Topband: BCB Filter - final selection

[Jim Brown]

On 4/17/2020 4:19 PM, Roger Kennedy wrote:

 > $180 for a receiver filter?   That's absurd !

That depends on the design criteria. I don't know how it is in your part 
of the world, but folks here who design and build stuff like to get paid 
a living wage. A filter that passes 160M but strongly attenuates 1710 
kHz (sidebands of 1700 kHz) is not a simple one. It requires a very good 
design and precision components, careful manufacturing, and precision 
alignment.

> (By the way, if you now have stations broadcasting between 1.6 and 1.7 MHz,
> how does anyone pick them up?  I don't know any broadcast radios that go
> above 1.6 !)

This is one of those frequency allocations that varies by region. In NA, 
the AM band, stations are assigned carrier frequencies from 540 to 1700 
kHz, and radios sold here are programmed for that coverage. This 
allocation has been in effect for several decades. By contrast, we have 
no LF broadcasting.

73, Jim K9YC