USB Isolator?

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Your_account

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Does it help to keep the noise out of my receiver?
THX
 

M105

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Get the antenna away from the computer. Using a USB extension cable helps with this if you are using a short or portable antenna cable. If listening to AM this is even more important.
 

a417

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if you can find an active USB 10m extension cable, you can put a good deal of distance from your largest RF source (ie computer). If you notice a marked decrease in interference, try shielding the SDR itself.
 

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does anyone here try it out?
And get the PC away is not possible all time because you can drill a hole in the wall.
 

ka3jjz

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Another thing to keep in mind is that the PC itself, or the monitor, can be a major source of RFI. Put chokes and beads on all the leads to/from the PC - that will help to stop these leads from being an unintentional radiator. Sometimes, not all the time, wrapping the leads that are long in a tight loop is enough (keep it together with wire ties).

Another pain in the neck are these cheap wireless mice, which often run right around 27 Mhz, and may send garbage right through the HF spectrum.

There have been whole books and articles on this very subject...Mike
 

ka3jjz

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Of course, it can't be stressed enough - getting the antenna outside, away from your home, and using shielded cable are the best (but certainly not) ways to keep noise level down.

There are SO many things in a home that can cause noise in a receiver that it beggars the imagination.

Mike
 

Your_account

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Another pain in the neck are these cheap wireless mice, which often run right around 27 Mhz
I neaver hear or see any of them. There is no Band who the can run?!

So back to Topic how about an USB Isolator?
I have the Problem when my Pi3 is powered Up there is a lot of noise! It is in an Metal Case.
 

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bharvey2

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Once in a while I connect my laptop to Yaesu HF rig via USB cable. I noticed it was pretty noisy. A series of clip on RF beads quieted things down quite a bit (as ka3jjz mentions above)
 

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ka3jjz

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You can't just pick a bead (or series of beads) and expect them to work. You must also consider the material, and sometimes the frequencies you want to protect.

I can't put my finger on it right now - I'm betting someone here knows - but there was a website (or was it a PDF?) that listed the various materials the beads (and chokes) are made of, their permeability, and the frequencies at which they're supposed to work...Mike
 

bharvey2

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If the RF noise is generated by the computer (very possible) the RF beads won't be of much help.
 

ka3jjz

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Maybe - the cables can act as unintentional antennas for the noise being generated in the device. You may need chokes, instead of beads, placed as close to the device as you can

Another source of issues are switching power supplies. They're well known noise generators, especially these el-cheapo ones like from Taiwan. Sometimes choking them off helps, although the little transformer in these things has next to no shielding, and is actually part of the cause of the issue. Sometimes getting a more up to date version of the power supply is the answer. What does that little Pi3 require in terms of power? Mike
 

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If the computer and monitor and other parts are not all FCC Part15 compliant, you may never get rid of the RFI or EMI they emit. And if they are compliant, they may be Class A or Class B compliant. Class A is for "office" use, and is not supposed to be sold for personal/home use, as it will always be excessively noisy. Even laptops.
 

Your_account

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If the computer and monitor and other parts are not all FCC Part15 compliant, you may never get rid of the RFI or EMI they emit. And if they are compliant, they may be Class A or Class B compliant. Class A is for "office" use, and is not supposed to be sold for personal/home use, as it will always be excessively noisy.
I am not from us. But when I have an training to become an IT Engineer our Instructor told us that no Pc, Laptop, Mobilephone,... could legaly sold in Austria because the dont pass an RF Test in an "independent" Test Lab. Such an Test would take 1 - 2 Years before the could pass and everyone know its impossible to wait that long...
What does that little Pi3 require in terms of power?
I dont know it powered with an small Cellphone USB Charger. And yes i tried several out and nothing chance on the noise floor.
Sometimes getting a more up to date version of the power supply is the answer.
The most USB Charger are the same crapy quality. The only thing who is different is the Name and the Logo.
If you not buy some Commercial (/ Med Aproved) Stuff you cant be sure that the quality is better.

The major problem is the noisefloor them self. The are not just a single freq.

And the other thing is protect the pc from an peak who comes troth the antenna.
 

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I still use Ferrites on my USB Cable. The help but not that much.
 

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I see spikes / spurs appear when my son wants to watch tv. Unfortunately, I am in an apartment and it sucks. People next door, people upstairs and people behind me. I get a ton of interference and can see the whole noise floor bounce up and down at times. Anyway, I cant seem to find it but there was a guy that took a roll od coax that was rolled up, and connected the center conductor to the metal housing on his usb extension cable and says the noise dropped.

Found it SDR for Mariners Moved to RTL-SDR for Everyone: Reducing electrical noise
 

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Yes I tried out but nothing. No difference between Metal Shielding or not.
And Ferriets doent bring that much/ anything.

I run ACARSDeco2 1x with and 1x without Ferrite Cores arround the USB.
No realy difference in kb size of the logfile.
 

dave3825

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Yes I tried out but nothing. No difference between Metal Shielding or not.
And Ferriets doent bring that much/ anything.

I run ACARSDeco2 1x with and 1x without Ferrite Cores arround the USB.
No realy difference in kb size of the logfile.
Wow,, I did the roll of coax and my noise floor dropped and so did some of the spurs/spikes...
Its only like 4 feet, not the 10m (32 feet) he tried.
 
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