1070 is difficult because 50-kW WTIC is 13 miles away on the opposite side of the valley and so far, I have not been able to hear anything on 1070 due to interference from WTIC on 1080. On the other hand (or other side of 1080), I have no problem hearing WBAL on 1090, so go figure.
1620 is difficult because there are only eight stations on 1620 in all the USA and none are local.
I made up my mind to tackle 1620 first. My plan was to tune all my radios to 1620 and listen to nothing until some anomaly in propagation sent a signal my way.
I did not have to listen long and heard a very weak signal way down in the mud: a Spanish station playing Latin music interspersed with current NOAA weather broadcasts in English.
My high school Spanish is not good enough to pick up enough intelligence from the spoken, broken-by-static Spanish to determine the source of the signal. But I was able to get enough intelligence from the weather broadcasts to determine that their source was a NOAA weather station in southern New England or southeastern New York.
But there are no AM radio stations on 1620 in all of New England or New York!
Google is my friend, so I Googled "1620 AM" to see what it came up with. The second item that Google found was a link to listen online to Restauracion 1620 - AM 1620 - New Britain, CT. New Britain is about 8 miles away, so I went to the webpage and when I listened online, voila! The radio signal on 1620 matched what I was hearing online with a slight delay.
The full name of the station is La Nueva 1620 AM Restauracion (The New Radio AM 1620 Restoration) and it has a website (http://www.restauracion1620.com/), but I have not been able to determine the legal status of the operation. Nevertheless, I entered La Nueva 1620 AM Restauracion in the log and plan to tackle 1070 next.