[HBR] Regen Birdies

[Bill Cromwell]

Hi Ron,

Did that regen have an rf amp and the associated tuned circuits? A regen 
doesn't need an rf amp for signal gain as the detector has plenty. An rf 
amp isolates the detector from the antenna and helps with rejection of 
signal 'far' removed from the operating frequency. My regens have the rf 
amp and the tuning is tracked with the oscillating detector. There is a 
gain control on the rf amp that really acts more as a variable 
attenuator. Some fellows add a potetntiometer in series with the antenna 
to reduce the input signals but that does nothing to filter signals 
outside the band of interest.

73,

Bill  KU8H


On 01/12/2015 08:43 PM, Ron Barlow via HBR wrote:
> Hi Bill,
>   I recently learned that, at least under extraordinary conditions, regens actually can have birdie problems. I was using a hb regen, while listening to 160m. I was hearing legit 160m signals well enough, but I was puzzled by the fact that I was also hearing numerous CW signals below 1800 Khz.
>   I discovered that the 2nd harmonic of the oscillating regen detector, was beating against incoming 80m signals, to yield audio output.
>   This problem was greatly exacerbated by the fact that I was using an 80m dipole, as a receive antenna.
>   As a result, the ~ 3.5 Mhz signals, that were delivered to the receiver, were actually much stronger than the desired ~ 1.75 Mhz signals.
>   I made certain to use the 160m antenna, for receive, as well as xmit purposes, after that experience!
>                                 73 de Ron  n4gjv
>    
>