[Lowfer] First Impressions: AMRAD Converter and Lowpass Filter

[Ben Hall]

Evening all,

Got the modified AMRAD converter / lowpass filter put together enough to 
give it a test run.

I am *very* impressed.  With the KX3 as the receiver, I heard more 
aviation NDB's than I think I've ever heard before on any receiver. 
(Yes, the RBL and RBA are both pretty irritated over this.)  I could 
even hear some of the 474 kHz WSPR stations by ear.

Only issue seems to be with the low-pass filter.  It works great up to 
about 512 kHz, then I get all sorts of currently unidentified stations 
centered at 530 kHz.  The worst right at 530 was a Spanish-language 
station - my Spanish was not good enough to identify the station.  As I 
tune up past 530, by the time I get to the low end of the AMBC all is 
quiet again.  The local powerhouses, 730 and 770 are still audible, but 
way down.  No other AMBC stations were perceptable.

I need to take the filter to the network analyzer at work.  I wonder if 
the 40 GHz network analyzer goes down to 500 kHz?  Hee hee.  ;)  We have 
some nice toys at work...and I don't get to play with them nearly enough!

I need to make some more interface cables, figure out the lowpass 
problems, and I should have the combo on the air this weekend listening 
for y'all.

thanks much and 73,
ben, kd5byb