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cw filters

Sep 12th 2013, 19:01

WD9DMM

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Hi,I would like get a cw filter for my 9 year old Icom mk11.I don't know a thing about filters.Could some one make a suggestion?
Matt Furlong wd9dmm
Jan 4th, 18:20

KO5Q

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Matt... I use an MFJ 784B, Tunable DSP Filter. It takes the audio from your rig as input. You can vary the filter frequency as well as the band width. It has several preset filters already built which are selectable with a rotary switch. Also provides dual freq settings/notches etc which can be used with RTTY or other multi tone modes. I find most of the time I can leave it set to a very wide bandwidth and get the filtering I need... As with any audio filter, if you titen up the bandwidth too much it gets a little "ringy" This filter also works with ssb... It has AGC, and noise reduction, as well as auto-notch modes. You have to provide it a speaker (I built one in). This filter works well in cases where you don't have, or can't get, an IF filter built into the rig. Its very versatile... I keep it in the audio out line of my homebrew qrp rig... I usually just use its audio amp, but being in line its immediately available as a filter when I need it, at the push of a button.
Jan 5th, 18:50

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
If you have a 706, it is likely that you only have one choice, the 500Hz 9MHz filter. They did make narrower filters, but they aren't available.

Zack W1VT
ARRL Senior Lab Engineer

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