RF Scan of Various Combinations of Dongles, Filter, and LNA

[geckoVN]

@abcd567

NOTE:
Do NOT use specified 12V DC Power supply, it will fry the Noise Source in a short time.

Looking back, we had this exact discussion a year ago. I did the measurements then, so I won’t bother doing them again, but I will repeat my findings:

@geckoVN

Looking at the BG7TBL Nose Source (mine it yet to produce it’s first nose), I just had a poke with a multimeter (Fluke 17b+).
Mine is the: 2016-03-06 with the BB5Z MIMIC’s (SBB-5089)

I set the input to: 12.00V (233mA)
Voltage drop across D2: 0.63V
I then measured the supply each MIMIC (w/ 50Ω load) at junctions of:
U2: R8/L6 - 4.73V
U3: R9/L7 - 4.82V
U4: R10/L8 - 4.66V
The Spec sheet gives Vmax as 5.5V.
I had to wind up the PSU to 16.5V to get 5.5V on the first MIMIC (U3)

Several people report these ‘noise sources’ run hot, but based on the measurements above, I’d guess one of the following:

• The MIMICs are non-genuine (ie. not as per the data sheet)
• The 12V PSU/Wall Wart etc. is putting out a lot more the 12V - Time for a new one.

Edit: I’ve had mine powered up for half an hour. While it’s getting warm, the 100Ω dropping resistors (R8, R9, R10) are hotter than the amplifiers.