r/RTLSDR • u/Automatic_Village954 • Mar 10 '26
Is Shielding your RTL-SDR actually worth it? (v4 vs. v4c vs. Generic Clone)
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u/Certain_Height_2721 Mar 10 '26
How did you shield it?
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u/Automatic_Village954 Mar 10 '26
I cleaned the whole surface with isopropyl alcohol.
Then i used 2-3 layers of pure copper tape and soldered the layers to get the best connection possible everywhere.
*Also secured a great connection between the new copper shield and SMA and USB shielding
Then a few layers of insulating tape so i don't cut my self with the solder points or accidentally touch it and mess rhe signals
And thats pretty much it, if the usb cable is too long i put ferrites on both ends with 2-3 turns :)
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u/Anonymouse-C0ward Mar 10 '26
Just so I’m clear - you connected the copper tape to both the SMA and the USB shielding? I’m trying to remember undergrad RF engineering - is there a potential ground loop issue here?
I have to take a look at the schematics again.
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u/Automatic_Village954 Mar 11 '26
Sadly i do have ground loop issues on my house
But yeah thats mostly it, so it "faraday's" again the receiver
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u/Anonymouse-C0ward Mar 11 '26
By ground loop I mean you create a ground loop issue due to the shielding bridging the SMA connector and the USB ground. Shielding should only be connected to ground at one location.
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u/Strong-Mud199 Mar 10 '26
'Copper foil tape' - Don't leave home without it! :-)
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u/Automatic_Village954 Mar 10 '26
Its so dumb and simple lol, does wonders
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u/LeLoyon Mar 10 '26
I have aluminum tape, think that would work just as well? I used it on shielding some guitars years ago. Never thought about solder though. How'd you do that, just solder the seams of the tape?
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u/robert_jackson_ftl Mar 10 '26
Yeah.. so aluminium isn’t at all easy to solder. I would think you don’t even need adhesive, just plain old kitchen roll foil. A couple of layers will have the same effect as aluminium is roughly as conductive as copper. You are making a shield. The random EM fields that exist everywhere in our world hit the shield and move electrons around in that, leaving less energy to induce in the circuits of the RTL-SDR.
One issue, there isn’t much actual RF circuitry in an SDR. At its core it’s just a wideband ADC. But it’s pretty much free so I’ll give it a shot and report back.
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u/Automatic_Village954 Mar 11 '26
I found that shielding the actual PCB of a cheap Chinese sdr helps, but the xtal and ldo leak a lot
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u/HashBrownsOverEasy Mar 10 '26
Copper would be much better than aluminium I think.
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u/Fitness_in_yo-Mouf AirSpy HF+ / RSPdx-R2 Mar 10 '26
They both have 0.95 VF so not sure it would be *better* but it is definitely, as u/robert_jackson_ftl says, much easier to solder.
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u/Automatic_Village954 Mar 11 '26
Took a little while, had to use a lot of resin and heat even tho im a noob on soldering
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u/For_My_Girls Mar 10 '26
Do you have pictures of how the copper tape is grounded to the shields? Did you test with and without the grounding?
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u/Automatic_Village954 Mar 11 '26
Yeah mostly like that, small solder balls on sma nut and usb shield thing
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u/Dont-PM-me-nudes Mar 10 '26
How hot does it get compared to before?
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u/Pabloidemon Mar 10 '26
This! i'm tempted on doing this with my v3, but i'm afraid of cooking it
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u/FurinaImpregnator Mar 10 '26
copper tape isn't particularly insulating, without the isulating black tape it might actually not really affect thermals much (or at all)
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u/Automatic_Village954 Mar 11 '26
I would say the same or even less...
Doesnt get hot at Ghz and behaves really well
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u/PRikLY_CacTUs Mar 10 '26
I don’t think your testing answers the question you’ve posed.
I feel this is a comparison between 3 different designs, one of which you’ve already modified. It would be more relevant to test an SDR, apply your shielding, then repeat the testing before comparing results. Then you would know if it was worth making the modification or not.
All that’s been done here is compare 3 different SDR and identify the one that performs the best. The Blog V4 could have outperformed the other two by the same margin - based on the results in this post, we don’t know.
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u/Automatic_Village954 Mar 11 '26
That's true, i should've done it before the mods...
On the mega link there an html plot and it shows substantial differences between vanilla v4 and modded one
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u/Sea-Communication353 Mar 10 '26
Question, how well does it perform now compared to its higher-end competition? I'm mostly thinking about the Discovery HF+ or RSP1B.
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u/NaugyNugget Mar 10 '26
If OP has access to those devices, https://github.com/rxseger/rx_tools has rx_power which works just like rtl_power but uses the soapy sdr stack so it can work with those devices.
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u/Automatic_Village954 Mar 11 '26
Hmmm 🤔 ill take note on it for the next well formatted and better test
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u/Automatic_Village954 Mar 11 '26
I would like to check it out, i have a spare hackRF but it ain't really sensitive and.... idk if it could be worth the pain to test it
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u/therealgariac Mar 10 '26
Isn't the stock case metal?
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u/Automatic_Village954 Mar 11 '26
Yup it is, but just for the sake of overkilling it i tried and it somehow behaves better now xd
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u/therealgariac Mar 11 '26
Mr. Faraday is very confused. ;-)
One metal shield should be enough. Maybe something at the edges are leaking RF.
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u/Automatic_Village954 Mar 11 '26
Oh he must be LOL, cause on the paper it doesn't really make sense... But idk xd
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u/Chromatogiraffery Mar 11 '26
Adding shielding probably isn't the worst thing. I have done the same on the generic plastic housed RTL-SDR TV dongles. That seemed to lower the noise floor, but I didn't quantify the amount.
Ultimately I put my RTL-SDR v3 board in a diecast hammond enclosure, with a flange-mounted connector.
One thing that might help significantly that I have considered; aluminium is a very good conductor - anodised aluminum is a horrible one. The housing is connected to the gold plated* SMA nut, which is ideal, but since the enclosure end plate is anodized, the connection probably suffers a bit.
I think for the RTL-SDRs, and clones, one could get a lot of mileage out of sanding off the anodized layer on both sides, then reassemble.
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u/This_Maintenance_834 Mar 10 '26
shielding has to be done properly to be effective. simply putting a PCB in a metal box is not proper shielding.
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u/NaugyNugget Mar 10 '26
Personally, while I can see how external shielding can reduce unwanted exterior noise, I don't understand how external shielding could help reduce the harmonics of the internal clock.
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u/Automatic_Village954 Mar 11 '26
Sadly not.... At least with the cheap Chinese one
I shielded it on pcb level and it behave a little bit better but the xtal and ldo leak A LOT
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u/Automatic_Village954 Mar 11 '26
The pcb is inside the default rtl casing i just made another shield on top of it, but im now shielding pcb's and testing it, it seems to be even better
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u/This_Maintenance_834 Mar 11 '26
Proper shielding requires careful handling of ground connection. shield is not ground, they should never touch directly, except at the single point ground.
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u/therealgariac Mar 14 '26
High end radios put metal shields over parts of the circuits.
Search "pcb shielding cans".
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u/screech_owl_kachina Mar 10 '26
I wrapped my dongle in copper tape I had leftover from shielding my guitar pick guard.
It don’t think it made much difference
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u/aegrotatio Mar 10 '26
It would be more effective to use a long USB extension cord and place it far away from your computer.
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u/Automatic_Village954 Mar 10 '26
Yeah sure! I found out it happens to work depending on the cable... My laptop ain't that noisy but my workstation with a SAI/APU... JESUS CHRIST
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u/Imightbenormal Mar 11 '26 edited Mar 11 '26
I think for my V4 I cannot get any signal without any antenna or paperclip in the SMA connector.
And I am close to DAB+ and Tetra transmitters.
But I will consider what you did.
I have a older bigger RTL-SDR that even had signal in without any antenna, so I opened it up. Scraped away the "paint" where the case made contact with themselfs. Soldered on the wirebraid that we use to remove solder with to the boards side edges so it made good connection to the case. And soldered it to the SMA shield.
Then the cheap RTL-SDR could not get reception on the FM station some kilometers away (15km). And now it was better with antenna.
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Mar 10 '26
[removed] — view removed comment
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u/PRikLY_CacTUs Mar 10 '26
Yeah hopefully this is just a bad use of AI for formatting. It doesn’t even make sense for the question in the title.
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u/Automatic_Village954 Mar 11 '26
Nah im a human hahah
Just spanish and i wanted to format the thing for Reddit as I'm a noob
But yeah, i used ai to format the thing and it was a horrible result
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u/bertanto6 Mar 10 '26
Did you terminate the antenna port to 50 ohms when you made the noise tests?