Rig back up - thoughts on early graphs?

One thought - for when I start putting the HabAmp back in - all things being equal (non-faulty usb cable etc), should the Rpi2 be able to consistently output the 5v the HabAMp needs, over one of the onboard USB’s?

Only other thing plugged in via USB is the dongle itself.

Saves another power plug if so…

Also, when looking at my stats from today - bear in mind that I’m currently using a splitter rather than a combiner to connect the coax feed from the dongle to the ant coax.

My original rig had the proper combiner, but when I rebuilt after “The Great Flood of 2015”, seems I bought the wrong one… :blush:

As @Caius points out, that’ll be attenuating the entire signal.

Will replace with f-type barrel connector when they arrive.

Even so, stats are still looking a darn site better than with the HabAmp…

Using your known good hardware config without habamp, have you tried swapping the mcx pigtails to see the if they are both good ?
I would feed the habamp from an external supply and swap out the USB power lead too.
I’m using habamp, no problems other than setting the dongle gain which is taxing.

@RadiostationX - I’ll see what I can do there, unfortiunately I havent got any other MCX / SMA devices to try them on.

I’ll try the diff power supplies for the amp, and put a multimeter across it.

From a very quick look at “Bias T’s” it’s a way of inserting power into the coax for amps etc - like I had before.

Could I use my Sat amp PSU to power the HabAmp via the coax?

Hi @cy80rg,
No the sat amp psu is more than likely 12-18v and the habamp regular version will only accomodate 5vdc on the bias tee.
I have a special edition version of the habamp, with 5-26v on the bias tee.
Anthony at nevis/uputronics adds some components (voltage regulator) to the stock version at customer request.
I can power mine via 5v USB or 5-26v via coax.

Currently on test station powered via mini usb socket on the amp by a ipad ac mains charger which is 5v @ 2a and usb to mini usb lead.
I selected the ipad charger as I know its a high quality psu unit and rated at 2amps.
It may be like using a sledgehammer to crack a nut though as the habamp needs just 56ma !

Works great.

Yes, I met Anthony there a couple of weeks back to get the HabAmp, nice little build! (On the device… lmao)
I understand re the PSU.

I See you’ve got the same as myself there (sans the mods) - i.e SMA to F-type etc. (EDIT - mine are on pigtails - I might look at getting “hard-plugs” like yours to avoid cable issues).

I have a “decent quality” PSU that can output 2v or 5v over named usb outputs (basically a multicharger) - I’ll try that and a new USB lead.

One thing I didnt notice on the Gain options was that “44.5” (which I had it set to when the HabAMp was in) isnt actually the highest manual gain option…

I might put the HabAmp back in, then test the remaining (2 afair) gain options to bring the signal back up.

However, with my rig working as well as it does without it, I’m quite tempted to leave it (I wont, but it is tempting! :wink: ).

I’ll try and post some pics of my rig later, but the lighting in the attic is rather poor for pics…


Hope this helps,


OK, so put the HabAmpp back in, different USB power supply.

Came back online c17:10 tonight, and all the stats have taken a nose dive again…

In the live Map, birds and messages have halved with the HabAmp in.

Have left Gain at “max” and PPM at 55 (I did check PPM with the HabAmp in, was around the same so left that for the moment).

Even with gain at Max the ADSB Signal stats are no where near clipping (in fact they’re going down), so didn’t seem much point in reducing the gain manually?

(Or is the logic here that with the Gain at Max, other signals are drowning out the specific ADSB signals?).

So, now got Dongle → Hab Amb → Ant; nothing else.

Will leave it and see what we get…


Thanks Radio Stationx - that’s what I’ve got on the ant end, the pigtail is the MCX through to the dongle.

Looks a useful site tho!

cy80rg: With just the dongle, HabAmp and antenna. Try viewing the live map and when you see aircraft being tracked try removing power from the amp only. Do you see any change? I see aircraft drop off and the message rate drop but not all. Just something to try to see if the amp is trying to work.

Thanks @eaglemark - I see what you’re thinking, if I remove power from the HabAmp and the bird count etc is pretty much the same, it shows the HabAmp is doing “5 10ths of nothing”…

I’ll give that a try this week (Im going to test gain at 44.5 (current), then the remaining two gain options for a day each).

TBH, unless anyone can think of any technical reason why my stats go to heck with HabAmp in (i.e tweaking gain etc etc), I’m fast coming to the conclusion the HabAmp’s faulty.

I’ll pick this up with Anthony in the not-too-distant future…

Beyond the HabAmp and supporting hardware…

  1. MCX to SMA for dongle (pigtail)
  2. SMA to F type (converter)
  3. 5v PSU
  4. c3ft USB power from PSU

Everything else is the same, which without the HabAmp produces the stats / range / msgs seen on my site 22/03/16, which is just Dongle → MCX - F Type → Coax → Ant.


You could try hooking up the HabAmp to a dongle and computer running standard SDR software, and see what the thing does with the signal and noise floor in the waterfall, maybe with a known-strong signal like a nearby fm station.

EDIT: Realized you have the filtered version so it’s not going to do a lot of good outside of 1090mhz. Still - you could visualize the ADSB signal and noise floor in an SDR# waterfall, or perhaps the RTL1090 sisex window. Just a thought.

Thanks JH,

Just going to run a multimeter over the SMA to make sure it’s getting power…

Meeting with Anthony next week to test / swap out the HabAMp…

Morning all,

Just a quick update…

Took my HabAmp to Anthony last night - to confirm, there was no fault whatsoever with Anthonys’ product.
Anthony ran the amp through his spectrum analyser and all performed as expected.

Turns out the issue was my SMA to MCX pigtail wasnt actually the one i’d ordered! (it didnt have the center pin - so was either broken or an rp-sma, afair).

Anyway, all in and working now - with the amp running directly off the RPi usb power.

Set the gain in mut down to 44.5, and get the stats below, looks pretty good! :slight_smile:

Peak level looks rather high, so I’ll tweak gain down a bit more tonight…

Just to check, I take it that with the SAW filter in the amp, there’s no point putting the “inline combiner” filter on the ant to “get more filtering”?
I believe the only way an additional filter would help is if I worked out what freq the noise was on, then used a filter specific to that freq?

Anyway, here’s my stats so far, comments and suggestions more than welcome!

(HabAmp went in c17:00 last night).


Stats look nice!

If it makes you feel any better, when I was first getting started I ordered a RP-SMA to SMA adapter to use an N-type to RP-SMA cable I had on hand for the Flightaware 1090 antenna…

Results were not good - Seemed like the antenna was junk so I kept using the beercan, **until an embarrassingly long time later when I realized the ADAPTER i ordered was the wrong polarity. The SMA end was going to the RP-SMA connector on the cable and the RP-SMA end was going to the SMA connector on the filter **

So this was actually adding an extra non-connection in the signal path, and I was still getting 50 mile range. :laughing:

Nothing a few bucks on amazon and a bit of embarrassment couldn’t fix.

@JonHanford - :wink: These things are sent to try us!

I would try backing your gain down one step at a time and watch results. Looks like you may have too much of a good thing now… :slight_smile:


Your stats look so much better today. Double and triple the preceding Wednesdays.

4 hours until 23:59 UTC and you have already exceeded all you AC and position reporting stats for the last fortnight.
200 reports from 200+NM

Maybe you do need to turn it down a little. What are your peak db levels? What about your noise levels?


Thanks guys :smiley:

Have started a new thread on this, thinking “tweaking gain” maybe a seperate topic of interest to others…