Head Amp Problem

[Llew]

My aero tracking figures went down suddenly yesterday, from 60-odd to 3 or 4. The LNA at the head of the colinear array had expired, causing a short on the power supply feeding up to it from my DIY power insert module.

The amp is an LNA4ALL module, which I've enclosed in a metal box attached the base of the colinear, which is on a pole clamped to the TV aerial on the wall.

I took it down today to inspect the amp, which was indeed shorting the voltage line to earth. Further inspection showed the culprit was the voltage regulator (a 5V AMS1117). This should be good for any V input of up to 15V. I'm supplying 12V, into which I have added a limiting resistor in my power insert circuit.That should have been sufficient to limit the current.

It's been up there for nearly two years powered by the same supply, so I can only think the regulator itself has died with an unknown fault condition.

Anyway, I've ordered a couple more LNAs. I'll just put the colinear outside the window in the meantime, Aero tracking will be reduced, but at least it'll still be feeding Flight Radar.

 

[RustySpoons]

Those AMS devices are notorious for failing on anything.

 

[Archive-8]

My aero tracking figures went down suddenly yesterday, from 60-odd to 3 or 4. The LNA at the head of the colinear array had expired, causing a short on the power supply feeding up to it from my DIY power insert module.

The amp is an LNA4ALL module, which I've enclosed in a metal box attached the base of the colinear, which is on a pole clamped to the TV aerial on the wall.

I took it down today to inspect the amp, which was indeed shorting the voltage line to earth. Further inspection showed the culprit was the voltage regulator (a 5V AMS1117). This should be good for any V input of up to 15V. I'm supplying 12V, into which I have added a limiting resistor in my power insert circuit.That should have been sufficient to limit the current.

It's been up there for nearly two years powered by the same supply, so I can only think the regulator itself has died with an unknown fault condition.

Anyway, I've ordered a couple more LNAs. I'll just put the colinear outside the window in the meantime, Aero tracking will be reduced, but at least it'll still be feeding Flight Radar.

Why not try a filtered pre amp like the uputronics amp?

From what I gather the lna4all is wideband?

 

[Llew]

Why not try a filtered pre amp like the uputronics amp?

From what I gather the lna4all is wideband?

Yes, LNA4All is HF upwards, but I haven'f found it lacking for my use on 1090.

I'll look up the Uptronics module, cheers.

 

[Archive-8]

Yes, LNA4All is HF upwards, but I haven'f found it lacking for my use on 1090.

I'll look up the Uptronics module, cheers.

1090MHz ADS-B Filtered Preamp

 

[Terryl]

My aero tracking figures went down suddenly yesterday, from 60-odd to 3 or 4. The LNA at the head of the colinear array had expired, causing a short on the power supply feeding up to it from my DIY power insert module.

The amp is an LNA4ALL module, which I've enclosed in a metal box attached the base of the colinear, which is on a pole clamped to the TV aerial on the wall.

I took it down today to inspect the amp, which was indeed shorting the voltage line to earth. Further inspection showed the culprit was the voltage regulator (a 5V AMS1117). This should be good for any V input of up to 15V. I'm supplying 12V, into which I have added a limiting resistor in my power insert circuit.That should have been sufficient to limit the current.

It's been up there for nearly two years powered by the same supply, so I can only think the regulator itself has died with an unknown fault condition.

Anyway, I've ordered a couple more LNAs. I'll just put the colinear outside the window in the meantime, Aero tracking will be reduced, but at least it'll still be feeding Flight Radar.

The maximum Vin for that device at +5 VDC output is < 12 V, it may be that your dropping resistor is too small, or could not handle the load, (wattage wise) you might want to drop it down to +9VDC or less.

http://www.advanced-monolithic.com/pdf/ds1117.pdf

 

[Llew]

The maximum Vin for that device at +5 VDC output is < 12 V

That's Vin-Vout., in my case 12V-5V=7V, which is less than the maximum 12V. Anyway, I'll be using a 9V adapter in future.