[Yaesu] Mechanical vs. Crystal filters

[Dave Holford]

mikea wrote:

>On Wed, Aug 16, 2006 at 07:38:02AM -0700, John Geiger wrote:
>  
>
>>Is there any reason why Yaesu has been using
>>mechanical filters in many of their latest
>>transceivers?  Aren't crystal filters better-even
>>though the mechanical filters have the "Collins" name
>>on them?
>>    
>>
>
>"Better" in what sense, John? 
>
>As I understand it, mechanical filters can be designed to have flatter
>response and steeper skirts than any crystal filter in the same price
>range, and that's what made them instantly popular. At the same time,
>they can exhibit mechanical ringing after the input signal stops, 
>which crystal filters don't do. 
>
>It's very much a case of deciding what you want to have and how much 
>you'll pay for it, and then looking at the resultant list. 
>
>  
>
What do the folks who really care about performance, and to whom price 
is not a consideration choose? i.e. AIRINC, Military, Marine, NASA, etc. 
Bearing in mind that there are a wide range of both crystal and 
mechanical filters - not all mechanicals have "COLLINS" written on them 
and some crystals have RACAL or PLESSEY on the labels.

Dave