New flight ads-b filter dissipoints for me at least

I was hoping to get improvement with a sprint tower within 7 blocks of my house. Put it online dropped 200 messages right away swapped it out jumped back up 200 (600+ vs 400+) put filter back in and again dropped 200. So that’s my experience so far.

Running pi2 with 1.15 mutabilty dev and fa antenna

Dongle mcx to sma then filter then sma to F then 6 feet of r6 cable then f to N then fa antenna mounted to interior 2nd floor window

I had a similar experience with the filter, but for me, the problem ended up being an SMA adapter. I swapped it for another and it instantly improved and gave me about 10-20% more planes/messages. It was a brand new SMA adapter from Amazon but apparently something wrong with it.

I have two I will give that a shot

I swapped out… Some improvement but still less than without the filter.

Message rate isn’t necessarily everything, what’s the impact on number of aircraft seen and range?

Which frequencies is the sprint tower on that are causing problems? I think they have both low band and high band holdings deployed depending on area.

Another poster found it tripled their range.

Positions and aircraft seen appear to be down a bit for this time of day. I belive the tower is 2.4 which was there old wimax tower and 900. May also have ATT on it that I can’t confirm though at the moment.

Range is down to usually the 60 to 120 is my best… Now the sub 60 is greatest

It’s a trade off between the insertion loss (degraded signal) created when adding the filter and the improvement obtained by filtering if there are other transmissions affecting reception.

If you have little interference caused by other transmissions, you will degrade your reception by adding the filter.

Sure sounds like that is your situation — and a good situation to be in.

A friend of mine has swapped out a NHP-1000 high pass filter for the Flightaware filter and his stats are up about 3x - he has cell towers about 200 yards away.

I’ve swapped out the SHP-1000 high pass filter and a SAW on one of my development ADS-B receivers, and I’m seeing improved stats. I’ll know how improved Saturday.

bob k6rtm

Sprint frequencys

1900MHz PCS 1850-1990MHz Traditional PCS
1900MHZ LTE 1850-1990MHz New Sprint 4G/LTE
800MHz/850MHz Cellular 824-896MHz Traditional Cellular

Internal antenna will be a problem - if you can mount it 4" - 6" outside of the glass you will probably double the range (would the HOA notice if it’s out the back?) - try hand holding it there

Then amplifying it would probably help.

HOA is not an issue for me…but needing to drill new holes to get wire outside isnt such a good or desired thing…hence the need to keep it in the house.

Thanks for the responses.

Maybe you could use one of these … 1440765853

  • but mounting the antenna outside would still mean making holes

Thanks for that idea. Drilling holes outside isnt much of an issue for me. Just dont want to srill holes through the basement wall to get cable out side to mount it.

The added cable length would require an amp and injector too…more stuff to dig into. Perhaps an early fall project before winter death arrives.

Starting to spend a lot more money then I originally intended funny how a hobby can do that to you.

Overcoming the hole drilling quandary is the easy part.

I mounted the PI B in a waterproof plastic utility box just outside the room where my wireless router sits. There is plenty of bandwidth available. The network is not a bottleneck.

I drilled three one inch holes in the bottom of the box to allow heat to escape. I found a Model B case with fan on Amazon for 8 dollars which keeps the unit under failure spec.

There were three members within 50 miles of me that had more messages and higher plane count than I did. I made it my mission to equal or exceed their counts.

I added the HABAMP LNA/SAW for $80 U.S. I moved from a PI B+ to a PI II B+. I changed the SDR dongle to an R820T2 unit. I replaced the thin WIFI extension cable from my chimney mounted antenna (now an FA unit, formerly a home made coxial colinear) with RG58 75 ohm (those Chinese can do anything). The actual impedance of the cable is somewhere between 1 and infinity -1 as it does conduct. I moved the HABAMP from the bottom to the top of the cable directly connected to the antenna after waterproofing it with RTV and electrical tape. I also added a Directv power injector to power the LNA.

With each addition and change I noticed an improvement in messages, messages per plane and plane count. I am now king of my local hill. Take that, sucka’s.

I have two changes remaining that will hopefully have the same improvement effect, converting to Dump1090-Mutability and replacing the cable with Quad Rg6 and no adapters.

My $50 dollar hobby has now reached about 200-240 bucks as I have purchased two of every combination of SMA, SMA RP and SMA-SMA-RP adapter. several pigtails, fans, power adapters, etc.

My page is

Now if someone could just explain how the “median daily stats” values somehow seem to be just snapshot of a random day of the previous week, I’d be pleased.

[quote="strmchaasr"Starting to spend a lot more money then I originally intended funny how a hobby can do that to you.]
The first 90% of the project takes the first 90% of the resources. The rest of the project takes the other 90% of the resources. :wink:

The added filter has had no effect on my statistics. However, I live in a hole in a valley w/ ridges E & W. View N ok, and sometimes pick up the odd U-2 out of Beale AFB. Poor cell service here, the phone works about half the time. But, when I take the station on the road, I think the filter will come into its own.[/quote]

It is the median of the last 7 daily totals. In other words, the fourth biggest day of the last week.

I just ordered the vision amp and power inserter. Just need to make sure how to hook those up properly.