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
|