[Yaesu] FT-1000MP: main rx AF hiss

[WD8ARZ]

Hello Steven, and thanks for passing on your observations about your
FT1000MP on the Yaesu Reflector. I have also posted this reply on the
FT1000MP reflector for their observations as well.

Please note that the default settings in the menu options are not generally
the ones most users end up liking. Check out the e-mail Archives for two
key sites of past messages at:
http://jehosophat.com/1000mp/
http://www.contesting.com/_yaesu/

I am only able to reproduce your situation on my FT1000MP by making changes
to the configuration for VFO A. There can be a difference with RF and
apparent audio levals between the two receivers depending on what filters
are switched in and weither the VFO A is set for Flat or Tune operation for
the front end amplifiers. When the gains are the same, I get virtual stereo
centeredness in my headphones (Vfo A to the left and Vfo B receiver to the
right - with no mixing of receiver audio from one side to the other). This
centeredness is maintained with just back ground noise on the low bands or
the high, and with signals tuned in. I noted that all noise went away when
the antenna is disconnected, so that is the band noise and the nature of
the beast for hf. Also note that the Menu options allow for setting the VFO
A to a variety of bandpass settings that affects high end roll off. With
the comments about CW settings, that tends to also lead to a gain/bandpass
difference between the two receivers in some way. 

If you manualy set each Vfo to the same frequency, it is a good bet that
the same filters are not selected. To insure that the Vfo B not only
matches in frequency but in mode and filters, set Vfo A first, then press
and hold the A>B button until the Vfo B matches.
My two receivers then mirror each other in sound quality and signal
strength this way. The only excptions are those settings that can be
applied to Vfo A that can not be set to Vfo B (certain filter options, if
shift, bandpass tuning, Dsp, Notch Filter, etc)

I wonder if in the menu operations that the options for how the two
receiver audios are mixed, seperated, and weither each has a seperate
volume control or a master volume and balance control that is at issue.
Depending on how those are set, the dual volume controls behave differently
and when set as the front as a master volume and the rear as a balance, it
is easy to have the balance off center and have very low output on one side
or the other.

If none of the above are at on your end, I would suspect a probelm that you
should contact Yaesu or your dealer about. 

73 from Bill - WD8ARZ
E-Mail Reply to:
wd8arz@null.net

----------
> From: Steven J. Franke <sfranke@uiwpls.ece.uiuc.edu>
> To: yaesu@contesting.com
> Cc: sfranke@uiwpls.ece.uiuc.edu
> Subject: [Yaesu] FT-1000MP: main rx AF hiss
> Date: Sunday, December 14, 1997 3:39 PM
> 
> Hi All,
> Just received a new FT1000MP and immediately noticed
> that the main rx audio (without EDSP) exhibits what seems
> to be an abnormally high level of AF hiss.  The sub-
> receiver sounds much better in this respect.  
> I have not measured absolute levels, but I would 
> estimate that there is a 10dB (or more) difference 
> in total AF noise between main and sub-receivers
> (no antenna connected, 500 Hz filters selected,
> CW mode, EDSP off).
> 
> This is not just a difference in audio gain
> between the two receivers, as CW/SSB signals
> are at approximately the same level at the 
> outputs of both receivers.
> 
> The hiss level varies with the RF gain setting, 
> so I suspect that it originates in the 455 kHz IF
> stage, after the filters.  Turning the EDSP filter
> on removes the out-of-band components of the hiss, 
> but I can still hear an extra contribution to the 
> in-band noise that is not present on the sub-rx.
> 
> The S-meter reading on live signals are identical
> for both receivers, so I don't think that there is
> a problem with RF/IF stage gains.
> 
> The overall effect is to make the main rx sound
> deaf compared to the sub-rx, especially on a 
> quiet band with narrow filters.
> 
> Has anyone else noticed these characteristics?
> 
> 73, Steve  K9AN
> Thanks/73 Steve, K9AN


--
FAQ on WWW:               http://www.qsl.net/k7on/yaesu.html
Submissions:              yaesu@contesting.com
Administrative requests:  yaesu-REQUEST@contesting.com
Problems:                 owner-yaesu@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm