Re: Swapping Standard 2.7 kHz 5-pole Filter

bill_w4zv <w0zv@...>

I received the following correction from Eric WA6HHQ. I did get my
previous info directly from Elecraft but apparently miscopied her name.

Hi Bill,

This is incorrect. The 2.7 kHz 5-pole can only be swapped for a 2.8
kHz or possibly the 2.1 kHz 8 pole filters. We require at least one
SSB b/w filter in each K3 as it ships since we must also transmit
through the filter for SSB and data modes. Transmitting through the
2.1 kHz filter will limit your tx bandwidth to that value. ( I'm not
aware of many choosing the 2.1 as their only SSB filter - I may drop
that as a swap option to make sure no overly narrow TX K3s get out
there and confuse the market.)

I'll post some more detailed DR numbers on the 5 pole vs 8 pole
filters in the next couple of days. The short answer is that the 5
pole filters have slightly less IMD3 dynamic range and a wider shape
factor than the 8 pole filters, but both are very good. The 250 Hz
8-pole and the 200 Hz 5 pole are both at least 95+ dB DR3 at 5 kHz,
with the 8 pole beating out the 5 pole by several dB. We've been
testing a number of each filter on a range of K3s to make sure we can
conservatively spec them across filter variations and rig variations. :-)

One other note - The sales person you talked to is Annika. There is no
Monica at Elecraft, unless they are hiding her somewhere! ;-) She was
clear on which filters could be swapped for the 2.7, but I'll check
with her for sure tomorrow.

73, Eric WA6HHQ
(Now back to work!)

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