Orion vs Saturn - Pros and Cons of each

[Joe]

Just wanted some help with differentiations of the two versions, with Thetis, using the raspberry pi 4, remote, latency, etc? Would using the Orion with static ip to a separate network adapter with the 2nd adapter interfaced to the internet help with the remote scenario, etc? Just different observations with benefits of each would be appreciated.

Thanks and 73’s
Joe
WD5Y

[w-u-2-o]

If you look at the hardware as a black box with the only interface being the Ethernet port, then theoretically there's no difference from that point outward. Because the messaging protocol almost entirely depends on UDP, provisioning an Ethernet link with the lowest UDP packet error & loss rates between the hardware and the thick client (Thetis) provides the best performance. Hence an Ethernet port on the thick client machine (PC) dedicated to only servicing the connection to the SDR hardware will remain the highest performance solution for both Orion (any variant) and Saturn.

That said, the GigE implementation on Orion is pretty threadbare. Timing closure is often barely adequate, there is no support for subnet masks, etc. Meanwhile the GigE implementation on the Pi is well proven and rock solid. This alone may or may not prove to be sufficient to eliminate any advantages of having a dedicated Ethernet link between the hardware and the thick client machine. There is no way to know until people start to report their experiences with Saturn.

However, a similar situation may also prevail on the Pi as on the PC. AFIAK, the CM4 modules will be provisioned with both WiFi and a GigE port. Dedicating the GigE port to only servicing the connection to the thick client machine, and using the WiFi for internet uplink, is probably going to be the preferred approach. Again, people will have to get some Saturns and start experimenting to see.

All in all, a mature GigE implementation on the Pi is probably the single biggest "pro" from a user perspective.

As for latency, it stands to reason that it is likely to be worse on the Saturn. The path from antenna to mic or speaker is simply longer. Assuming the use of VAC, and only considering the path of the digital IF data, on the Saturn it must be transferred over PCIE to/from a driver on the CM4, and transferred to/from the driver through the middleware software ("p2app"), then finally transferred to/from the Pi Ethernet driver and interface. Measurements will need to be made and compared.

The biggest "con" on the Saturn side is the additional complexity associated with the care and feeding of the Pi. People will now need to learn how to administer the Pi version of Linux. People without front panels will have to learn how to connect via SSH. Everyone will have to know how to configure the WiFi and the Ethernet port. How to run and configure p2app. How to use the app provided that runs on the Pi to upgrade the FPGA firmware. Those who wish to regularly update the Pi operating system will be at risk of things breaking due to such updates. Finally, AFIAK, the Pi will be configured to use eMMC storage. If someone wants to completely re-image their installation that requires obtaining access to a specific USB port that is only available inside the unit, and learning how to do all that.

Another unknown is how shutdown of the Pi is being handled. Simply slamming the power off on a Pi generally leads to file system corruption. This is not an issue for Orion.

You focused only on the Thetis case. One big "pro" of Saturn is that, for those who wish to utilize piHPSDR, it provides the look and feel of a "regular radio". I don't know how popular that use case will be. If most people decide to use the G2 with Thetis they may start to wonder why they bought the version with the front panel.

[Joe]

Scott,
Thank you very much for that information, I had questions but was unsure about asking at this point before the new hardware is out. I knew you could explain very well. This clears up many questions especially with regards to Thetis and both platforms. I see many discussions on Thetis in other forums, etc., it is driving many people to the Anan hardware for sure and I see it making Apache Labs a stronger company for it, which is good for all of us. Again, thanks.

73’s
Joe
WD5Y

[W4WMT]

Something to ponder:
Is the Saturn being manufactured under openHPSDR licensing?
Or is this now a totally new platform and considered completely proprietary to Apache Labs?
73,
Bryan W4WMT

[wevets@gmail.com]

It just occurred to me that Apache is likely to be supplying the Pi4 Compute module and Raspian software loaded along with their own software. If so - they will need to provide the Raspbian Source code on their web site to be GPL2 compliant. I don't imagine this will give them much heartburn since they are already an Open Source based product.

Didn't see it available on the Downloads page yet.

Steve

[w-u-2-o]

Is the Saturn being manufactured under openHPSDR licensing? Or is this now a totally new platform and considered completely proprietary to Apache Labs?

AFAIK, it's still considered a derivative work, same as all the preceding designs. The Saturn board is essentially identical to an Orion MKxx board except for the Xilinx FPGA and the CM4 support circuitry.

It just occurred to me that Apache is likely to be supplying the Pi4 Compute module and Raspian software loaded along with their own software. If so - they will need to provide the Raspbian Source code on their web site to be GPL2 compliant. I don't imagine this will give them much heartburn since they are already an Open Source based product.

Didn't see it available on the Downloads page yet.

Apache doesn't develop or supply any software or firmware. They might place copies on their website, or might not, and they might do the favor of preloading some or all of it onto hardware they deliver, but they are purely a hardware company where amateur radio is concerned.

Raspian is Raspian and comes from the Raspberry Pi Foundation.

The Xilinx firmware and the required Linux app's come from Laurence Barker, G8NJJ. It's all open source. His GitHub repository is: https://github.com/laurencebarker/Saturn

piHPSDR comes from John Melton, G0ORX. Also open source. His GitHub repository is: https://github.com/g0orx/pihpsdr

[wevets@gmail.com]

Scott,

If they are preloading software onto the G2 hardware (and I'm guessing they are - you want the radio out of the box experience to be pleasant) - then they are a distributor according to the GPL2 and thus should also supply a link to the Raspian source some place.

If you are supplying binaries - then you must supply the source. A link to the Raspian source is likely just fine to be compliant with the license.

Steve KA6S

[w-u-2-o]

I suppose that depends on your definition of "supply".

IMHO, Apache does not supply anything but hardware. No Apache employee writes or produces a single line of code. But that's just my opinion, I'm not an open source license expert nor an Apache employee.

[administrator]

Hello Steve,

Apache is loading the Raspberry Pi OS with all the required drivers/software preinstalled, we will be shortly uploading a copy of the OS image.

Regards,

Tony

Scott,

If they are preloading software onto the G2 hardware (and I'm guessing they are - you want the radio out of the box experience to be pleasant) - then they are a distributor according to the GPL2 and thus should also supply a link to the Raspian source some place.

If you are supplying binaries - then you must supply the source. A link to the Raspian source is likely just fine to be compliant with the license.

Steve KA6S