Feedback on possible KerberosSDR V2 Hardware

Discuss KerberosSDR - 4x Coherent RTL-SDR
rtlsdrblog
Site Admin
Posts: 2384
Joined: Mon Nov 19, 2012 11:54 pm

Feedback on possible KerberosSDR V2 Hardware

Post by rtlsdrblog » Tue Nov 05, 2019 9:41 pm

We're considering how to make the next version of the KerberosSDR hardware and would like some user feedback:

Initial thoughts on V2 hardware are:

[*]RF Input Switches - This will remove the need to disconnect the antennas during calibration
[*]Built in Computing with Gigabit Ethernet + WiFi - A built in processor with preinstalled software. This will allow for essentially plug and play direction finding and PR. It will also allow for coherent data to be easily streamed out of the device for use on a PC/GNU Radio etc via a TCP connection. Could also allow for multiple other use cases.
[*]Bias tees
[*]Proper PD USB-C handling + the ability to use a barrel plug pack
[*]An improved form factor

Are there any other things people might like to see? For example, considering perhaps a small LCD screen too.

Target pricing: US$199, would you be interested?

dg9bew
Posts: 2
Joined: Mon Mar 18, 2019 7:08 am

Re: Feedback on possible KerberosSDR V2 Hardware

Post by dg9bew » Tue Nov 05, 2019 9:43 pm

I would buy one :)

awdmesh
Posts: 9
Joined: Tue Oct 22, 2019 4:23 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by awdmesh » Wed Nov 06, 2019 12:04 am

I like the idea of built in software for an all in one device. Would you be sticking to the same way it works in the raspberry pi or laptop software? Meaning, would it still be pushing out info on port 8081 with the DOA information being the same? I have a plugin for some mapping software that’s pulling that info in using the lobs being generated by the Kerberos/pi.

Would you still make the v2 available for those that want separate hardware?

rtlsdrblog
Site Admin
Posts: 2384
Joined: Mon Nov 19, 2012 11:54 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by rtlsdrblog » Thu Nov 07, 2019 1:08 am

awdmesh wrote:
Wed Nov 06, 2019 12:04 am
I like the idea of built in software for an all in one device. Would you be sticking to the same way it works in the raspberry pi or laptop software? Meaning, would it still be pushing out info on port 8081 with the DOA information being the same? I have a plugin for some mapping software that’s pulling that info in using the lobs being generated by the Kerberos/pi.

Would you still make the v2 available for those that want separate hardware?
Yep it would be the same method, or at least that would remain as an option. Idea is that DFing and PR would run natively on board, just turn it on, connect and use. But at the same time you can also easily access the coherent samples over Ethernet, and process them on a fast PC, if say you want high FPS PR, or want to do something more intensive like beam forming + PR.

What mapping software + plugin are you using? Can you share or is it private?

awdmesh
Posts: 9
Joined: Tue Oct 22, 2019 4:23 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by awdmesh » Thu Nov 07, 2019 1:26 am

I’ll check, but I don’t think it can be shared. I’d still love to talk with you guys on what I’m trying to do though. I do have a question for you guys, if you have the Kerberos setup stationary with say a circular array and your trying to push the DOA to an external system and the Kerberos itself has no gps, how do you ensure the lobs being overlaid over a map is correct in relation to N, S, E, W? I’ve been racking my brain and it’s probably something that’s so simple to understand. Would it be helpful if the next version of Kerberos could accept a usb gps? Does that even matter when doing dfing?

rtlsdrblog
Site Admin
Posts: 2384
Joined: Mon Nov 19, 2012 11:54 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by rtlsdrblog » Thu Nov 07, 2019 11:52 am

awdmesh wrote:
Thu Nov 07, 2019 1:26 am
I’ll check, but I don’t think it can be shared. I’d still love to talk with you guys on what I’m trying to do though. I do have a question for you guys, if you have the Kerberos setup stationary with say a circular array and your trying to push the DOA to an external system and the Kerberos itself has no gps, how do you ensure the lobs being overlaid over a map is correct in relation to N, S, E, W? I’ve been racking my brain and it’s probably something that’s so simple to understand. Would it be helpful if the next version of Kerberos could accept a usb gps? Does that even matter when doing dfing?
You just aim the antenna array with antenna 1 facing North, or in whatever reference you prefer. 0deg is then from wherever antenna 1 points.

A USB GPS isn't going to help you with a bearing if it isn't moving. GPS needs movement to be able to determine a bearing. Only a compass can help when stationary.

awdmesh
Posts: 9
Joined: Tue Oct 22, 2019 4:23 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by awdmesh » Thu Nov 07, 2019 12:10 pm

Makes total sense, thanks! I’d still be interesting to have gps on the Kerberos (for when it’s moving) itself and have that information being pushed out to an external source that has offline maps and the ability to overlay the information from multiple sources.

Streets814
Posts: 5
Joined: Tue Oct 15, 2019 12:44 am

Re: Feedback on possible KerberosSDR V2 Hardware

Post by Streets814 » Thu Nov 07, 2019 12:49 pm

A little background first. I have had my ham license for a little less than a year now. Other than radio communications, what attracted me to the hobby is Direction finding and data over radio (see AREDN project.) I have purchased another Direction finder (http://members.chello.nl/~w.hofman/pa8w/rdf.htm) and (https://radiodirectionfinding.wordpress.com/) if you are familiar with RDF mapper (http://www.musther.net/RDFMapper/) you most likely know about the direction finder linked above.

Having purchased the RDF42 (which cost between 2-3 times the price of the Kerberos SDR by the way) I came to the harsh realization it was a bit more complicated to assemble than I anticipated. Unfortunately, as a result, it sits in its original box with all the pieces unused. I have been following this project for a while now wanting to try it out, but hesitant to not have another unused device sit on my shelf. The idea of a plug and play ready to use version greatly appeals to someone like me. To be honest I want to pull the trigger on purchasing just to support the project.

With that said here are some things someone of my ability/knowledge (minimal) would find interesting or would like to see:

• Truly plug and play. Its easier (for somone like me) to tinker and learn than to have to build from scratch. while the Kerberos board is a lot easier than other systems I have seen, the easier to get started the better.

• If you add a small screen as mentioned something like the RDF42 screen (https://radiodirectionfinding.wordpress ... ot-screen/) makes a lot of sense. Right half has a direction bearing pointing in last X amount of directions averaged. The "ex" (bottom right) shows when an accepted signal has been sent to the computer. Center bottom is the symmetry meter above that (numbers) and to the left of that (bottom left corner) is the elevation meter which I am not sure how works to be honest. You can see the "quality" of the signal in the center of the screen just to the left of the direction pointer showing "Q8." I believe the signal is graded 0-8 and can be used by the user to set a rejection threshold. Meaning if the user sets the threshold at 5 any signal lower will be ignored and not sent to the computer for direction finding.

• Anything that will assist with using multiple devices together. As stated above I am also following the AREDN project a lot as well. The idea of a ham radio mesh network using wifi on the ham bands over long distances may have a lot of options with the kerberos. If I have multiple sites and install a kerberos on each site I could (in theory at least) simultaneously get a reading from the kerberos and see in real time the direction/source of the signal using mapping software like the rdfmapper.

•Ease of use. If there are easy to find simple to understand controls/features it makes life simpler for someone at my level. dials, knobs, sliders (real or virtual) that are self explanatory go a long way. I am not suggesting dumbing down the project but rather quick access to learners rather than digging deep into the settings like advanced users. Maybe a basic GUI for new users?

• Price. While you have no complaints from me on the affordability of this device and project as it is by far the lowest priced direction finder option that I came across (by a large amount.) The ease of affordability on the wallet will keep this project in as may hands possible.

ac8dg
Posts: 10
Joined: Fri Jul 19, 2019 12:37 am

Re: Feedback on possible KerberosSDR V2 Hardware

Post by ac8dg » Thu Nov 07, 2019 9:05 pm

I don't like idea of an rpi with wifi built into the enclosure along with the sdr's. The extra spurious rf that close to the sdr's really degrades the radio performance.

That said, if the proper shielding can be maintained (for the price), then something to simplify the use is needed. I don't like having to power the sdr box, then power up an rpi, then power up an android (tablet/phone). And the calibration for every frequency change procedure is ridiculously complicated.

A built in "compass" lcd display that makes the unit work "out of the box" would be great. all the gps maps are just cosmetic frills and bloatware.

rtlsdrblog
Site Admin
Posts: 2384
Joined: Mon Nov 19, 2012 11:54 pm

Re: Feedback on possible KerberosSDR V2 Hardware

Post by rtlsdrblog » Fri Nov 08, 2019 3:53 am

ac8dg wrote:
Thu Nov 07, 2019 9:05 pm
I don't like idea of an rpi with wifi built into the enclosure along with the sdr's. The extra spurious rf that close to the sdr's really degrades the radio performance.

That said, if the proper shielding can be maintained (for the price), then something to simplify the use is needed. I don't like having to power the sdr box, then power up an rpi, then power up an android (tablet/phone). And the calibration for every frequency change procedure is ridiculously complicated.

A built in "compass" lcd display that makes the unit work "out of the box" would be great. all the gps maps are just cosmetic frills and bloatware.
RFI is definitely a concern and would need to be addressed for it to work. That said i'm sure there is a way to properly shield the computing hardware.

The proposed screen could definitely have a compass display. I really disagree regarding GPS+maps being just frills though. With multipath a big problem with DFing, what's really needed is some system like what we have on Android that can average the data on a map, and calculate an actual location. With a simple compass display this just isn't possible, and you could just end up going round in circles.

Post Reply