Would wrapping the unit in AlFoil tape help shield it?

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bubblegumpi
Posts: 49
Joined: Fri Oct 14, 2016 11:41 pm

Would wrapping the unit in AlFoil tape help shield it?

Post by bubblegumpi » Sun Oct 16, 2016 8:49 am

I noticed putting a usb cable whit a ferrite chock on it reduced noise floor level. The cable had those two barrel things near the ends. Although one time I opened up one of those to just find some sort of cable strain relief, but what else would it be. Would sticking metal to it work as a test? Or are the fields too weak?

Also can you buy the ring shaped magnets online and just make your own by doing one turn through it, two on both ends? Then I could make a bunch out of existing cables.

So until a find a metal case for it I was thinking wrapping it in AlTape with the tape conduction the gold connector. Stupid idea or would it do something? I have a noisy(you can actually hear the high pitched ringing) but necessary SWMode power supply that runs the USB hub I plug the Play into. :idea:

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bubblegumpi
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Joined: Fri Oct 14, 2016 11:41 pm

Re: Would wrapping the unit in AlFoil tape help shield it?

Post by bubblegumpi » Sun Oct 16, 2016 12:20 pm

I paused the waterfall display, wrapped it in tape and noticed the noise went down about 1-2 db. Seems like it worked or there is just a noisy environment around me. :shock:

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DanubeBCL
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Re: Would wrapping the unit in AlFoil tape help shield it?

Post by DanubeBCL » Sun Oct 16, 2016 12:25 pm

The answer may sound blunt, but it is:
When shielding the unit with foil improves the noise situation then it helps against electric stray fields.
When shielding the unit with a steel cabinet (iron) improves the noise situation then it helps against magnetic and electric stray fields.
But when you do not have these situations shielding is useless, but it cannot harm. You have to try!

The most noise comes in through the antenna. In this case one must place the antenna as far away from the noise sources as possible. Some amount of noise can be induced into the coaxial cable. In this case a common mode choke at the antenna input of the receiver helps.

Summary: Shielding can help, it is not a bad idea, but it is no warranty against noise. I would prefer the steel cabinet against magnetic and electric fields.

All my receivers have a common mode choke at the RX input. This is very helpful against local noise induced into the coaxial cables from close noise sources like switching power supplies, USB noise or similar. But when the noise is caught by the antenna, nothing helps except setting the antenna up in the Arctic ;-) where no civilisation is near. This may sound funny, but the urban noise situation is getting worse and worse (switching power supplies, homeplug powerline modems, VDSL spectrums, "smart" home networks...) and it is in most cases not the noise in your own house but that one coming in from your neighbours.
73, Heinrich

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F1BJB
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Location: Beauvais France

Re: Would wrapping the unit in AlFoil tape help shield it?

Post by F1BJB » Sun Oct 16, 2016 6:05 pm

It is very simple and cheap to try this.
My SDRplay is wrapped in aluminium foil since I have it.
As said it can only improve so I keep it like this.
One of my goal when I did it was that in the FM band with no aerial it receives as little as possible.
On that ground it improved a lot.
A thing I found important is the grounding of the foil to the aerial connector AND the USB one.
On HF I found also useful to avoid ground loops between the antenna ground and the PC power plug ground.
I achieved that with a small ferrite transformer at the base of the vertical and in the middle of the dipole.

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DaveB
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Re: Would wrapping the unit in AlFoil tape help shield it?

Post by DaveB » Mon Oct 17, 2016 7:32 pm

As F1BJB has done I wrapped my SDRPlay in aluminium foil the day I bought it - and it reduced interference on weak FM signals from the SDRPlay to nothing. I made sure the foil was grounded to the antenna connector - using a small cable tie to pull it tight - and made sure it was not connected to the USB ground. Clip on ferrite beads on the USB lead and the aerial lead are also used.

In fact clip on ferrite beads are used 'everywhere' - on all interconnecting cables i.e. antenna cables, power cables, video cables, usb cables. So make sure you get some to fit on your USB hub cables and the power supply. As far as I can tell it is preventing any noise from my set up from getting into the FM band - but it can't stop external sources of radiated noise e.g. from someone's solar lights (+30dB above the usual noise floor when it get's dark).

David

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xdtony
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Re: Would wrapping the unit in AlFoil tape help shield it?

Post by xdtony » Tue Nov 01, 2016 6:24 pm

There is a metal case available for SDRplay now (you can find it on eBay). It's another option for you if you don't want to wrap your device with foil tape, which may void your warranty if you're not carefully enough.
Last edited by xdtony on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
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DaveB
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Re: Would wrapping the unit in AlFoil tape help shield it?

Post by DaveB » Thu Nov 03, 2016 11:11 pm

But when the noise is caught by the antenna, nothing helps
There is some form of solar powered lighting nearby which puts out around 30dB above the noise floor shortly after sunset As seen on the waterfall at thje bottom end of the FM broadcast band. I'm 99% sure it is solar powered and not just on a light sensor as when the day is cloudy/overcast - there is no interference.

Needless to say it kills DX stone dead - Im pretty sure I know where it is - and fortunately - for this time of year the solar panel will be in the shade. I do not think it would be prudent to go knocking on neighbours doors to confirm where the culprit rally is - but I've had the mad fantasy of equipping a small GoPro drone with a paint pall gun and painting evry solar panel it can find :lol:

I suppose if you have bucket loads of money you could locate your antenna and SDR receiver remotely in an area of low noise and operate it over the internet - transferring the I/Q signals to your home QTH

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g1hbe
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Location: Cheshire, UK

Re: Would wrapping the unit in AlFoil tape help shield it?

Post by g1hbe » Fri Nov 04, 2016 9:32 am

Well, there are many 'web sdrs' online. Some do only amateur bands, others cover 0 to 30 MHz. Hope the noise goes away BTW.

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Andy

DanubeBCL
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Joined: Sat Jul 02, 2016 12:39 pm

Re: Would wrapping the unit in AlFoil tape help shield it?

Post by DanubeBCL » Fri Nov 04, 2016 12:34 pm

DaveB wrote:I suppose if you have bucket loads of money you could locate your antenna and SDR receiver remotely in an area of low noise and operate it over the internet - transferring the I/Q signals to your home QTH
That's what I am dreaming of daily. I already checked out a couple of affordable real estates in the country. But, believe me or not: Most of them were already haunted by RF noise as well, even when they werde located in a rural area where one might think that RF noise should not be so strong. In one case a wind turbine in a distance of 1000 meters spoiled the complete LW and MW band up to lower shortwaves.
The places which were RF quiet had several disadvantages:
They were very expensive.
There was no electric power and no internet available.
The local mobile phone providers block the IP ports which are needed to run a remote server.
The authorities do not allow to erect small huts or similar for your equipment, not speaking about masts for antennas.

The biggest plague here in Europe are the homeplug powerline modems (PLC, PLT, powerLAN, dLAN a.s.o). They are in almost every household in the vicinity and spoil the band from 1.6 to 68 MHz with extreme broadband noise within a radius of 300 to 500 meters. All with permission from the lawmakers and the authorities, of course.
73, Heinrich

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NN4F
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Re: Would wrapping the unit in AlFoil tape help shield it?

Post by NN4F » Fri Nov 04, 2016 3:09 pm

Grounding your RSP will make a big difference to....I did it via the SMA connector with a simple lug
rspgnd.jpg
rspgnd.jpg (57.91 KiB) Viewed 10800 times

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Paul Jones - NN4F, Charleston SC
http://www.facebook.com/groups/SDRPlay

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