[ICOM] IC-7000 AM Modulation Problem

[D C *Mac* Macdonald]

The basic question here is whether Icom's 40W output
figure for AM mode is stated for carrier or for PEP.

I have never given it much thought, but I seem to
remember that the instructions for my 735s said to
set AM carrier output at 40W.  Voice characteristics,
even with peak modulation of 100%, should still keep
average dissipation to within device limits.  Whether
that peak modulation would cause the peak voltage
limits of the devices to be exceeded is another matter.

What does Icom's user manul state about carrier level
setting when using AM?  That should settle the matter.

Mac - K2GKK/5
Oklahoma City



----Original Message Follows----
From: Gary <n6lrv at cox.net>
Reply-To: ICOM Reflector <icom at mailman.qth.net>
To: ICOM Reflector <icom at mailman.qth.net>
Subject: Re: [ICOM] IC-7000 AM Modulation Problem
Date: Mon, 03 Apr 2006 22:24:54 -0700

Larry I was with ya all the way till the end of your email when you 
mentioned
you set the carrier output power to 25 watts, etc. etc.

You realize (I hope) that the IC-7000 is only capable of 40 watts max output
power in AM mode on HF & 6m right? It's even less for 2m and 70cm (20w and 
14w
respectively).

Gary

Larry Harrison wrote:

 > 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