[Yaesu] FT1000MP 70Mhz Inrad Amp Mod WD8ARZ results.

[WD8ARZ]

Hello FT1000MP users. I got the inrad mod on Monday via priority parcel
post. I was pleased with INRAD sending me a email when they got my order,
and another when it was shipped. Very nice of them!

First thing I did was read the instructions and get a handle on the task to
be done. Fortunatly its a easy install, just be very careful when putting in
the plastic standoffs on the printed circuit board in the MP. If you use
pliers and you slip, you can drag the tool across runs and damage them.

The first thing I did was go to the AM broadcast band and find a stable
signal that was less than S9 (so I could get a better spread of the smaller
units used), I found one steady at a S7. I marked down the reading and the
frequency.

I removed the bottom cover, installed the INRAD board, and I left the bottom
cover off. I hooked the radio back up, found the earlier reference signal,
and dropped the Menu 9-1 setting until I got the same earlier reading. This
took me from its factory setting of 13 down to a setting of 9. I then made
up a arrangement where I could switch the INRAD amp in and out for
comparision purposes. This allowed me to make checks hot while the radio was
on..... so the comparisons were in real time with no delay. I dont recommend
this to those that are not hot circuit savvy and dont know how to avoid
circuit losses........

There is no doubt that the RF amp stage noise can now over ride the IF amp
stage noise. I was concerned about front end overload, and worsening of the
noise blanker splatter effect. I tuned all bands, and made in and out
comparisons and did not determine any situation where the INRAS amp in line
contributed to any known issues at this time.

The end result is that the signal to noise ratio, noise blanker performance,
syncronous a.m. mode, and over all audio for all modes is improved. I was
surprised and very impressed with the improvment below 500khz! As the
instructions also state, .... receiver which has better, more pleasing
sound. I have to agree with that!

I then played with 'by the ear' copy of weak signals on 10-20 meters that
did not move the s meter. When I could not make out the words at a IF gain
setting of 9, I started increasing. Some times IF gain of 10 did make an
improvment, BUT on 40 meters and down, the noise energy made a setting of 9
better. Further more I determined that on weak power line interference, a IF
gain of 11 or more made the noise blanker less effective. These same checks
with the INRAD out of circuit proved the merits of the mod.

Bottom line is I would say to do the mod as its worth the money..... Cant
say that the hiss issue was that noticable to me before the mod, but the
back ground noise is lower after the mod, and when I do the switching in and
out procedure and setting the IF gain to the setting before the mod.

The cw second mod did not seem to me to be worth the change for my
radio..... I did live tests on signals with the cap in and out, could hear a
difference, but not enough to bother with......especialy as the dsp did more
than the cap did anyway......so for my radio, I did not add that capacitor.
I prefer in the main receiver to have some higher cw passband in the audio
so I can copy voice audio in cross mode operation. When I dont want that, I
switch in the dsp...... so have the best of both worlds. Please note as it
says in the instructions, this capacitor mod is for cw only, and even then
only when the dsp is off. It has no other effect on the sound quality of
other modes such as sideband or ssb.

To find the capacitor referred to in the INRAD mod, locate ON THE INRAD amp
board a capacitor numbered C3. Be on the side of the MP so that you can read
the writing on the MP circuit board that the INRAS pcb is mounted on. About
3 inches to the right of this C3 cap on the MP pcb, is the cw modification
target cap.

Advise to those that think more is better. Turning up the Menu 9-1 to high
for your radio over all system gain will only worsen the performance of the
radio. Especially on Noise Blanker performance. It is my theory that the DSP
will work better too because the energy in the pass band it is working with
is improved, and there is more of the signal you want to hear and less of
the noise. I actually now can hear in some situations the weak signal voice
audio "stand out and up front" more than before the mod. I have not
experienced that before the mod. I would get less listening fatige, and
improve the intelligibility of a signal, but rarely make it 'stand out' as
it does now...... so pushing the IF gain to high will begin to undo the
improvements....... self control now guys, self control.... hi hi

I post most of my information about the FT-1000MP to the dedicated email
reflector at:
http://jehosophat.com/1000mp/

My FT-1000MP is over one year old and has the following information:
FT1000MP serial number:        7C170105  ( January of 1997)
CPU Version leval:                     1.30
Menu 9-8 Date:                           970214c2   (Feburary 14, 1997)

Good luck

73 from Bill - WD8ARZ
wd8arz@null.net











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