Low Noise Amplifier

Would FA consider making a LNA available in a similar way to the antennas and filters?

An interesting design for one can be found here fabiobaltieri.com/2014/06/22/lna/

It is suitable for mounting in a waterproof tube similar to the way the filter is supplied.

Also supply with it a power injector styled as USB dongle (containing resettable fuse, inductor, capacitor, LED to show it’s delivering power, SMA M + F connectors).

As a wideband amplifier it would be usfull for more than just ADS-B.

I’ll add my name to PeterHR’s request. A good quallity LNA small enough to remotely mount near the antenna would be a great addition to the currently available FA filter & antenna.

The four items together would (including the power injector to run from a Pi USB port) would provide a know reliable solution to most of the hardware issues that come up in the forum space.

The only other things that would be required are SMA adaptors and pigtails - they can easily be found on ebay / amazon

(Would also be good to put them in a Europe based shop - import duty / tax is paid depending on the value of the item that is the cost of the item + the packing and transport charge)

What would be nice is an all in one kit with the adapters and all…perhaps at a better price to buy all at once.

Sounds good, but many don’t need the filters or need a less obtrusive antenna (to sneak past the HOA in the USA)

A single source for everything is ideal - and just pick off whats needed from a list

In North American these guys on eBay have everything. FA’s antenna and filter, any and all adapters plus pre-made cables with your choice of ends. I choose to buy all I needed from them instead of taking the Amazon route. They were very accommodating with my order and gave me a deal on shipping.


Well, considering everything is available, I might be able to provide these depending on demand. …(And assuming they work well).

Here’s my current candidate for LNA, $12 on eBay:


At 1090 MHz, one unit gives +18 dB gain, the other one +17 dB.

I add a SOT-23 3.3 volt voltage regulator and a USB plug, so I can power it directly from a USB port on a Pi. I’ve replaced the input capacitor with a lower value to reduce gain at lower frequencies, but with the FlightAware bandpass filter, that’s not really needed.

You could also use a TO-92 style regulator, again soldering it to the pcb and tacking on the USB cable for power.


From the gold tone I’m guessing that LNA uses SMA connectors? No mention of it in the listing.

There are tons of similar listings on eBay. Must be a hot item.

Welcome back to the forum after a long absence … :smiley:

Thanks! I’ve been busy with so many projects. This is only one of my hobbies. But now that the weather is getting cooler I won’t mind going up on the roof. Also, leaves are falling so my reception is getting better! :laughing:

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I ordered one of those from ebay and will give it a try. Unfortunately it ships from china so it will be a while before it gets here. Once installed I’ll post some before and after map images from VRS.

i had ordered some PCBs based on this design a little bit ago. Probably sitting at my house now, but i’ve been on a long vacation so haven’t gotten time to try to set one up yet though.

I’ve been thinking of the bare PCB route for this one – that way I can put on male SMA connectors and ditch the male-male adapters.

Switching from a female to a male SMA on an assembled board isn’t that difficult; you have to first destroy the existing connector using cutters that won’t be damaged by cutting the connector posts.

bob k6rtm

(returning briefly before getting pulled back into chaos)

I have one now built.

I had the pcb house put on most of the parts that they had in there parts library, so i only had to add the amp (PSA4-5043+) and the voltage regulator (MIC5301-3.3YD5)

Going to do the modification to the rtl-sdr at the bottom of fabiobaltieri.com/2014/06/22/lna/ to have it insert the 5v on the line. I had two power inserters at home, but both were above the 6v max of the voltage regular i put on. Perhaps i’ll switch the voltage regulator out to something with a wider input range. There are a lot of options in that tsot-23 package format.

I’ve had this delivered

cosycave.co.uk/index.php?id_ … er=product

It’s 2cm wide and 3.5cm long

It has a capacitor on the output side, so all I need to do to power it up the line is to fit an inductor from the output pin to the +5-15v point and fit a capacitor from that point to GND.

I intend to solder fly-leads directly onto the board for connection to the antenna and to the down-lead.

For mounting it may be possible to prepare 5cm of 22mm copper pipe (that’s about 3/4") by soldering an end-cap on it. slide the amp inside and block the bottom with a plug of hot melt glue (or a wine bottle cork notched for the cables)

Cable tie it vertically to the mast end-cap up.

(as delivered it has one of those protection diodes mounted on the pads bottom left)

I will apologize in advance for my relative ignorance of most things having to do with electronics, especially solid state. But is there a LNA available somewhere that can just be put in line with the feed line and plugged into a power source and run successfully without any need for me to modify it or add to it which would likely lead to me screwing up! Something out of the box ready to go and a reasonable price. I’m probably asking for something that doesn’t exist from what I’ve read on here but asking is free… I hope :slight_smile:

I’m trying to alleviate or at least compensate for the fact that I have and must have the feed line that is close to 50 feet in length. The loss per foot is relatively low, but adds up quickly.

Thanks in advance for any and all suggestions.

The standard satellite TV amps such as the perfect vision amp ( http://amzn.com/B00EPHDPME ) works well and fits your requirements. You can find them cheaper in other places. Then you just need a power injector and a DC blocker (depending on your antenna).

Search the forum - there is so a lot of postings on amps, including graphics explaining everything visually.

Here is the assembled amp with the added PSA and voltage regulator.

I had a RTL-SDR dongle which can do 5v Bias tee by just bridging two pads. The rest of circuit is already on the RTL-SDR.com dongle.


the LNA would need to work with this receiver…


the one that looks like a dongle. has a SAW filter.