HI, i have just got my tinySA from China.

Please check this video and tell me if it is genuine

First run a selftest.
After that upgrade the FW.
If you want to be sure open the case and post a picture of the PCB?

Hi Erik,?

self test positive

here is the photo inside:?

there is nothing written on the pcb on the diplay side.

?

I left the FW upgrade as last step, not done yet.

Your OK!
Fully genuine
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If you have the capability I suggest to solder 33pF 0603 SMD capacitors on the open positions C13, C17 and C20. This will reduce the currently visible 48MHz harmonic spurs to almost zero.
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Thank you!

i've got it at a bargain price and only after reading this group i suspected that it could be a copy. I thought that there were no fakes (yet) for the tinySA.

?

I've seen only now your second reply

Ok for the 33pF capacitors, i will.

Thank you Erk!

On Wed, Nov 25, 2020 at 05:13 AM, Erik Kaashoek wrote:

If you have the capability I suggest to solder 33pF 0603 SMD capacitors on the open positions C13, C17 and C20. This will reduce the currently visible 48MHz harmonic spurs to almost zero.

Erik,
? I had some 22pF smd caps on hand, so with magnifying goggles and soldering iron in hand I installed the capacitors in the prepared positions. No awards for straight alignment of the installed capacitors, trying to tack solder one side in place so I could solder the other side was a bear.? Anyway, here are my results:

?Unmodified, LOW and HIGH Inputs-Open? ? ? ? ? ? ? ? ? ? ?22pf capacitors installed, LOW and HIGH Inputs-Open.??
?? ? ?

? ?So yes the 48MHz harmonic spurs are visibly reduced by the addition of the capacitors.? I also looked at the LOW INPUT with telescopic antenna attached before and after the modification:

?Unmodified, LOW Input-Antenna? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?22pf capacitors installed, LOW Input-Antenna.
?? ? ?

? ? ?The over the air signals swamp the 48MHz harmonic spur modifications.? If the tinySA is primarily used with the supplied telescopic antenna, then the addition of the decoupling capacitors is not going to be of much use.


?With the output of an RF generator (?-30dBm, 175MHz?) attached directly to the LOW INPUT,? no 48MHz related harmonics are visible with the 22pf capacitors installed (other visible signal is FM band related).
??

? ?

0603? capacitors 33pF

? Great foresight to add the pads for additional decoupling capacitors.

? - Herb

Thank you for the screenshots Herb.

Can i use the nanoVNa signal generator attached directly to the tinySA input without attanuator?

On Wed, Nov 25, 2020 at 06:16 AM, Massimo Martini wrote:

Thank you for the screenshots Herb.

Can i use the nanoVNa signal generator attached directly to the tinySA input without attanuator?

? ? If the tinySA is in its normal auto settings mode, then it should adjust its internal attenuation automatically to prevent the output of the NanoVNA from over driving its input.? In manual mode, I would suggest setting the internal attenuation to 20dB.? No external attenuation is necessary.

? ?Beware that the above applies to the LOW INPUT.? The HIGH INPUT does not have the input attenuation and filtering that the LOW INPUT does so a external 20dB attenuator would be a wise choice when the NanoVNA is connected to it.? Without the attenuator the tinySA will not be harmed by the NanoVNA but a lot of spurious signals may be produced.

? - Herb?

? ?- Herb

Hi Eric

Is there any downside to fitting these capacitors, bearing in mind that they were omitted from the unit??

Regards
Jeff

No
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开云体育

I checked my tinySa this afternoon after getting some 33pF caps from spares box and the caps were already fitted. H/W V0.3, serial number 20100409. Not checked value so I can only assume they are 33 puffs.

On Wed, Nov 25, 2020 at 10:05 AM, geoff M0ORE wrote:

I checked my tinySa this afternoon after getting some 33pF caps from spares box and the caps were already fitted. H/W V0.3, serial number 20100409. Not checked value so I can only assume they are 33 puffs.

I wonder what the hardware rev # or serial number? was when they started installing these caps?

Roger

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开云体育

I'm guessing that the serial number is the date plus a number. 200912xx would be 12 Sept 20, 201004xx would be 4 Oct 20 etc. Only Erik can confirm. I found that replacing the unit back in the case was a bit of a fiddle but OK in the end. Perhaps the Chinese ladies who do the assembly have more nimble fingers than mine.

Hello Erik,

> Is there any downside to fitting these capacitors, bearing in mind that they were omitted > from the unit??

Why were C13, C17 and C20 not populated to begin with? ?The cost could not have been that much? ?There are no drawbacks for adding? ?I see you suggested 33pf whereas walker used 22pf; any reason for the difference??

Thank you for your time, ? ? ? ? ?larry

Hi,

I made the same guess about those numbers. I am thinking those Chinese ladies have more practice than any of us:)

73,

Bill KU8H

bark less - wag more

On Wed, Nov 25, 2020 at 03:37 PM, Lawrance A. Schneider wrote:

Hello Erik,

> Is there any downside to fitting these capacitors, bearing in mind that they were omitted > from the unit??

Why were C13, C17 and C20 not populated to begin with? ?The cost could not have been that much? ?There are no drawbacks for adding? ?I see you suggested 33pf whereas walker used 22pf; any reason for the difference??

Thank you for your time, ? ? ? ? ?larry

Larry,
? I happened to have 22pf smd capacitors in my capacitor kit but no 33pf's.? The 22pf's worked for me so any any value close to 33pf will probably work.? I think it was only after user's questioned Erik about the 48MHz spurs that he tried installing the 33pf capacitors and realized that they were useful.? hugen probably started installing the capacitors on later production runs at Erik's suggestion.

- Herb

Hello Herb,

> Hugen probably started installing the capacitors on later production runs at Erik's suggestion.

I have version H0.3 . ?But again, the terminals are there so why not populated? ?My 75 year old eyes and hands will be having a hard time. ?Plus, I have 0 (zero) SMD caps. ?I'll ask my friend Andy at the Uni if he has some. ?The problem is 'she who must be obeyed' will not allow me anywhere near the Uni. ?Last I heard, there were 47 cases there.

Thank you for your reply, ? ? ? ?larry ? ??