[1000mp] mixing inrad and yaesu filters

[Glenn Rattmann]

At 06:40 PM 1/1/2004 +0000, you wrote:

>>  the Collins filters have a much
>> broader shape-factor.  Are there other factors that would indicate that
a Collins filter
>> should be used for CW, over a regular crystal filter?

> The only advantage that a mechanical filter has, is price.. A crystal
>filter is superior to a mechanical filter. Shape factor is an indication of
>the quality of the filter. The lower the number, the better is the quality..
>A shape factor of 1 is a "perfect" filter..i.e. the the sides of the
>response curve are vertical.

Agreed.

>The modern penchant for Collins filters is misleading...

Oops-- that depends.

Sometimes the broader response of the mechanical filter is exactly what I
am after.  Steepest possible skirts and narrowest possible BW are not
always what you want.  What you want is versatility in the receiver.  In my
Mark V, I left in the Yaesu (supplied) 500 cycle filter for the 8.2 MHz IF,
and added the INRAD/Collins mechanical 500 for the 455 IF.  I know neither
the Yaesu or Collins has the skirts of the INRAD 400 or 500 crystal filter.
 But, this pair gives me the equivalent of a "broad" 500 cycle filter.
This is excellent for general operating, and most contesting too-- you
don't miss stations calling off-frequency.  For the occasional tough going,
I select the pair of INRAD 250's in another position.

I also have the INRAD pair of 1800 cycle guys in the optional NAR position
for occasional SSB use in QRM.  In the menu, I also selected that pair as
the NORMAL position for CW.  So, I have 3 BW's available for CW-- 1800,
500, and 250-- all paired, with the 500 setup deliberately chosen to be a
"middle-range" quality filter.  I also put another INRAD/Collins 500 in the
one available slot for the second receiver, using similar logic.  It's
great for finding guys in split DX pileups (not too narrow).

In the main receiver, to me it wouldn't make sense to have a pair of 250's
along with a pair of INRAD 400's instead of 500's, for example (too close
in performance).

By the way, on CW the mechanical filter has a smooth, mellow response which
is a pleasure to listen to.

73,

Glenn K6NA
(I've also replaced the Yaesu 2.4 SSB filters with a pair of INRAD 2.1's...
just to finish my description FWIW.  If you are a SSB contester I recommend
this.  One of them is soldered in....