LO device?


dave cossar
 

HI Has anyone ever tried one of these from Banggood

 

 

https://uk.banggood.com/Geekcreit-Signal-Generator-Module-35M-4_4GHz-RF-Signal-Source-Frequency-Synthesizer-ADF4351-Development-Board-p-1416998.html?akmClientCountry=GB&gmcCountry=GB&currency=GBP&createTmp=1&utm_source=googleshopping&utm_medium=cpc_bgcs&utm_content=garman&utm_campaign=pla-gbg-ele-pc&gclid=EAIaIQobChMIhYrbnb2M4gIVaLftCh0vxAADEAQYASABEgL36PD_BwE&cur_warehouse=CN

 

 

Dave


Andy G4JNT
 

Yes, I've had two of that type (the black PCB) one of another Chinese low cost type (using a green PCB) and at least three of the decent properly made ADF4351 boards by SV2AFN

It was reported om in this group a few years ago - several people found that specific PCB, the black one, had a fake chip where the output divider couldn't go below 16.  Ie it was probably an ADF4350 device although labelled ADF4351.    Fortunately mine was going into a project that only needed to go down to 200MHz so teh fake chip was satisfactory

 The green PCB version was Ok

There are several versions of those cheap Chinese modules, some said to have better decoupling than others.

I'd never buy a Chinese one again, the SV2AFN ones are so much better made, properly decoupled and don't have fake chips.

As for the outpiut quality - it's mostly dependent on the quality of the reference you put in.  Raw 10MHz output from GPSDOs aren't always the best reference for synthesizers.



Andy G4JNT
 

Ah, didn't look carefully enough.   That's a complete module with controller and OLED
Didn't see its a new version

Not sure I'd ever trust a low cost synth module from China ever again tho.

Not sure I'd trust anything from China these days



On Sat, 11 May 2019 at 14:13, Andy G4JNT via Groups.Io <andy.g4jnt=gmail.com@groups.io> wrote:
Yes, I've had two of that type (the black PCB) one of another Chinese low cost type (using a green PCB) and at least three of the decent properly made ADF4351 boards by SV2AFN

It was reported om in this group a few years ago - several people found that specific PCB, the black one, had a fake chip where the output divider couldn't go below 16.  Ie it was probably an ADF4350 device although labelled ADF4351.    Fortunately mine was going into a project that only needed to go down to 200MHz so teh fake chip was satisfactory

 The green PCB version was Ok

There are several versions of those cheap Chinese modules, some said to have better decoupling than others.

I'd never buy a Chinese one again, the SV2AFN ones are so much better made, properly decoupled and don't have fake chips.

As for the outpiut quality - it's mostly dependent on the quality of the reference you put in.  Raw 10MHz output from GPSDOs aren't always the best reference for synthesizers.




Richard <richard@...>
 

the suppliers name should be a clue
Bl***y awful noisy goods
Richard

On Sat, 2019-05-11 at 14:20 +0100, Andy G4JNT wrote:
Ah, didn't look carefully enough.   That's a complete module with controller and OLED
Didn't see its a new version

Not sure I'd ever trust a low cost synth module from China ever again tho.

Not sure I'd trust anything from China these days



On Sat, 11 May 2019 at 14:13, Andy G4JNT via Groups.Io <andy.g4jnt=gmail.com@groups.io> wrote:
Yes, I've had two of that type (the black PCB) one of another Chinese low cost type (using a green PCB) and at least three of the decent properly made ADF4351 boards by SV2AFN

It was reported om in this group a few years ago - several people found that specific PCB, the black one, had a fake chip where the output divider couldn't go below 16.  Ie it was probably an ADF4350 device although labelled ADF4351.    Fortunately mine was going into a project that only needed to go down to 200MHz so teh fake chip was satisfactory

 The green PCB version was Ok

There are several versions of those cheap Chinese modules, some said to have better decoupling than others.

I'd never buy a Chinese one again, the SV2AFN ones are so much better made, properly decoupled and don't have fake chips.

As for the outpiut quality - it's mostly dependent on the quality of the reference you put in.  Raw 10MHz output from GPSDOs aren't always the best reference for synthesizers.



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 Richard Bown
 
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Brian Flynn GM8BJF
 

Hi Dave,
That is a new board to me as it has the microcotroller chip on it along with an OLED display. 
Some of the earlier more basic boards  used pretty ordinary voltage regulators and were quite Phase noisy.
I see this one uses a Linear Technology chip which I take to be a low noise voltage regulator so the PN performance is probably OK.
The "black ADF4351 boards" use a generic LM1117 regulator which could be improved on
If it is an issue you can add LF decoupling to the power rails on the board.
 
The ADF4351 is quite useful chip and can provide a reasonably clean signal. A 4 GHz signal generator for £25 cant be too bad!
I made myself a simple sig gen using one of the "black boards" and Cypress USB interface which can be made to work
with the AD demo  software quite easily. I have had about a dozen of these sig gen boards from China and never had a problem with any of them.
They do what they say in the ads and are about a tenth of the price of the actual AD demo boards.
73s
Brian GM8BJF