Hello,
I wrote a new software for the SMA Spectrum Analyzer 138MHz-4.4GHz. More details on my blog:
http://vma-satellite.blogspot.pt/The pictures you show are from the NWT4000. This is a different device than the one your subject title mentions!
NWT500 -> Original device. This uses the german software that is shipped with all clones.
NWT4000 -> Modded device with extendend frequency range.
SMA Spectrum Analyzer 138MHz-4.4GHz -> Lowcost copy of the NWT4000, featuring only one ADF4350. This means that the a signal can EITHER be read or output, but not simultaneously! Hence this device is no good for antenna tuning!
SMA Spectrum Analyzer 38MHz-4.4GHz -> Lowcost copy of the NWT4000, featuring only one ADF4351. The only difference is the ADF4351 instead of the ADF4350 and subsequently the price.
While the NWT devices are good for antenna tuning, which was the original intent of these devices, the SMA ones are nice as spectrum analyzers.
However, the original software was not exactly built for this purpose. Sure enough, a spectrum mode exists (sweep), but it lacks many features common in a spectrum analyzer.
This is why I developed my own program. It is what it is, made by myself for my own education and fun, but I think it is actually quite good and lets one play with a spectrum analyzer that costs around 50 Euro!
I do own professional equipment (mostly field meters for TV, CATV and SAT), but for an amateur the SMA Spectrum Analyzer is a great toy.
Careful with the input signal, though: I killed the mixer within 3 days, because I forgot about the 14/18V of the LNB power... A DC blocker is mandatory for SAT applications and recommended for CATV (due to possible power for active elements in the distribution network). Connecting plain reception antennas should be OK without a DC blocker.
Replacing the M810 mixer is not difficult, but best done with a heat gun soldering station. The IC's can be bought cheaplit at Alixexpress.
Hope this helps regarding this device.
Regards