They’ve started shipping a few.
Some progress…
Muthu Lakshmi: I checked and see that this item was shipped form our fulfillment center in Breinigsville, PA, USA.
This will take only $hours to reach your location.
In this case, I’ll ask our shipping team to check for the order and process this order soon to deliver to you.
I received another update from Amazon. My order, that was due on Wednesday, has now shipped and has a delivery date on Monday. Good news.
Marty
I called Friday to ask why my order, placed Thursday, wouldn’t be delivered until next Wednesday. The Amazon rep checked his records, and told me that none would be available for shipment until Tuesday. When I mentioned that the item page indicated that orders placed Friday could be delivered on Monday, he checked his records again, then offered to upgrade my shipping to one-day, with delivery on Monday. I didn’t bother to ask how this was possible, just took the free upgrade and said “good bye”. I just received an Amazon notification that the item was shipped today, with UPS delivery on Monday.
It’s worth the $20 to see if those 3 cell towers 5 blocks away are interfering with my reception!
Lots of towers near me. When I added the filter my stats went up about 20%.
Arriving Monday by 8 pm.
Shipment details
Latest update: Yesterday
5:36 PM
Package received by carrier
Philadelphia, PA, US
Carrier: UPS, Tracking #: 1Z88Y7Y21xxxxxxxx
3:16 PM
Package received by carrier
Breiningsville, PA, US
Package has left seller facility and is in transit to carrier
US
After reading all these posts, I feel lucky that I did not have to go through all this disappointment & frustration with delayed shipping by Amazon.
Know why? I never ordered the filter 
I received my filter today and installed it. I get substantially increased range, but when the filter is installed my receiver is unable to synchronize with other MLAT sites. I left it installed for several hours just in case, but it never was able to succeed. I removed the filter, and immediately was able to synchronize.
Any ideas? I like the increased range, but not at the cost of half the positions…
What gain setting are you using? The default autogain?
I’m running stock PiAware. I have not modified the gain settings. Here’s a graph of planes that have position over the last 24 hours. Notice how it drops dramatically for several hours Sunday evening. (The black line is the distance to the furthest away plane.)
Just to be clear, I can see plenty of aircraft on the PiAware dump1090 web interface - just not their positions.
Mine arrived today. Wrong color. Sending it back.
Did realize today missing one connector to get it installed. Blah. Ordered on eBay. Be here when I get back from the shores of CT (mmmm Mystic Pizza).
Received mine today through Amazon Prime and it’s now in service.
However, when I tested for continuity before putting the filter in the circuit, the center connectors did not test positive for continuity although the shield did.
I thought bandpass filters should show continuity, but then I am not that skilled in electronics and my test equipment is pretty basic - a multimeter).
It seems to be working fine and am seeing approximately the same range of signal levels I had before. Too soon to tell if it’s helping or not – not enough aircraft around today to draw a conclusion.
How should it test for continuity?
There are many ways to design a filter, and I don’t know the schematic for this one, but I would not expect it to pass DC.
Passive band-pass (and high-pass) filters generally use series capacitors and inductive shunting for the low-cut (removing the too low frequencies). The high-cut (removing the too high frequencies) is generally done with series inductors and shunting capacitors.
There are many ways to design a filter, and I don’t know the schematic for this one, but I would not expect it to pass DC.
Thanks very much for the info.
My filter arrived today. The network analyzer’s Ethernet connection is misbehaving, so I don’t have screen shots yet. But I do have test data:
Measured:
Center frequency: 1068 MHz
Insertion loss: 1.47dB
3dB BW: 229.5 MHz
Q: 4.667
Frequency response is down a measured 44dB at 900 MHz – this is superb! Down 45dB at 850 MHz. The 3dB point is around 950 MHz.
My buddy down in Thousand Oaks got his today as well – he replaced the NHP-1000 high pass filter I sent him with the new filter and saw his numbers jump tremendously (3x - 4x), now seeing aircraft out 200 miles where before he didn’t see anything out past 60.
I put this one on one of my experimental boxes after 5pm local, replacing a Mini Circuits SHP-1000. We’ll see how it looks, but I think I want 2 more of these!
This is a winner!
–bob k6rtm
Posted a review on Amazon – why haven’t any of you other folks done that? And when will Amazon have more in stock? I want 2 more!
–bob
I am not reviewing until I can see more stats. It has only been one day for me.
Bob,
Do you think the FlightAware filter made the difference or the saw? Can he take the saw out and see what the difference is?
Mark n4obf
Thanks! Amazon has >100 in stock but is having some problem. 
Mark–
He isn’t running a SAW – Flightaware antenna, LMR-400 cable, Flightaware filter, SDR. He estimates the cell towers (Verizon and Sprint) are around 200 yards from his antenna. The improvement is all in the Flightaware filter, and as I said, he was running an NHP-1000 previously. Without the NHP-1000 high pass, he wasn’t picking up much of anything on ADS-B, swamped by the cell towers. (He’s posted a review on Amazon as well.)
The way things look, not sure I’d add a SAW – I’m going to send him a 16 dB LNA without the SAW. I’ve also swapped the SHP-1000 on one of my test boxes for the Flightaware filter and will watch it over the weekend.
Take a look at https://flightaware.com/adsb/stats/user/hoffchas – I think you’ll be able to tell when the new filter got swapped in! (Posting with his permission)
73 de k6rtm