[Elecraft] 200 Hz 5-pole filter

[Eric Swartz - WA6HHQ, Elecraft]

Not in most cases, since turning on the attenuator significantly reduces the MDS (sensitivity) of the RX. IMDDR3 is the difference between the input RX sig levels that created the IMD and the MDS of the RX. It may increase IMDDR3 slightly, or even reduce it, depending on which RX stages go into distortion at high levels first. But who wants a deaf RX that can not hear down to the noise floor of the band?

What turning on the attenuator (or having a poor sensitivity RX) -does- do is artificially increase the iP3 number, rendering it meaningless as a number for comparing different receivers which have -different- RX sensitivities for that measurement. Some manufacturers have gamed this number for years.

For best comparisons, receivers should be compared at the same sensitivity level. 

Eric
elecraft.com
_..._



> On Jul 25, 2015, at 11:17 AM, Joe Subich, W4TV <lists at subich.com> wrote:
> 
> 
> On 2015-07-25 2:04 PM, XE3/K5ENS via Elecraft wrote:
> > Apples and oranges.
> 
> Nonsense.  The IMDDR3 of a conventional transceiver will improve
> significantly if one turns on the attenuator.  Reducing overall
> input to the Flex series 6 to keep the level below the ADC limit
> is no different than adding an attenuator to a conventional
> transceiver.
> 
> 73,
> 
>   ... Joe, W4TV
> 
> 
>> On 2015-07-25 2:04 PM, XE3/K5ENS via Elecraft wrote:
>> Apples and oranges.
>> 
>> The K3 is still no 2 with the 200 Hz 5-pole filter.  You just can no longer
>> buy the radio with that filter.
>> 
>> I have always found it a little strange that Sherwood never stated that
>> the filters used in his test were optional on the K3?
>> 
>> If the K3 was tested with the stock filter it may make it into the top 10.
>> 
>> Don't get me wrong I have a K3S on order.  I'm just looking at the data.
>> 
>> 
>> 
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/200-Hz-5-pole-filter-tp7605299p7605322.html
>> Sent from the Elecraft mailing list archive at Nabble.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 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 eric.swartz at elecraft.com
>