[Elecraft] K-1 4-band Availability/Status?

Sat Mar 7 01:34:59 EST 2015

Hi all,

The KFL1-4 module needs trimmers that are both wide range and extremely temperature stable, due to the high loaded Q of the band-pass filters. To emulate this stable capacitance with trimmers now available, you'd have to use a hand-selected C0G cap in parallel with a much smaller trimmer for each of the original 16 trimmers. This would be extremely tedious for builders. So, while it is possible, it is not practical. 

Wayne
N6KR

----
http://www.elecraft.com

> On Mar 6, 2015, at 8:33 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
> 
> The part number for the bare KFL1-4 board is E100129 as listed in the KFL1-4 manual.
> 
> I do not know whether Elecraft has any boards in stock, but one could ask.  Good luck with your project(s).
> You would also need the firmware E610010 as well as the other parts such as relays, connectors, crystals etc.  If you downloaded the KFL1-4 manual before it was removed, you are 'in luck'.
> 
> 73,
> Don W3FPR
> 
>> On 3/6/2015 10:03 PM, Dr. William J. Schmidt, II wrote:
>> There is probably some middle ground here to satisfy most people in this
>> situation.  It's completely understandable and correct that Elecraft would
>> not want to spend the effort to re-engineer this board.  However some of us
>> on channel don't see the task as rocket science and in most cases would be
>> glad to provide that expertise as a side effort just to make that equipment
>> useful.  If Elecraft had even something as simple as unpopulated boards to
>> purchase for use as prototypes, it would make that task quite simple.
>> 
>> 
>> Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
>> 
>> Owner - Operator
>> Big Signal Ranch - K9ZC
>> Staunton, Illinois
>> 
>> Owner - Operator
>> Villa Grand Piton - J68HZ
>> Soufriere, St. Lucia W.I.
>> Rent it: www.VillaGrandPiton.com
>> 
>> email:  bill at wjschmidt.com
>> 
>> -----Original Message-----
>> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Don
>> Wilhelm
>> Sent: Friday, March 06, 2015 8:05 PM
>> To: Ross Primrose; Phil Wheeler; elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] K-1 4-band Availability/Status?
>> 
>> 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.
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