Adalm-Pluto Rev D

Hallo Miro,

from time to time, there where reports about unexpected frequency offsets with the Pluto. I am not sure but my recommendation is, bring all calibration settings in the Console to zero. Use all the options that are shown. Probably in the Plutos firmware are factory offsets.
This happend to me using the pluto not for satellite operation but on 2m and 70cm. Returning to Sat-mode I found a strange offset altoughan external Leo Bodnar Clock is applied. After a cold start all was fine again.

Yout settings of the environmental variables above seem to be ok.
73
Andreas

Hi Andreas

not sure what do you mean "bring all calibration settings in the Console to zero"

I was trying to set ad936x_ext_refclk to 0 or leave blank, but it did't help.

73 Miro

Hello Miro

With searching "Pluto 40000000" I found 8 threads. Hope this helps.

Hi Miro,

most of the Pluto users operate with the SDR-Console written G4ELI, Simon. This program allows all you need for satellite operation. There are menues to adjust the 40 MHz Pluto-clock. The receive frequency can be locked with the help of the PSK-Beacon. The transmit frequency is controlled by the 40 MHz clock only. To adjust the transmit use XIT, nothing else. If the external clock is GPS-locked there is no need for adjusting anything. But sometimes unexpected offsets occur. The solution was set all the values in the SDR-Console menues to zero and do a cold start.
Set all the hooks also. We assume, there are correction values stored in the Pluto which cannot be changed easily setting the variables.
May be we continue discussion per email. <mycall>@t-online.de
73s
Andreas

Hello

my solution is shown here:

https://hf5l.pl/en/adalm-pluto-revision-d/

73

Miro SP5GNI

Not sure if this has been picked up on yet or not, but there is info about activating the 2nd RX/Tx paths here: https://ez.analog.com/adieduca…tivate-the-2nd-rx-channel. I haven’t tested it on mine yet!

Matt M5MAT

So how do people who also use a Revision D Pluto with an external 40 MHz reference on DATV wide band manage this frequency shift please? I want to buy a spare Pluto, but am currently using an earlier revision which doesn't have this problem. I was hoping the on board coaxial sockets would make an external injection of the reference easier, not more problematical!

Thanks!

Hi,

This syntax works :

fw_setenv ad936x_ext_refclk_override "<25000000>"

If you use a new tcxo inside he pluto the external ref command does not work ... cause new tcxo has no enable pin (to switch it off) .. i rerouted that switching transistor from enable pin of xo ... to enable pin of the power supply ic for the clock (u12) .. now i can have both .. a stable internal clock and still have the option to feed external 40 megs in

(feel free to ask for details)

the pluto has a frequency "nailed in stone" in uboot-extra-env.dfu.

example:

VíÞserial=1044734c9605000cf9ff120010c84f79ec productkey=d9f04f074f5e6992d04b879a176410570a3ed77a ad936x_ext_refclk=<39999843> ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ

now the pluto "thinks" on boot he has a ref clock tha is157 hz low

xo correction = 40 000 000 plus setting also 40 megs in sdrconsole and all is well

in pluto options calibration set the checkbox to "apply corrction when connecting to pluto" and the 40 megs is sent to pluto on boot

LET THE TX OFFSET AT 8089.5!! and set XIT to 0 !!!

if done well you should be spot on (except the doppler shift of around 150hz)

Quote from SV1BDS

Hi,

This syntax works :

fw_setenv ad936x_ext_refclk_override "<25000000>"

Thanks for this information, that is reassuring!

Here is an interesting Phenomime

I did enter "fw_setenv refclk_source external"

Also did reboot the Pluto Rev C

But this seems not to disable the internal clock. So without connecting to the external connector it just carries on receiving the signals just fine. Same as before the command. Shoudnt fw_setenv refclk_source external disable the internal clock source?

Béla

As far as I remember the SW recognises the HW revision and rev D commands shall not work on rev C HW.

Basically the command switches a GPIO which controlls the switchi g HW. I modified my Pluto and had to add a parallel resistor to the rev resistor. The same generates an analogue value which is evaluated at startup. Check the associated schematics.

Sorry for resurrecting an old thread.

I'm new to QO-100 and I've just ordered an Adalm Pluto. I plan to replace the TXCO with TG2520SMN 40.0000M-ECGNNM3.

This will be enough for digital modes FT8/FT4 ?

Because this TXCO doesn't have an E/D pin, I will loose the option to switch to external reference using CLK_IN u.fl connector.

Is there any option (cheaper than using a LeoBodnar GPSDO) for a 40Mhz ref in ? I have a 10Mhz OCXO and I can try to get 40 or 50MHz, but phase noise is what worries me.

vy 73,

Petronel

YO8SEP

Hi, at the moment I'm going with reference to 25 mhz, I've tried both with gpsdo and with tcxo, and it's absolutely not bad!

iu4gav what TCXO are you using ?

Petronel,

from 10MHz OCXO (squarewave) you can extract 50MHZ harmonic with crystal and buffer this with inverters and feed into pluto.

Divided by 2 can be used for LNB!

Found this somewhere, do not remember where.

25MHz for the pluto is out of spec as far as I remember , might work or not.

In a second step you may sync the OCXO to GPS ... ... always good to have enough ham projects

I do not recommend to remove original TCXO because you have to apply a lot of heat. Disable it by EN input and place the new TCXXO elsewhere on a small PCB.

Looking at ADALM-PLUTO details, I can't find if external CLK_IN should be sine or square-wave.

Quote from DL5LF

Petronel,

from 10MHz OCXO (squarewave) you can extract 50MHZ harmonic with crystal and buffer this with inverters and feed into pluto.

Divided by 2 can be used for LNB!

Found this somewhere, do not remember where.

25MHz for the pluto is out of spec as far as I remember , might work or not.

In a second step you may sync the OCXO to GPS ... ... always good to have enough ham projects

I do not recommend to remove original TCXO because you have to apply a lot of heat. Disable it by EN input and place the new TCXXO elsewhere on a small PCB.

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As per the document, the pluto supports colck from 10 to 80 mhz!

iu4gav

You are right.

I remembered some of the numerous discussions about this topic in this forum, e.g. here

YO8SEP

It shall be square wave within the specified limits: 1.3Vpp. There are also various discussions and measurement results in this forum.

Here is the diagram of Rev. D