Correct me if I am wrong but splatter is energy outside the intended 3kHz
occupied bandwidth of the signal caused by over-modulation. If there
was splatter "up and down the band" surely it would show. If I can
see a CW signal, it means I can see energy is there even though I can't
properly analyze it. In fact, energy beyond +_ 15kHz and above -100 dbm
IS noticeable although it leaves you to wonder. The spectrum analyzer
module has a 25kHz filter. The 1200 and 1300 series IFR's are a little
better and can actually resolve individual Bessel nulls in an FM signal.
The old Motorola R-2000 and Cushman CE-6's are "has-beens" (and
thousands of amateurs dream).
There is a seperate mode for looking at detected audio and envelope
patterns from the RCVR module, and a built in 2-tone generator. it's
really about deriving from what you can do rather than dwelling on
what you can't.
In any case, I have resolved that the noise I was seeing was probably due
to a bad hermetic relay (known intermittent) in the power divider path,
since attenuators and power sensing and switching are the only difference
in the signal path between the TX port and the hi-sensitivity antenna port.
Using a Termaline and iso-tee cleared up the problem. Also I have padded
the mic to bring the mic gain control closer to 12 o'clock and the ALC
action is normal now.
This is definitely a "service" instrument rather than an "engineering lab"
instrument. Most of the two way shops these days seem to be more
concerned with sales and political concerns and all the equipment is junk.
They wanted to borrow mine all the time. Fat chance!
Jim, ac6tk
----- Original Message -----
From: "Tom Rauch" <w8ji@contesting.com>
To: "AMPS" <amps@contesting.com>; "J. Bradshaw" <ac6tk@cybertime.net>
Sent: Tuesday, January 02, 2001 19:48
Subject: Re: [AMPS] 6146 splatter help? IFR overload
: Hi Jim,
:
:
: > resolution is 30 kHz so it doesn't tell you much of anything of the signal
: > except that it's there. Dynamic range is spec'd at the antenna port as -30
:
: Then you can not possibly measure splatter with that unit, unless
: you are interested in splatter 60 kHz or more away. To paint a
: picture of the signal it must have a selectivity much less than that
: of the signals.
:
: > to -100dbm. There is no scan. Thumbwheel switches control the PLL's so
: > you have to manually flip up and down in 10MHz increments to search. No
: > peak storage. I'll have to upgrade someday soon, but at least it works
: > and nobody touches it but me.
:
: If it does not store peaks, and read the highest peak as it sweeps
: many hundreds of times, you won't be able to use it on voice
: accurately.
:
:
: 73, Tom W8JI
: w8ji@contesting.com
:
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