Ross,
That vital part is the availability of the 1 to 40pF trimmer capacitors
- which also had a very tight temperature compensation characteristic.
The KFL1-4 used 16 of them.
Due to their wide capacity range, the same capacitors could be used in
all 16 positions and provide successful tuning.
Those capacitors have been discontinued by the manufacturer.
The problem is that there are no substitutes that could be used for all
16 positions, and it would take a great deal of engineering effort to
determine the suitable substitutes for each position on the 4 band
board. In other words, would a 3 to 15pf trimmer be suitable in the C1
thru C4 locations and would a 12 to 30pF trimmer be suitable in the C5
thru C8 locations and so forth. Furthermore, if the 17 meter band were
chosen instead of the 15 meter band, which low range trimmer capacitors
would be used for each band.
I am speaking of examples for the engineering effort that would be
required to select the best capacitor for each position and each band
choice. It is not a trivial exercise.
I certainly would not want to do experiments to select the appropriate
replacement trimmers necessary to resurrect the 4 band board, and I am
certain the engineering staff does not have the time to do that work.
The documentation would get more complicated as well - for example, "if
you have chosen the 15 meter band, use the red trimmer capacitors at
location Cx but if you have chosen 17 meters, use the yellow trimmers at
those locations"
Hopefully you get the point of the complexity created by those wide
range trimmer being no longer available. The values I have proposed
above are only numbers off the top of my head for examples, they have no
value in the real world.
73,
Don W3FPR
On 3/6/2015 6:46 PM, Ross Primrose wrote:
Looking at the parts list, I can't imagine which part is no longer
available....
73, Ross N4RP
On 3/6/2015 4:37 PM, Phil Wheeler wrote:
Confirm. Something related to a vital part(s?) no longer being
available.
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
