FlightAware Discussions

New model of BG7TBL noise source





Oh, it is a nose source, interesting :joy:


Well spotted :rofl:



The SMPS I think is this one:

The amplifiers I think that they are an alternate marking of SBB5089Z:

In this case, the SMPS absolutely needs to make exactly 5V, to feed those amplifier IC’s.
The 12V can be applied via limiting resistor directly to D4, does not need stabilization of any kind.


My experience (and other’s as well) is that feeding the device at 12V DC converted this device into a frying pan (unless you add a cooling fan).

At 5V DC it not only stayed nominally hot, but also performed good.





See my site www.pa0nhc.nl for checking and changing.
73’s, Nico.


Nice cat :slight_smile: & nice PCB Catalog


Hey, there is a difference in what a board should do and what actually is doing.

My latest experience: this SATA adapter that I just received in mail, well wrapped and protected.

The capacitor was just rolling in the box. The board would randomly lock up the computer. Don’t know if is because of that capacitor or is something else not caught by QC.


See : www.pa0nhc.nl
Do not feed with 5.0V. The MMICs then will be under powered. In a good PCB, the MMICs automatically get a correctly 5V if the PCB is powered by 12V. The (12V - 5V =) 7V drop occur over R8, R9 and R10.
I measured a PCB surface temp of abt. 65C. That feels hot. But MMICs will not be damaged.
I installed the 78L09, its output C’s and the changed 100 Ohm series R5 for D3 externally on top, like a hey stack. All components must be connected as short as possible near the D3. It is not looking nice, but it works. The 78L09 ensures good separation from power supply noises, as all extra 100uF capacitors do too.

I drawed a PCB according to these mods…


Characterizing the SWR of an Antenna with a Noise Source and an RTL-SDR


Low cost zener-diode noise generator for use with above spectrum analyzer
Source: http://hansvi.be/wordpress/?p=91

Above circuit is based on the circuit below
Source: http://holdenc.altervista.org/avalanche/

Another Noise Generator.
Source: http://www.n5ese.com/noise.htm



The LED above is installed backwards, it will just illuminate nicely, that will never work as noise genrator. You need a Zenner diode in reverse connection.