[Elecraft] KBPF3A switching frequencies and performance

[Russ Tobolic]

 Hi Ben:
You had me curious with your request.  I started to check my KBPF3 (modified to the "A") and noticed something that now bothers me.  I tried going down from 160M and it appears that the switch over to the AM broadcast band occurs precisely at 1700,000  Kc.  When I tune to  1.699999 the relays click.  But the anomaly(?) I am seeing at the switchover point is a big drop in the signal level.  At my QTH during the daytime the nominal noise level at 1700.000 Kc is about S7.  When I switch to 1.699999 the noise level drops to S2.  At the high end the switchover occurs at 2109.999+ with a drop in the noise level from S9+10 to S3.  I don't use the K3 for listening to AMBCB but only in the case of checking my 160M  receiving loops with some stations high in the AM Band.  I checked on 80M and got similar results.  At the low side the switch occurred at 3299.999 with a drop in the noise level from S5 to S2.  On the high side the switchover occurred at 4209.999+ but here the noise level increased from S4 to S6. I don't know if this helps you any on at least these 2 bands.  If I get the time I'll try to check the rest.  Now I'm bothered by the changes in signal levels at the switchover points (ignorance is bliss).   I wonder if anyone else has ever noticed this or do I have an issue with my KBPF3?

Russ, N3CO
    On Friday, April 16, 2021, 12:39:28 PM EDT, w4sc <w4sc at windstream.net> wrote:  
 
 Looking for details of switch over frequencies and expected performance of the KBPF3A in its various bands, 

There is improvement in the BCB and below 500KHz with the KBPF3A enabled, however the other SW BCB bands I have tried are lacking.

Has anyone measured the performance of the KBPF3A?

Ben W4SC

Sent from Mail for Windows 10

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