[HBR] HBR - BFO progress

[Ron Barlow]

Hi Breck,
 
 Thanks for your posting!
 
 I see a problem with the suggested Colpitts circuit, that you provided a link to. If I understand the labeling on the schematic diagram correctly, there is a .01 mfd capacitor, on each end of the RFC. The cap on the left side of the choke, is electrically in shunt with the 180 pf cap, that comprises part of the oscillator tank circuit. 
This will profoundly alter the feedback ratio, and the resonant freq of the tank ckt.
 In fact, the feedback ratio will be altered to the point that I seriously doubt that the circuit will oscillate at all.
 
 I believe that the .01 cap on the left side of the choke should be removed.
             
        73 de Ron   n4gjv


________________________________
From: B. Smith <smithab11 at comcast.net>
To: HBR Receiver List <hbr at mailman.qth.net> 
Sent: Sunday, January 5, 2014 11:36 AM
Subject: Re: [HBR] HBR - BFO progress


I highly recommend that the builder do the BFO first. You will get your 
feet wet and solve a major problem with construction.  My best luck has 
been with a colpits oscillator but others were tried See:
(http://k4che.com/HBR/BFO%20Coil%20Page%201and%20photos/BFO%20Coil%20Page%20%201.htm)
k4che
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