Chinese ADF4351 signal source


Richard Ferryman
 

I have been looking at a Chinese signal source using an ADF4351 and sold for around £30.  This one has a large LCD display and several functions and looks to have an SMA connector for an external reference but the spec doesn't say much.  I am looking at it a general signal generator for my QO-100 activities.  Does anyone use on of the boards and are they of any use??  Are there any really bad sides?
Dick G4BBH


geoffrey pike
 

That's a good price, apart from spectral purity which varies alot with these boards in general
it may be worth checking the minimum frequency step as some are as high as 100 KHz
and you may need to consider an external ref also as some of the on board xtals are way off
cheers
Geoff
GI0GDP


On Monday, 23 November 2020, 10:35:27 GMT, Richard Ferryman via groups.io <g4bbh@...> wrote:


I have been looking at a Chinese signal source using an ADF4351 and sold for around £30.  This one has a large LCD display and several functions and looks to have an SMA connector for an external reference but the spec doesn't say much.  I am looking at it a general signal generator for my QO-100 activities.  Does anyone use on of the boards and are they of any use??  Are there any really bad sides?
Dick G4BBH


Robin Szemeti - G1YFG
 

I'd concur with the crystals being way off ... I used an external cheap chinese "golden" TCXO and I have to say it is solid as a rock in terms of frequency ... during the low band cumulative, the TCXO refused to come at all ... when the contest finished, it sprang into life!   I discovered if turned all the fans off in the shack, and listened very carefully out of the window, I could faintly hear Andy JNT laughing in the distance ...

The actual Chinese 4351 boards seem fine .. you must check the value of the charge pump resistor though and make sure you set it the same in your software programmer.


On Mon, 23 Nov 2020 at 11:45, geoffrey pike via groups.io <gi0gdp=yahoo.co.uk@groups.io> wrote:
That's a good price, apart from spectral purity which varies alot with these boards in general
it may be worth checking the minimum frequency step as some are as high as 100 KHz
and you may need to consider an external ref also as some of the on board xtals are way off
cheers
Geoff
GI0GDP


On Monday, 23 November 2020, 10:35:27 GMT, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:


I have been looking at a Chinese signal source using an ADF4351 and sold for around £30.  This one has a large LCD display and several functions and looks to have an SMA connector for an external reference but the spec doesn't say much.  I am looking at it a general signal generator for my QO-100 activities.  Does anyone use on of the boards and are they of any use??  Are there any really bad sides?
Dick G4BBH


--
Robin Szemeti - G1YFG


Andy G4JNT
 

😅😈😅😈😅😈😅😈😅😈😅👍💀😈



On Mon, 23 Nov 2020 at 11:57, Robin Szemeti - G1YFG <robin@...> wrote:
I'd concur with the crystals being way off ... I used an external cheap chinese "golden" TCXO and I have to say it is solid as a rock in terms of frequency ... during the low band cumulative, the TCXO refused to come at all ... when the contest finished, it sprang into life!   I discovered if turned all the fans off in the shack, and listened very carefully out of the window, I could faintly hear Andy JNT laughing in the distance ...

The actual Chinese 4351 boards seem fine .. you must check the value of the charge pump resistor though and make sure you set it the same in your software programmer.

On Mon, 23 Nov 2020 at 11:45, geoffrey pike via groups.io <gi0gdp=yahoo.co.uk@groups.io> wrote:
That's a good price, apart from spectral purity which varies alot with these boards in general
it may be worth checking the minimum frequency step as some are as high as 100 KHz
and you may need to consider an external ref also as some of the on board xtals are way off
cheers
Geoff
GI0GDP


On Monday, 23 November 2020, 10:35:27 GMT, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:


I have been looking at a Chinese signal source using an ADF4351 and sold for around £30.  This one has a large LCD display and several functions and looks to have an SMA connector for an external reference but the spec doesn't say much.  I am looking at it a general signal generator for my QO-100 activities.  Does anyone use on of the boards and are they of any use??  Are there any really bad sides?
Dick G4BBH


--
Robin Szemeti - G1YFG


Dave Cutts
 

I use a cheap 4351 board (about £13) from china, locked to GPS to injection lock the 116MHz crystal on a DDK Anglian Transverter. Works great, just programmed for the one frequency.

73 Dave G4FAW


Richard Ferryman
 

I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


Robin Szemeti - G1YFG
 

The chinese modules have the ADF4351 so will have the same steps as any other ADF4351 system ... how you program it is what matters, there are low spur modes, many parameters can affect output quality .. but, in terms of step size, they will behave just like any other ADF4351. I tend to stick to "integer N" modes as the spurs appear to be lower than running in fractional N ... so I pick my references to be an integer division of the output frequency.


On Mon, 23 Nov 2020 at 14:37, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


--
Robin Szemeti - G1YFG


Clint Sharp <cjaysharp@...>
 

Think that's the thing, the ADF4351 chip itself is programmable in very small steps but on the boards with control interface sometimes have a minimum step size enforced in the firmware amd the only way to solve that is to reprogram the MCU


On Mon, 23 Nov 2020, 14:43 Robin Szemeti - G1YFG, <robin@...> wrote:
The chinese modules have the ADF4351 so will have the same steps as any other ADF4351 system ... how you program it is what matters, there are low spur modes, many parameters can affect output quality .. but, in terms of step size, they will behave just like any other ADF4351. I tend to stick to "integer N" modes as the spurs appear to be lower than running in fractional N ... so I pick my references to be an integer division of the output frequency.


On Mon, 23 Nov 2020 at 14:37, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


--
Robin Szemeti - G1YFG


Andy G4JNT
 

Well, not very small.  Teh ADF4351 has a maximum Denominator register of just 4096, so your minimum step is going to be afew kHz  or so at 10MHz type reference frequencies and OPdiv = 1

If you want REALLY fine step size, use the ADF5355 with a double Fract-N set for mHz resolution   at GHz frequencies
See http://g4jnt.com/ADF5355_Synthesizer_Control.pdf for programming info for that device



On Mon, 23 Nov 2020 at 15:39, Clint Sharp <cjaysharp@...> wrote:
Think that's the thing, the ADF4351 chip itself is programmable in very small steps but on the boards with control interface sometimes have a minimum step size enforced in the firmware amd the only way to solve that is to reprogram the MCU

On Mon, 23 Nov 2020, 14:43 Robin Szemeti - G1YFG, <robin@...> wrote:
The chinese modules have the ADF4351 so will have the same steps as any other ADF4351 system ... how you program it is what matters, there are low spur modes, many parameters can affect output quality .. but, in terms of step size, they will behave just like any other ADF4351. I tend to stick to "integer N" modes as the spurs appear to be lower than running in fractional N ... so I pick my references to be an integer division of the output frequency.


On Mon, 23 Nov 2020 at 14:37, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


--
Robin Szemeti - G1YFG


Clint Sharp <cjaysharp@...>
 

Depends on ref frequency but yes, you're correct, it's not always 'very' small, I should have said 'smaller' however, they're still limited by the on-board controller firmware on some of the boards which have OLED/TFT display and a UI, I'm not sure if you can bypass that with the serial/USB ports though?


On Mon, 23 Nov 2020 at 15:57, Andy G4JNT <andy.g4jnt@...> wrote:
Well, not very small.  Teh ADF4351 has a maximum Denominator register of just 4096, so your minimum step is going to be afew kHz  or so at 10MHz type reference frequencies and OPdiv = 1

If you want REALLY fine step size, use the ADF5355 with a double Fract-N set for mHz resolution   at GHz frequencies
See http://g4jnt.com/ADF5355_Synthesizer_Control.pdf for programming info for that device



On Mon, 23 Nov 2020 at 15:39, Clint Sharp <cjaysharp@...> wrote:
Think that's the thing, the ADF4351 chip itself is programmable in very small steps but on the boards with control interface sometimes have a minimum step size enforced in the firmware amd the only way to solve that is to reprogram the MCU

On Mon, 23 Nov 2020, 14:43 Robin Szemeti - G1YFG, <robin@...> wrote:
The chinese modules have the ADF4351 so will have the same steps as any other ADF4351 system ... how you program it is what matters, there are low spur modes, many parameters can affect output quality .. but, in terms of step size, they will behave just like any other ADF4351. I tend to stick to "integer N" modes as the spurs appear to be lower than running in fractional N ... so I pick my references to be an integer division of the output frequency.


On Mon, 23 Nov 2020 at 14:37, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


--
Robin Szemeti - G1YFG



--
Clint. M0UAW IO83

No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.


Robin Szemeti - G1YFG
 

The Chinese boards I have used have had no controller on board, just the SDA/SCL pins which I connected to an Arduino and some suitable code, so I was able to program it just how I liked.  

On Mon, 23 Nov 2020 at 16:28, Clint Sharp <cjaysharp@...> wrote:
Depends on ref frequency but yes, you're correct, it's not always 'very' small, I should have said 'smaller' however, they're still limited by the on-board controller firmware on some of the boards which have OLED/TFT display and a UI, I'm not sure if you can bypass that with the serial/USB ports though?

On Mon, 23 Nov 2020 at 15:57, Andy G4JNT <andy.g4jnt@...> wrote:
Well, not very small.  Teh ADF4351 has a maximum Denominator register of just 4096, so your minimum step is going to be afew kHz  or so at 10MHz type reference frequencies and OPdiv = 1

If you want REALLY fine step size, use the ADF5355 with a double Fract-N set for mHz resolution   at GHz frequencies
See http://g4jnt.com/ADF5355_Synthesizer_Control.pdf for programming info for that device



On Mon, 23 Nov 2020 at 15:39, Clint Sharp <cjaysharp@...> wrote:
Think that's the thing, the ADF4351 chip itself is programmable in very small steps but on the boards with control interface sometimes have a minimum step size enforced in the firmware amd the only way to solve that is to reprogram the MCU

On Mon, 23 Nov 2020, 14:43 Robin Szemeti - G1YFG, <robin@...> wrote:
The chinese modules have the ADF4351 so will have the same steps as any other ADF4351 system ... how you program it is what matters, there are low spur modes, many parameters can affect output quality .. but, in terms of step size, they will behave just like any other ADF4351. I tend to stick to "integer N" modes as the spurs appear to be lower than running in fractional N ... so I pick my references to be an integer division of the output frequency.


On Mon, 23 Nov 2020 at 14:37, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
I think it will be useful. Most of my external references are 10MHz which are GPS locked and based on 10MHz double oven.  I now hace a Leo Bodnar GPSDO so I should be able to set up the second output for whatever reference I need whils the output 1 runs 10MHz for my IC-9700.
I have a gut feeling that the Chinese module will have very big frequency steps.
Dick


--
Robin Szemeti - G1YFG



--
Clint. M0UAW IO83

No trees were harmed in the sending of this mail. However, a large number of electrons were greatly inconvenienced.


--
Robin Szemeti - G1YFG


Richard Ferryman
 

The main problem I have with this module is that it does not have an input for external 25MHz source.  There is an SMA connctor marked MCLK but this turns out to be an output from the internal (crap) 25MHz reference which is a mile off 25MHz and not very clean..
Otherwise ist seems useable.
Dick


Andy G4JNT
 

You have to remove the L feeding DC to the on board OCXO.   Then move a link or two to get your external input



On Sat, 26 Dec 2020 at 11:41, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
The main problem I have with this module is that it does not have an input for external 25MHz source.  There is an SMA connctor marked MCLK but this turns out to be an output from the internal (crap) 25MHz reference which is a mile off 25MHz and not very clean..
Otherwise ist seems useable.
Dick


Andy G4JNT
 

I just took delivery of an ADF5355 synth (against all my principles, from China) and it had the same really poor 25MHz CXO on board.   I tried it, before doing the mod and it was unbelievably off freq - some 1000 ppm.

After converting for external 10MHz source (which is not really optimum frequency for that chip, but does work if you enable the ref-doubler) seems to work fine, but will benefit from the DC supply decoupling mods.



On Sat, 26 Dec 2020 at 11:54, Andy Talbot <andy.g4jnt@...> wrote:
You have to remove the L feeding DC to the on board OCXO.   Then move a link or two to get your external input



On Sat, 26 Dec 2020 at 11:41, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
The main problem I have with this module is that it does not have an input for external 25MHz source.  There is an SMA connctor marked MCLK but this turns out to be an output from the internal (crap) 25MHz reference which is a mile off 25MHz and not very clean..
Otherwise ist seems useable.
Dick


Robin Szemeti - G1YFG
 

Check the value of the charge pump resistor also

On Sat, 26 Dec 2020 at 11:58, Andy G4JNT <andy.g4jnt@...> wrote:
I just took delivery of an ADF5355 synth (against all my principles, from China) and it had the same really poor 25MHz CXO on board.   I tried it, before doing the mod and it was unbelievably off freq - some 1000 ppm.

After converting for external 10MHz source (which is not really optimum frequency for that chip, but does work if you enable the ref-doubler) seems to work fine, but will benefit from the DC supply decoupling mods.



On Sat, 26 Dec 2020 at 11:54, Andy Talbot <andy.g4jnt@...> wrote:
You have to remove the L feeding DC to the on board OCXO.   Then move a link or two to get your external input



On Sat, 26 Dec 2020 at 11:41, Richard Ferryman via groups.io <g4bbh=btinternet.com@groups.io> wrote:
The main problem I have with this module is that it does not have an input for external 25MHz source.  There is an SMA connctor marked MCLK but this turns out to be an output from the internal (crap) 25MHz reference which is a mile off 25MHz and not very clean..
Otherwise ist seems useable.
Dick


--
Robin Szemeti - G1YFG


Richard Ferryman
 

I had to borrow a neighbours young daughter to use the microscope as my eyes are no longer useful for anything smaller than a klystron.
The chinese do believe in being simple.  The SMA MCLK pin is fed from the oscillator via a 0 ohms resistor.  The ADF4351 ref in (pin 29) has a capacitor and 0 ohms in series also to the oscillator.  Now I need to teach my assistant hoiw to solder..........
Dick


G0FCU
 

Could someone tell me the components that need to be changed on the ADF4351 (black eBay) board to enable a 10 MHz reference input?

I can't find a circuit diagram on-line. Earlier in this thread Andy mentioned an inductor to be removed (L1?) and some other links to be changed.

Thanks
Simon
G0FCU (new to microwaves so bear with me!)


Robin Szemeti - G1YFG
 

This one?

image.png


R5 is the signal from the onboard xtal
R8 is the signal from the SMA socket
L1 is the power to the onboard xtal

Check also the value of the charge pump resistor and make sure it matches the value set in the software you use to calculate the numbers ... I *think* it is R7 on that board, but please check.  It connects between pins 7 and 20.  Most of the software is set up to expect a value of 1K ... these boards often have 5.1K  in that position ...  if the numbers don't match the software, you'll run out of tuning range.


On Sun, 3 Jan 2021 at 07:14, G0FCU <simon@...> wrote:
Could someone tell me the components that need to be changed on the ADF4351 (black eBay) board to enable a 10 MHz reference input?

I can't find a circuit diagram on-line. Earlier in this thread Andy mentioned an inductor to be removed (L1?) and some other links to be changed.

Thanks
Simon
G0FCU (new to microwaves so bear with me!)


--
Robin Szemeti - G1YFG


G0FCU
 

That's the one. So I need to remove R5 and L1 and thanks for the heads up about the charge pump resistor.

Many thanks
Simon.
G0FCU.


On Sun, 3 Jan 2021, 07:44 Robin Szemeti - G1YFG, <robin@...> wrote:
This one?

image.png


R5 is the signal from the onboard xtal
R8 is the signal from the SMA socket
L1 is the power to the onboard xtal

Check also the value of the charge pump resistor and make sure it matches the value set in the software you use to calculate the numbers ... I *think* it is R7 on that board, but please check.  It connects between pins 7 and 20.  Most of the software is set up to expect a value of 1K ... these boards often have 5.1K  in that position ...  if the numbers don't match the software, you'll run out of tuning range.

On Sun, 3 Jan 2021 at 07:14, G0FCU <simon@...> wrote:
Could someone tell me the components that need to be changed on the ADF4351 (black eBay) board to enable a 10 MHz reference input?

I can't find a circuit diagram on-line. Earlier in this thread Andy mentioned an inductor to be removed (L1?) and some other links to be changed.

Thanks
Simon
G0FCU (new to microwaves so bear with me!)


--
Robin Szemeti - G1YFG


G0FCU
 

Thanks for your help Robin, all working fine now. I had to amend F1CJN's Arduino sketch to set the charge pump value as you suggested. The recharge pump resistor is not R7 as far as I can work out but could be a seemingly unlabelled resistor next to R3.

Thanks
Simon.

On Sun, 3 Jan 2021 at 08:26, G0FCU <simon@...> wrote:
That's the one. So I need to remove R5 and L1 and thanks for the heads up about the charge pump resistor.

Many thanks
Simon.
G0FCU.

On Sun, 3 Jan 2021, 07:44 Robin Szemeti - G1YFG, <robin@...> wrote:
This one?

image.png


R5 is the signal from the onboard xtal
R8 is the signal from the SMA socket
L1 is the power to the onboard xtal

Check also the value of the charge pump resistor and make sure it matches the value set in the software you use to calculate the numbers ... I *think* it is R7 on that board, but please check.  It connects between pins 7 and 20.  Most of the software is set up to expect a value of 1K ... these boards often have 5.1K  in that position ...  if the numbers don't match the software, you'll run out of tuning range.

On Sun, 3 Jan 2021 at 07:14, G0FCU <simon@...> wrote:
Could someone tell me the components that need to be changed on the ADF4351 (black eBay) board to enable a 10 MHz reference input?

I can't find a circuit diagram on-line. Earlier in this thread Andy mentioned an inductor to be removed (L1?) and some other links to be changed.

Thanks
Simon
G0FCU (new to microwaves so bear with me!)


--
Robin Szemeti - G1YFG