[Elecraft] Birdies

[Wayne Burdick]

Hi Wilson,

What bands and frequencies?

Virtually all high-dynamic-range superhets have some birdies. These are usually caused by high-order mixer products interacting with the VFO, BFO, etc. We went to some lengths to minimize them, e.g. by using a balanced low-pass filter in the mixer's commutating path. But there will still be a few, typically on the highest bands (10 and 6 m).

Some birdies can be substantially suppressed on a per-band basis using a built-in spur-avoidance tool in the CONFIG menu. See the "SIG RMV" menu entry description in the owner's manual. 

73,
Wayne
N6KR



> On Jul 1, 2022, at 11:23 AM, Wilson Lamb via Elecraft <elecraft at mailman.qth.net> wrote:
> 
> 
> I've meant  for years to ask about the birdies I hear from my K3. 
> At many frequencies across HF, I hear obviously internally generated birdies. 
> They are very narrow and quite strong. 
> I've noticed recently that I can cause them to occur by setting the high and low ends of the filter to overlap (zero or negative bandwidth), but there are still come heard with normal settings. 
> I see this regularly, on two K3, so feel it must be something experts know about? 
> Thanks, 
> WL 
>