Building a new receiver, this is going in a prime location - Suggestions for receiver/preamp/filter please

This has developed into a really interesting discussion but I’m not actually seeing much other than suggestions to use either a basic dongle (such as the RTL-SDR.com one I mentioned), an AirSpy Mini which seems to offer a possible slight increase in performance or go all out with a Mode-S Beast. The kit for the Mode-S Beast could well be the way to go although calling it a kit when all one has to do is solder a handful of LEDs is a bit misleading!

I can’t remember exactly how I built my current receivers, I seem to remember I used the default FlightAware Image but I have the ADS-B Receiver Project front end with the Performance Graphs and System Info - Does that make sense? I’ve set up a temporary port forward so you can see my receiver here

If that’s what I’ve done, would it be possible to repeat this on a new build and have it work with a Mode-S Beast out of the box? With the Uputronics preamp/filter I mentioned before, I’d need to tweak the gain and is that as simple as now, ie editing /boot/piaware-config.txt?

Actually, does the ADS-B Receiver Project still exist? The link at the bottom of my page goes somewhere very dodgy looking!

As always, thanks for all the advice - This is an interesting read.

The github page is still working fine. GitHub - jprochazka/adsb-receiver: Create your own ADS-B receiver and web portal.
No changes to the code since October, so at least the graphs portion should be good to use.
If you use it to try and install dump1090-fa it fails at the moment i believe, but that’s not really a problem when using the piaware sd-card.

[quote=“keithma, post:41, topic:44963”]
If that’s what I’ve done, would it be possible to repeat this on a new build and have it work with a Mode-S Beast out of the box?/quote]
I believe you can use a piaware image and then install only the graphs from the receiver project.
(That also fits with the link to your receiver)

Mode-S Beast connected per USB should work withtout problems by using the piaware config option:
receiver-type beast

This configures PiAware to talk to a Mode S Beast connected by USB directly to the Pi. Set “receiver-type” to “beast”. No further configuration is needed.

No you can’t change the gain on the Beast as far as i know.
You would have to test the hardware and maybe buy an RF attenuator if the signal is too strong.
After doing a very quick google search it seems that at least one guy doesn’t need an attenuator using the HAB amp: http://www.grg.org.uk/cleeve-ads-b/

I believe they call it kit also because they don’t test the function. (Probably the function of the rest of the hardware is still tested during production)
Anyway it’s just final assembly as the rest of the board is SMD right?

On the improvement with the airspy mini vs the v3 i would wait a day, then you can check https://flightaware.com/adsb/stats/user/navzptc and compare both of his sites :slight_smile:

(He is using a samplerate of 20 though, which might not work on the Raspberry Pi, it works for one user called burgdorfer at least, but his station doesn’t have as many planes in view due to terrain)

In Europe there are more overlapping messages due to more ATC interrogations. This means outside the EU the benefit of the airspy mini might be smaller.

my lna gain is 27, your two lna’s are somewhere between 28 and 30…so our topology is nearly the same and our gains (excluding dongle gains) are nearly the same. when i ran my v3 (with splitter losses) at -10 i had about 14% >-3dB messages but had max aircraft and position counts. when i dropped to 49.6 gain in the v3 i saw 5% >-3dB but saw reductions in both aircraft and positions. i originally had v3’s on both sides of the splitter, one side running -10 and the other running 22.9 gain (so i could see local airport traffic without dropouts). when i added the mini (in the hopes of being able to run just one site given the increased dynamic range of the mini) i saw basically the same aircraft counts but more positions (ie 3.3% but before playing with the gain/sample rate)

You might now be able to go down 1 or 2 more steps on the airspy so you can see local traffic without losing positions/planes further out.
Or you could probably continue to run 2 stations so you can see local traffic.
(Those two stations could locally be integrated into one SkyView (separate from the other two Skyviews), in fact i should write a script for that)

yes, next step is to try g=19 and compare data. i have been using a site about 60 nm from me to compare data. this site has historically been higher ranked than my site (usually higher aircraft and similar positions. so far today this site has 1% more aircraft
but 6.4% fewer positions…so far the mini is looking good at g=20 with the splitter gone.

i will advise tomorrow after i reduce gain this evening

I guess knowing that you are reducing the gain on the airspy anyway you could always put the splitter back in. Seems like i was quite mistaken believing the airspy needed a stronger signal :slight_smile:

it would be great to hear from prog on some of these issues/comments. so far the mini has been fun. i do agree that SoNic67’s request for more info would help us all…i think the mini is a very nice product…but would like some more documentation

I will shut down the v3 site tonight after midnight GMT as it will have been running 2 days odd and has shown how airspy out performs v3 using same conditions - hope it helped.

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Thank you for that comparison!

79W_positions 79W_aircraft

24.01.2019 at 50.88N,0.79W

Comments from me:
Difference is not expected to be as big in areas with a reduced message rate. The Airspy is good at receiving messages that overlap, this is not going to be as beneficial when not in Europe as the message rate is greatly increased due to more frequent ATC interrogations and pretty busy skies.

That’s quite a noticeable difference. I don’t think our group can justify the cost of the Beast so this may be the way to go. Thank you for the very useful comparison.

/edit - I’ve not looked into the Airspy at all, how straightforward is it to use it with a vanilla out of the box FA image?

hello navzptc, thanks for the great data. in the states (mississippi) after 24 hours i noted a 3.6% increase in aircraft and a 14% increase in messages with the mini (this is in reference to a nearby site that i could never outperform with my v3, so the actual improvement over the v3 is larger than stated). i am 47nm away from the closest major airport

I’ve made a script to configure and install it: HOWTO: Airspy mini and Airspy R2: Piaware / dump1090-fa configuration

Be aware with a Raspberry Pi the higher sample rate used in the comparison will not work due to lacking CPU resources and the difference to another dongle might not quite be as much.
It is still sampling at 12 MHz compared to the standard dongle which is sampling at 2.4 MHz.
I’m not sure how much the difference between 12 MHz sampling and 20 MHz sampling is, but navzptc wrote the performance was pretty much the same.
(retman describing his improvements above is using it with a Raspberry Pi running at 12 MHz)

Bit of a bump but this is finally nearly built and should be going live in the next week or so. I have to say that I’m rather looking forward to it. Sadly it’s going to be behind a CGNAT so I won’t be able to directly share the web interface but I’m looking into a way to take a screen grab of the Skyview map every few minutes and push it to a web site for anyone to look at if they’re interested.

Here’s the work in progress - We won’t be going PoE but running a voltage up to it with a dedicated PSU in the box driving the Pi 3B+ with a feed to the preamp. I’m happier doing this than powering it through the AirSpy as when I did that before, the preamp stopped working after a while.

This build is very similar to the one on my ham radio mast at the moment so I know it’s a decent design that works well and can stand up to the weather.

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Looks very nice and tidy

You may want to consider putting a fan on the CPU.
An airspy needs a lot of CPU and the RPI will throttle back if it gets too hot.

The fan that comes with the POE module is fine(I see that you prefer not to go this route). You can set custom speeds for it.
https://www.raspberrypi.org/forums/viewtopic.php?t=221639
There are other fans that are available to suite.

It’s a valid point, thanks.

How much power is that power supply rated for?

That USB cable to the airspy probably drops some voltage which is probably why the preamp stopped to work.

The airspy mini gets quite hot, if you have some spare small heatsinks laying around it probably doesn’t hurt to place one or two onto the airspy.

The PSU module is good for three amps. and the pre-amp failure I was talking about before was in a completely different installation, totally unrelated to this one so that’s irrelevant. That’s also a decent suggestion about heatsinking the Airspy, thanks.

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It seems LM2596 DCDC - not good. Usually it needs a big radiator.

I’ve used dozens of them over the years without any problems.