Remote Bandwidth

[R L]

Hi all, 

Can anyone tell me what bandwidth I will need to operate the Hermes out of home on the remote PC side? I would like to use it at work to listen sometimes. I have a solid 45mbps down at work and wonder if that will be enough? The Hermes transceiver will be at home and my speeds are 500 down and 35 up. 

Thanks all.

Rob

["Christoph v. Wüllen"]

That depends how many RX channels you use at which sample rate.

If you are doing PURESIGNAL, you have 4 channels, else
you have 1 or 2 channels, depending on whether you have 1RX or 2RX.

With n channels, you have about (6*n+2) bytes per sample
(it is slightly more), this you have to multiply with your sample rate.

So:

no PURESIGNAL, 1RX, 48k sample rate ==> 3 MBit per second
PURESIGNAL, 192k sample rate ==> 40 Mbit per second

Note the problem is usually not the (nominal) band width but the
jitters, that is, small breaks in the data stream.


BUT BUT BUT BUT, you need MUCH LESS bandwidth if having
a "local" computer communicating with HL2 and use a
client-server software for doing radio. As far as I know
Quisk and piHPSDR have such a feature, and most likely
other SDR programs have it as well.

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[dsolbe...@gmail.com]

I have been using a local PC running Thetis and a virtual desktop application.  I find that Tight VNC works very well but it doesn't have audio, so you need another application for the audio.  Some other VNC applications, like Team Viewer have audio. Remote Aud works good for audio.

I use the VNC to provide access to all of my other stations applications: remote antenna switch, auto tuner, amplifier controller, and SteppIr controller.  This setu lets me run my station from anywhere.  I was able to work Bouvet and Crozet on FT8 from motels!

Good luck with your remote station.

73

Don K9AQ

[R L]

Thank you both for your answers. To give a bit of background, I currently use an IC-7300 remotely with their software and it only uses less than 1MBps to run remotely on the remote PC side. Before I invested in the Hermes I wanted to get an idea of what I may need.  I will research the info you both gave me and see where I end up with it.  I won't need PURESIGNAL, and 48k sample rate will work just fine for my needs of mainly listening while working. So I *think* the Hermes may be a viable solution for me.  I do want to check out the piHPSDR as I have never heard of it. But yes,  around the 3MBps rate would work out great with the settings you mentioned above and my available bandwidth. 

Thank you!!

Rob

[Dan Cusick]

NoMachine nx is free and supports audio quite well.  

73,

Dan

W9IRL

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[Heath Petty]

The low bandwidth with the Icom is due to the fact that its only sending audio and waterfall data over the network connection. The Hermes lite 2 sends  full I/Q data over UDP, and that requires much more bandwidth, and a consistent network (i.e. very low jitter). As mentioned, both piHPSDR and Quisk have a remote head feature, where the I/Q data from the HL2 is processed on your "local" system, then the audio, control, and waterfall data is sent to the remote station. This is basically the same thing that Icom's remote software works. There is a server running on the Icom radio (I have an IC-705 which has this same feature) and the Icom software connects to that server. Running with these remote heads has the advantage of using much less bandwidth, and better able to handle WAN networks (higher jitter). 

Remember that HL2 is actually fairly simple, and the heavy lifting is done in software on your computer. 

-Heath

[DL1YCF]

Note that the bandwidth requirement for client/server applications should be very similar, since it is by far dominated
by transferring audio. In piHPSDR, the waterfall data is about 10 kByte/sec. The audio data (audio is sent in mono
to save bandwidth) is 96 kbyte/sec about 750 kbit/sec, and unless down-sampling before transmission and up-sampling
at the client side, this requirement is fairly constant across different client/server solutions.

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[Dave Lapp]

You might want to take a look at using Quisk with your HL2. It uses 2 instances of Quisk, one on a computer in the "remote" location with the HL2 and the other running on a computer at your location. 

I have not used this setup and don't recall the details of the protocols used to communicate between the 2 ends but I do know that several users have reported success and satisfaction using it. The support list for Quisk is on Groups.io (https://groups.io/g/n2adr-sdr/topics) and someone there can probably answer your question with regards to Quisk remote.

73

Dave VA3DPL/VE3LHO

[ron.ni...@gmail.com]

For receive only, using one slice at a 48k sample rate, only 3.145 Mbps (bits per second) of network bandwidth is required for the Protocol 1 IQ data packets.  Multiples of that for higher bandwidths or more slices (as might be needed for adaptive pre distortion).  However, to transmit a clean signal, a magnitude higher bandwidth to the HL2 may be needed to keep the worst case latency jitter below 10 mS or so, due to possible network contention or buffering (common over WiFi or cellular links).  73, Ron, N6YWU