I decided to see what output came out of the AD8302 phase comparator on my interferometer board – no aerials.
Is anyone able to explain to me what I seeing on plots below from Radio Sky Pipe II?
Output of AD8302 Interferometer Board no aerials attached to Nooelec LANAs 231123@2025:
This gives a background reading with no aerials – no random signals – the inner and outer coax are not connected via aerial so I guess this means impedance extremely high and unpredictable.
Output of AD8302 Interferometer Board no aerials attached to Nooelec LANAs 231123@2030 with outer braid of 2xcoax inputs shorted:
Same as previous plot, but here I have shorted the outer part of the SMA connector on one of the two inputs into the LANAs (amplifiers on each SMA coax input) with the same on the other input – appears to be no difference from plot above.
Output of AD8302 Interferometer Board no aerials attached to Nooelec LANAs whip aerial on one input 231123@2031:
I own ONE whip aerial only for UHF amateur radio work – so I tried connecting it to one of the inputs and leaving the other aerial input without an aerial – I can’t see any obvious change but don’t know if I would expect to do so or not.
Output of AD8302 Interferometer Board no aerials attached to Nooelec LANAs showing changes in trace without making changes to setup 231123@2034:
There looks like a radical change in the trace below = however no change was made in the aerial inputs (no aerials on either input) or board otherwise between left side, middle and right side – showing the effect of changing environment on plots.
Output of AD8302 Interferometer Board 50 Ohm dummy loads attached to Nooelec LANAs 231123@2040:
I thought maybe dummy loads on both inputs might put the two inputs into phase…..appears not! Clearly I don’t understand about this.
Output of AD8302 Interferometer Board inner-inner and out-outer connection on both coax inputs to Nooelec LANAs 231123@2050:
I also thought that connecting the two inner cables on both SMA coaxial inputs together and the two outer shields on the connectors together might put the system in phase and give me a flat line – but again it appears I am wrong!