[CQ-Contest] 419A Bandpass Filter - Value?

[Mark n2qt]

Competency coupled with test equipment is important of course.  I had more trouble
fixing the burned out 160m section of a new to me DS600.  

I agree, although I have no actual hardware to verify, I like everything about  va6am’s
filters.  However I guess I’ll just keep using what I’ve got. 

Mark. N2QT

> On Feb 20, 2021, at 4:14 PM, Jim Brown <k9yc at audiosystemsgroup.com> wrote:
> 
>> On 2/20/2021 10:29 AM, Mark n2qt wrote:
>> Replacing the micas with Cornell Dubilier CDV style micas helps as those parts
>> have better specs for RF.  I ran rtty contests at 100 watts with no subsequent failures.
>> (My problem was always on 15)
> 
> The problem with changing or replacing parts in this filter set is that 1) it's very hard to take apart to replace the parts and 2) each filter in which parts are replaced must be re-aligned with good instrumentation, AND measurements must made with the enclosure in place because it affects the filter's tuning. So in practice, you've got to measure, tweak one or more coils by squeezing or spreading them, put it back in the enclosure to measure again, repeat, repeat, repeat, repeat until you get the SWR and transmission loss VERY low in the passband.
> 
> The Dunestar filter sets, and the higher priced units that WX0B sells are FAR superior. The high power VA6AM and 4O3A filters designed to go on power amp outputs are also excellent.
> 
> 73, Jim K9YC
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