FlightAware Discussions

Suggestion to Flightaware: Built in Filter in Pro Stick

Suggestion to Flightaware: Built-in Filter in Next Gen Pro Stick

how about gain?

Sent from my SM-N910F using Tapatalk

I think you misunderstood. This chip is a filter chip, not an amplifier chip.

Filters dont have gain, they have attenuation or insertion loss. It is the amplifiers which have gain.

Insertion loss of 1090 Mhz Filter model TA1090EC shown in the photo above = 3 dB maximum.

Download specifications of TA1090EC filter (pdf) from manufacturer’s site:


A brillian idea.
I ordered an extra chip with my miniadsb.
I would try it, however, I already have really good cavity filters that have significantly less loss.

The only problem with adding the filter is that it will be a one trick pony. It won’t be useful on any other frequency.
For about $US20 total, it is well worth a go.
I think it is a great idea.

Another option, if possible, would be some sort of enabling jumpers.

To part pay for the filter ,Perhaps v2 could be made with a cutback on the plastic used in the case, slim that width down a lot perhaps then we could fit something in the usb skt next door, or underneath without having to jump thro hoops getting extra leads. :unamused:

Its a brave station that tries out 2 prosticks with one pi no ext leads… been there failed that, enuf said !
SMA a great addition if it was not for the fact they are sent from Satan himself as they have a tendency to unscrew themselves at random without warning and are not at all tolerant to being moved.

sorry, i means how about differences compared to pro stick?

Sent from my SM-N910F using Tapatalk

It is a ProStick with built-in filter, so external filter will not be required. This means:

  1. One component less to handle/connect.
  2. The filter+prostick+pi combo is too long to fit inside a box and needed a pigtail to reduce length. With built-in filter, it will be much easier to fit Pi+prostick inside a box.
  3. The filter chip is $2.60 in retail. The cost of prostick with built-in filter will be $17+3=$20, as compared to $17 + $22 = $39 for prostick + separate filter.

This is a good idea. Most people buying a Pro are probably using it for ADS-B. With proper soldering gear and a steady hand, one could put some short leads on the ground pads and mount the filter across the connector, cutting the antenna port trace Nd bring it up to the filter, and then down to the other side of the trace. Totally doable.

The filter chip shown in the photo I posted, was installed in ProStick by photoshop, not by soldering. :slight_smile:

I am waiting delivery of this filter which I have purchased 3 weeks ago from Ali Express (lot of 5 for $13). Will cut the copper strip from center pin of sma connector with a sharp knife to break the circuit, then try to solder the filter chip. Not an easy job due to small size of SMD devices. Needs a very steady hand, and a sharp eye.

Even if I dont succeed, does not matter. Including this filter chip to prostick during manufacture is not at all difficult. The pcb will require a minor modification, and rest goes as normal manufacturing.

Too bad it wouldn’t be as easy to put inline between the amp and tuner so wouldn’t have to eat that ~2.7db insertion loss. Naturally the pre-canned FA setup with filter and dongle suffers the same fate with the amp in the dongle, but it would be more efficient to amplify a non-attenuated 1090 signal (or at least not after suffering another 2.7db loss on top of cable losses). I don’t think amplifier saturation would kick in if no filter pre-amp. Interesting idea nonetheless, be interested to see how it pans out.

Will it be possible to bypass it (or will you sell two versions of the ProStick)? The reason I ask is I’ve got the current ProStick and the FA filter, and the filter made things significantly worse for me. I’m not in an especially “noisy” environment in that the nearest cell towers are some distance away, so it’s hard to see how a filter is going to do anything for me, other than attenuate a good signal!

Please note abcd567 does not work for FlightAware and his posts do not represent our future plans.

Well that’s quite funny!

Of course, I dont work for Flightaware, and my post is only my suggestion to Flightaware.

Although most forum members are aware of this fact, it is wise of you to highlight this for those who are not aware.

Maybe put it in the subject to make it clearer.


2 SMA connectors and a scrap of double-sided pcb material, connections made with 30 gauge wire. Note crossing wire providing ground and some isolation between input and output sides. (I do a lot of surface mount work.)

Yeah, it’s not stripline, but for the lengths of those lines, the added inductance doesn’t result in a lot of pain on top of what the SAW inflicts. Even could have taken a couple of mm out of the pcb length and shortened things a bit, but it works nicely.

Provide an insulating layer above the mess (cardboard or heavy paper works nicely) and then cover with copper tape to hide your sins and provide a bit more isolation.

I’ve built a few of these; on later ones, I used a male SMA on one end and a female SMA on the other to eliminate that extra cable or barrel connector.

And I like the FlightAware filter – lower insertion loss, and if I still have something nasty in its passband, I’ll cut a stub to take that out.

bob k6rtm

But pretty close to the mark … lol :slight_smile:


That is all.

The reply of mduell was quiet appropriate at the time & under the circumstances it was given. If posts prior to mduell’s post are read, it will be clear that:

  1. Some members have misunderstood my suggestion as Flightaware’s plan for next version of Pro Stick, and started asking questions/clarifications as if I work for Flightaware.

  2. At that stage Flightaware did NOT have any plans for a built in filter.

In view of above facts, it is not fair to laugh at mduell’s responce. It was a very appropriate and necessary reply at that time.