Topband: Transmit High Pass Filters for BCB Interference

[Richard (Rick) Karlquist]

On 7/29/2019 10:33 AM, Grant Saviers wrote:
> Here is what I used when I had the same problem 50kw line of sight 4 
> miles 1MHz.  Expensive, but worked very well.
> http://herostechnology.co.uk/pages/RF_Filters.html
> 

Yes, at 1 MHz, this would work well.  Other hams would be
advised that it is ineffective for QTH's with stations
high in the BCB.  The data sheet goes to a lot of trouble to
obfuscate this.  At my QTH, I have a strong BCB station
right at 1.7 MHz.  This fact rules out a large number
of filters.  You can see in the photo in the data sheet that
only 3 toroids are used.  This explains the poor performance
at 1.7 MHz.  As always, YMMV.

Rick N6RK