[App_rpt-users] Hissing noise

[Alejandro Pereida]

Thanks for the advices Benjamin will follow your recommendations to try table down the issue,
Originally I thought it could be the repeater itself but any local traffic within the repeater is fine, audio
has very good quality. It is only when I connect to nodes via the internet when I get the strong hiss.

Will post the results, thanks

Alex N2IX

> On Dec 9, 2017, at 9:50 AM, Benjamin Naber <Benjamin at Project23D.com> wrote:
> 
> Does the hissing noise come from *any/all* remote nodes you connect to
> or get connected from? Try nodes that you have previously never
> connected to remove any potential bias.
> 
> Disconnect the radios and connect a communication quality speaker to
> the audio out of the URI. You may have to simpleusb-tune-menu to get
> the audio to a volume you can hear, but do not overdrive! Do this to
> see if the noise you hear is indeed coming from the internet.
> 
> 
> The next thing I would do is use zoiper or the public access number,
> 763-230-0000, and connect to *your* node number. Then connect to other
> active nodes using the same star commands, and listen very closely to
> the audio. This will be a baseline (in this case, a *rough* baseline).
> Your connection to the ASL public SIP or telephone portal should be NOT
> taken as a pure standard, as the codec for SIP or PSTN phone may not be
> ulaw/related, which you can change the SIP codec. More grains of salt
> added, the speakers on any phone/tablet tend to not be as good as full
> size speakers in a quality radio.
> 
> Given that all of the nodes systems I have built, the large count of
> dialing into ASL or my nodes, never has a hissing noise, or anything
> else that would be considered objectionable, has ever been heard.
> 
> ..... Post your results, be as specific and organized in you writings
> as possible.
> 
> ~Benjamin, KB9LFZ
> 
> 
> 
> On Fri, 2017-12-08 at 22:44 -0800, Alejandro Pereida wrote:
>> Hello all:
>> 
>> I just finished building a 900 MHz repeater using a pair of TK-941
>> radios, I’m using a DMK URi and a Pi3 with the latest version of
>> asterisk
>> when using locally the repeater the audio ie very good, but most of
>> the audio coming from internet linked connections come in with a
>> strong constant hissss noise, in some cases the noise can be weaker
>> or stronger than others but only happend to audio coming into the
>> repeater from the internet.
>> 
>> Any ideas what this may be?
>> 
>> Thanks
>> 
>> N2IX
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