[ARC5] BC-221 question

[Richard Knoppow]

    I tried to attach a copy of the patent but it was rejected by 
the list moderator as being too large.
    For those interested its number 02222043  available from 
Google Patents or the USPTO site. I think a Google search will 
find it.
    It was introduced commercially on the HQ-120-X (X means it 
has the crystal filter) and shortly after on the Super-Pro. 
Earlier Super-Pros had crystal filters but they were of a much 
cruder design.

On 5/22/2020 6:35 PM, Richard Knoppow wrote:
> FWIW, Hammarlund had a patented crystal filter.

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL