[R-390] R-390A Mechanical Filter replacement

Thu, 12 Jun 2003 08:31:56 -0400

Pointer to KIWA data:  http://www.kiwa.com/kiwa455.html

It says "The Standard Filter Module is an encapsulated filter consisting of
three ceramic filters with input and output buffer amplifiers".

So if that is not suitable, why not do what they did, stating with standard
455 ceramic filters, and possibly some of those there terminal monolithic RF
amps for isolation.  Inside the box for the four mechanical filters, there
is plenty of room to put a substitute.

IMHO $50 does not sound unreasonable compared to a new Rockwell mechanical
filter.  However the Ceramic filters (CFM2 from Digikey) prices are less
than $3 each for 4/6/8/10/12 khz wide
Of course these are only two section:

STANDARD FILTERS SELECTION GUIDE
TYPE CFM2/CFM3
TOKO Center Bandwidth Selectivity Ripple Insertion Input/Output
Part Frequency (Fo)* at 6dB at Fo?9kHz in Pass Band Loss Impedance
Number (kHz) (kHz) (dB) (dB) (dB) (kW)
CFM2
AHCFM2-450Z  450?1.0 4.0?1.0  24.0 min. 1.0 max. 7.0 max. 1.0/1.5
AHCFM2-450AL 450?1.0 4.0 min. 18.0 min. 1.0 max. 6.0 max. 1.0/1.5
AHCFM2-450BL 450?1.0 6.0 min. 16.0 min. 1.0 max. 6.0 max. 1.5/2.0
AHCFM2-450CL 450?1.0 8.0 min. 12.0 min. 2.0 max. 6.0 max. 2.0/2.0
AHCFM2-450DL 450?1.0 10.0 min. 9.0 min. 2.0 max. 6.0 max. 2.0/2.0
AHCFM2-450EL 450?1.0 12.0 min. 6.0 min. 2.0 max. 6.0 max. 2.5/2.5

However the 6 element, I suspect, are comparable to the existing Collins
filters, two in series would be even better of course.

TYPE LFY/LFYM
TOKO Center * Bandwidth Bandwidth Attenuation Insertion Input/Output
Part Frequency at 6 dB at 50 dB fo ? 100 KHz Loss Impedance
Number (kHz) (kHz) (kHz) (dB) (dB) (kW)
LFY
ALFY455H 455?1.0 ?3.0 min.  ?9.0 min.  35.0 max. 6.0 max. 2.0
ALFY455G 455?1.0 ?4.5 min.  ?10.0 min. 35.0 max. 6.0 max. 2.0
ALFY455F 455?1.0 ?6.0 min.  ?12.5 min. 35.0 max. 6.0 max. 2.0
ALFY455E 455?1.0 ?7.5 min.  ?15.0 min. 35.0 max. 6.0 max. 1.5
BLFY455D 455?2.0 ?10.0 min. ?20.0 min. 35.0 max. 4.0 max. 1.5
BLFY455C 455?2.0 ?12.5 min. ?24.0 min. 35.0 max. 4.0 max. 1.5
BLFY455B 455?2.0 ?15.0 min. ?30.0 min. 35.0 max. 4.0 max. 1.5

-----Original Message-----
From: Joe Foley [mailto:[email protected]]
Sent: Wednesday, June 11, 2003 7:18 PM
To: [email protected]
Subject: Re: [R-390] R-390A Mechanical Filter replacement

--- Cecil Acuff <[email protected]> wrote:
> I think the KIWA filter modules would be the way to
> go...unless you are just
> trying to go back to L\C filtering...
++++++++
Well, yeah, kind of,

The KIWA is expensive, I think it would be good if it
fit in the same place as the mechanical filters, too.

And, of course, it HAS to sound good,..... maybe
better.

Joe

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