[INRAD] filter comparison

[Anders Janis SM4RNA]

Hi Zoli.

I have posted 2 messages  that not have come thru the reflector.

I try once more:
------------------------------------------------------------------------------
Hi Clark! (and others)

It seems to mee that you only sent this message to me and not to the
reflektor. I do the same mistake myself from time to time. Anyway here is is
for the reflector.

Ok, my judgement was a bit harsh, I admit to that. But the  fact that the
simpler Murata filters like the CFK445HT do not comply with their own
specifications makes me go balistic. A CFW445HT is specified to 6kHz is
always measured to more than 8kHz. That is just not acceptable. Kiwa has
filters in the same size that is pin compatible that do have the bandwith
promised. Thats the way to go! The skirts has the same steepnes on both
brands though.

In my IC-775DSP I have put in a Kiwa 6kHz filter instead of the (promised to
be 6kHz) CFW455HT, The CFW455HT I put in the 15kHz spot. I do not use FM and
the 8,2kHz measured Murata filter is perfect for medium wave AM. A Murata
filter is ok when one knows what bandwith it really has. ;)

To go back to the CFJ 455 K12 (and similar) it is ofcourse better than the
small ones. I sold my Kenwood 850 as I did not like the blow by sound in
SSB. Then I did not have the knowledge och the skill to change the filter.
Later I bought a ICOM IC-746 and there the PCB is prepared with tracks
making it possible to remove the Murata and put in a FL-80 och a INRAD
455kHz filter. I installed a 2,4kHz INRAD and then it got compleatly quiet
outside the passband. I think a those that prefer the Murata rather than the
2,4kHz Inrad do that becaurse that they really find the 2,4 a bit narrow. If
I would have put in a 2,8kHz, even those that were in doubt would prefer the
Inrad. I have noted Clark that you are both a Murata fan and a 2,8kHz fan so
I might bee right on that one. ;)

Than ofcourse, as you say Clark, the $ plays a part to.

Then I wonder what you other consumers think about that the radio
manufacturers re-use the incorrect Murata specifications in their
specifications?

73 de Anders


----- Original Message ----- 
From: "Clark Savage Turner" <csturner at kcbx.net>
To: "Anders Janis SM4RNA" <sm4rna at telia.com>
Sent: Saturday, September 09, 2006 9:55 PM
Subject: Re: [INRAD] filter comparison


>I disagree strongly with the opinion that Murata ceramic (CFJ 455K series)
>filters are junk.  Certainly, crystal filters, at a much higher cost, can
>give you a better shape factor, but by a surprisingly small amount.  I very
>much admire what Murata can put into a tiny package (the CFJ 455 K12 is the
>finest example) with decent skirts, small package and low cost.  A crystal
>filter at the same bandwidth does indeed improve the interference up the
>skirts (I often use them) but does not make the difference between copy/no
>copy on any SSB signal I've ever found.  I've done careful comparisons (at
>my home, Kenwood 440 and 850, switched filtering) and though I prefer
>crystal filters, the ceramics do a decent job by themselves.  The Muratas
>do spec out to a fairly wide range of bandwidths, as Anders states.
>
> If you really want/need a Murata K5, I probably have one lying around in a
> drawer.  I may even have a K12 lying around too.  I've replaced them in
> several radios with INRAD 2.8's that I prefer.
>
> Clark
> WA3JPG
>
> On Sep 8, 2006, at 2:19 PM, Anders Janis SM4RNA wrote:
>
>> If you mean the Murata, you could buy the one that I removed from a
>> IC-746
>> and put in a INRAD 2,4 kHz in instead, but it seems that I did not bother
>> to
>> keep it. It seems like I put it just  just where it belongs. In the
>> garbage
>> bin.
>> ......
>
>> The Murata filters for SSB is just a joke.
>>>
>>> OK1VWK:
>>>
>>>> Murata CFJ455K (K5 and next versions) 11-pole ceramic filter is
>>> usualy used in 2nd or 3rd IF stage across of all amateur radio
>>> manufacturers.
>>>
>>>         I believe Milan meant to say 2-pole not 11-pole.
>>>
>>>                                         73,  Bill  W4ZV
>>>
>
>



----- Original Message ----- 
From: "Zoli Pitman HA1AG" <ha1ag at yahoo.com>
To: "Anders Janis SM4RNA" <sm4rna at telia.com>; "Saandy" 
<alexeban at bezeqint.net>; "'Bill Tippett'" <btippett at alum.mit.edu>; 
<list at inrad.net>
Sent: Wednesday, September 13, 2006 11:35 AM
Subject: Re: [INRAD] filter comparison


> Hello Anders et al,
>
>> If you mean the Murata, you could buy the one that I
>> removed from a IC-746
>> and put in a INRAD 2,4 kHz in instead, but it seems that
>> I did not bother to
>> keep it. It seems like I put it just  just where it
>> belongs. In the garbage  bin.
>
> It's a bit too harsh statement IMO. The Muratas are not bad
> for their size and for their price. I replaced mine in the
> 2nd RX of my MP (with a INRAD 455/2000) and measured the
> params of both filters with proper matching (wound the
> transformers for both sides). I started to publish the
> findings on my web-site but have not finished it
> completely. It is still on my to-do list and will be done
> within a few weeks.
>
> Actually the INRADs are sharper on the side and it gives
> you a difference between 2 and 4 kHz from ur RX freq on
> both sides. It is just a fact of physics nothing else.
> Unless you use big antennas in a crowded RF environment
> you will hardly notice the difference. But this is my
> subjective opinion.
>
> 73, Zoli HA1AG
> www.hg6n.hu/ha1ag
>
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