Has anyone had experience with the $30 Nooelec LANA LNA? I would power it via usb in my attic. The description indicates that some dongles will require a DC block. How can one determine the need for a DC block? I’ve seen prices ranging from $10 to more than $30. Recommendations?
Oh no, I wouldn’t even consider a wide band amplifier. I only want to amplify signals in the frequency range I’m listening to.
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Which 1090 MHz lna that is available in the US do you recommend?
Try
RTL-SDR Blog ADS-B Triple Filtered LNA (Bias Tee Powered)
From https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
New Product: RTL-SDR Blog 1090 MHz ADS-B LNA
or a 1090Mhz pre-amp from here:-
https://v3.airspy.us/product-category/preamps/
They are the US distributor of uputronics/Hab/Nevis Amps
I have both. I think the rtl-sdr one is better for noisy environments.
Can the Airspy preamp be powered by a usb cable? I do not have a bias-tee injector. I already have a FA filter on the FA antenna.
edit.
Only the airspy/hab/nevis amp can be power by USB.
I’m sorry to say that I can’t recommend this one any more. We have one of these at the Martello Tower Group site and 5W of 144MHz transmitted from the same site absolutely kills it. The message and aircraft rates drop instantly to zero. My friend Tony has the same LNA which exhibits the same symptoms.
I have the first one and 100W from 1.8MHz to 30MHz plus 50MHz has no effect on it and I can also transmit 50W on 144MHz and 430MHz from very close by with no problems.
The rtl-sdr LNA needs a bias-t for powering it.
Just use it with this dongle: https://www.amazon.com/NooElec-NESDR-SMArTee-SDR-R820T2-Based/dp/B079C3FHPG
Or get this bias-t with screw terminals: Electronics, Cars, Fashion, Collectibles & More | eBay
5 V to the screw terminals, you can graph the 5 V from the pi contacts rather easily, then you only need to connect the positive wire.
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I ordered the $30 RTL-SDR unit from Amazon. It should be delivered by Friday. I’ll see if I can enable bias-tee on any of my dongles. They are all in the attic. IIRC I have to enable it from Windows.
You have a rtl-sdr blog v3 dongle?
Most other dongles don’t have a bias-t.
I believe I have 2 v3 dongles. They are in my attic and I do not know how to check them via ssh. A ladder is in my future. 
Back to your original question:
The reference design specifies a diode pair on the input for ESD protection.
Any/all dongles using the ref. design will need external DC blocking if there is a risk of an amp feeding DC down the feed.
The short answer is that any dongle not specified as having DC blocking should be assumed to need it.