[Elecraft] K3 Crystal Filter Installation

[Dick Dievendorff]

Hi, Gary.

Elecraft recommends installing the filters in descending bandwidth order. Since you have the FM, AM. 2.8, 2.1 and 400 Hz filters (all 8-pole), you should install the filters:

13 KHz FM filter in FL1.  This is required, as only FL1 may be used to transmit FM.
6 KHz AM filter in FL2.
2.8 KHz filter in FL3.
2.1 KHz filter in FL4.
400 Hz filter in FL5.

Then you can configure the filters either from the K3 front panel's CONFIG menu or you can use the K3 Utility's Crystal Filter Configuration page, which you reach from the Configuration tab, click the "Edit Crystal Filters" button.

The K3 Utility Help has an example of one user's settings. In your case, you'll be putting the values 

13.00, 6.00, 2.80, 2.10, and 0.40 in the "bandwidth" row for FL1-FL5.

All of these are 8-pole filters so you'll put 0.00 in each of the five "freq offset" entries.

The K3 Utility Help has a table of suggested "starting point" values for loss compensation (gain), as the narrower filters have more insertion loss than the wider filters.  Start with values 0, 0, 0, 2, and 7 for FL1-FL5.  You may need to play with these values later so that a steady carrier stays at a more or less constant volume as you adjust the bandwidth.

Now there are a set of check boxes to indicate which filters are enabled for receiving. 

I'd enable all filters for CW, USB, LSB, and Data.   The rationale for enabling very narrow filters for USB and SSB is that sometimes you might use these modes in a Data mode context (AFSK?)

Enable FL1, FL2, FL3 and FL4 for AM.  You might want to use your 2.8 and 2.1 KHz filters when listening to an AM station in a crowded environment.

Enable FL1 for FM receive.

Then you choose which filter you're going to use for transmit. For CW and SSB, you must use the 2.8 KHz filter, so select FL3. For AM, use FL2, your 6.00 KHz filter.  For FM, use the 13.00 KHz filter, which must be in FL1. This isn't really a choice, FM is always transmit-enabled on (only) FL1.

Click "Apply" or "OK" and the K3 Utility will send all these choices to the radio.

Note that you can do this with the K3's front panel CONFIG menu as well. Some find it easier to use the K3 Utility for this step, but it's certainly not the only way to do it.

73 de Dick, K6KR





-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Gary Gregory
Sent: Friday, June 13, 2008 1:10 AM
To: elecraft at mailman.qth.net
Subject: [Elecraft] K3 Crystal Filter Installation

Hello,

It would appear as though I have bit off more than I can chew as the saying
goes.
Today two optional filters arrived and have to be installed.
Currently there are 3 filters used (2.8, 2.1 and 400Hz) and they are in
positions FL-1, FL-2 and FL-3
I have to add the FM and 6.0Khz filters.
I assume (hate that word) that reading the manual I will place the widest
filter in FL-1..? (6.0Khz, followed by the FM, 2.8, 2.1 and 400..??)
I have also become confused with the values to enter in the Config menu.
If anyone can e-mail me direct with some more specific details I would
greatly appreciate it.
regards,
Gary
K3/100 #679

-- 
Stokers...we get ya goin'
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