[1000mp] Mechanical x Crystal Filters

Mon, 7 Apr 2003 12:32:24 -0700

Eric:

I am sure you will receive a variety of opinions.

I am sure you are referring to the specific filters used in the MP radios.
There, the mechanical filters tend to be a bit less "rectangular" in their
response--more slope in the passbands, and more gradual transition to the
stopbands.

In my case, I moved the 500 Hz Collins mechanical filter from the 3rd IF to
the subreceiver, where a wider "window" is more suited to listening to split
pileups, etc. I replaced it in the main receiver with very sharp INRAD 250
Hz and 400 Hz filters. I intended also to replace the 2nd IF CW filter with
an INRAD, but decided that the required unsoldering/soldering was not worth
the effort.

Some contesters do not like very sharp CW filters because one may not hear a
caller who is slightly off frequency. In those cases, I "open up" to the 500
Hz (400Hz) position, and rarely use the 250 Hz, except for weak-signal
DXing. However, I do like the steep skirts on the INRAD units.

Garry, NI6T

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Eric Castro
> Sent: Sunday, April 06, 2003 21:28
> To: [email protected]
> Subject: [1000mp] Mechanical x Crystal Filters
>
>
> Hi,
>
> My name is Eric - PY2EMC and I am trying to understand the differences
> between crystal filter versus mechanical filter.
>
> I want to understand where and when I can use one or another.
>
> Where can I found this information ?
>
> I appreciate any help.
>
> 73's & DX
> Eric - PY2EMC
> http://www.cwsp.org.br
>
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