[Elecraft] filter offsets question

[Ron D'Eau Claire]

David, there are both 5 pole and 8 pole filters available from Elecraft. The
8-pole filters have a somewhat flatter passband and steeper skirts than the
5-poles. (These are crystal filters and the "poles" refer to the crystal
poles in each filter - more poles means better filtering but more complex
matching of the crystal elements required for correct performance, hence
greater cost). 

Because the specs on the 5-pole filters are a little looser their exact
center frequency may shift slightly. The "offset" is a value entered to
center up a 5-pole filter on the K3's intermediate frequency. The 8-pole
filters are extremely consistent and need no offset correction. 

The "standard" 2.7 kHz filter is a 5-pole filter, hence a correction value
is provided. The 2.1 KHz and 250 Hz filters are both 8-pole types and the
"correction" is zero. 

73,

Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of David F. Reed
Sent: Sunday, February 19, 2012 3:08 PM
To: 'Elecraft (Elecraft)'
Subject: [Elecraft] filter offsets question

I am confusing myself, so I thought I'd ask this helpful forum for some 
advice and help.

I note the filter settings in the K3 Utility; I further note that for 
most of my filters, the offset is 0.00 but for the 2.7 KHz filter it is 
-0.85.

So why is it that, and no offset for the 2.1 KHz filter or the 250 Hz 
filter?

Just hoping to better understand my rig...

Thanks and 73 de Dave, W5SV
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