Power Line Noise Infecting Instruments?

Obviously, or you wouldn't be alive to complain about the alleged EMI/RFI.

I pointed you to LISN boxes, which are the correct way to couple to the power lines. Although the boxes need to be properly shielded, they're easy to build. The main benefits are:

1. If you wire it correctly, you will NOT have 240VAC on your scope ground lead.
2. A standardized line termination so that it looks the same no matter where you make the measurement and what equipment you use.

Maybe. The frequency response of your HP 8566B is 100 Hz to 22 GHz with a minimum IF bandwidth of 10 Hz. In order to see anything in the

50 Hz region, you would need to switch to the 10 Hz bandwidth, where you can then complain about the long time it takes to display something useful. If you look at the middle of Pg 10, you'll find the specifications for power line related sidebands, all of which are -60dB or better. You can see 50/60Hz sidebands on various signals, but you will have to work hard to see them.

That's easy enough to test. Disconnect your 2ft wire antenna, terminate the input connector with a shielded 50 ohms termination, and photograph what you see on the screen. If you do see FM stations, then they are leaking into the instrument somehow.

Do you have everything put together including all shields, covers, and the case? These are rather important for keeping RFI out the box.

Then, what are you doing? Describing what you are NOT doing isn't very helpful. If you have nothing attached to the power lines, how do you know that the FM stations are arriving via the power lines? It would be helpful if you would describe what tests and logic you used to determine that the FM stations on the screen were arriving via the power lines. Also, a photo of your setup.

Yes, you can use a spectrum analyzer for sniffing the airwaves. However, that's not how power line conducted radiation tests are performed and is insufficient to demonstrate that the FM signals are arriving via the power lines.

I have 2 working spectrum analyzers and 4 communications service monitors with built in spectrum analyzers. I won't count my collection of RTL2832U dongles that can be used as a spectrum analyzer, and various audio/vibration analyzers. Since I have twice as many spectrum analyzers as you, I must therefore know twice as much about spectrum analyzers.

I supplied those links on the basics of spectrum analyzer operation because you made a few fundamental mistakes describing your alleged problem. Your replies to my requests for photos and more information do nothing to change my assessment.

I wouldn't spend as much time trying to answer your questions and unscramble whatever you're doing, if I were a Usenet troll. You've made a few fundamental mistakes and I consider it my duty to leave no mistake un-criticized. I try not to be personally insulting, but it's difficult to suggest that you could use some basic help in operating a spectrum analyzer without seeming critical. If I've offended you, it was not my intent. Please accept my apology.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

You are continually misconstruing and/or misunderstanding what I have said and I can't determine if you're doing it on purpose. Either way I'm not prepared to continue this discussion with you any further. Sorry if I have you wrong but that's how it is.

This clip shows just how much noise can vary even between outlets on the same lead or spur:

Talking about making things even more difficult for yourself! With a phone, it's a couple of buttons to email (or text) a photo. At least my phone, asks whether I want to downsize the file before I send it. IIRC, I have a choice of four or five sizes between 10% and the original file.

>

The variations in what sounds like AM BCB demodulated audio are more a function of what's plugged into adjacent outlets than any characteristic noise pickup. The Entech Wideband Powerline Analyzer seems to be a broadband RF amp and AM detector. A device with a fairly large amount of capacitance across the power line, or some kind of series resonant trap across the line in the AM BCB region (about 1 MHz), will have little detected "noise". I was unable to find a manufacturers web pile, user manual, service manual, schematic, operational description, or clues as to how it works, what's inside, and how it couples to the power line.

This is either a variation or an improved clone: See the product description for additional clues. 10Khz to 10Mhz and

2VAC maximum which means it probably won't see/hear/smell 100MHz FM band signals, much less demodulate anything that can be heard with an AM detector.

Like I said... RF is magic and this is a great example of a device that operates by magic.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Of course, I find the manufacturer immediately after punching the "send" button.

The back of the unit shows that it was made by AlphaLab Inc of Salt Lake City, Utah as Model Sniffer v2.0. Trifield is owned by AlphaLab Inc which at least has a web pile that shows a rather wide variety of electromagic meters: Unfortunately, no docs, details, or additional clues.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

If that works for you, then fine. Personally I like to crop and tweak the image for focus, contrast and brightness before uploading it and my app of choice for that is GIMP under Linux. Only takes me a few seconds now I've done it so many times.

If you're looking for noise floor and unit self-noise, you terminate the input with 50R.

If you're trying to pick up extraneous noise, do what you're doing.

If you're trying to separate external noise from a specific signal measurement, turn the target signal off to get an idea of what is extraneous in the measurement being made.

Don't blame the SA for measuring noise that is there.

Clean measurements require clean environments.

RL

Don't open the box.

Don't look at line frequency noise without a suitable attenuator/clipper on the front end.

...otherwise the next owner of your SA will have a piece of junk.

RL

There are some pretty awful wall warts around without proper Y caps, for example. Cheap cloned phone chargers, for example. Also cell phones (like the one probably in your pocket) can cause issues but it's more sporadic usually.

I have tons of 50 ohm terminations, but they're all SMA types. The best I could do would be a 50 ohm dummy load which has a length of 50 ohm coax terminated with an N type, which the SA accepts. Should do the trick.

Always useful to know the background RF environment, I reckon.

Absolutely; fully agree. Well I found the cause of the noise! Some idiot had placed an insulating washer between the case and a ground tag on the main IF board! It should have been put back together in a different order!

No worries. I've found the problem now, but the rails I referred to were low voltage outputs from a linear supply anyway.

Your complaint was that you have to send huge files. You don't. There is no way you can move a file from a camera into the computer, edit it, and email it in seconds. Not happening, even if you have everything in front of you (I'm sure that's not always possible, either).

If it's out of focus, you can't make it "in focus". Not possible. The information is lost.

Den torsdag den 25. maj 2017 kl. 00.53.59 UTC+2 skrev snipped-for-privacy@notreal.com:

I haven't tried but it could be close, with phone setup to save photos to dropbox folder

You can if it's a "light field" camera :)

Also, when the exact blurring function is known, deconvolution can produce remarkable improvements in focus.

Maybe you have one of the widgets they use on TV for reading license plates from security cameras, three blocks away?

There was a demonstration in the 1980s of a photo of the Arc de Triomphe so badly blurred you could just make out the inverted-U shape. I think it must have been an extremely high quality image, because the researchers demonstrated enhancement to the point that you could read the writing on the foundation stone.

IIRC they manually tweaked a Fourier transform according to the known blurring function, and a forward transform returned a focussed image. At least, that's what little I understood at the time. I didn't know what convolution was back then.

But if the information isn't there, it isn't there and nothing can bring it back.

On a sunny day (Wed, 24 May 2017 16:17:26 -0700 (PDT)) it happened Lasse Langwadt Christensen wrote in :

Yea, was wondering My Canon camera, take picture of circuit, whatever, take sdcard out, put it in PC, mount it (using command line history), copy to pictures dir (using command line history), start 'xv' as viewer, crop the part I want to be seen, other manupilation options (mouse click) select save, upload to website (is script). Maybe 60 seconds.

View in browser (typing URL takes as much time).

unmount sdcard (command line history), (you should really try zhs as shell) put back in camera store camera in bag. blabber about it on usenet, now we are at least 10 minutes into the action..

But... I could do it with the webcam connected to the PC, write a script that does it in one second. ImageMagick

Or just live stream everything.... Just net-delay.