[CQ-Contest] Difference between the ICE 419 419A & 419B bandpass filters

Jim Brown k9yc at audiosystemsgroup.com
Wed Sep 10 12:10:53 EDT 2014

On Wed,9/10/2014 6:48 AM, Jay Terleski wrote:
> The AS-419 is manually controlled with pushbuttons, and also is on the
> Shacklan 4 wire network, as well as can be controlled with a DB9 input jack
> like the 419b from ICE.  See it here
> http://www.arraysolutions.com/Hamation/bandpasser/bandpasser_II_AS_419.htm

Based on my testing and review of bandpass filters a few years ago, I 
would expect Jay's implementations in his redesign to be significantly 
better than Ice's. There were several problems with the ICE filters. 
First, their capacitors were under-rated for real world conditions, so 
even a modest mismatch would fry them. Second, relays tended to go 
intermittent, and fixing that required major disassembly (and probably 
realignment). Third, their attenuation characteristics weren't very good.

In my tests, the W3NQN-designed filters that Jay sells were the best 
performers in every respect.

73, Jim K9YC

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