We throw these away at my shop, or I should say, âtheyâ (those who know not of things RF) throw them away. I collect them up and use them in my ham shack or for other projects.
Yes, I paid $5.99 (plus tax) for a strap-on, but it looks like you got the better answer with a piece of aluminum foil from an Arbyâs Roast Beef Sandwich or someting like that for the LNA.
What did you do? This will be very helpful to all of us. Thanks, Ken
This is the reverse thinking of others that the CHIP is the problem since it is the source of the interference we are trying to mitigate.
Your approach allows the CHIP to be the âbad boyâ (and run its WiFi we all need), and protect the most sensitive portion of our set up - - the LNA. Wow - - Iâm game to try.
Actually, I used heavy duty aluminum foil, although regular would work.
Find a small container of some sort, a matchbox, a blister pack, a mini dv tape case, something that is the size that will allow the SMA connectors to be exposed, but enclose the LNA PCB. Put LNA in. Cover with foil, making sure the foil is in contact with at least one of the SMA connectors. Tape it up. Watch noise go away to a great extent.
OR⌠use wide clear packing tape to wrap the LNA up, leaving just the connectors exposed. Cover this with foil. Make a tiny window to see the LED. Tape over or use large shrink wrap to seal it all up, except for the SMA connectors. Make tiny hole to see LED. Connect to your antenna and RTL. Enjoy.
I used this method on a LNA for my ADS-B receiver as well, for the same reason. The LNA did not feature a metal can over the amplifier section, and so was susceptible to stray RF from a nearby cell tower getting in that stage. Covered it up and watched plane count increase dramatically.
Iâm awed by what I learn here. Your solution is so simple, Iâm blown away that no one has mentioned it before.
First thing Friday morning, Iâm going to run some comparison tests: 1) Your solution with tape over the LNA then wrap it with aluminum foil (being sure to ground the foil), 2) Moving the LNA/SDR away from the CHIP using the ferrite isolator, and 3) A control with no mitigation.
I wish the Lantern didnât have so many screws to hold it together
One does need to exercise caution if wrapping up the LNA itself with no case or covering. Donât allow the foil covering to touch any part of the circuit board foil or component side. Donât compress the foil covering down flush with the circuit board foil or component side, to prevent any sort of inductive coupling or capacitive disruption. The old school small cardboard match box with sliding tray is perfect for this application.
Cant wait for your tests. I would try this now but my setup is frozen to my porch railing. Thatâs what keep it in place the other day when I had 65mph winds. But I might be willing to get the heat gun out if it means more SNR.
versus my previous default baseline configuration with just the double loop Radio Shack snap-on ferrite isolator - - SNR (dB) 8.87 with Rssi (dBm) -111.08:
My conclusion is the double loop Radio Shack snap-on ferrite isolator produced a higher SNR, but the aluminium foil wrapped LNA also did a credible job increasing the SNR and costs pennies.
@zoltan I suggest you redo my tests in Chicago with 4 identically configured Lanterns all running at the same time. My tests spanned 30 minutes because of the setup/tear downs required, so my receive signal levels were not consistent throughout my tests.
If you start with all 4 units in a âfactory delivered configurationâ, they should all record the same SNRs and Rssi when set up on your roof about 20 feet apart. Then add a double wrapped ferrite isolator on 2 of them, and an aluminum foil wrap around the LNA on the other 2. Perhaps, you could make the small box @k5ted suggested. This should give you a more reliable quantitative result.
For now, Iâm going to leave the ferrite isolator in my Lantern and run it for a couple of days to see how it performs. My Symbol Error Rate in all tests was 0, but I didnât run the tests long enough to get useful Packet Error Counts. Ken