bad signal

[Radio2.0]

Hey
I use an 1090 Yagi Antenna. Before my dad attached the new Antenna (and turn the Mast a little) the Signal decreased.
RTL1090 show me THR: -72db [19]
What does it mean?!
What could happened to my Antenna that the Signal dropped so much?
Thx

[G4UMW]

THR shows the average noise level, not the signal level. It's all explained in the RTL1090 documentation.

[Radio2.0]

So which Number is better 19 or 8 ?!
Sorry the documentation is worst for RTL1090.

[G4UMW]

The 19 is the absolute hex equivalent of -72 so effectively they are the same thing. What was your db figure before?

[Radio2.0]

sorry i dont understand anything in the "Radio Language".
Is the value good or bad?

[G4UMW]

See my previous question - what was the db figure before?

[Radio2.0]

http://radarspotting.com/forum/index.php/topic,4750.msg22292.html#msg22292

[G4UMW]

The -79 db figure appears better as it implies less noise.

[Radio2.0]

That means the noise level on the dongle with LNA is much higher?

[G4UMW]

Yes. You may well be overloading your dongle with the signal from your amplifier. This could appear as noise to the  RTL1090  software. An article in a UK radio magazine this month also described signal overload of a dongle when using a preamp.

[Radio2.0]

Is there an way to see the Signal Quality?
I know the software is a beta... (I fond no way to use some other SDR 1090 Application wo support more than one SDR Dongle. In RTL1090 i use one as an master and the other send there UDP Data.)

[G4UMW]

Not as far as I know.

The problem is that both your dongle and the preamp are wide-band devices. Anything your antenna collects will be amplified, not just the wanted signal.

A preamp should only have enough gain to overcome the signal loss in the feeder between antenna and receiver. It is NOT designed to function as a substitute for a poor or badly-sited antenna.