[1000mp] AF DSP in the Mark V

[Mike Schatzberg]

Hello Yaesu Fans....

I have been reading some of the postings about the use of the Contour =
algorithms in the Mark V, and note that many people seem to be =
disappointed with their performance....

I have been using audio DSP for many years now, and have applied some of =
the techniques that seem to work well with the Texas Instrument DSP chip =
in my old AF DSP unit.....

The audio input level to the chip, has a lot to do with the =
effectiveness of the noise reduction....normally, I control the AF gain =
on my transceiver, to provide the best signal to noise ratio and drive =
to the chip, while adjusting the noise reduction level on my DSP =
unit.....also, careful manipulation of the audio output is needed as =
well, once again while considering the signal to noise ratio and =
interference reduction.....this is particularly true when trying to =
reduce white noise while listening to extremely weak signals....

Therefore, you may wish to do more than just toggle back and forth =
between the contour selections on the Mark V, as the manual =
suggests....consider all the possibilities for adjustment......namely, =
AGC for example, will probably yield the best results in the FAST =
position, to help with level control....the interplay with the RF gain =
control, and the AF gain control can also help with the signal to noise =
ratio, for any given contour selection....operation with direct mixer =
injection, IPO on and lit, will also be found to be helpful in obtaining =
the best signal to noise ratio.....especially with very weak =
signals.....

The same is true for the NR settings....just pushing the buttons, trying =
to obtain the best results, probably will not give the operator much =
satisfaction in many cases....manipulation of all the tools available =
will help improve the readability of weak signals to some extent, in =
almost every case...

I find myself with the IPO engaged, and preamps off most of the =
time....it does take some skill and experience to learn to operate audio =
DSP......much trial and error with levels is required, but worth the =
effort.....

I would encourage some of the list members who have had some =
disappointment, to attempt to adjust their equipment to optimize the =
interference reduction capabilities within the Mark V..... some other =
considerations in AF DSP will extend to the menu selections in the Mark =
V, and choice of Carrier Offset for example....Clearly, it is possible =
that some operators will experience good results with their basic =
overall menu selections, and others will not.....

It is unfortunate that there is not an advanced DSP primer within the =
manual, but these techniques can be developed with some time and careful =
consideration.....

See what you think!

Happy Dxing and 73,

Mike Schatzberg
WB2AJI
http://www.qsl.net/vu2wap/wb2aji/


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