce RF into the radio even at or especially at low PWR settings)...

VK3KYY
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Location: Melbourne, Australia

Re: DM-5R: bad audio/motorboating

Post by VK3KYY » Fri Jun 02, 2023 8:55 pm

My motorboating is common on all these cheap handheld radios when using an external mic

And the RD-5R is the cheapest lowest quality radio which the firmware supports.
The RD-5R also won't support hotspot mode because it injects too much RF into its own USB connection

W7ML
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Joined: Sat Jul 17, 2021 12:48 am
Location: Los Angeles, CA USA

Re: DM-5R: bad audio/motorboating

Post by W7ML » Fri Jun 02, 2023 10:05 pm

I reviewed all of the "motor boating" posts that came up in my search and most are not helpful to my situation. This one:
kt4lh wrote:
Sat Nov 21, 2020 2:28 pm
If you're using an external hand mic, that's common, and unlikely it would matter if it was the original firmware or OpenGD77. If you're not using a handmic, odd, never heard of this (typically called 'motor boating' from the noise) just using the HT directly.
Well, I am using the HT directly: no hand mic, and it is occurring whether using the Diamond RH-77CA extended dual band ducky, or connected directly to my Comet tri-bander on my 2nd story roof.

I hope we can find the problem, as it negates my ability to use the Open Firmware; the responses are so negative to my audio.

The best feature for me in the Open Firmware is the ability to manually enter any TalkGroup number without having to resort to the CPS via computer.

I am not looking for hotspot capability as I am a member of the PAPA System which has 3 DMR repeaters in my local vicinity.

Thank you again.

W7ML
Posts: 83
Joined: Sat Jul 17, 2021 12:48 am
Location: Los Angeles, CA USA

Re: DM-5R: bad audio/motorboating

Post by W7ML » Sat Jun 03, 2023 12:06 am

Update: continued experimentation on the external antenna is better received audio.

I’ll test transmission later.

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