Re: Sony M37W


Guy Atkins
 

Hi Rick,

Is the filter you are referring to from the 8dwa seller in Poland the Murata CFWLA450KJFA? (Old part #CFWS450IT?)

In the chart shown in his auctions, this is the narrowest 450 kHz filter available, but it is not 2.2 kHz, but +/- 2.0 kHz, for a total nominal bandwidth of 4.0 kHz.

Also, I see that the stop band attenuation--at only -50db instead of the usual -60db-- is a rather poor figure of 15 kHz total. Thus the shape factor is not very good.

An alternative filter to consider and which I'm currently using in a Sangean ATS-909X as a narrow position replacement is the CFWLA450KL6A002-B0 (what a mouthful!). This filter is 2.8 kHz and works very well as a narrow AM or SSB filter. For AM mode use, it helps to offset tune by 1 kHz for the best sound quality.

This 2.8 kHz, 450 I.F. filter goes by the ICOM part number of 2020001470. It's available for $10.07 each at ICOM America. It's used as a stock narrow filter in the ICOM PCR-1000, PCR-1500, and PCR-2500 receivers.

Last week I stopped by ICOM's parts department in Bellevue and they have some of these in stock.

73,

Guy Atkins
Puyallup, WA

--- In ultralightdx@..., Rick Robinson wrote:

I replaced both the FM and AM IF filters in my M37W with better muRatas
and am very impressed with the results. It's interesting that they use
a dual coil ferrite antenna for MW. As Allen in Newfoundland has shown,
these are great little radios. If anyone is interested in replacing the
MW filter, there is an ebay dealer in Poland that sells the 2.2kHz
muRata filters for 450kHz IFs. I have dealt with him and highly
recommend him.

Rick

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