SBS-1 diminshed range performance over time (issue solved)

[KCT_99]

Hi everyone,

I did some reading on here and it seems that a few SBS units have developed this common fault. So now my beloved SBS-1 gives me reduced range performance as well.  I am using it with a FlightAware antenna and a Triquint TQP3M9037 LNA. Years ago, when I took this combo into operation, it performed beautifully with ranges well exceeding 200nm. Today it seems that about 100nm is the best it can do. The performance reduction seemed to have occurred gradually over time. The LNA has it's own dedicated linear power supply independent of the SBS-1. As I was operating this setup nonstop for many years it could be possible that the supplied switch mode power supply may have degraded over time and provides now unstable and/or noisy supply voltage. So I replaced the SBS-1 supply with a new one, but still gives same poor reception results.
Then I thought perhaps the LNA has occasionally over-driven the RF input on the SBS-1 and perhaps that may have degraded the internal SBS-1 RF input stage <- U200 (DFAA) which turns out to be a MAX2611, so I replaced that and again no improvement in performance. I now have a RF limiter connected to the SBS-1 RF input to protect it from over drive, just in case.
I have tried the original antenna as well, made little to no difference, perhaps that antenna has a less gain than the FlightAware antenna. I now ordered a Panorama AS-1105 to try but I have the feeling this would not make a difference either.

But what puzzles me is when I have the RF signal disconnected from the SBS-1 while I have Basestation started, the moment I make the RF signal connection I get briefly the usual range performance in excess of 200nm.

Keyword: briefly

What am I missing ? Can someone offer me some assistance ?

Also, I was wondering my SBS-1 does not have the network daughter board installed. I would be very grateful for some information on the header connection pin out so perhaps I can craft my own Ethernet add-on.

===========================================
EDIT:

Well, I found the issue. Turns out I have a media PC nearby that is causing strong interference on 1080MHz. Unfortunately the ASD-B filters are too wide-band to suppress this signal as it is so close to 1090MHz. Further investigation revealed its is the HDMI connection that spreads the love, but only if I have it connected to a Monitor. If I connect this PC to a monitor by VGA connection, no problem, the ADS-B frequency spectrum remains clean. Soja with the reception sensitivity sorted out I get the usual 200nm range - sweet.

Next project is to fumble an Ethernet upgrade into this unit.

[Anmer]

Bedtime here in the UK.  Will reply again tomorrow.

[Anmer]

Morning now and a new Government to boot!

I've known of a few SBS-1s to fail lately.  Old age maybe?

But before we come to that conclusion, have you tried a different coax cable and/or connectors?  And is the BNC connector on the SBS-1 good?

Looking forward, and if necessary, I'd suggest replacing the SBS-1 with a suitable DVB-T receiver and Raspberry Pi.  You can still use Basestation and even gain an Ethernet network connection, wired or WiFi. And continue to use your existing antenna.

More on this later, if needed.

[KCT_99]

Hi Anmer,

hehe, yeah it is hilarious seeing everyone on TeeVee freaking out about Team Farage.

Well, I have not yet given up on the old trusty SBS-1 just yet. Yes, I have tried a combination of different cables and it did not make any difference.
By just looking at the BNC connector it appears in good condition but that means little. If all else fails I might attempt to replace it with an SMA connector which I feel is much better suitable for this application.
I do however suspect that perhaps the first capacitor C183 in the signal path right next to the BNC connector could be cracked as the board is permitted to flex quite a bit when the cable gets attached.

By all means please, come forward with the DVB-T receiver and Raspberry Pi solution, this interests me.

[Anmer]

By all means please, come forward with the DVB-T receiver and Raspberry Pi solution, this interests me.

Good Morning.  Farage has a team of 4!  But a mouth of 30 

Suitable DVB-T receivers used to be cheap but demand has pushed the prices up in recent years.

I'll post his link as it explains what you need.  But shop around.

https://uk.flightaware.com/adsb/piaware/build/

The receiver connects to an antenna as normal and then by USB to a Raspberry Pi running suitable software.  That provides decodes Mode-S messaes.

There other examples of similar setups, such as:

https://www.flightradar24.com/build-your-own

Sharing data with FlightAware and/or FR24 gets you free Business accounts which can be useful.  But you don't have to share your data if you prefer not to.

ModeSMixer2, a small free app, allows for the decoded data to be available on specified ports.  Basestation can use the "Network" connection to access the data.

All my SBS receivers are now in storage!

[KCT_99]

Perfect !

That is exactly what I was looking for since I am not familiar with anything other than PC and Microsoft.

Now I got to study this Pi solution.

Thanks for pointing me there.

[Anmer]

Post back here if you need help.

[KCT_99]

Will do.

One more question, unlike the SBS-1, does this proposed solution also process signals on 978MHz ?

[Anmer]

Not sure as 978MHz isn't used here.

There's a load of posts about 978MHz processing on the FlightAware forum:

https://discussions.flightaware.com/search?q=978MHz

[KCT_99]

What do you think of this kit ?

https://youtu.be/pLzv5Jl6KdQ?si=JKsICIlje9A4v2G9
https://store.adsbexchange.com/products/deluxe-dual-sdr-feeder-kit

I am not sure what it takes to make it so that it feeds data to Basestation, if possible at all.

[Anmer]

What do you think of this kit ?

In a word - "Expensive"

For GBP £278 you get:

2 x USB SDR's
1 x Raspberry Pi4B
1 x Aluminium Case
1 x MicroSD card (pre-loaded with freely available and free software)
1 x SMA Splitter (for two antennae feeds)
1 x 1090MHz filter
1 x Rubber Duck antenna

One could buy these components separately for a lot less.  But as an out-of-the box (albeit no included power supply) it should meet your needs.  Assuming you have a 978MHz external antenna?

I am not sure what it takes to make it so that it feeds data to Basestation, if possible at all.

As for Basestation, ModeSMixer2 goes "looking" for available port data and outputs it on a nominated port in BaseStation format.

The above solution (and anything similar) doesn't need to "feed" BaseStation.

[KCT_99]

Yes, I totally hear you, bought separately this might cost less, but for me it would be more of a convenience factor and the packaging all in one is neat too, which I like.
I have a couple extra power supplies floating around here, maybe I can use one for this and if not, there is Amazon for that....
At this point I don't have an antenna for 978MHz yet, I will have to try with the included indoor antenna and see how that goes. If this is not working well, I will have to find an outdoor one.

My apologies, I am not familiar with this ModeSMixer2.  Is that a software add-on for the PC to work with BaseStation ?

[Anmer]

My apologies, I am not familiar with this ModeSMixer2.  Is that a software add-on for the PC to work with BaseStation ?

ModeSMixer2 is a small Exe file.  To access the Exe, one needs to create a small .Bat (text) file which tells ModeSMixer2 where to find suitable data and where to output it.

There's a long message thread here that might be uiseful to read.  But ModeSMixer2 is no longer supported though it works fine.

ModeSMixer2 for Windows can be downloaded from here.

Here's my Bat file:

Code Select Expand

@echo off
CMD /c I:\MSM2\modesmixer2.exe --inConnect 192.168.1.136:30003 --inConnect 192.168.1.136:30105 --filter-nocountry --outServer sbs10001:10002
exit
IP address 192.168.1.136 is my RPi connected to my local network.

Run the Bat file before launching BaseStation.

Set BaseStation Settings -> Data Source to Network and Settings -> Hardware Settings -> Network to the IP address where ModeSMixer2 is found and the appropriate port number, in my case port 10002

[KCT_99]

Thank you very much Anmer,

you are very helpful, very much appreciated !

Cheers