[Elecraft] Roofing Filters

[Craig Rairdin]

I miss a 100Hz filter, which I use in the K2 all the time during contests. I
ordered the 200Hz and 400Hz filters for CW and am hoping that's what I want.

Craig

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Toby Deinhardt
Sent: Tuesday, May 01, 2007 3:36 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] Roofing Filters


>  How many roofing filters do you need in a K3?

I belong to the liberal arts faction...

In other words I don't know what I am talking about... ;-)


I ordered my K3 with the secondary RX, 6kHz Filter, FM Filter, 2x 
2.7kHz and the CG frontend filter.

As for the other roofing filters, I also am unsure what I should 
order - mainly because we do not know yet, when which filters will be 
avaidable, and we do not have any hard data on the filters themselves.

If the variable filters have no real disadvantages (factors such as 
skirt steepness down to c. -30dB, image rejection for IF to NF, 
impulse behaviour, etc.), then I personally would try and cover as 
large a bandwidth range as possible with the variable filters.

My dream configuration could look like this:

RX1

1) 200Hz (or 250Hz)
2) 300Hz to 600Hz variable
3) 600Hz to 1.2kHz variable
4) 1.2kHz to 2.4kHz variable
5) 2.7kHz (or 2.8kHz)

RX2+CG

1) 300Hz to 600Hz variable
2) 1.2kHz to 2.4kHz variable
3) 2.7khz (or 2.8kHz)
4) 3kHz to 6kHz variable
5) FM

OTOH, if the A/D and AGC are good enough, we might be able to do with 
only few well choosen bandwidths.

I doubt Elecraft will offer a 3kHz to 6kHz, and 600Hz to 1.2kHz is 
also not very likely. But maybe the firmware will allow people who 
have the right skills to design and build their own filters.

I do think this will become an area for much discussion in months to 
come, especially if third parties also start to offer roofing filters 
for the K3.


vy 73 de toby
-- 
DD5FZ, 4N6FZ (ex dj7mgq, dg5mgq, dd5fz)
K2 #885, K2/100 #3248
K3/100 #??? (< #200)
DOK C12, BCC, DL-QRP-AG
 

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