It has been very interesting, reading the recent e-mails concerning the use
of DSP, in particular on the FT1000MP, and prompted me to go back and
experiment with not just the dsp but the basic rx settings (IF shift/width,
notch, pitch, etc) on my particular main transceiver, an FT1000MP.
What I had discovered in the past - and forgotten until I saw the recent
postings - was how much difference these controls on weak signals can make
on any make of radio. However, these things are a matter of trial and
error and vary not just from radio manufacturer to radio manufacturer but
from individual radio to radio - and on its particular compliment of IF
crystal filters and their type (and probably on the IF alignment of the
particular radio as well).
The tricky thing is that using these controls practically for weak CW work
is something that is usually poorly covered by manuals and also depends on
the frequency response of your particular ears. Coming up with a
combination that will work for everyone, even for a particular
configuration of a particular type of radio, is virtually impossible.
On my old IC751A, I discovered of a combination of using the IF shift and
engaging the notch filter and tuning the notch filter control in the manner
of a bandpass filter could render a very weak unreadable signal readable.
I cannot explain why this worked - but it did, in around at least a third
of cases, for my ears.
Similarly, I played around this morning on 1.8 and 3.5MHz with my very
basic configured FT1000MP (2 x standard Yaseu 500Hz filters) listening for
very weak signals. Although I cannot say that any of the dsp settings I
tried made any difference to reading/finding signals, I did come upon a
combination of using the pitch control and IF shift that actually brought a
couple of signals out of the noise that were really not there at all with
the basic setting that I had used before.
The basic thing I rediscovered was the old timer's trick of reducing the
pitch of a signal to a very low beat (in this case about 350Hz) can make a
huge difference to signal readibility - even if like me you are used to
listening to signals at around 800Hz.
With both 500Hz filters in circuit, the pitch control of my FT1000MP
reduced to 350Hz and the IF shift set around half a division to the left of
centre, signals were readible in the noise that I could barely tell were
there with just the 500Hz filters in circuit and the pitch set to the
central 800Hz position. It was a revelation.
Now to many old hands on this reflector, all the above might seem like to
teaching a chicken to suck eggs. However, what works for YOU is going to
vary from radio to radio and on your own set of ears. Experimenting with
all the facilities on the radio from time to time and trying new things is
an exercise well worth doing.
Vy 73,
Steve, VK6VZ
P.S. I would like to correct the FT-1000MP settings I gave previously:
Pitch = 300 Hz (not 350), DSP on in LSB, both 250 Hz IF filters, Contour
full CCW, NR full CW, both Shift and Width about 1/2 division CW from
detent (adjust by ear). Note that the last setting is dependent on
whether you use USB or LSB in CW. For LSB shift is CW...for USB shift is
CCW. Steve must be using USB CW. de W4ZV
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