Stop transmitting occasionally...

VK3KYY
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Re: Stop transmitting occasionally...

Post by VK3KYY » Thu Feb 20, 2020 9:24 am

OK

F6GVE
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Re: Stop transmitting occasionally...

Post by F6GVE » Sat Jul 18, 2020 2:18 pm

EB3AM wrote:
Wed Feb 12, 2020 9:35 pm
Hello, I have been seeing an error in the hotspot mode.
Occasionally, while streaming internet audio, it stops transmitting, although the Pi-star still indicates TX. When this broadcast ends and another begins, the radio transmits again.
By monitoring the same TG with a Hat, the transmission is still active.
Hello, do you still have this trouble? Or did you find a workaround?
I have a new DM-1801 for a hospot use and I have the exact same issue

F6GVE
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Re: Stop transmitting occasionally...

Post by F6GVE » Mon Jul 20, 2020 10:56 am

I think I found what was wrong

When I built the USB cable, I sold the "-" and the shield wires together.
I also had some micro drops when receiving from the hotspot-TX (DM-1801) even with the lowest power (13 mW) and no matter the antenna used.

I have unsoldered the shield from the USB part of the cable and everything seems allright at the moment

VK3KYY
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Re: Stop transmitting occasionally...

Post by VK3KYY » Mon Jul 20, 2020 11:29 am

F6GVE wrote:
Mon Jul 20, 2020 10:56 am
I think I found what was wrong

When I built the USB cable, I sold the "-" and the shield wires together.
I also had some micro drops when receiving from the hotspot-TX (DM-1801) even with the lowest power (13 mW) and no matter the antenna used.

I have unsoldered the shield from the USB part of the cable and everything seems allright at the moment

I can't see how that would fix it unless you only soldered the shield at one end, hence you made a small antenna from the shield

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F1RMB
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Re: Stop transmitting occasionally...

Post by F1RMB » Mon Jul 20, 2020 11:30 am

Hi Luc,
F6GVE wrote:
Mon Jul 20, 2020 10:56 am
I think I found what was wrong

When I built the USB cable, I sold the "-" and the shield wires together.
I also had some micro drops when receiving from the hotspot-TX (DM-1801) even with the lowest power (13 mW) and no matter the antenna used.

I have unsoldered the shield from the USB part of the cable and everything seems allright at the moment
Yeah, D- is not the ground, D+ D- are differential pair.

Cheers.
---
Daniel
73 de Daniel.

VK3KYY
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Re: Stop transmitting occasionally...

Post by VK3KYY » Mon Jul 20, 2020 11:39 am

Yikes

I presume he meant that he had soldered the shield to the -ve "Negative" connection.

data line "D-" is not ground !!!

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F1RMB
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Re: Stop transmitting occasionally...

Post by F1RMB » Mon Jul 20, 2020 11:44 am

VK3KYY wrote:
Mon Jul 20, 2020 11:39 am
Yikes

I presume he meant that he had soldered the shield to the -ve "Negative" connection.

data line "D-" is not ground !!!
Ahhh, okay :D
73 de Daniel.

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F1RMB
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Re: Stop transmitting occasionally...

Post by F1RMB » Mon Jul 20, 2020 11:47 am

Anyway, shielding is overrated 😆
73 de Daniel.

VK3KYY
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Re: Stop transmitting occasionally...

Post by VK3KYY » Mon Jul 20, 2020 11:55 am

F1RMB wrote:
Mon Jul 20, 2020 11:30 am
D+ D- are differential pair.
Yes. In theory there should not be much pickup on a differential pair, even though the wires are not a twisted pair.

Its more likely there is general RF induction through the whole cable, which gets rectified somewhere in the RPi into DC which causes problems.

F6GVE
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Re: Stop transmitting occasionally...

Post by F6GVE » Mon Jul 20, 2020 12:27 pm

It will be more explicit like that ;)

Image

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