[Elecraft] KFL1-4 Options Question

[Wayne Burdick]

On Nov 23, 2009, at 8:16 PM, Ross Primrose wrote:

> Couldn't you just change the component values to raise the lower LPF  
> to
> say, 16MHz, and run 30m & 20m through the lower filter, and 17m & 15m
> through the existing higher LPF?

Probably, though I haven't tried it. Our original intent was to cover  
40 m as well.

73,
Wayne
N6KR

>
> 73, Ross N4RP
>
> Don Wilhelm wrote:
>> Curt,
>>
>> Not practical.  Yes, that might work, but you would need to design  
>> your
>> own board (or highly modify the KFL1-4 board).
>> The reason is in the Low Pass filters - there are only 2 - the  
>> board is
>> wired for 2 bands to use the lower frequency LPF and two more bands  
>> use
>> the higher LPF.  The lower band LPF has a cutoff somewhere near 11  
>> MHz.
>> The lower 2 bands use this LPF.  So the lowest low band must be  
>> higher
>> than 1/2 the cutoff frequency - and in ham band language, that  
>> means 40
>> and 30 are a good pair.  The higher band(s) Low Pass filter cutoff is
>> just above the 15 meter band, so it is usable for any bands between
>> about 12 MHz and 22 MHz - that means any two of 20, 17 and 15 meters.
>> are the possibilities, but the board is wired so only 2 of these  
>> bands
>> can be used.
>>
>> You might want to consider a 4 band board plus an additional 2 band
>> board - say for 80 and 17, and configure the 4 band board for 40,  
>> 30 and
>> 20,15m.  That would give you coverage from 80 thru 15 meters with a
>> filter board swap.
>>
>> 73,
>> Don W3FPR
>>
>> rhulett1 at comcast.net wrote:
>>
>>> Since the KFL1-4 module allows either 17 or 15 selected at build  
>>> time, I'm wondering whether building say ??,20,17&15 (leaving out  
>>> 30M or 40M)is workable. It seems to me that this ought to work  
>>> fine.  With sunspot count increasing, am wishing for 4 band module  
>>> more focused to the higher bands.
>>>
>>> I personally find the K1 a really enjoyable little QRP rig to use,  
>>> and have a bunch of gear dwarfing it's diminuative size sitting  
>>> idle on the desk.  I actually like using  XIT on the K1 better  
>>> than using split on my QRO rigs for working DX. Recently have had  
>>> VK2, EA1, E51, 5N0, CT9, KL7, and GA5 QSOs with 3 watts on 17 and  
>>> 15.  It would be nice to not need to change filters to QSO both of  
>>> these bands.
>>>
>>> 73, Curt KB5JO
>>>
>>>
>>>
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>
>
> -- 
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> minimum transmitter power necessary to carry out the desired  
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>
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