Good rationale Dave,
I had also decided to use the PROC switch, but I didn't know all the
rationale behind it. I need details of where to find the leads and how
interface them to the Inrad filter. I have the 600 Hz roofing filter.
Can you please send me some more details?
Tnx,
Chas, W1CG
At 01:26 PM 8/7/2005, you wrote:
This is to clarify my rationale for using the PROC switch to activate the
Inrad roofing filter
modification. For those not familiar with the history of this, I
performed this modification to my
Omni VI+ (opt 3) over 2-1/2 years ago while testing various home-designed
roofing filters, and
needed a front panel selection capability so that I could record A/B test
data while still keeping
the N1 (500 Hz) and N2 (250 Hz) filters independently selectable.
The primary requirements (for the modification of the Inrad roofing filter
implementation) were:
(1) the implementation needed to simply take the roofing filter selection
off of the N1/N2 buttons,
(2) without incurring any additional components, with a (3) minimum of
effort, and (4) with minimal
impact to other operating modes and functions. These requirements
narrowed the design to only one
choice of front panel switch . the PROC switch, which is a "hard" switch
with push-push states.
The question has been raised on the reflector as to why not use the FM or
VOICE or other main keypad
switches to select the Inrad roofing filter, switches that (appear to)
have less of an impact on
operational modes than the PROC switch.
The first reason is that ALL of the main keypad switches are "soft"
switches, which are scanned by
the microprocessor, and do not provide a permanent status of the selected
state. Use of any of the
soft switches for this modification would require an additional PC board
with buffer and latch
circuits, contrary to requirements 1, 2 and 3, and would require removal
of the Logic Board in order
to implement the interface in hardware. Further, use of the FM button
would require a software
change, as once the button is depressed; the radio is in the FM mode!
Use of the VOICE button on the main keypad would, in addition to the above
four requirements,
require the optional voice board to be installed, a further complication
of requirements 1-4.
Dave, K1FK
Fort Kent, ME
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