This EKKO stamp of CKWX is on auction right now on eBay:
http://cgi.ebay.ca/ws/eBayISAPI.dll?Vie ... 0542751942
Although I'm sure the price won't end there, it is currently at 99 cents with free shipping.
EKKO stamps were extremely popular in the last half of the 1920s when every listener was a DX'er. Send a station a dime and an accurate reception report and you got an EKKO stamp in the return mail.
The Depression killed the EKKO company, whose large stock of bank note quality blank EKKO stamps was liquidated to companies that sold them to stations at much lower prices. They cut costs by doing the rubber stamp approach you see here for the call letters. Or by just selling the blank stock to stations who did their own rubber stamping.
The beaver pattern seen here was intended for Canadian stations.
Bottom line: this EKKO stamp is almost certainly from the period 1930-35.
