New to group and to the TinySA Ultra. Bought from R&L & arrived with latest FW. Would like to use SD card in PC reader - I need pointers for removal/replace SD card from SA. Couldn't find info on Wiki & I sure don't want to damage new SA.
Thanks

Amanda, your email on qrz is not valid. Drop me an email to mine and I will give you further info.

73 Dave

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John,

For instance?? Sure I could look up diode data sheets & spend considerable time reviewing specs.? It sure would be easier if you (someone) provided some examples.? Then the time could be spent searching the random parts drawer-bin, or shopping for one of the examples.

THANKS Eric & everyone else for the info [EDUCATION]!? Remain WELL & be SAFE!

Mrs. R A

- - - - - - - - - - -

Martin, I agree, the 1N4148 is the diode that is probably in every junk box and will work. I just thought about trouble shooting I have done in the past especially on tube receivers and TV audio IF in the late 60s and 70s (yes I am dating myself here lol) It is just too easy to touch the wrong pin and suddenly have the full local oscillator signal going into the probe.For sure strong enough to generate a 10dbm or more signal at the input of the TinySA if using the 4148s.I have used the BAT45 many a times in similar applications,it's low capacity makes it a good candidate for higher frequencies. However, they are hard to get these days unless one buys some questionable ones from E-bay. But there are ample of similar low capacity small signal schottky diodes available for people to chose from.

John

Martin, I agree, the 1N4148 is the diode that is probably in every junk box and will work. I just thought about trouble shooting I have done in the past especially on tube receivers and TV audio IF in the late 60s and 70s (yes I am dating myself here lol) It is just too easy to touch the wrong pin and suddenly have the full local oscillator signal going into the probe.For sure strong enough to generate a 10dbm or more signal at the input of the TinySA if using the 4148s.I have used the BAT45 many a times in similar applications,it's low capacity makes it a good candidate for higher frequencies. However, they are hard to get these days unless one buys some questionable ones from E-bay. But there are ample of similar low capacity small signal schottky diodes available for people to chose from.

John

On Fri, Feb 9, 2024 at 11:43 AM, Amanda Hambidge wrote:

Hi Dave,?
not being in the know about pcb files, how do I go about sending the info to the PCB manufacturer you used?

regards
Amanda M0DZO

I am away from home until Monday, but there is a chance I have a spare board I can post you FOC. I will drop you an email via your QRZ email.

73 Dave

Suggest you contact your supplier as this is not easily to fix with some setting
--

As the generator output power is decreased from the starting value of -17dBm, the signal level received drops into the receiver noise at around -30dBm and then at around -40dBm the signal level received on the directly connected receiver starts to come up out of the noise again but then it drops down again quickly by -50dBm or so generator setting. The receiver is fine and working normally with an antenna and I have detected this issue with 3 different receivers.

On Fri, Feb 9, 2024 at 01:16 AM, John Cunliffe W7ZQ wrote:

I would say 2 low capacity? diodes like the BAT45 or similar would be the better option

Hi John,

Yes I'd agree.

My thinking was to use parts that folks were likely to have lying around, and 1N4148's seemed to be a better option than nothing.

It was to try and limit short duration spikes due to the coupling capacitor charging / discharging, more so than RF limiting, but I take your point.

Regards,

Martin

On Fri, Feb 9, 2024 at 04:46 AM, Bob Ecclestone wrote:

I have now extracted my foot from my mouth and have put my teeth back in:-)

Hi Bob,

Ha, you and me too.

The number of times I've pressed send and then immediately had a Doh moment...

Someone once said "you learn more from your mistakes" if that were true I'd be competing with Einstein.

Regards,

Martin

Hi Dave,?
not being in the know about pcb files, how do I go about sending the info to the PCB manufacturer you used?

regards
Amanda M0DZO

On Fri, Feb 9, 2024 at 08:21 AM, G4AON wrote:

the design by Marek

Marek's design is very good if you actually require an active probe.

They have their uses, but in my experience in most cases, you don't require the additional sensitivity or high input impedance that they can provide. A simple passive probe is adequate, plus you can inject signals with it too.

However, it is worthwhile having an active probe on hand, as in the very few occasions you may need one, they are invaluable.

Like everything else, the more tools you have, the easier the jobs become.

Regards,

Martin

Where, from what do You see that the pdf is directed to TinySA ?

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There has been quite a thread on this forum on the construction of a probe that limits the signal level into the spectrum analyser, I built one based on the design by Marek, notes and details of both are in the files section of this forum. It is powered from USB, or any 5V supply.

73 Dave

Thank you. I have the sa4. I hold down the jog wheel ans power to enter DFU.
Will the stm32 see this as I follow the tinySA_Firmware_update_stm32CubeProgrammer?
I ask because the pdf seems geared towards toward the TinySA.

On Fri, Feb 9, 2024 at 05:45 AM, <phyzxengr@...> wrote:

OR actually I am in the tinysa

tinySA or tinySA3 -> tinySA
tinySA4 -> tinySA Ultra

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And don't forget the DC Block, particularly if working on tube (valve) equipment.

Cheers...Bob VK2ZRE

And maybe I have the wrong bin file.

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Hi Martin,

You are absolutely correct. I thought about it a bit more pretty much as soon as I pressed "send'.
I have now extracted my foot from my mouth and have put my teeth back in:-)

Firstly, there are two modes:
1. SA Mode where probe is used on the input to the TinySA. I believe the -52dB is pretty close in this case. But I will check.
Again, you are correct that the compensation capacitor will make the probe attenuation frequency dependant, depending on the input capacitance of the TinySA.

2. Sig Gen Mode where the probe is used to inject a signal into a circuit.
Here the impedance at the injection point will most likely be much higher than 50 ohms and therefore the attenuation will be less, probably much closer to your 20-30dB.
I can't argue with you practical experience here. I have also used a probe in similar circumstances but never measured the results.

I recently purchased a handheld digital oscilloscope and had intended doing some frequency response measurements on it using a TinySA as a generator and the TinySA Ultra to measure the level with the CRO bridged across the Ultra input.

I had also intended to check a few discrete frequencies using the x10 probe on the input to the Ultra. 455KHz, 10.7MHz for peaking IFs and 147MHz. The CRO is supposed to be good to 180MHz. I have already checked that I can see 147MHz from the TinySA in generator mode and I can. I did not have an SMA "T" at the time, so I could not do the 3 way test.

The use of the oscilloscope probe is a very convenient means of connecting to a circuit under investigation, both in probing and injecting a signal.

Still a work in progress.

Cheers...Bob VK2ZRE

OR actually I am in the tinysa


I need explicit instructions for the Ultra, please. The index site doesnt seem to have it.

I have STM loaded and the current Ultra bin file.
It is safe to follow the TinySA update pdf or is there a TinySA Ultra update pdf?