[Elecraft] Roofing Filters

[Wayne Burdick]

We actually test at higher levels than this. 

The hardware AGC is *after* the crystal filter. Gain control prior to the filter is in discrete steps under control of the user: preamps and attenuator sections.

Wayne
N6KR



> On Jun 22, 2017, at 1:20 PM, Joe Subich, W4TV <lists at subich.com> wrote:
> 
> 
> >          Could you elaborate on "dynamic range" in crystal filters?
> 
> All crystals have imperfections (flaws).  Those flaws create distortion
> when the crystal is driven with a high level signal and the distortion
> (non-linear response) results in intermodulation distortion (IMD).
> 
> The K3/K3S operates the crystal filter at a higher level than many other
> receivers.  Thus, testing the filters for linearity at the maximum
> signal level (equivalent to S9 +40 dB - where the hardware AGC engages)
> is important to assure the best possible performance over the entire
> operating range of the K3/K3S.
> 
> 73,
> 
>   ... Joe, W4TV
> 
> 
> On 6/22/2017 3:12 PM, Bob wrote:
>> Hi Wayne,
>>         Could you elaborate on "dynamic range" in crystal filters?  A quick search did not yield a definition.  A SWAG might be another term for ultimate rejection or it with ripple in the passband...
>>         Just curious.
>> 73,
>> Bob
>> K2TK ex KN2TKR (1956) & K2TKR
>> On 6/22/2017 12:54 PM, Wayne Burdick wrote:
>>> Yes. We screen every INRAD filter. Those that don’t meet our dynamic range targets are rejected.
>>> 
>>> Wayne
>>> N6KR
>>> 
>>> 
>>>> On Jun 22, 2017, at 9:46 AM, Vic Rosenthal <k2vco.vic at gmail.com> wrote:
>>>> 
>>>> I recall Wayne saying that Elecraft tested filters received from INRAD for some specific performance characteristics. I don't remember the details.
>>>> 
>>>> Vic 4X6GP
>>>> 
>>>>> On 22 Jun 2017, at 17:14, Clay Autery <cautery at montac.com> wrote:
>>>>> 
>>>>> INRAD makes Elecraft's filters as I understand it...
>>>>> 
>>>>> I'll be getting mine from Elecraft directly.
>>>>> 
>>>>> ______________________
>>>>> Clay Autery, KY5G
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at 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 lists at subich.com
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at 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 n6kr at elecraft.com