[Ground-station] UI for SDR

Bruce Perens bruce at perens.com
Sat Jun 30 17:22:58 EDT 2018

I am running all-OpenWRT. They have made it easier to buy new equipment by
providing an "ideal for OpenWRT" list at

The release candidate for OpenWRT 18 is quietly being tested (look in their
downloads directory) and seems to work pretty well so far. I have
previously reflashed some Ubiquiti equipment to OpenWRT, for example their
2.4 GHz dish with built-in AP. For the firewall I have a Turris Omnia box,
which uses a fork of OpenWRT that they maintain and automatically update.

The Zyxel Amor Z2 (NBG6817) is $170 at Amazon and really impressive for
running OpenWRT. 4G flash and 1/2 G RAM onboard, 1W 2.4 GHz, 0.2W 5 GHz.
And it's based on WiFi chips that have good Open Source drivers.

Regarding TCP/IP networking for Amateur Radio, sometimes it's wrong for
voice. Comparing the size of an IPV6 header and 40 ms of Codec2 speech
demonstrates the problem, the data payload can be smaller than a single
address, not to mention the entire header. Connection-based protocols
rather than packet switching can make more sense for voice.

Regarding building data networks that support multicast, yeah, it would be
nice to have multicast that works, and I often wonder if the best way to
solve this on the internet is to create a global VPN with distributed hubs
and multicast routing between them. Run the client connection over
websockets so the ISP firewalls can't mess with you.

I think Amateur IP should be IPV6-only. There is no point in putting effort
into IPV4 strategies any longer.



On Sat, Jun 30, 2018 at 1:23 PM, Phil Karn via Ground-Station <
ground-station at lists.openresearch.institute> wrote:

> On 6/28/18 08:14, Michelle Thompson via Ground-Station wrote:
> > Douglas (and all),
> >
> > What are your thoughts on a UI design for IP multicast-based SDR?
> >
> > The distributed and flexible nature would seem to be something that
> > should come through.
> >
> > I think there's broad agreement about panadapter+waterfall being the
> > very best UI for narrowband signals of any type.
> Agreed.
> >
> > Is there something as compelling for wideband digital?
> Wideband signals are really too specialized to give a general answer. If
> we're trying to build something like an Internet, then standard Internet
> network monitoring and management tools would be appropriate.
> But what levels are you interested in? If you're interested in the
> physical layer, you'll want to see physical layer stuff like RSSI, noise
> and interference levels, bit error rates, retransmission rates,
> modulation and coding scheme (MCS) adapatations over time, etc.
> At higher levels you can use standard Internet packet tools like
> Wireshark (which can decode 802.11 control packet headers if they're
> available from the hardware).
> I recently bought a bunch of Ubiquiti access points that come with their
> own management package called "UniFi". I was reluctant at first since
> it's proprietary to them, but it looks fairly nice. You run it on a
> local system (including Linux) and talk to it with a web browser. Among
> its utilities is a way to command an access point to do an RF survey and
> plot local activity as measurements of signal strength and intensity (%
> of time busy) vs frequency.
> Soapbox time....
> I would like IP (and IPv6) multicast to be a central feature of any
> large-scale ham Internet that we build. I think it's an absolute natural
> for traditional ham radio applications, especially nets and roundtables.
> A *lot* of work went into IP multicasting about 20 years ago yet it's
> largely stillborn in the public Internet. It *is* heavily used in some
> walled gardens such as AT&T U-verse and some corporate Internets. The
> closest approximation to what hams might already know is a DMR
> "talkgroup", which is a very pale imitation of what's possible with IP
> multicast.
> My baseline multicast application for many years has been a tactical
> digital voice net. I've been thinking about this ever since 9/11 when I
> heard about how many first responder lives were lost to the
> communications failures within the WTC towers. Today I *know* we could
> build a very effective prototype using just RPis and USB headsets, and
> we could extend it into a much larger network.
> Here's where I think hams could still make a significant contribution to
> the state of the art. We could basically do what Motorola should have
> done years ago, except that they're such a monopoly in the public safety
> radio business that they've had no incentive to innovate. Our advantage
> as hams is that we don't need a financial incentive to do that; it comes
> naturally. That's why we were playing with TCP/IP over radio in the mid
> 1980s, long before the world saw it coming.
> Phil
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Bruce Perens K6BP - CEO, Legal Engineering
Standards committee chair, license review committee member, co-founder,
Open Source Initiative
President, Open Research Institute; Board Member, Fashion Freedom
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