[Elecraft] K3 Future Factory Hardware Updates; + New beta f/w release 3.27

[N8LP]

SPICE modeling showed that the higher current was necessary to maintain the
same maximum signal handling, but I don't remember doing IMD before/after
measurements to verify that. Obviously, Elecraft feel that the device can
handle the extra signal without increasing current.

Larry N8LP



Don Wilhelm-4 wrote:
> 
> Joe,
> 
> Are you making an assumption that the P3 input impedance is 50 ohms?
> That may or may not be true. I don't know the design parameters of the 
> P3, but it certainly occurs to me that it is not necessary to use a 50 
> ohm input impedance.
> 
> Yes, SDR-IQ and LP-PAN have the 50 ohm input, so connecting those 
> devices to the K3 IF Out would cause loss.
> 
> 73,
> Don W3FPR
> 
> Joe Subich, W4TV wrote:
>>   
>>> A 50-ohm match is not required in any case.
>>>     
>>
>> That’s not exactly true.  With devices like LP-Pan or 
>> SDR-IQ that have 50 Ohm inputs connected to what is a 
>> high impedance output, the transfer loss (antenna to 
>> IF) was still in the range of -6dB even with the N8LP 
>> modification.  The rest of the solution was to use a 
>> Clifton Labs Z-10000 buffer amplifier (high impedance 
>> input) in a unity gain configuration, install a 4:1 or 
>> 9:1 (step down) transformer, or modify the SDR-IQ for 
>> a 200 Ohm input.  
>>
>> 73, 
>>
>>    ... Joe, W4TV 
>>   
>>
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