Recent Posts

1

RF, Microwave, Ham Radio / Re: High bandwidth FM signal generation

« Last post by enemra on Today at 03:51:47 pm »

Guys, thank you very much for the answers but a humble request - please do not post answers in the context of jammers or do link my previous posts like the user coppercone2 being smart. I am not working on jammer.

It is all about I want to create interference and come up with resilient communication solution for space-terrestrial based broadband communication. This involves a tiny band of frequencies over 400MHz bandwidth.

@coppercone2 (smart guy): My amplifier post was for a different frequency and does not involve FM there.

2

General Technical Chat / Re: Why Circuit Breakers DON'T Protect People (electric shocks)

« Last post by AVGresponding on Today at 03:50:07 pm »

Yeah, take that article with a pinch of salt; it's by Schneider Electric.

Better that than Hager. 

I wouldn't trust any manufacturer to not try to use the opportunity to sell you their product.

3

General Technical Chat / Re: A serious (as in not troll) requestfor help w/ultrasonic transducer

« Last post by IanB on Today at 03:46:39 pm »

There is a revelation that came to me somewhat late in life.

As a child, whenever I needed a widget for some project I might be working on, I would think "Where can I buy such a widget?" Only later, did it become apparent to me that if you need a one-off widget of a particular size and dimension, well maybe you could make it. For me, it was like, "Oh...you can make a thing? You don't always have to buy it?"

4

General Technical Chat / Re: ultra sonic transducers

« Last post by pete g on Today at 03:45:42 pm »

yes, i thought their might be a mathematical way to figure out the power needed. if, say i need to transmit a hundred feet how much power would i need? it's hard to get at the dogs as theres  thick bushes blocking the way. theres one commercial unit that says 150 feet range. true? it sounds like from what you folks say, its going to be quite difficult to do. some guys are putting the ultra sonic signal thru very powerful amps. i don't think i want to go there. the last thing i want is to hurt the dogs.

5

RF, Microwave, Ham Radio / Re: High bandwidth FM signal generation

« Last post by enemra on Today at 03:43:36 pm »

Nope. If thats the case i wouldnt come here to the forum. Moreover, I should be very strong enough to understand such stuffs if it is military.

6

RF, Microwave, Ham Radio / Re: High bandwidth FM signal generation

« Last post by mawyatt on Today at 03:43:10 pm »

Check out the DARPA program Computational Leverage Against Surveillance Systems or CLASS.

https://www.darpa.mil/program/computational-leverage-against-surveillance-systems

We developed the computational chip over a decade ago for CLASS.

Best,

7

Beginners / Re: Convert US standard 115V to International 230V

« Last post by radiolistener on Today at 03:37:39 pm »

but AGAIN you missed the fact that OP clarified before your first reply that the 20A input was NOT the actual maximum input current established by some empirical means, but a mystery number from a long-gone employee.

Yes, when I posted my first message in this topic, I didn't notice that he don't have other power supplies and 20A is a mystery number.
And what? This is the reason you're attacking me? 

Sorry, but it looks very strange from my point of view.

By fully understanding the thread up to the point where you first replied, you would have already known that all of the system is powered by the two SMPSs, both of which are already universal input. So you’re suggesting doing what it already did.

And? I don't see a big problem here. It was clarified in the followed messages and we just follow forward. Isn't it? What is the reason to return back again and again?

And I don't see why it leads to such kind of aggression and attempt to shift discussion to persons instead of technical topics?

Don't you think you're fixated on some nonsense which makes no sense to devote so much time?

8

Projects, Designs, and Technical Stuff / Re: Firmware mod for GWInstek GPP series lab bench power supply

« Last post by Pr Utser on Today at 03:33:58 pm »

Hi @Wade2019,

I have not tested the mod on a GPP-1326 myself but I see no reason why it would not work.
The mod has been developed to support all GPP-x32x models.
Personally I tested it on a GPP-4323 with LAN option but without GPIB option.

Maybe others could comment on what they are using.

9

Test Equipment / Re: New 2ch pocket DSO+SG - Zeeweii DSO2512G

« Last post by Aldo22 on Today at 03:33:52 pm »

It may be caused by the multimeter - multimeters also have a frequency range.

Absolutely, that's why I only compared the different voltage ranges at 1kHz and DC.
At 1kHz, the multimeter is quite accurate.
Then you can increase the frequency and look at the frequency response ("hobby accuracy" of course...)

10

Buy/Sell/Wanted / Re: FS: Affordable DMM Checkers: AC Reference, DC Reference, OHMS Reference, etc.

« Last post by watchmaker on Today at 03:25:40 pm »

Yup!!

Interestingly, all my instruments agreed as shipped.  I cannot adjust the HP, the Keysight or the 8842.

This is indicative of "inter rater" reliability;which is a precursor to validity; which in this case would be verification against a standard such as NIST.

As for my uses, I kind of doubt I have time to get far enough along to be concerned with nano amps, let alone pico amps.  I am just starting capacitors and inductors.

I WOULD be very interested to learn where such measurements are used.  I know it is not an issue of "trivial precision".

FWIW, I have come to conclusion that the way to bring the world crashing to its knees is to end capacitors.  Who the hell knew?

Regards,

Dewey