Receiver audio distortion

WA2DVU
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Receiver audio distortion

Postby WA2DVU » Tue Jan 30, 2018 12:50 am

I have had my 7000 for a few weeks with no problems. Turned on today and rx audio was very distorted. Rebooted PC, turned software and 7000 on and off a few times, disconnected 7000 from LAN and connected it directly to PC . No cure. Deleted software from PC and reloaded it and rig worked fine. Is this a known problem or just a glitch. Great rig and really glad that the other rigs were not being shipped before the 7000. 73,

Bill, WA2DVU
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w-u-2-o
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Re: Receiver audio distortion

Postby w-u-2-o » Tue Jan 30, 2018 2:52 am

Sounds like a corrupt database file. I'd characterize it as a glitch.
WA3GIN-Dave
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Re: Receiver audio distortion

Postby WA3GIN-Dave » Fri Sep 13, 2019 12:21 pm

While listening to the 7000 this morning receive audio became distorted. I was running task manager in the "Performance" mode. At the time I saw big hits to the Ethernet throughput of the PC running HPSDR. Typically ,Power SDR uses about 55Mbps (version 3.4.9) but the hits were dropping throughput down to 20-30Mbps. As it turns out the PC running HPSDR is connected to a Gig switch which also serves a MacBook Pro which was running Chrome and at the time it streaming a news video. When I cancelled the video download the HPSDR PC throughput returned to 55Mbps and as you would expect the audio became crystal clear! I guess this is an example of network congestion. So, one must appreciate that there are external network factors, such as the MacBook Pro connected to the same switch but downloading from the Internet that can produce LAN congestion in the switch: even though the SDR PC and the ANAN are utilizing a (so called) dedicated LAN connection theoretically not dependent upon unrelated Internet throughput on another port in the switch. Maybe there is something that can be configured in the switch to prevent this unwanted interaction.
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w-u-2-o
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Re: Receiver audio distortion

Postby w-u-2-o » Fri Sep 13, 2019 12:53 pm

Dave,

You need a "non-blocking" gigabit Ethernet switch. A non-blocking switch will deliver wireline speeds between any two ports regardless of what the other ports are doing. Such switches need not be expensive. There is a Netgear 8 port GigE non-blocking switch on Amazon for under $20. In other words, at those prices nobody should be using a switch that is not non-blocking.

73,

Scott
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Re: Receiver audio distortion

Postby WA3GIN-Dave » Fri Sep 13, 2019 1:39 pm

Thanks Scott, I thought the TP-LINK TL- SG-105 was a non-blocking.
K9RX
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Re: Receiver audio distortion

Postby K9RX » Fri Sep 13, 2019 1:47 pm

Forgive my ignorance Scott - I copied what you had there "Netgear 8 port GigE non-blocking switch" and pasted that in to Amazon - it came up with a list of switches - none of them said "non-blocking" .... so obviously that is not the term they use in advertising. They do say unmanaged and managed ... not sure what else I should be looking for. I don't know that I have any issues with my current switch, I am not currently running Thetis but will at some time - a good ways in the future when it's thoroughly rung out ... but if indeed one of these is available for $20 I'll get it just to see if that helps say in the drop outs for WSJT ... and as a prep for the future. Help?

Gary
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Re: Receiver audio distortion

Postby w-u-2-o » Fri Sep 13, 2019 6:28 pm

Gary,

Here's the search I used:

https://www.amazon.com/s?k=non-blocking+gigabit+switch

The very first hit for me is the Netgear 8 port switch:

https://www.amazon.com/NETGEAR-Ethernet-Unmanaged-Internet-Splitter/dp/B00KFD0SYK

which, if you look at the spec's, clearly says "non-blocking".

The first search link above is not 100% reliable in that every product listed might not be non-blocking. However you can usually look up the spec's at the manufacturer's web site to check on that. Nearly all TP-Link products are.

Here is a simple definition of non-blocking:

https://www.pcmag.com/encyclopedia/term/48037/non-blocking

As you get into larger switches the backplane or "fabric" will be specified in terms of "x" amount of gigabits/sec. For example, in a 48 port switch it may not be practical to support full non-blocking performance, but maybe it can achieve some significant fraction of that.

At any rate, given that a reasonable level of non-blocking switch performance is available at the lowest consumer price points for small switches, there really isn't any reason that switch performance should be any impediment to radio performance.

73,

Scott
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Re: Receiver audio distortion

Postby K9RX » Sat Sep 14, 2019 1:05 pm

Thanks Scott,

So the definition is worthless - "non-blocking, that which does not block" . Doesn't relate to any other facet or name used like managed vs. non-managed... and the only one I've found so far is that plastic cased one, the Netgear that specifically says 'non-blocking' and also says no config needed. Some of the others mention the ability to optimize through configuration - something as I'm not an IT manager (nor desirous of being one) I'm not prepared to mess with ... seems a bit of a crapshoot unless you find one that says "non-blocking".

Of course as we both know if you do a

non-blocking gigabit switch

search you'll get everything that matches ANY of the words ... instead I did a

"non-blocking" gigabit switch

search and found the GS308, metal, non-blocking (mentioned WAY down the page) and doesn't require configuration.

At $21 I'd have to agree it's worth having if only for the comfort that it is optimal. It probably will have zero impact on the latency issues re digital mode but what the heck... it's on order.

THANKS!

Gary
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Re: Receiver audio distortion

Postby K9RX » Sat Sep 14, 2019 1:19 pm

And then just to be sure - I checked the one I'm currently using, a Netgear GS105, a good 5+ years in service ... and its data sheet, found online, says "non-blocking" ... so I guess I'm there already!

Gary
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w-u-2-o
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Re: Receiver audio distortion

Postby w-u-2-o » Sat Sep 14, 2019 8:48 pm

Gary,

I cannot understand what you find lacking in the definition of "non-blocking" as the term is used for computer networking, but I suppose that's probably irrelevant.

The data sheet I found shows your switch provides up to 10Gbps non-blocking performance on its backplane, which should be more than enough to allow one computer to stream video from the internet and while the radio-PC link suffers no ill effects. Typical video streams are only around 8Mbps. Even if it was 10 times that it shouldn't matter.

Are you results repeatable?

73,

Scott

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