pre amp and ANRB

[Boudewijn]

Is it possible to use an amplifier on the ANRB?
I have a LNA-5000 or want to buy a Uputronics.
Someone says to me that's not possible because of the SAW-filters in the RadarBox.
Does anybody have experience with this?

[neroon79]

Hi Boudewijn

You can stay with the LNA-5000, although a special 1090MHz might be better as it blocks out, or better reduces signal strength of frequencies above and below 1090MHz. But you must be careful, because if short HQ coax cable and high gain antenna is used the reception components of the RB might get overloaded. Antenna gain, cable atennuation and amplifier gain must be balanced to avoid problems caused by too high signal levels at the tuner/input filters of any reception equipment. Of course the amp should be installed close to the antenna.

While installing a RB Comstation I experimented with an wide band LNA to make GPS available to the RB comstation. It delivered very good results. Due to the VHF reception capability of Comstation and legal reasons of receiving ATC in Germany I decided to set up a more complex installation consisting of a narrow band 1090MHz LNA, a GPS signal filter with a LNA for GPS and to separate antennas. One special ADS-B and one special GPS. Neither a useful VHF ATC nor an ACARS reception is possible with this installation. Which is good, as both is illegal in Germany.

Ingo

[Boudewijn]

My ADS-B antenna has a gain of 3.5 dB. Instead of the LNA5000 I was thinking of the Uputronics mounted under the antenna. Would that be a better solution?

The antenna cable is low loss and 10 meters long. I am at 35 meters hight and receive about 200-350 aircraft per moment (of course less in the evening and night). However, my antenna is blind to the South East.

https://ibb.co/dg5HHd

I would not make such a problem of Ingo. You only receive something and who checks that? Fortunately, that is allowed in the Netherlands.

[neroon79]

The amp must be installed close to the antenna. If it is installed close to the receiver many weak signals have already been drowned in the white/pink noise before their signal is amplified.

For remote diagnosis/check the following is needed: Gain etc. of amp & insertion loss of its BIAS-Tee, attenuation of cable per 100m or ft, if one is used: insertion loss of splitter/combiner, number of connectors in the line.

It only needs one stupid neighbour that doesn't like the sight of your ADS-B antenna on top of the roof and you will have an uninvited visit of the authorities. So better to be (almost) safe with this point.

Ingo