[ICOM] re: 706 on HF

[David J. Ring, Jr.]

ANF is exactly for steady carriers!  That is what it was designed for.

You're not going to get rid of wide-band noise with a manual or automatic 
notch filter.

The noise signal is much to wide to be notched out.  No notch filter will 
get rid of buzzing.ds

I've never had to use the manual notch filter - I've checked it out and it 
is very sharp, but when on CW, I simply press the CW button on my IC756PRO 
and hold it and it goes to CW-R which changes the BFO injection frequency so 
that you're listening on the other side of zero beat.  It almost always gets 
rid of any steady carriers except if they're within about 200 Hz.

You might investigate some of the devices made by MFJ and others that allow 
the user to actively cancel the local noise.  Notice this will not not work 
on QRN - only the noise type of QRM - not distant signals, just local QRM 
like buzzes.  (QRM means man-made interference while QRN is atmospheric 
noise).

73
David N1EA
----- Original Message ----- 
From: "Hart" <hartengel at sympatico.ca>
To: <icom at mailman.qth.net>
Sent: Monday, June 05, 2006 5:01 PM
Subject: [ICOM] re: 706 on HF


I have been using my 706mkIIg for the past year with an mfj 989d tuner, 
butternut vertical and a Ameritron amp. For HF use I find that this rig has 
a serious design flaw and that is there should have been a manual notch 
filter on it. The ANF is ok but it is only good for filtering out operators 
who tune up or cw transmitions. Living here in the city you get a lot of 
buzzing noises and it would have been nice to have that manual notch to zero 
out these types of problems. The other is that the DSP filters are not 
really all that good when the bands are noisey, you have to get yourself a 
DSP unit that runs in line with the audio out. Other than that the radio is 
an all round good rig. The radio does tend to heat up but that is normal for 
these types of all band compact rigs to that.

----
Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
Icom Users Net: Sundays, 1700Z, 14.316 MHz
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