Where to buy Frequency counter for the Stryker SR-497HPC / SR-447HPC (old version)? Shawn January 29, 2021 20:24 Updated Search the internet for a FC390 or FC30 frequency counter. Related articles SR-447HPC / SR-497HPC Setup Guide SR-447HPC & SR-497HPC Manual Low Speaker Volume or Low Talkback Even With Control Set to Max Does the 955 have all the am channels that 497 does? What Size Power Supply Do I Need? Comments 0 comments Article is closed for comments.