3 Day Review

WA2ZKD

I have had my system on the air since Thursday evening. I had a BO with Seeed and got one of the latest batch.  Here are  a few observations and thoughts.

• FedEx was pretty quick with delivery from China, < week.
• Assembly of the kit was easy other than the tedious fumbling with the nylon standoffs with their metric thread
• System booted up and ran flawlessly, first try. I used a 4A supply from an Odroid I had.
• Being close to several AM BC stations, I have a HPF on the feed to stop OV. I'll replace it with notch filters soon.
• I put a 50 ohm load on the antenna and things looked clean, my interference comes in through the antenna I am guessing. Likely some 60 Hz hum via a conducted path, TBD
• I put the unit in a partial Faraday cage, not sure if it helps. (see pix below)
• will be adding more ferrite and a different PS this  week

WA2ZKD

More testing for interference....

• added Type-43 ferrites on all cables. 
• terminated antenna input in 50 ohm, things look very clean on spectrum analyzer display and with a narrow waterfall
• I must have lucked out, as a I see no evidence that 5V switcher is causing an issue
• I do see some 60 Hz spurs down near the 80M WSPR freq. but they are only there when an antenna is attached. Need to work on source of those, will DF with my ICF7600

WA2ZKD

Even though I saw no evidence of PS spurs, I have since switched to a Linear Supply.

I also designed a 3 channel notch filter scheme to overcome overload on from nearby AM BC stations.

WA2ZKD

over the months, I added a the notch filter described here: 

http://forum.kiwisdr.com/discussion/593/am-overload-solved#latest

With that is place I have been able to explore the entire range that my antenna permits. I have almost 75 stations from 60-550 KHz logged and an AMBC station on every MW 10 KHz channel except 4. Those 4 are just too close to the AMBC TX that are only 2 miles from my QTH.