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Re: Pluto:: Spurious Emissions

jdow
 

Ba-da-bing as they say in the vernacular.
{o.o}

(Besides, EVERYTHING is "just physics". So it was sort of a null statement. OTOH, in general lowering levels keeps you out of the non-linear regions or D/A overload or other nasties.)

On 20220205 14:57:05, Boudewijn (Bob) Tenty VE3TOK wrote:

The attenuation happens before the final in the Pluto NOT after it, see  https://wiki.analog.com/university/tools/pluto/users/transmit

Bob VE3TOK

On 2022-02-05 16:11, Jean (DJ0VL) wrote:
Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
-- 
There is nothing permanent except change
 
-Heraclitus
Re: Keyboard shortcut for voice keyer

Max
 

On Sat, Feb 5, 2022 at 10:34 PM, <cedric@...> wrote:
I found the screen where keyboard short cuts can be set, but I don't find the voice keyer in the list. Can I use F1 to F4 for the voice messages 1 to 4?
Could be wrong, but as far as I know it's only possible to assigned keyboard shortcuts to items which appear in the top of screen "tabbed" menus (Home, View, Receive, Transmit etc) in the top ribbon bar. Even then some of those do not work. It's an area I think Simon has said he will come back to (hopefully).

I am like you. I would like any button visible on the screen on any panel to be assignable to a keyboard shortcut, but I don't think that this is high on Simon's list of priorities, if at all.

So unfortunately the answer is almost certainly "no" sadly, unless I missed something.

73

Max
Re: Pluto:: Spurious Emissions

Boudewijn (Bob) Tenty VE3TOK
 

The attenuation happens before the final in the Pluto NOT after it, see  https://wiki.analog.com/university/tools/pluto/users/transmit

Bob VE3TOK

On 2022-02-05 16:11, Jean (DJ0VL) wrote:
Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
-- 
There is nothing permanent except change
 
-Heraclitus
Re: Virtual Here And Local Network

mikeshtml@...
 

I suspect your Ubiquiti AP's are enforcing some type of security where they don't allow access to another host on the wired LAN, or they are are acting as a router / DHCP Server, and firewall. I suggest comparing the ip addresses of a wired host that works to a wireless host that doesn't. If they are in a different ip network, then they are routing.

The ip address and subnet mask of a Windows host can be shown at the command prompt with "ipconfig" command.  

Wireshark is a free packet tracing tool that might help. I used it daily at work before I retired.

Mike
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

i guess a lot of these spurii come from exactly those couplings internally (and externally) ... that explains very well why they go down with lower power out

maybe also the iq correction on lower setting works better .. who knows what all does happen inside that magical chip ;-)

fcc (and bnetza and others) dictate that the unwanted signals should be 60 db below main signal ... so .. stay at -20dbm and you are safe

set to -40 dbm and you are superclean (with around 70 dbc)

and do not use the "tx boost" ... that makes things worse!!

dg9bfc sigi

Am 05.02.2022 um 23:38 schrieb jdow:

Voltage variable attenuators also have IMD. Are you measuring right at the output of the attenuator or is there a buffer on chip? It will also affect the cross coupling within the chip between the output and the other pins on the chip and internal connections on the chip.

{^_^}

On 20220205 13:11:24, Jean (DJ0VL) wrote:
Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
Re: Pluto:: Spurious Emissions

jdow
 

Voltage variable attenuators also have IMD. Are you measuring right at the output of the attenuator or is there a buffer on chip? It will also affect the cross coupling within the chip between the output and the other pins on the chip and internal connections on the chip.

{^_^}

On 20220205 13:11:24, Jean (DJ0VL) wrote:

Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
Keyboard shortcut for voice keyer

cedric@...
 

I found the screen where keyboard short cuts can be set, but I don't find the voice keyer in the list. Can I use F1 to F4 for the voice messages 1 to 4?

73

Cedric, ON4CKM
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

you should ot use an attenuator but lower drive in your software ...thats a different thingy

what did i measure??

i measured the level of the unwanted spurious signals compared to main signal ... worst case (full power) these levels are around 42 dbc

with -20 dbm these spurii are around -58 to -60 dbc (just at the fcc border) .. going up to over 70 dbc with very low setting (-40dbm or so)

for an easier read (nicer view) i added 50 db to the one row of values (shifted to be in the same range as the other value) SD is SPURII DISTANCE (db below main)

that way the two lines fall in the same range and so the diagram is easier to read (otherwise the one line would be 50 db lower and outside of diagram)

now clear??

dg9bfc sigi



Am 05.02.2022 um 19:20 schrieb Jean (DJ0VL):

Hi Sigi,

Thanks for your thoughts and for the diagram. To be honest, I do not clearly understand what you measured and what your diagram is telling me.

I second your statement that generally an amplifier generates less non-linearity products at lower output levels. Looking at the datasheet, you will notice that the AD9363 manages its output level by a variable attenuation - not by a variable amplification - and therefore, I do not expect a noticable improvement of non-linearity effects with reduced output levels.

I'm lacking equipement for a serious spurious measurement, like a spectrum analyzer being able to visualize the third harmonic that is stated at -30dBc in the datasheet. I can reproduce that IMD3 of a Pluto @2.4GHz is at around -38dBc and it is not getting any better when reducing the output power of the Pluto.

Anyway, I'm running the Pluto at output levels < -10dBm, as my PA has enough gain and I did not want to spend an extra attenuator in front of it.

73 Jean DJ0VL
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

... the signal is not lowered with setting an attenuator in line but with setting lower levels in software .. thats a different thingy

that way the mixing products and spurii are lower ... do not couple backwards into the chip (into earlier mixer stages) and so overall the signal is cleaner

pure plain old physics(on a quite modern trx chip) .. lower levels do couple less with earlier stages causing lower spurii

remember all that does happen inside one single chip!! (so explain it like a "conventional transceiver" is not correct but comes close)

i will try it ... say you have a tx signal at 2400 ... and a spurious at 2400.1 .. that comes backwards into the trx chip and causes another mixing product at 2399.9... that also again mixes with the 2400 and 2400.1 giving even more mixing products (at 2399.8 and 2400.2 and so on) ... if you lower the overall gain then the spuri on 2400.1 is lower and the mixing product on 2399.9 also is lower (in sum all mixing products go down with lower power)

i do know that is not the really correct explanation ... but it comes close enough to give you a good idea what does happen (a few of these mixing things can be surpressed or lowered in software but thats another story)

so ... i hope that you now understand why lower power gives cleaner signals (not to mention imd products on very high driven amp stages)

dg9bfc sigi

Am 05.02.2022 um 22:11 schrieb Jean (DJ0VL):

Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

and when you read trough the pdf file you see that at -40dbm, the pluto is superclean ... spurii beginning above -30dbm (and are much higher on fullpower)

so ... cleanest signal is with VERY low power from the pluto and even more amplification behind it

dg9bfc sigi

Am 05.02.2022 um 19:49 schrieb Julian Bone via groups.io:

The Libre Space Foundation produced a document entitled 'Evaluation of SDR Boards and Toolchains' which can be found easily online.
The Pluto comes out well considering its price, very clean actually.
I think the concern was over Amateurs possibly interfering with the ISS and satellites if SDR platforms were of poor quality.
My experience of the Pluto, is that it is very sensitive to clock issues like jitter, producing lots of spurii with a poor clock.
Spurii frequency changing with clock amplitude.
The new version of Pluto has a clock reference buffer which should help to eliminate these issues.
These points may have nothing to do with this string but I felt might be of interest.  

Re: Pluto:: Spurious Emissions

Jean (DJ0VL)
 

Please enlighten me: which plain pure old fashioned physics does reduce the spurious level (in dBc, not dBm) of a constant signal that is reduced by adding attenuation?

73 Jean DJ0VL
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

you can send that to analog devices students forum .. they sure would love to read it :-)

have a nice day (evening)

dg9bfc sigi

Am 05.02.2022 um 21:42 schrieb jdow:

The alternative was a college level lecture that I (fortunately?) do not feel up to delivering today.

{^_-}

On 20220205 12:39:19, Siegfried Jackstien wrote:

... thats not what he was asking for hi hi

ROTFL :-)

dg9bfc sigi

Am 05.02.2022 um 21:34 schrieb jdow:
Physics, plain pure old fashioned physics.
{^_^}

On 20220205 01:07:36, Jean (DJ0VL) wrote:
Hi all,

I often read the recommendation to operate the Pluto at lower output level and use external amplification if applicable.

Can anybody please explain why the output signal of the Pluto should get cleaner (in terms of dBc spurii or imd) when the output level of the AD9363 is decreased?

73 Jean DJ0VL


Re: Pluto:: Spurious Emissions

jdow
 

The alternative was a college level lecture that I (fortunately?) do not feel up to delivering today.

{^_-}

On 20220205 12:39:19, Siegfried Jackstien wrote:

... thats not what he was asking for hi hi

ROTFL :-)

dg9bfc sigi

Am 05.02.2022 um 21:34 schrieb jdow:
Physics, plain pure old fashioned physics.
{^_^}

On 20220205 01:07:36, Jean (DJ0VL) wrote:
Hi all,

I often read the recommendation to operate the Pluto at lower output level and use external amplification if applicable.

Can anybody please explain why the output signal of the Pluto should get cleaner (in terms of dBc spurii or imd) when the output level of the AD9363 is decreased?

73 Jean DJ0VL


Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

... thats not what he was asking for hi hi

ROTFL :-)

dg9bfc sigi

Am 05.02.2022 um 21:34 schrieb jdow:

Physics, plain pure old fashioned physics.
{^_^}

On 20220205 01:07:36, Jean (DJ0VL) wrote:
Hi all,

I often read the recommendation to operate the Pluto at lower output level and use external amplification if applicable.

Can anybody please explain why the output signal of the Pluto should get cleaner (in terms of dBc spurii or imd) when the output level of the AD9363 is decreased?

73 Jean DJ0VL

Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

especially the jitter and phase noise has to be good ...

and ... the power supply of the reference (if you use an internal reference) has to be superclean!!!

there is a reason why analog devices uses a separate special low noise voltage regulator chip ONLY for that reference

any slight noise in the reference voltage also mixes up with your main reference signal (causing all kind of nasty spurii and such)

pay attention on the level!! analog devices prints on the pcb max voltage of 3v ... but the chip manufacturer of that buffer ic claims for max voltage of 2v !!!! so better stay safe and set that below 2v!!... cause a buffer ic is used ... even a way lower reference voltage does work just fine :-)

greetz sigi dg9bfc

Am 05.02.2022 um 19:49 schrieb Julian Bone via groups.io:

The Libre Space Foundation produced a document entitled 'Evaluation of SDR Boards and Toolchains' which can be found easily online.
The Pluto comes out well considering its price, very clean actually.
I think the concern was over Amateurs possibly interfering with the ISS and satellites if SDR platforms were of poor quality.
My experience of the Pluto, is that it is very sensitive to clock issues like jitter, producing lots of spurii with a poor clock.
Spurii frequency changing with clock amplitude.
The new version of Pluto has a clock reference buffer which should help to eliminate these issues.
These points may have nothing to do with this string but I felt might be of interest.  

Re: Pluto:: Spurious Emissions

jdow
 

Physics, plain pure old fashioned physics.
{^_^}

On 20220205 01:07:36, Jean (DJ0VL) wrote:

Hi all,

I often read the recommendation to operate the Pluto at lower output level and use external amplification if applicable.

Can anybody please explain why the output signal of the Pluto should get cleaner (in terms of dBc spurii or imd) when the output level of the AD9363 is decreased?

73 Jean DJ0VL

Re: Pluto:: Spurious Emissions

Julian Bone
 

The Libre Space Foundation produced a document entitled 'Evaluation of SDR Boards and Toolchains' which can be found easily online.
The Pluto comes out well considering its price, very clean actually.
I think the concern was over Amateurs possibly interfering with the ISS and satellites if SDR platforms were of poor quality.
My experience of the Pluto, is that it is very sensitive to clock issues like jitter, producing lots of spurii with a poor clock.
Spurii frequency changing with clock amplitude.
The new version of Pluto has a clock reference buffer which should help to eliminate these issues.
These points may have nothing to do with this string but I felt might be of interest.  
Re: Pluto:: Spurious Emissions

Jean (DJ0VL)
 

Hi Sigi,

Thanks for your thoughts and for the diagram. To be honest, I do not clearly understand what you measured and what your diagram is telling me.

I second your statement that generally an amplifier generates less non-linearity products at lower output levels. Looking at the datasheet, you will notice that the AD9363 manages its output level by a variable attenuation - not by a variable amplification - and therefore, I do not expect a noticable improvement of non-linearity effects with reduced output levels.

I'm lacking equipement for a serious spurious measurement, like a spectrum analyzer being able to visualize the third harmonic that is stated at -30dBc in the datasheet. I can reproduce that IMD3 of a Pluto @2.4GHz is at around -38dBc and it is not getting any better when reducing the output power of the Pluto.

Anyway, I'm running the Pluto at output levels < -10dBm, as my PA has enough gain and I did not want to spend an extra attenuator in front of it.

73 Jean DJ0VL
Re: Bricked my Ettus X310

Charly DF5VAE
 

Hi Sigi,

The UBX board in the X310 has a max theoretical bandwith of 160MHz.

At 50MHz Bandwith (max BW I can set in SDR console) I see about 14 to15% load on the 10G link, but the GTX 1650 gets loaded faster than the 10G Link..

73, Charly
Re: Pluto:: Spurious Emissions

Siegfried Jackstien
 

at first .. near every transceiver runs cleaner with lower power setting :-)

if the tx signal (after internal mixing in the trx chip) is given out at a bigger level ... and a few mixing products couple backwards into one of the earlier stages you will get even more mixing products (its not the exact explanation ... just a bit easier to explain it that way)

all that is inside that ONE transceiver chip so not easy to expain what exactly does happen (maybe something you better ask in the analog devices students zone??)... but i did do some measurements ... and yes the "unwanted" mixing products and spurious signal are lower with lower power setting

as an example ... on full power the pluto has spurii at around 40 db below main signal ... but with 20 db lower power out the spurii are 60 db below main (just at the "fcc" border)

or in other words ... if you lower the output 20 db ... the spurious signals are lowered by 40 db (just rough numbers)

so ... i highy recomment to use much lower output of the pluto and add another gain stage behind it

a wideband lna like the skyworks 65017 is a good example what can be used (it is my "add behind pluto workhorse") .. nearly flat 20 to 21 db gain from 50 megs up to 6 gi

yes near flat ... does not drop down that much on upper end ... at low end 21db but still 20db at top end .. so a superb add on for the pluto

regarding imd ... that is also better with lower power (similar as with near any amp ... lower = cleaner)

see picture ... i measured the spirious distance on 13 cm (qo100 uplink) depending on output power and you see ... lower is better

in one of the last versions simon made some changes in the filter settings and i did not do those tests again (one day when i have time) ... that signals may be better now ... but it is for sure not 100% clean (on full power) so even if with the newer version the filtering is better ... these spurii are there and can only be held below fcc border if you use low output ... a rough number ... set pluto to -20 dbm and add a sky17 to get back to 0 dbm ... skyworks still has 20 db headroom (max output 100mW) so runs clean and pluto gives a cleaner signal on - 20 dbm ... ;-)

dg9bfc sigi



Am 05.02.2022 um 10:07 schrieb Jean (DJ0VL):

Hi all,

I often read the recommendation to operate the Pluto at lower output level and use external amplification if applicable.

Can anybody please explain why the output signal of the Pluto should get cleaner (in terms of dBc spurii or imd) when the output level of the AD9363 is decreased?

73 Jean DJ0VL

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