Important issue with Rev.C / D Plutos and GPS locking

[Basil]

Dave G8GKQ has asked me to send to the list what were originally private mails regarding the later Pluto Rev. C and D versions when used with an external frequency reference. I am in a bit of a bind with work so excuse the copy pasting, but we think the information needs disseminating more widely. Please DO NOT inundate the Analog Devices support forum with questions, this matter is almost certainly out of their hands and remit...

As sent to Dave via PM:

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It SEEMS, at the MOMENT, with many caveats, that there MAY be an issue with the recommended Portsdown 4 firmware and Rev C / D Plutos used with an external reference. Perhaps, when you have a few minutes you could look at this thread I have running on the AD support forums, it seems there COULD be an inconsistency between the PD4 recommended firmware the latest Plutos when used with external references. AD are asking if the source code is available to look at?


https://ez.analog.com/adieducation/univ ... sue/465755


Later I added:

There does indeed seem to be an issue. I loaded Analog Devices v 0.34 firmware and commanded
# cat /proc/device-tree/model and it returned Rev.C

I then loaded the recommended PD4 firmware and commanded again

# cat proc/device-tree/model and it returned Rev.B

As it sees it as Rev.B it is impossible to lock it to an external GPS via the onboard PCB connector socket.

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So it seems those of us using the likes of a Leo Bodnar as a frequency reference ON REV.C / D PLUTOS ONLY, are not in reality locking anything despite there being no warnings, *dependent on what custom firmware is in use*.

How to find out? If you have set your Rev.C /. D Pluto to use an external reference open a serial connection with the likes of PUTTY.

Ideally ave PUTTY connect at 115200 and no flow control. Type at the # prompt:

# cat proc/device-tree/model

See what is returned, it should be Rev.C (or maybe D).

If it returns Rev. B then, despite you having set it to use an external reference it won't be doing so and is still running off of its internal xtal...

Now, caveat, big caveat, I did get my Portsdown 4 to run on later than the 2010rc firmware, with APPARENTLY no obvious issues, whether it was then using the external reference I don't know, I will check. I was made aware of the issue when using my late model Pluto on the narrow band SSB portion of the Oscar 100 satellite and noted the 10.750 GHz beacon was well off. It's not at all obvious on the WB portion but if you have bought a Bodnar for your Rev.C / D and think it;s working with whatever version of custom firmware, it may be worth verifying this.

If you have modded a Rev.B to use an external reference by removing or bypassing the surface mount oscillator, you're laughing, it will be fine.

Progress ehh?

[G4HTZ]

Not sure this is relevant but this guy seems to have locked his Pluto ok to a Leo Bodnar unit

https://youtu.be/o2IeXpsOQig

[Basil]

Thanks for the link Steve, he will have been using a later version of custom firmware, the issue is it won't lock when using the Portsdown 4 firmware, FIRM2101RC.sip, (that's the only one recommended and supported by Dave for use with a PD4), because the recommended firmware pre-dates versions C and D Plutos.

So either F5OEO can be persuaded to alter the FIRM2101RC firmware, or supply some sort of patch, or Dave can be persuaded to make the PD4 work to his satisfaction with later firmware that recognises a Version C or D Pluto. It may be. given the source code, someone at Analog Devices could modify it to work with current Plutos, too.

I get the impression Dave's a bit whatsitted off with all the Pluto changes though

Is F5OEO still actively developing Pluto firmware?