Hi.
The cheap SKA spectrum analyzer will only use input or output connector at a time. Not both simultaneously!
I explain this in my blog. See web link in my profile.
Regards
Thanks! I wasn't 100% sure what I was paying for. But in the spirit of exploring new gadgets I decided to go for this one. I wasn't 100% sure whether this can transmit and receive at the same time, but thanks for your nice review, it is now clear that the device can either transmit OR receive - not both at the same time.
For antenna testing simultaneous transmitting and receiving is not a must as one can use a VSWR bridge to check antenna tuning which requires only the transmitter to work.
It seems that if one wants to use this device as a spectrum analyzer, one can use this device as a receiver but one needs to have an external signal generator. That's why some sellers are offering those wideband noise generators with this gadgets which can be used as poorman's signal source.
I do already have a signal generator "35 M ~ 4.4 GHz signal source ADF4351", so in principle I could use this as a tracking signal generator with the signal source/receiver I just bought. In order to get a decent frequency performance I need to modify those two designs so that they will use the same good quality, oven compensated external oscillator for the timebase at least.
The output signal from the signal source/receiver and the ADF4351 contains quite a lot of harmonics. This may or may not be a problem. The ADF4351 datasheet
http://www.analog.com/media/en/technical-documentation/data-sheets/ADF4351.pdf states that the VCO fundamental frequency is from 2200 MHz to 4400 MHz. I am not sure, but it might imply that at that frequency range the signal quality is decent without too much of harmonics. At the lower frequencies which are generated by a divisors the signal will contain more harmonics. For better signal output quality one can use filtering or use some other signal generator/architecture.