[Elecraft] K3 Rx IMD

[Geoffrey Mackenzie-Kennedy]

Sorry for being slow to reply.

Oh yes, a coil wound on a core made from "Ferrite" or "Powdered Iron" will 
be a source of IMD products, the culprit being the core. The level of the 
IMD products generated by a core depends on a number of factors, which we 
could discuss "Off List" if you wish.

While I understand Lyle's point concerning the AGC, I cannot shake my 
suspicion that something in or near your antenna is behaving as a mixer, and 
is the source of IMD products. The problem with adding the DDS' signal by 
coupling to the antenna is that you have no control over "unwanted" mixers 
in the vicinity. To disprove (or confirm) my suspicion, my suggestion is 
that you build a hybrid combiner, and use it to inject the BC and DDS 
signals into the K3.

73,

Geoff
GM4ESD


On Wednesday, November 24, 2010, at 7:59 AM, Ramiro Aceves wrote?


> Can the toroid  inside the antenna T tunner
> be the culprit? Any ideas to test will be welcome.