[ICOM] IC756 PRO 3 PROBLEM with DSP

[Dave Meitzen]

Does the Onmi VI+ have a narrow CW roofing filter? Think heavy QRN bleed in
to the PRO III IF? Thanks for shareing this with the group -- excellent
info. Like to know the resolution I have a Pro III :>))
Thanks
Dave


-----Original Message-----
From: icom-bounces at mailman.qth.net
[mailto:icom-bounces at mailman.qth.net]On Behalf Of Steve N4LQ
Sent: Monday, December 20, 2004 5:20 PM
To: ICOM Reflector
Subject: [ICOM] IC756 PRO 3 PROBLEM with DSP



Subject: IC756 PRO 3 PROBLEM with DSP


I received a new PRO-3 last Thursday from AES. The DSP has a problem
especially when using the NR. The problems is distortion products resulting
in large noise spikes, far outside the bandwidth setting.
Last night I made some recordings using Spectrogram. Band, 80m, Conditions-
Heavy QRN, BW-250hz, NR ON, DSP CW-soft. I recorded both  the OMNI VI+ and
PRO-3 connected to the same antenna. Please see the scope patterns at this
link:

www.webham.com/PRO3.jpg

When listening through wide range headphones which are plugged directly into
the PRO3, the spikes are very annoying and make copy almost impossible.
Turning off the NR helps some. There is certainly a problem with the DSP. At
this time I do not know if it's just my rig or an engineering problem.

Note: Before this, I owned a PRO2 for 2 years so I am quiet familar with how
the radio SHOULD function.

I am contacting AES tomorrow. Hopefully they will provide an exchange.

Stay tuned for further developments.


Steve N4LQ

IC756PROIII
IC-756PRO3
IC756 PRO 3
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