[Elecraft] K3 & ADAT ADT-200A by HB9CBU

[David Cutter]

John

Can't help you with numbers, just the experience of friends in that 
situation, ie they can operate with special receivers having special mixers, 
often home brew, whereas it is impossible without.

David
G3UNA

>
>
> David Cutter wrote:
>> Some folk suffer extremely strong QRM from broadcasters on 40m 
>> (particularly on the east coast of Scotland) and to them there is a real 
>> desire for the best possible gear to hear weak stations amongst huge bc 
>> signals from Europe.  That's where receivers like the Perseus and others 
>> come in to their own.
>>
>>
>
> Hi David,
>
> Yes I can see your point, and I am certainly not questioning the benefit 
> of High Dynamic range receivers in those situations. I guess what I am 
> having a hard time understanding how it would be possible for any 
> receiver, regardless of the dynamic range of the receiver, to receive a 
> weak signal 2 Khz away from, say a 80db over 9 broadcast or other signal. 
> Would not the IMD, sidebands, and splatter from the broadcast station 
> itself be so severe as to prevent this? Or am I overstating the effects of 
> transmitted phase noise and IMD? As I mentioned in my previous post, there 
> is no way I could see operating 2 Khz away from the very strong signal of 
> my  ham neighbor. His transmitted IMD would be way too severe. But  I can 
> easily operate 20 Khz  or more away with the K3.  To me, any minor 
> difference in close in dynamic range between say the Perseus and the K3 is 
> of little or no importance in this situation. I could not receive a weak 
> signal so close to such a strong signal anyhow because of his transmitted 
> IMD. But the wider spaced number's matter a great deal, and that is what 
> concerns me when I see a 117-123db BDR as compared to 140db at wider 
> spacings.
>
> 73,
>
> John, KD8K
>