[ICOM] IC-7000 AM Modulation Problem

[Adam Farson]

Hi Bill,

You made an excellent point. The spectrum scope in the IC-756-series radios
has 1 kHz RBW at -6 dB. This is comparable to my HP853A/8558B spectrum
analyser. The IC-7800 has 1 kHz RBW for span = 12.5 kHz and up, and 100 Hz
for 2.5 kHz span. I am not sure about the 781, but its 390 kHz scope IF has
a 2-pole ceramic filter.

One can see IMD3 and IMD5 products quite clearly on the IC-7800 scope. Of
course, a "real" spectrum analyser has a much wider range of span, sweep
range, resolution bandwidth (RBW) and input attenuation settings, but the
Icom spectrum scope is an excellent compromise given its field of
application.

Cheers for now, 73,
Adam VA7OJ/AB4OJ


-----Original Message-----
From: icom-bounces at mailman.qth.net [mailto:icom-bounces at mailman.qth.net] On
Behalf Of William Lambing
Sent: 07 April 2006 10:57
To: ICOM Reflector
Subject: Re: [ICOM] IC-7000 AM Modulation Problem

Adam, there is a guy who posts on QRZ.com that vehemently states that any
radio with a display (read 781, 756 etc) is totally worthless as any kind of
analyzer.

I almost got into an argument with him a year or so ago, since at the time I
had a Tek analyzer and the 756 Pro and they pretty much agreed.  He said
.... essentially ... bunk.

Bill, W0LPQ



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