On Saturday, July 19, 2014 2:34:40 PM UTC-4, Michael Black wrote:
On Sat, 19 Jul 2014, dave wrote:





Very , very difficult. Even after it is close enough(!)in resonant

frequency- there are a few MORE extremely critical parameters involved ...

This is why true "Crystal Filters" were so expensive,even when they were

mass produced ...





You can get nice 5 pole filters for about a hundred bucks can't you (I

haven't checked for a few years). For relatively wide band SWL cascaded

ceramic resonators should suffice).



Expensive is relative.



I remember wanting an SSB filter for something about forty years ago, and

they were maybe forty dollars, expensive for a kid on allowance. I

thought a replacement part would be cheaper, but checking with Heathkit

for one of their SSB filters turned out they were more expensive. I

eventually found a second hand filter, though it clearly had never been

used.



So I suppose a hundred dollars now is a better price, but still one of

those more expensive components.



And consiering the cost of replacement filters (or even optional filters),

a receiver or transceiver must be pretty cheap since it includes not only

the filter, but all the other parts. I suspect they get a good deal for

bulk purchase, but don't pass it on for people wanting to buy a

replacement filter.



Ceramic filters, if you can live with the low IF, obviously has provided a

much better level of filter without the cost of crystal or mechanical.



Michael
================================================== ============================== I just checked the latest price of Icom's SSB filter(FL-222). It Is currently in production for their R-75 receiver. List price is...$300 !!!