Hi Jay, I thought it was 1800hz also. Good, now how do I calibrate ARGO v.128??? I'll give it a shot, but I could use a bit of advice for sure. These HP's have a really hot receiver. I noticed quite a bit of signals that my Kenwood 440 wouldn't hear. I just got it today and am trying to figure it out with no manual. I'm getting there. Thanks, Mike http://www.geocities.com/we0h/index.html