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 get it. I still wonder
whether Jason ever had a narrow filter in the normal 9 MHz IF optional
narrow filter position, and how the performance amongst 40 meter SWBC
stations and strong amatuer signals compared with the new mod and the
filter earlier on in the IF. His post sounded to me like he had never
had a filter in the regular narrow slot, and went straight to the Inrad
mod. I guess I may have read somthing into his post that wasn't really
there.
DE N6KB
Ken I think that you may have misunderstood where the roofing filter is in
the "food chain". The "stock" Omni V and VI have 2-pole filters at the very
front end of the 9 MHz IF board. These filters are 12 to 15 kHz (yes that's
kHz) wide and hard wired. Their purpose is a first line of defence for
nearby signals.
The InRad mod goes in front of this filter and gives the operator the option
to significantly narrow the front end of the 9 MHz board. It's location is
between the RF board and the 9 MHz board. The mod contains a 4-pole filter
(either 600 Hz or 2400 Hz). The NAR switch(s) are used to (a) control the
roofing filter and/or (b) the NAR filter. The roofing filter is not located
at the end of the 9 MHz "food chain" like the NAR filters. It is actually
at the opposite end of the 9 MHz schematic.
The roofing filter can be switched in or out so that the operator does not
lose any functions (e.g. FM or a wider 2,800 Hz IF filter) by installing the
mod.
I have installed the 2400 Hz version in my Omni V.9 and, other than a small
glitch with the cabling, found the process relatively painless.
73,
Rick
VE7TK
Website: http://www3.telus.net/ve7tk
---------------------------------------------
Date: Thu, 13 Jan 2005 21:35:59 -1000
From: Ken Brown <ken.d.brown@verizon.net>
Subject: Re: [TenTec] INRAD Omni VI roofing filter kit - success
To: tentec@contesting.com
Message-ID: <41E7765F.7050306@verizon.net>
Content-Type: text/plain; charset=us-ascii; format=flowed
Hi Jason,
I understand why someone with a non plus or version 3 upgraded Omni VI
would want the Inrad modification, in order to get another
narrow 1st IF
filter option. And I can also understand that even if you already had
two narrow filter options in a version 3 or Omni VI +, there
might still
be some improvement in BDR by adding the Inrad modification. What I
don't understand is why don't you have a filter in your Omni VI NAR
slot? It seems like it would have been much easier just to
plug a filter
in there. That would have also been a big improvement, even if
not quite
as good as the Inrad mod, and cheaper and easier to do.
DE N6KB
I don't have a filter in my Omni VI NAR slot - it used to be
my "Mute"
button but now it becomes the enable/disable switch for the INRAD
roofing filter.
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