Recent Posts

1

Microcontrollers / Re: MSP430 for new designs?

« Last post by josip on Today at 11:16:45 am »

Nothing changed with TI MSP430 family in last 7 years, when FRAM series was filled up. Last year they enered to Cortex-M0+ world, with MSPM0(C/L/G).

2

RF, Microwave, Ham Radio / Re: HFH ROHDE & SCHWARZ RECEIVER LOOP antennas

« Last post by A.Z. on Today at 11:15:46 am »

would this be empire loop antenna?

are you referring to this one ?

https://www.recycledgoods.com/empire-devices-lp-205sc-loop-antenna-12/

3

Test Equipment / Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

« Last post by Darkover on Today at 11:10:14 am »

I have RTB2002 for about 3 years and his 2 RT-ZP03 never show any sign of any leakage. They are perfectly dry. Maybe external causes? Proximity with some flowers, herbal decorations?

I never faced the problem you described! Is there any special gas in your enviroment?

However the probes from R&S not good anyhow. Buy some from PMK!

https://www.pmk.de/en/products/pml_high_z_tastkoepfe      PML712

They are smaler and the middle pin has a spring. They are so good that other famos company are buy them
and print there name on it and sold them for the double price 
Unfortunatly R&S is to stingy to put good probes to >4000Euro scope.

Especially if you use the probes with the ground-spring you will never look back to the old ones!

Olaf

4

Test Equipment / Re: HP Logic Analyzer Inverse Assemblers

« Last post by Nemesis1207 on Today at 11:09:45 am »

Never mind, got that sorted. I was loading files onto the unit via ftp, since the 1670G has a LAN port. I thought I'd setup my ftp client to transfer everything in binary mode (IE, don't try and do newline translation), but it turns out there was a sneaky setting to treat all files without extensions (like "i68000_p") as text, meaning it was corrupting the binaries. The inverse assemblers now appear to load. Just got to mess around with pod mappings now so they work properly. At least while going around in circles over the last two days I've got setup to build these things from source, so I'll be able to hack away at them.

5

Repair / Re: Solartron 7081 Earthy Processor Board Reverse Engineering

« Last post by Eleclu on Today at 11:09:41 am »

Yes this was definitly not intended. I will fix the mistakes and update the files.
Thank you for taking a careful look at the files
This mistake happend after some minor corrections, which were necessary as I tested the first pcb version.

6

Test Equipment / Re: SDS800X HD Bugs/Wanted Features

« Last post by newbrain on Today at 11:07:56 am »

Some days ago I posted a couple of screen captures to show that FFT decimation is just that, i.e. no filtering to prevent alias.

I used the output of my TinySA, since I had it handy, assumed the 2nd harmonic came from that, and had no way to verify.
This morning I used a self built AD9954 based DDS, at 400 MSa/s, with 9th order 35 MHz elliptic low pass, set to 10 MHz and about -3 dBm.

The output spectrum is quite good, here's a TinySA capture (it had been verified also with a R&S costing 3 × my car...unfortunately no longer available to me).


The FFT in the SDS804X (cough, 824) shows quite a pronounced number of harmonics, fiddling with channel 1 vertical setting it is possible to reduce them a bit, but never at the levels shown by the SAs.


More than a bug reporting, this is a question: is this level of harmonic distortion - which I assume coming from the front-end - normal for a scope of this class?
I can live with that, this is just to make sure my scope is OK. With the pitiful FFT of my previous DS1054Z, this kind of check was unthinkable...

EtA: and yes, I see the noise floor is much lower in the FFT. Harmonics are still higher though, and the capture is with the setting for vertical that gave the best results.

7

Test Equipment / Re: Rigol DHO 4400

« Last post by Pinkus on Today at 11:04:58 am »

Check the DH0800 thread. I remember, they made it possible to have access to Android and they installed a driver for an USB Wifi dongle.

8

Beginners / Re: Using a CC Power Supply in Series with a Battery to Limit Output Current MPPT?

« Last post by MrAl on Today at 11:04:34 am »

Hi all, hopefully some of the clever people hear can put me straight on this as have had a good dig around the google verse and forum and cant find this scenario discussed.

With my limited experience and and small scale experiment this appears to be viable but sure I'm missing something.

So here is the situation. Lets assume we have a multiple 12V car batteries with "effectively" unlimited current output potential. We want to hook it up as an emergency "fake" solar input to an MPPT solar charge controller.  It well understood that this isn't a good idea as the MPPT will see the high current capability as effectively a dead short and the tracker may do all sorts of odd things. 

So we could get a beefy DC-DC converter with CC/CV and use that to limit current. But that is a fairly expensive solution as soon as we go much over ~36V DC-DC threshold that most cheap Power supplies can do.

So it go me thinking.  If current in a series circuit is limited to the smallest current source and you wanted say a ~100V CC DC Supply.  Could you have 7x12V Batteries in series with an 8th connected also in series via a 12-36V Boost converter.  Then lets say the PSU is set in CC mode to 3A @16V.  Does this mean we now have a 100V 3A supply overall.  Is the PSU now handling 300W(100*3) or is it just doing 48W(16*3). Does it depend if it high or low point in the circuit.  Or is that the crux of why it cant work, the small PSU would effectively see the full 300W and 84V(7*12V) across its input and basically blow up.

---

POC Bench experiment to prove very basic concept was 3x9V batteries in parallel as a ~9V/6A supply in series with a PSU to power a ~35V LED.  Was able to set the current limit for the whole circuit via the PSU in this setup but overall voltages/current were also within limits of the supply itself.

---

So please be kind and educate me where my logic is wrong with the above as sure I must be missing something as otherwise this would be a solution or idea that cropping up everything to Current limit batteries without high voltage DC-DC power supplies.

I don't think you can do that, but I may not understand what you want to do exactly.  Maybe draw up a diagram that makes it unmistakably clear.

You might be able to use a power resistor in series with the batteries, but you would end up wasting power, depending on how much you needed to limit the current.

9

Test Equipment / Re: new killer scope in town - a true game changer from R&S - RTB2002 & RTB2004

« Last post by Robaroni on Today at 11:03:20 am »

There's no oil of any kind in scope probes, that's external.

10

Test Equipment / Re: SDS800X HD Bugs/Wanted Features

« Last post by tautech on Today at 11:00:25 am »

Are you testing 1.1.3.5 like we are ?

How could i? But if i would, i would have really made sure that i "slept well, and would not have a itchy bite in the morning".

Put some cream on the itch and be patient, there will be a new firmware for you to drive right into soon.

There are many changes, several more than have been reported here.