And let's keep in mind that the IF DSP rigs like the PRO and PRO2 do
NOT have a carrier balance or insertion frequency adjustment. The SSB
signal is generated as a mathematically perfect signal in the DSP
world and short of changing the firmware nothing is going to alter the
occupied spectrum of the transmitted signal.
I agree fully with Tom's remarks. There is only so much you can do
with a conventional filter rig before you run into "there ain't no
free lunch."
73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 IC-765 #2349 IC-756 PRO #2121 IC-756 PRO2 #3235
----- Original Message -----
From: "Thomas Jednacz" <tjednacz@ieee.org>
To: "Barry N1EU" <n1eu@yahoo.com>; <tentec@contesting.com>
Cc: "Peter AA7E Finch" <aa7e@juno.com>
Sent: Wednesday, January 15, 2003 3:05 PM
Subject: RE: [TenTec] Re Microphones--one more thing (long)
> Hello all:
>
> Sorry to jump in and spoil your fun. DO NOT change the carrier
offset. You
> will then be transmitting on both upper and lower sideband!! Filter
rigs are
> set at 300 Hz cut off so the filter slope will will get you -30 dB
on the
> other sideband. If you change the offset the filter will not have a
steep
> enough slope to drop the other sideband to the required level.
Filter rigs
> are not adaptable to less than 300 Hz audio without creating
problems. I
> have looked at the fellows on 178 and find that they are using up to
40 dB
> boost (over normal audio levels) at 100 Hz and driving the audio and
or A/D
> converter in the DSP chip crazy. They say their RF stages are all
linear.
> True - BUT they generate all kinds of junk in the audio stages by
driving
> them non-linear and transmit 12 - 15 KC wide signals when they only
intend
> to transmitt 4Khz. A full DSP rig (Pegasus/Jupitor, Icom 746
Pro/756Pro,
> Kachina, and of course the new Orion) are the only ones that will
properly
> transmit 100Hz to 4 Khz audio and be clean.
>
> Play with equalizers and all the other audio stuff but don't try to
make a
> system design do what it is not supposed to do. Do not consider
HI-FI/SSB
> with anything but a full DSP radio as above.
>
> When playing with HI-FI/SSB lets understand what we are doing, use
good
> engineering practices and have some courtesy in sharing frequencies
with our
> fellow hams.
>
> Tom, W7QF
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