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RF, Microwave, Ham Radio / Re: NanoVNA Custom Software
« Last post by ALW on Today at 08:50:26 am »
Thanks a lot JoeSmith for this excellent SW. I am learning to use it... Available options are massive, but I believe it is very powerful.

As for the readability issue on high density screens, I think I found a solution in Win10 that works nicely.
In C:\Program Files (x86)\NanoVNA_V2Plus right-click the .exe, select "properties" tab "compatibility"
Click "Change high DPI settings"
Select "High DPI scaling override" option "System (enhanced)"

In my case that made the display crisp and clear and very well readable. Only drawback is that some vertically rotated graph legends were cut off, but I can imagine what they say.
Thank you HB9EVI for your reply.

I just need to clarify some things.

1. To look at the signal from the LINE OUTS that are balanced, would I place a 600 Ohm load across HOT and GROUND and measure across HOT and GROUND?

2. I would still use the FFT function on the oscilloscope, but have the oscilloscope connected to the notch filter output.  The notch filter input would be from HOT and GROUND of the LINE OUT.

3.  Are there any notch filter ICs or active notch filter circuits you would recommend? 


Microcontrollers / Re: Help to start with STM3L412 and libopenCM3
« Last post by psysc0rpi0n on Today at 08:47:39 am »
I'm not sure how the prescaler value works. Apparently this is where you put the upper limit of our counter. So, in the example I'm following, is said that:

Probably an english language thing. Prescaler = scale the clock, so divide it down. Its not an upper limit, that would be related to the preload or max register value.

So if the timer is 80MHz, then prescale is set to 10, now the timer will run at 8MHz.
Assuming 16-bit timer, max prescale is probably 65536. So prescale by whatever makes sense to you, since you need low timer resolution, maybe 10000 or 40000.

I know what the prescaler is meant to do. What I'm not sure about is how it relates to the value I want/need the led to blink.

You say the if the timer is 80Mhz, thhen prescale is set to 10. How do you know this?

Did you take the heatshrink off Q3/Q5? according to the drawing they should be in a sleeve an in contact with that white ceramic washer (which is BeO so don't break it). If they are not in good therml contact you may have issues.

The heat shrink was already off and nowhere to be found. No idea why. I've got a 5100 manual on the way from America.  Will be interesting to see if there is a difference on Detail "B"

The isolator output is a reasonable value.  It may be drifting a little but it is close enough that it shouldn't stop the meter from displaying value.

I will reattach Q3/Q5 before sending the meter off for adjustment.   That assuming I can find someone who will adjust a Dana 5100.

5100AF Isolator schematic attached.  The 5100 is close but not identical. 

The GDS3000A series is a whole lot bigger indeed and in the video it also says 800x480. Not sure whether the resolution is a big issue though. It is just that pixels are more visible. Using an 8x8 font on a 10" 1920x1024 screen is not going to be readable so in the end you end up using the same amount of display area to show something. Last year I used a 7" 1024x600 display in a HMI project. The result is a display with fantastic looking text and graphics. But from a functional point I could have used a 400x240 display as well.
Test Equipment / Re: New GW Instek GDS-3654A/3354A - when will we see them?
« Last post by 5q5r on Today at 08:35:06 am »
Any idea what that 3x4 matrix of controls is at the top right?

Number pad, good for spectrum analyzer or AWG use (hm maybe no AWG though).


Ooh, nice! An actual version of it in the wild! It can't be THAT long before they actually start selling them then, I guess. 😊
Mechanical Engineering / Re: Getting 10 small steel plates manufactured
« Last post by EPAIII on Today at 08:31:43 am »

First I am somewhat new to this BB and hope it is OK to offer to do this work for you here. In addition to electronic shops, I also have a machine shop. The nut plate, by itself seems to be dead simple and easy to make. For that alone, I could make ten of them for about an hour of time and the cost of the materials. I am in the US in Texas and do not know about shipping to Canada.

But from your photos, it appears that the nut plate mounts to either the uprights or some other member of the desk and that mount is more messed up than the nut plate itself. They appear to be welded together. So, do you have a way of attaching the new nut plates? Perhaps additional holes in an angle bracket so it could be bolted together. Or do you have a local welding shop which can do the work? This may determine the type of steel used as some alloys will be more suitable for welding. 

I would also need some better photos showing exactly where and how they are used so I could be sure the new ones would be suitable. Otherwise, you would have to assume all responsibility for that.

Also you appear to need new screws. I could provide them, but would need to know more about them; mostly the exact length needed. And would a different screw thread be acceptable or must it be the same, M6 thread as the originals. I have more M5 hardware than M6 and more English (inch sized) fasteners than metric.

Being new to this board, I do not see how to send a private message with my e-mail so we could communicate that way. If you are interested, perhaps you could send one to me with your e-mail.

Edit: I did manage to send a PM with my e-mail. Respond via e-mail address if you wish to continue.

Paul A.

Yes the plate is much more like 4mm thick. I call it a plate but it's much more like a strip.

I knew I was in trouble when I unscrewed the bolt and I felt it start binding towards the end of the travel, I knew it was damaged. The threads are clogged with material, guess I also need a M6x1 die.

Maybe there's some M6 screws I can buy but I wanna keep these.

I'm wondering if there's some industrial standard to this. The holes seem to be on 22mm centers.

edit: seems to be more likely to be M6X0.75mm screws, and in any case it looks like it's the threads in the screws that have been crushed, trying to re-tap them might not even work.

I just found some M6x1 bolts in my junk and they are coarser than the IKEA screws. Guess my visual estimates suck.
General Technical Chat / Forum Help? Fixing account name
« Last post by unkown_h on Today at 08:28:18 am »
I am sorta unsure where to post this, when I was setting up my account I accidentally fat fingered and miss spelt my account name. I sorta just forgot about it as I don't post all that often. After studying the smf manual I am assuming that eevblog has display names disabled, so I can't fix it my self. If some one could tell me how to contact some support, or fix it (it should be unknown_h) that would be great.
Other Equipment & Products / Re: Any opinions on the AiXun T3A?
« Last post by wraper on Today at 08:27:39 am »
I doubt any controller, even jbc, handles such situation.
If the MOSFET shorts out, you'll have a bad day.
But it should be sized to make sure it won't happen easily.
Don't get paranoic! :scared:
JBC uses transformer, not SMPS, so output voltage is not stable. Current sensing in that case can be helpful to measure actual power delivered and adjust on/off time accordingly to deliver desired amount of power. Or to detect type of cartridge used based on current consumption. Most likely the only thing it can protect is electronics in case when cartridge is shorted.
I don't have JBC but ERSA I-CON has current sense as well. It won't help at all if pass element (TRIAC) is shorted.
Some of the soldering on those boards is shocking, Fraser. I've seen better done at home on kitchen tables.

(And, just for total clarity, I am not suggesting Fraser soldered any of the above).
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