[Yaesu] Mechanical vs. Crystal filters

[Bob W7AVK]

Hanns - Not a guru on the subject but I seem to remember the 300 hz, CW 
Collins filter in the 75S series receivers was not a mechanical unit but 
a crystal unit.

Your differences make show how the the state of the art in filter design 
has changed from the 1950s when the Collins unit was designed and 40 
years later.

Just my $0.02

73  Bob  W7AVK



Hans Remeeus wrote:

> The Inrad #705F (500 Hz) and #712F (300 Hz) Collins filters have a shape 
> factor of more than 2.5.
> 
> #705F -  BW6: 595 Hz, BW60: 1,560 Hz (pancake)
> #712F -  BW6: 340 Hz, BW60: 850 Hz
> 
> The Inrad #528 (500 Hz) and #703 (400 Hz) crystal filters have a shape 
> factor of 1.7.
> 
> #528 -  BW6: 520 Hz, BW60: 870 Hz
> #703 -  BW6: 445 Hz, BW60: 760 Hz
> 
> All are 455 kHz IF-filters.
> 
> Please notice for example the significant difference between #705F and 
> #528.
> 
> Price of Collins filters: $125
> Price of crystal filters: $155
> 
> For $30 more you get filters with a much better shape factor and 
> performance!
> 
> 
> 73,
> Hans Remeeus (PA1HR)
> http://www.remeeus.eu
> Communication is about people, the rest is technology.
> 
> 
> 
> KC3VO at aol.com schreef:
> 
>> How about a comparison of filters with the SAME bandwidth?    You 
>> compared two sets of entirely DIFFERENT filters!  Compare SSB 455 khz 
>> crystal filters to SSB 455khz mechanical filters, of the same 
>> advertised bandwidth, and also note size and cost, if possible. 73, KC3VO
>>
>>
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