[RTTY] Icom IC-756 PRO III vs. IC-7600 on RTTY

[Salvatore Irato]

Hi all,
what a question about the 7600!
I am not the best one to answer on the subject as I already have written 
my opinion on eHAM. A great place for everybody of us. Nonetheless I 
would like to write something as dialectics is a a part ours life and as 
an old time reader here and elsewhere on the subject matter all around. 
Not to forget the list of the same brand RTX that I happily operated in 
the past and continue to operate now, no blame no strange things. Just a 
technical opinion about a product, or a series of products, that anybody 
could buy and enjoy using it.

First of all, how I could say it, it's not a problem of language. It's 
just a problem of the number of buttons that the owner of the newest 
IC*M gears have to push for the TPF function.
BTW it's only a button or two to push and some hundreds dollars more. 
Why anybody is so interested to tell that the TPF is perfectly working 
on 7X00. Yes, the TPF is perfectly working inside those newest radios, I 
personally checket out the item several times, it's a well knowed thing. 
But, the TPF inside the newest 7X00 radios isn't the same thing as for 
the TPF inside the 756PIII. I was just writing this, no more. Quick and 
dirty, easy to see, also without a waterfall inside a PC, just with the 
barebone radios.

Why the newest TPF aren't the same al the oldest? It's easy to say, let 
me try.
Oldest TPF buttons have two functions, a single pus engaged the Twin 
Peak Filter AND one filters of choice, by default this is the 250Hz.
Newest TPF buttons engage only the Twin Peak Filter. The filter remain 
the same. This newest TPF way to work, IMHO, is wrong.

The TPF feature of the 756PIII is a single push of a button away from 
the user and is useful as is.
The TPF feature on the newest 7X00 gears is a push on two different 
buttons, in the best case, to make it useful as before.

Try to do this in contest or with strong signals nearby inside filter #1 
or #2 used at default values. Those buttons to be used to engage the TPF 
are also somewhat well away each one to the other. And even worst when 
you have to get back to filter #1 and no TPF to search the next signal, 
so more push on 7X00, still one on the 756PIII. Five pushes instead of 
two, seems enough to to be wrong.


In the real world all this could be solved with two CAT commands in a 
macro of N1MM. Half hour of work, if there are CAT code provided by the 
manufacturer, plus the time to test it. The effect of a old and right 
TPF+250Hz filter is quite visible in the decode waterfall of the radio, 
7600 I mean.

There are also other side effects as anybody could think. Use TPF in 
contest starting with 2400 HZ or 500 Hz filter on a 756P#, you wipe out 
all the nearby signals. Use the TPF with the same filters on a 7X00 you 
will wipe out nothing until you change manually the filter to #3.

IMHO this TPF setup is an awful step backward for the newest 
transceivers. I am so happy with the oldest that I simply couldn't 
understand what was the technicality behind this choice, maybe done by 
somebody that never used manulay RTTY FSK on a 756PIII. I have some 
ideas, but will difficult to carry on. Anyway, ours mileage may be 
variable.

   That's all folks.


                                        73 de iw1ayd Salvo