Lee,
Just noticed your post. I nearly got caught out and was about to post 'basic' advice then remembered Shortwing is one of the early homebuilders which is why he is swapping dongles off eBay. This is a strange one!
We are obviously thinking along the same lines so I will post what I have already typed on the basis that it might also help others.
Shortwing,
You say you
...have three of the small adaptors, the one on the known good hardware list, I have tried all three and my PAW won't pick up any traffic. It shows RED in the admin page
Your Home screenshot shows that you had a good GPS fix and that your P3i transmitter is working (TX=1300), but no PilotAwares received (RX=0) since you powered up (00:40 minutes ago). You must have received ADSB traffic at some point in those 40 minutes - viz. ADSB DVB-T 'Connected.(Msgs=1072), but no recent ones (+0) in I the last 5 seconds - which is why the ADSB symbol has gone back to red. This home screen would be 'normal' for a unit sitting away from traffic, e.g. indoors or inside a hangar (or in my living room at 2am), but you have been at this game long enough and will have tested it outdoors (I note the screenshot was taken Sunday afternoon), so we need to dig a bit deeper.
Your Traffic Screenshot BTW seems to show only a Mode S transponder but weirdly with no Hex ID or SIGnal strength. Any idea why? Did you test in the plane?
Edit [Aside to Lee - wondered if this could be a report of a 'short squitter', but didn't think PAW reports those. If it was, would it not show the Hex? Not something I have ever seen before]
There
could be an issue with the SDR dongles. Checking the link from the 'Known Good Hardware List' I notice that the seller has ended the listing because...'there is an error in the listing'. He doesn't say what the error was, but as you will be aware, in the early days we found that some units advertised as Realtek RTL2832U didn't have the correct R820T Tuner chip in them and wouldn't work, hence why we started the 'Known Good Hardware List' in the first place. We of course have no control over where the sellers source their supplies. This may of course not be the issue.
Steps to try:-
If you haven"t already done so, try a different antenna, or a length of thin wire carefully pushed into the centre
only of the connector on the SDR dongle (even a short length such as a straightened paper clip should allow your unit to see CAT ADSB out in the open if they are around). We have had a couple of recent cases where the fault was in the antenna
lead or inside the base, not the dongle.
Not sure your Configure Screen will help, but worth posting it anyway so we can see your settings and also anything else that appears on your Traffic Screen.
Let us know how you get on.
Regards
Peter