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@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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