Langstone loses its extended frequency range periodically.

[n5bravofoxtrot]

I am running g4eml / Langstone-V2 on an RP 4 with a Rev. C. Pluto.

I've followed the directions at https://wiki.microwavers.org.uk/Langsto ... _the_Pluto to extend the frequency range to the ad9364 range so that I can operate on 222 MHz and 24 GHz (with the x5 MULT setting). This all works fine.

Except that on occasion it forgets that its frequency range is extended and, after some lengthy problem discovery process, I have extend it again.

This happens often enough that I've been on watch to see if I can see what happens. Today I caught it in the act.

I was switching bands when the RP crashed, as it does sometimes. When I rebooted, the frequency extension was no longer working.

Powered down, connected directly to Pluto, putty in to COM11 and set the extension again.

Rebooted Langstone. Crashed on the first boot up, as it often does. Second time it came up with the frequency extension working as desired.

The instructions mention an additional step 'fw_setenv compatible ad9364' for use with a Rev D. Pluto. I have both done and not done this additional step. It seems to make no difference, either on the frequency extension working properly, or losing it sometime later. My current Pluto is Rev C. It replaced a Rev B. that got broken a few months ago. I don't have any record that I ever had this problem on Rev B but that doesn't mean I didn't, just that if I did it didn't get written down in a searchable way.

Does anyone know why this FW setting is getting lost in a crash sometimes? Any ideas as to why the system would crash occasionally on band switching or more frequently on the first boot up of the day? Crashes don't always result in loss of FW setting, as far as I can tell, but now that I know what I'm looking for maybe I'll have better data later.

I'm not asking for anyone to fix anything, I just want to understand what is going on, in the case that someone else has encountered and understands this issue.

Thanks and 73, Courtney N5BF

[g4eml]

Langstone does not deliberately make any changes to the Pluto's configuration settings. So in theory nothing should ever change. I have never seen the issue you describe and don't recall anyone else reporting it.

The Pluto is however known to be very critical of power supply fluctuations and random crashes are not uncommon wherever it is being used. Langstone lockups can normally be traced back to such Pluto failures. Making changes to the power supply arrangement is normally the best way to reduce such failures. Some people have had success using the auxiliary power connector. Some have added a series diode in the positive power line to reduce the Pluto voltage to about 4.7v. some have just used a different cable or USB port. There doesn't seem to be a universal fix that works for everyone.

The configuration settings are stored in the Pluto's flash memory. I can only assume your particular Pluto is corrupting that memory area when it crashes. This is probably being detected on the next reboot and the memory is then being restored to default.

Colin G4EML