Pluto QO-100 drift and frequency shift, how much is normal?


Chris Wilson
 

11 May 2021

I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...


The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?


I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?


Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?


Thanks for any advice. Chris, call sign 2E0ILY

Screenshot of received signal showing frequency shift and choppy drift at:

http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg


--


Best regards,
Chris mailto:chris@chriswilson.tv


Siegfried Jackstien
 

YOU CAN NOT USE IT WITH THE STOCK XTAL!!!

greetz sigi dg9bfc

Am 11.05.2021 um 17:07 schrieb Chris Wilson:

11 May 2021

I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...


The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?


I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?


Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?


Thanks for any advice. Chris, call sign 2E0ILY

Screenshot of received signal showing frequency shift and choppy drift at:

http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg


Chris Wilson
 

Hello Siegfried,

Tuesday, May 11, 2021

OK, I knew the stock oscillator was poor, I hadn't realized it was THAT poor, it was just a quick test, I had little hope of the satellite hearing me at all, to be honest. I have the Leo Bodnar programmed for 40 MHz for the Pluto and 25 MHz for the LNB, I am just calming myself ready for my surgery on the Pluto PCB :)

Whilst I have your ear, how much drive should I set the Bodnar GPSDO output to for drivng h l reference please Sigi?

Thanks for the warning and quick reply.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


SJ> YOU CAN NOT USE IT WITH THE STOCK XTAL!!!

SJ> greetz sigi dg9bfc

SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...

The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?

I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?

Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?

Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg



SJ>


Siegfried Jackstien
 

if you are lucky your pluto is a new one (rev c/d) ... that has an internal socket for external clock and needs just a firmware command to use that external signal and switch off the internal clock

analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer chip inside has a max input level (from data sheet) of 2v max so better stay below that ... it should lock with only 0.5 to 0.8v level so better stay lower to be on the safe side

greetz sigi dg9bfc

Am 11.05.2021 um 17:07 schrieb Chris Wilson:

11 May 2021

I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...


The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?


I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?


Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?


Thanks for any advice. Chris, call sign 2E0ILY

Screenshot of received signal showing frequency shift and choppy drift at:

http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg


Phil Hazelton
 

Siegfried, can you explain how to do the firmware change on Pluto to switch to external clock? Thanks, Phil, G8PJH


Chris Wilson
 

Hello Siegfried,

Tuesday, May 11, 2021

Thanks again Sigi, unfortunately my Pluto arrived from Mouser as a revision B. So I will need to remove the xtal oscillator and solder a coax going to a bulkhead SMA socket I have put in the end of the case. Should i ground the outer braid of the coax at the side of the xtal oscillator pads, th the ground plane? I will feed it 40 MHz from my Leo Bodnar GPSDO. Thanks.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


SJ> if you are lucky your pluto is a new one (rev c/d) ... that has an
SJ> internal socket for external clock and needs just a firmware command to
SJ> use that external signal and switch off the internal clock

SJ> analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer
SJ> chip inside has a max input level (from data sheet) of 2v max so better
SJ> stay below that ... it should lock with only 0.5 to 0.8v level so better
SJ> stay lower to be on the safe side

SJ> greetz sigi dg9bfc

SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...

The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?

I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?

Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?

Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg



SJ>


Chris Wilson
 

Hello Phil,

Wednesday, May 12, 2021

I am no Sigi, but maybe this will help Phil? They cite the C version in the details on changing clock:

https://wiki.analog.com/university/tools/pluto/devs/booting?s%5B%5D=reference&s%5B%5D=clock&s%5B%5D=pluto


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


PHvgi> Siegfried, can you explain how to do the firmware change on
PHvgi> Pluto to switch to external clock? Thanks, Phil, G8PJH


Phil Hazelton
 

Hi Chris,
Thanks for that, but Where do I actually enter these commands? Thanks
Phil

On 12 May 2021, at 14:35, Chris Wilson <chris@chriswilson.tv> wrote:

Hello Siegfried,

Tuesday, May 11, 2021

Thanks again Sigi, unfortunately my Pluto arrived from Mouser as a revision B. So I will need to remove the xtal oscillator and solder a coax going to a bulkhead SMA socket I have put in the end of the case. Should i ground the outer braid of the coax at the side of the xtal oscillator pads, th the ground plane? I will feed it 40 MHz from my Leo Bodnar GPSDO. Thanks.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


SJ> if you are lucky your pluto is a new one (rev c/d) ... that has an
SJ> internal socket for external clock and needs just a firmware command to
SJ> use that external signal and switch off the internal clock

SJ> analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer
SJ> chip inside has a max input level (from data sheet) of 2v max so better
SJ> stay below that ... it should lock with only 0.5 to 0.8v level so better
SJ> stay lower to be on the safe side

SJ> greetz sigi dg9bfc

SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...

The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?

I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?

Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?

Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg



SJ>







Siegfried Jackstien
 

we could "swap" plutos ... if you need the new version (for leo bodnar cause used outdoors) i could offer you a rev c if you send me the rev b ...

or ... i could modify also a rev b for you (with external in and stable internal clock switchable without firmware hacking but with a flipswitch)

so .. what wever you need / want ... i can offer it :-)

and ... does it not look much better in a metal case compared to that blue soap box?!?

greetz sigi dg9bfc


Am 12.05.2021 um 13:35 schrieb Chris Wilson:

Hello Siegfried,

Tuesday, May 11, 2021

Thanks again Sigi, unfortunately my Pluto arrived from Mouser as a revision B. So I will need to remove the xtal oscillator and solder a coax going to a bulkhead SMA socket I have put in the end of the case. Should i ground the outer braid of the coax at the side of the xtal oscillator pads, th the ground plane? I will feed it 40 MHz from my Leo Bodnar GPSDO. Thanks.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


SJ> if you are lucky your pluto is a new one (rev c/d) ... that has an
SJ> internal socket for external clock and needs just a firmware command to
SJ> use that external signal and switch off the internal clock

SJ> analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer
SJ> chip inside has a max input level (from data sheet) of 2v max so better
SJ> stay below that ... it should lock with only 0.5 to 0.8v level so better
SJ> stay lower to be on the safe side

SJ> greetz sigi dg9bfc

SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...
The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?
I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?
Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?
Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg


SJ>






Chris Wilson
 

Hello Phil,

Wednesday, May 12, 2021

Are you able to access your Pluto via ethernet? Using a USB to Ethernet converter? That's how I reprogrammed the firmware. It may be possible via plain Jane USB, but that's not within my experience.

Using ethernet you find the IP address of the Pluto, probably by looking in the Network settings in your router, and use the application called Putty (Google it) to "speak" to that IP address using what's called SSH. Putty then gives you a DOS like access to the Pluto firmware and you enter the commands in said box.

I am pretty sure you can do this from a plain USB port, but I am unsure just how, sorry.

The ethernet stuff sounds complicated, but it's not as bad as it sounds once you give it a go.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


PHvgi> Hi Chris,
PHvgi> Thanks for that, but Where do I actually enter these commands? Thanks
PHvgi> Phil
On 12 May 2021, at 14:35, Chris Wilson <chris@chriswilson.tv> wrote:
Hello Siegfried,
Tuesday, May 11, 2021
Thanks again Sigi, unfortunately my Pluto arrived from Mouser as a revision B. So I will need to remove the xtal oscillator and solder a coax going to a bulkhead SMA socket I have put in the end of the case. Should i ground the outer braid of the coax at the side of the xtal oscillator pads, th the ground plane? I will feed it 40 MHz from my Leo Bodnar GPSDO. Thanks.

Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv

SJ> if you are lucky your pluto is a new one (rev c/d) ... that has an
SJ> internal socket for external clock and needs just a firmware command to
SJ> use that external signal and switch off the internal clock
SJ> analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer
SJ> chip inside has a max input level (from data sheet) of 2v max so better
SJ> stay below that ... it should lock with only 0.5 to 0.8v level so better
SJ> stay lower to be on the safe side
SJ> greetz sigi dg9bfc
SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...

The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?

I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?

Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?

Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg



SJ>









PHvgi>


Siegfried Jackstien
 

a series cap ... two 1n4148 antiparallel to ground and another cap towards ref in (tcxo pad)

that "clips" level at plusminus 0.6v or 1.2v peak tp peak

preventing you from cooking the reference input of the trx chip

greetz sigi dg9bfc

Am 12.05.2021 um 13:35 schrieb Chris Wilson:

Hello Siegfried,

Tuesday, May 11, 2021

Thanks again Sigi, unfortunately my Pluto arrived from Mouser as a revision B. So I will need to remove the xtal oscillator and solder a coax going to a bulkhead SMA socket I have put in the end of the case. Should i ground the outer braid of the coax at the side of the xtal oscillator pads, th the ground plane? I will feed it 40 MHz from my Leo Bodnar GPSDO. Thanks.


Best regards,
Chris 2E0ILY mailto:chris@chriswilson.tv


SJ> if you are lucky your pluto is a new one (rev c/d) ... that has an
SJ> internal socket for external clock and needs just a firmware command to
SJ> use that external signal and switch off the internal clock

SJ> analog devices write that max sigfnal is 14 dbm (3v pp) but the buffer
SJ> chip inside has a max input level (from data sheet) of 2v max so better
SJ> stay below that ... it should lock with only 0.5 to 0.8v level so better
SJ> stay lower to be on the safe side

SJ> greetz sigi dg9bfc

SJ> Am 11.05.2021 um 17:07 schrieb Chris Wilson:
11 May 2021
I got my Pluto mounted at the dish, which is a 1.8 meter PF. I have only opened up the Pluto frequency width and enabled both processor cores in the firmware, which is V0.33. Th Pluto xtal oscillator is stock. I ran it into the AD CN-0417 pre amp that I was going to use to feed my SG Labs 20W PA. For testing I thought I would see if the satellite could hear me just using the CN-0417 output direct to the POTI, I did not expect it would...
The software is SDR Console, locked to the beacon, and it "talks" to the Pluto via an ethernet cable and ethernet to USB at the Pluto. In SDR Console I have an RX offset of 9750MHz set and a TX offset of 6089.5MHz set. Is this TX offset correct please?
I TX'd an FM signal with the software set to 10.489730 and I could indeed see my signal on the UK based Goonhilly web SDR,, but it was way off frequency, and drifting in steps. Is this to be expected until I muster the courage to try and remove the stock oscillator and feed the PCB with a GPS locked 40MHz from my Leo Bodnar GPSDO?
Given the signal strength from just the CN-0417 (although I am unsure if it's linear at that level), once the frequency issue is sorted, might I even be heard on SSB without the PA?
Thanks for any advice. Chris, call sign 2E0ILY
Screenshot of received signal showing frequency shift and choppy drift at:
http://www.chriswilson.tv/first-tx-at-10dot489730-off-frequency-fm.jpg


SJ>






m0hbk
 

Hi Sigi, name is Carlos and callsign M0HBK. This is my first post and appreciate your help.

I recently received my new Pluto and, as per the PCB, it is a revision D. Having experienced yesterday the significant drift during my first two QO-100 QSOs I have decided to use an external GPSDO to correct this. I guess similar experience as mentioned by Chris 2E0ILY in his message.

I have ordered a GPSDO (Leo Bodnar Mini Precision GPS Reference Clock) as well as the required cables from eBay and I was wondering if you or any other of the members in this group have used this new rev board and can assist and confirm with the process and instructions that I have researched and believe that need to follow.

1. Assume that the signal from the GPSDO is connected to the connector in the Pluto labelled CLK-IN
2. Can I adjust the signal level of the GPSDO to a value below 1V (you mentioned in your message to Chris that is should be about 0.5 to 0.8V) or do I have to add an attenuator?
3. I would like to confirm the command to switch the Pluto to the external reference oscillator fw_setenv refclk_source external
4. If I program the GPSDO for a different reference frequency, say 25MHz, would this be the command that I need to use in the Pluto to change from 40MHz to 25MHz? fw_setenv ad936x_ext_refclk '<25000000>'  Are the brackets required?
5. As I never have used the Leo Bodnar Mini Precision GPS Reference Clock l am also looking for guidance on the settings. 
 
Appreciate any hints and tips that you might have and also if you can point me in the right direction.

Many thanks and 73,

Carlos M0HBK
 


Simon Brown
 

Sigi’s the expert but:

 

  1. I think so
  2. Yes – there’s a software program for the Leo Bodnar GPSDO
  3. Sigi?
  4. Always use 40MHz – if you bought a dual Leo Bodnar GPSDO then you can use 40MHz on Pluto and another value elsewhere.
  5. I can show you my settings, I have the dual GPSDO

 

Simon Brown, G4ELI

https://www.sdr-radio.com

 

From: main@SDR-Radio.groups.io <main@SDR-Radio.groups.io> On Behalf Of m0hbk
Sent: 13 May 2021 07:27
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] Pluto QO-100 drift and frequency shift, how much is normal?

 

Hi Sigi, name is Carlos and callsign M0HBK. This is my first post and appreciate your help.

I recently received my new Pluto and, as per the PCB, it is a revision D. Having experienced yesterday the significant drift during my first two QO-100 QSOs I have decided to use an external GPSDO to correct this. I guess similar experience as mentioned by Chris 2E0ILY in his message.

I have ordered a GPSDO (Leo Bodnar Mini Precision GPS Reference Clock) as well as the required cables from eBay and I was wondering if you or any other of the members in this group have used this new rev board and can assist and confirm with the process and instructions that I have researched and believe that need to follow.

1. Assume that the signal from the GPSDO is connected to the connector in the Pluto labelled CLK-IN

2. Can I adjust the signal level of the GPSDO to a value below 1V (you mentioned in your message to Chris that is should be about 0.5 to 0.8V) or do I have to add an attenuator?

3. I would like to confirm the command to switch the Pluto to the external reference oscillator fw_setenv refclk_source external
4. If I program the GPSDO for a different reference frequency, say 25MHz, would this be the command that I need to use in the Pluto to change from 40MHz to 25MHz? fw_setenv ad936x_ext_refclk '<25000000>'  Are the brackets required?

5. As I never have used the Leo Bodnar Mini Precision GPS Reference Clock l am also looking for guidance on the settings. 

 

Appreciate any hints and tips that you might have and also if you can point me in the right direction.


Many thanks and 73,

Carlos M0HBK
 


--
- + - + -
Please use https://forum.sdr-radio.com:4499/ when posting questions or problems.


Siegfried Jackstien
 

all well explained here

https://wiki.analog.com/university/tools/pluto/devs/booting?s%5B%5D=reference&s%5B%5D=clock&s%5B%5D=pluto

......

If you want to replace the 40 MHz oscillator, and insert a 20 MHz (20000000 Hz) clock:

# fw_setenv ad936x_ext_refclk “<20000000>“

The quotes need to be there to escape the <>, which need to be there since this goes into device tree

change to your needs

.....

so the quotes and the <> needs to be there

...

about the level ...

i did not write it has to be 0.5 ... but it will work with that low value

data sheet of the buffer amp says MAX 2v (80mw or +19dbm)

and here the data from leo bodnar

+13.3dBm, drive setting 32mA
+12.7dBm, drive setting 24mA
+11.4dBm, drive setting 16mA
+7.7dBm, drive setting 8mA

........

so i think any setting in the leo would work fine ... but the low setting should be enough

dg9bfc sigi


Am 13.05.2021 um 06:26 schrieb m0hbk:

Hi Sigi, name is Carlos and callsign M0HBK. This is my first post and appreciate your help.

I recently received my new Pluto and, as per the PCB, it is a revision D. Having experienced yesterday the significant drift during my first two QO-100 QSOs I have decided to use an external GPSDO to correct this. I guess similar experience as mentioned by Chris 2E0ILY in his message.

I have ordered a GPSDO (Leo Bodnar Mini Precision GPS Reference Clock) as well as the required cables from eBay and I was wondering if you or any other of the members in this group have used this new rev board and can assist and confirm with the process and instructions that I have researched and believe that need to follow.

1. Assume that the signal from the GPSDO is connected to the connector in the Pluto labelled CLK-IN
2. Can I adjust the signal level of the GPSDO to a value below 1V (you mentioned in your message to Chris that is should be about 0.5 to 0.8V) or do I have to add an attenuator?
3. I would like to confirm the command to switch the Pluto to the external reference oscillator fw_setenv refclk_source external
4. If I program the GPSDO for a different reference frequency, say 25MHz, would this be the command that I need to use in the Pluto to change from 40MHz to 25MHz? fw_setenv ad936x_ext_refclk '<25000000>'  Are the brackets required?
5. As I never have used the Leo Bodnar Mini Precision GPS Reference Clock l am also looking for guidance on the settings. 
 
Appreciate any hints and tips that you might have and also if you can point me in the right direction.

Many thanks and 73,

Carlos M0HBK
 


Phil Hazelton
 

Can someone please explain where and how you can input these firmware parameters?
Philip 


On 13 May 2021, at 12:03, Siegfried Jackstien <siegfried.jackstien@...> wrote:



all well explained here

https://wiki.analog.com/university/tools/pluto/devs/booting?s%5B%5D=reference&s%5B%5D=clock&s%5B%5D=pluto

......

If you want to replace the 40 MHz oscillator, and insert a 20 MHz (20000000 Hz) clock:

# fw_setenv ad936x_ext_refclk “<20000000>“

The quotes need to be there to escape the <>, which need to be there since this goes into device tree

change to your needs

.....

so the quotes and the <> needs to be there

...

about the level ...

i did not write it has to be 0.5 ... but it will work with that low value

data sheet of the buffer amp says MAX 2v (80mw or +19dbm)

and here the data from leo bodnar

+13.3dBm, drive setting 32mA
+12.7dBm, drive setting 24mA
+11.4dBm, drive setting 16mA
+7.7dBm, drive setting 8mA

........

so i think any setting in the leo would work fine ... but the low setting should be enough

dg9bfc sigi


Am 13.05.2021 um 06:26 schrieb m0hbk:
Hi Sigi, name is Carlos and callsign M0HBK. This is my first post and appreciate your help.

I recently received my new Pluto and, as per the PCB, it is a revision D. Having experienced yesterday the significant drift during my first two QO-100 QSOs I have decided to use an external GPSDO to correct this. I guess similar experience as mentioned by Chris 2E0ILY in his message.

I have ordered a GPSDO (Leo Bodnar Mini Precision GPS Reference Clock) as well as the required cables from eBay and I was wondering if you or any other of the members in this group have used this new rev board and can assist and confirm with the process and instructions that I have researched and believe that need to follow.

1. Assume that the signal from the GPSDO is connected to the connector in the Pluto labelled CLK-IN
2. Can I adjust the signal level of the GPSDO to a value below 1V (you mentioned in your message to Chris that is should be about 0.5 to 0.8V) or do I have to add an attenuator?
3. I would like to confirm the command to switch the Pluto to the external reference oscillator fw_setenv refclk_source external
4. If I program the GPSDO for a different reference frequency, say 25MHz, would this be the command that I need to use in the Pluto to change from 40MHz to 25MHz? fw_setenv ad936x_ext_refclk '<25000000>'  Are the brackets required?
5. As I never have used the Leo Bodnar Mini Precision GPS Reference Clock l am also looking for guidance on the settings. 
 
Appreciate any hints and tips that you might have and also if you can point me in the right direction.

Many thanks and 73,

Carlos M0HBK
 


m0hbk
 

Hi Simon,

Many thanks for your reply and I would like to take you up on your offer of sharing the settings that you use in your GPSDO.

Appreciate also all the work that you have done with SDR Console. It is great and I am still in the steep learning curve. Thank you!

73, Carlos


m0hbk
 

Thanks for confirming Sigi and for taking the time to go into some of the details and sharing the analog devices link. Very much appreciated.

I expect delivery of the GPSDO on Friday so that I can continue experimenting and setting up my station. 

73, Carlos


m0hbk
 

Phil, you might want to take a look at this video that might help you out https://www.youtube.com/watch?v=5V6CxTBDHVY&t=2s 


Phil Hazelton
 

Hello to all,

I have finally got all my components hooked up to form a QO 100 station, my TX path is a Pluto into a 6 dB attenuator, CN0417 feeding a SG labs v3 20watt amplifier, 3 metres of low loss eco flex 150 cable feeding a home made POTTY antenna on a 80cm dish.

Using the test tune on SDR console, I can generate 16 Watts at the output of the rig. However, when connecting the cable and dish for a “live” test, I can only see my signal on SDR console showing about S4/S5, most of the other signals I see are S8/S9. Does this suggest something wrong with my POTTY? Any thoughts would be appreciated.

Phil G8PJH


Siegfried Jackstien
 

first of all... why the 6db attenuator?? better use lower power from the pluto (much cleaner then) and throw out the 6db pad

16w should give a signal WAY OVER the beacon level with your 80cm dish

how did you tune your poty??

an analyzer is a MUST HAVE for tuning!! .. only swr does not work!!

how did you measure the 16w??

we need some more info for precise help

did you use n socket on poty? or a (maybe lossy) pigtail or sma adaptor??

did you measure swr?? how?? sg labs has forward and reverse bridge ... so you could measure swr easy within the amp but swr does not tell you if the antenna is circular ...

but even if not (wrong tuned and linear) you would loose 3 db and even then your signal should be stronger as s4 to s5

so definitely something is wrong there

do not try to transmit with high power if your antenna is not well tuned (or you will maybe cook your amp)

greetz sigi dg9bfc


Am 16.05.2021 um 12:24 schrieb Phil Hazelton via groups.io:

Hello to all,

I have finally got all my components hooked up to form a QO 100 station, my TX path is a Pluto into a 6 dB attenuator, CN0417 feeding a SG labs v3 20watt amplifier, 3 metres of low loss eco flex 150 cable feeding a home made POTTY antenna on a 80cm dish.

Using the test tune on SDR console, I can generate 16 Watts at the output of the rig. However, when connecting the cable and dish for a “live” test, I can only see my signal on SDR console showing about S4/S5, most of the other signals I see are S8/S9. Does this suggest something wrong with my POTTY? Any thoughts would be appreciated.

Phil G8PJH