[TenTec] INRAD Omni VI roofing filter kit - success

[Rick Williams]

I think you have it Clark.

Just to clarify, the roofing filter is in series with the existing 15 kHz
filter.  Of course the existing 15 kHz filter adds little or nothing to the
rig selectivity after the mod.  On the Omni VI and V rigs jumper "25"
connects the RF board to the 9 MHz board at their respective "25" headers.
With the roofing filter the stock "25" jumper is removed and the mod goes in
the line between the "25" connector on the RF board and the "25" connector
on the 9 MHz board replacing the stock jumper.

The remainder of you analysis is dead on.

73,
Rick
VE7TK

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To: 	tentec at contesting.com
Subject: 	Re: [TenTec] INRAD Omni VI roofing filter kit - success
From: 	Clark Savage Turner <csturner at kcbx.net>
Reply-to: 	tentec at contesting.com
Date: 	Fri, 14 Jan 2005 12:30:27 -0800
List-post: 	<mailto:tentec at contesting.com>

On Jan 14, 2005, at 10:38 AM, Ken Brown wrote:

    Hi Rick,

    Yes I understand where that Inrad mod puts the new roofing filter. I
guess what I did not understand is that with only one NAR button on the Omni
VI (non version 3 or Plus) you sort of have to leave out the "regular"
narrow 9 MHz optional filter. ... Now I 


I think you still misunderstand (or else I do :-)

The roofing filter mod switches in/out at a point before ANY of the optional
filters in the OMNI VI (the NAR in the 9 MHz position or the others in the
6.3 MHz position). It is where Ten Tec has a small 15 kHz wide filter
already, and the roofing filter puts another filter in line (or out of line)
where that 15 kHz wide filter already sits in the line. So the filter that
gets switched out of the line is this little 15 kHz wide filter in the line
BEFORE any of the filters we normally think about. It is NOT any of the 8
pole crystal filters, stock or optional.

So, ALL the Ten Tec optional filters may be utilized. You lose nothing at
all. You do not lose any mode that requires wider bandwidth either, because
the roofing filter takes itself out of line for FM (and you can do it with
the NAR switch anyway, depending on your choices).

The only thing you might have wanted is a separate switch to put the roofing
filter in/out even when you have the NAR filter pressed. Normally, the NAR
switch (or ONE of the NAR1 and NAR2 switches in the OMNI VI plus and option
3 versions) puts the roofing filter in line. You could, conceivably, use
another switch somewhere else, and put the stock 15 kHz roofing filter in
line (roofing filter mod out of circuit) when you wanted to without
reference to any other switch.

Now, even if you have NO filter in the NAR position, you still will use that
button to switch the roofing filter in/out of the circuit. You don't need a
filter in there (but, of course, it adds to selectivity!)

Clear as mud? If I misunderstand your words and appear condescending, I
apologize in advance. Wish I could diagram this, it would be much simpler.

Clark
WA3JPG