I believe my receiver is microvolt sensitive and that the loop will
deliver a relatively good signal to the receiver even though the loop
isn't terribly efficient. If I build selectivity into the front end of
the receiver, do I really need high Q (200)??

I think the answer is NO.....

Well, this is a good opportunity to examine that tumble down the slope
to the Q = 2 (caused by the severe loading of your proposed design).

The correlative to this is, how much selectivity do you need in a
field where stateside VLF is relatively rare? Further, by the action
of the strong filtering that usual attends the "I" and "Q" channel
processing, you could easily repair any shortfall.

However, back to that Q = 2. That still offers respectable (not
fantastic) selectivity against signals out at the bottom of the AM
band which is 10f (one decade) away.



OK, I'm not sure how we got back to the Q=2 scenario. I think my
proposed design is the old series tuned loop, which I have firmly
rejected.

With no tuning in the front end, the Q of the receiver would approach
1.......Yes, I understand that.

I understand the answer you gave initially, which was 'I think the
answer is NO....'.

I understand the degree of protection against signals in the bottom of
the bc band.

When you said "Well, this is a good opportunity to examine
that tumble down the slope to the Q = 2 (caused by the severe
loading of your proposed design)"...................did you mean
to say or to infer '(caused by the severe loading of your old (now
defunct) series resonant loop design"???

All is in agreement above EXCEPT in not sure why the reference to the
old design.

Thanks again.

T