Topband: MFJ259B QUERY

[Mr. and Mrs. Magoo]

I'm cutting a couple of 1/4 wave sections on topband and, in tuning for X=0, 
I notice that this value exists over about 30+ khz.  If I "fine tune" for 
R=1 and X=0 there is still a healthy bandwidth of perhaps 20 khz.  This 
complicates cutting the lines exactly where I want them.  Is this a common 
occurrence in using the 259B?  I was not expecting the "dip" to be so broad.

Bill, VE3NH