[ICOM] IC-7000 AM Modulation Problem

Tue Apr 4 13:51:31 EDT 2006

Hi Larry,

Glad I was of some help. That's a nice analyser system. I have an 853A with
8558B plug-in. Less than 10 hours on the beast! Its minimum RBW is 1 kHz.
Wish it had 100 Hz, but then again, the price was right.

Please keep me posted on your results.

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 Larry Harrison
Sent: 04 April 2006 10:34
To: ICOM Reflector
Subject: Re: [ICOM] IC-7000 AM Modulation Problem

Thanks Adam

I have a HP 8552B, 8553B, and 8556A LF plugin with tracking generator in
addition to the IFR-1200S and will try your sugestion.

73 Larry K3JRR

----- Original Message -----
From: "Adam Farson" <farson at shaw.ca>
To: "'ICOM Reflector'" <icom at mailman.qth.net>
Sent: Tuesday, April 04, 2006 07:00
Subject: RE: [ICOM] IC-7000 AM Modulation Problem

> Hi Larry,
>
> There could be a problem in the way the 7000's DSP algorithm generates AM.
> In the IC-756Pro series, AM works really well.
>
> Have you had a look at the carrier and sidebands on a spectrum analyser, 
> for
> test-tone and voice modulation? The spectral content and amplitude of the
> sidebands may give an indication of what is going on. With the spectrum
> analyser connected, it may also be useful to do a swept baseband 
> measurement
> with a single tone in the range 200 Hz to 2.9 kHz, with 1 kHz as 
> reference,
> and take a screenshot if possible. If you find an anomaly, this will be 
> hard
> evidence that you can submit to Icom America. I would suggest 100 Hz or 
> 300
> Hz RBW.
>
> I made a little study of AM in he 756Pro series. (I have not actually
> operated AM since 1963, but that is a story for another evening.)
>
> http://www.ab4oj.com/icom/pro_notes.html#AM
>
> http://www.ab4oj.com/icom/dsp_am.html
>
> 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 Larry Harrison
> Sent: 03 April 2006 22:13
> To: ICOM Reflector
> Subject: [ICOM] IC-7000 AM Modulation Problem
>
> Hi All,
>
> I recently purchased an IC-7000.  A fine radio in all respects except my
> radio will only modulate 30% or less with VOICE.
> It will modulate 100% with a 1000 Hz tone.
>
> Is there anyone else who owns an IC-7000 with this problem.
>
> If you have never checked your IC-7000 on AM, would you please do so to 
> find
> out what your 7000 does on AM.
>
> I have found several postings on eHam.net by others who have reported this
> problem.
> I have contacted ICOM Re this matter, and have received an unfavorable
> response from them.
>
> Please email via the Reflector or directly to me, harrisonl at comcast.net if
> any of you are experiencing this problem.
>
> I operate AM as well as SSB, and CW. I sure would appreciate any help from
> any of you as my IC-7000 transmitter is totally useless on AM.  Sure hate 
> to
> have spent $1499 for a radio that has a problem, that so far has not been
> resolved.
>
> By the way, the AM modulation percentage problem has been confirmed with 
> the
> built in wattmeter, an oscilloscope, IFR-1200S communications service
> monitor and a Bird 43 Peak Reading Wattmeter. All testing was performed 
> with
> the carrier set at 25 Watts (1/4th of 100 Watts for proper head room).
>
> 73
> Larry K3JRR
>
> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
>
>
>
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> ----
> Your Moderator: Dick Flanagan K7VC, icom-owner at mailman.qth.net
> Icom Users Net: Sundays, 1700Z, 14.316 MHz
> Icom FAQ: http://www.qsl.net/icom/
> 

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

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