[arm-allstar] USB Cables With the Most Shielding?

[Dustin Perdue]

I have found, with some USB cables, that there is enough play that moving a cable slightly will ruin your day. The thickness of the cable is less of a problem than the connectors themselves, in my general experience.

Sent from my zippo


> On Jun 15, 2021, at 09:45, David McGough via ARM-allstar <arm-allstar at hamvoip.org> wrote:
> 
> 
> Chris,
> 
> Switching wall-warts don't typically have 60Hz or 120Hz audio noise. It's 
> almost always much higher frequency buzz---like in the 1KHz to 3KHz range.
> 
> Since the noise is intermittent, some type of poor connection (somewhere) 
> might also be the cause.
> 
> 
> 73, David KB4FXC
> 
> 
>> On Tue, 15 Jun 2021, "Chris Smart via ARM-allstar" wrote:
>> 
>> I'm using the wall-wart I bought with a Pi 4.
>> 
>> I have a ferrite choak on its cable right at the Wall-wart end, and I am 
>> not hearing 120 Hz on my audio.
>> 
>> 
>> Now it's just the 1,046 Hz I'm sortig out. right now it's absent, as 
>> long as I don't move anything on the desk. :)
>> 
>> 
>> 
>>> On 2021-06-15 8:55 a.m., "David McGough via ARM-allstar" wrote:
>>> Hi Chris,
>>> 
>>> If you're hearing the whine on both RX and TX, the noise is probably audio
>>> path related; likely a ground loop or other ground noise.
>>> 
>>> What type of power supply are you using on the RPi board?  I have seen
>>> situations where very noisy AC switching power supplies (mostly "wall
>>> warts") would produce a whine that got in the audio. Frequently these have
>>> significant and detectable AC leakage showing up as common-mode noise on
>>> the DC power output.  This can rip the USB audio to shreds!
>>> 
>>> I know numerous different power supply and wiring protocols have been
>>> developed and adopted by various AllStar users.  I prefer powering the RPi
>>> board via a DC-DC converter, directly from the radio/repeater power
>>> source.  I keep all my grounding points a the same physical spot,
>>> minimizing the potential for ground loops / noise.  Since I went to this
>>> strategy, my audio noise issues have reliably disappeared.
>>> 
>>> 
>>> 73, David KB4FXC
>>> 
>>> 
>>>> On Tue, 15 Jun 2021, "Chris Smart via ARM-allstar" wrote:
>>> 
>>>> Hmm, good question.
>>>> 
>>>> Right now it's completely gone, but if I move that USB cable a little, I
>>>> can bring it back easily enough. Sometimes I hear it on TX, sometimes on
>>>> RX. sometimes both.
>>>> 
>>>> 
>>>> 
>>>> On 2021-06-14 10:38 p.m., "David McGough via ARM-allstar" wrote:
>>>>> Hi Chris,
>>>>> 
>>>>> How is the whine getting into your node---via an audio or RF path??
>>>>> 
>>>>> 
>>>>> 73, David KB4FXC
>>>>> 
>>>>> 
>>>>> On Mon, 14 Jun 2021, "Chris Smart via ARM-allstar" wrote:
>>>>> 
>>>>>> Hi.
>>>>>> 
>>>>>> 
>>>>>> I'm running an Alinco node radio and the RIM-Alinco device, along with
>>>>>> the supplied short, very thin USB cable. I'm tired of gently moving the
>>>>>> bulk of that USB cable around, an inch this way or that, and it going
>>>>>> from major USB wine (1,046 Hz) to nothing.
>>>>>> 
>>>>>> 
>>>>>> Do people here have a prefered brand of USB cable with lots more
>>>>>> shielding, including ferrite? I believe I need USB-A to MINI-B, right? I
>>>>>> always get mini and micro B confused.
>>>>>> 
>>>>>> 
>>>>>> I'm also going to put a serial cable on the back of that port so I can
>>>>>> get the RIM-Alinco much farther away from the transmitter, since it's
>>>>>> running 5 watts.
>>>>>> 
>>>>>> I want the best-sounding, quietest node in town, and I"m almost there. :)
>>>>>> 
>>>>>> 
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>>>>>> 
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>>>>>> 
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> 
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